CONTENTS · of ongoing projects of NHPC Ltd and NTPC Ltd such as Parbati Stage II and...

CONTENTSPage No.

FrOm EdiTOr’S dESk 2

Articles

• RoleofGeologyandSpecialRockMechanicsTestsinTBMTunnelling–APerspective 4 –V.M.S.R. Murthy and Anand Gautam

• InfluenceofAnisotropicStressConditionsonDesignofDevelopmentWorkingsinBordandPillarMining 16 –R.K. Sinha, M. Jawed and S. Sengupta

• StrataMonitoringStudiesinBlastingGalleryPanelDuringDepillaringBasedonFieldInstrumentation 25 –S. Kumar Reddy and V.R. Sastry

Mr.DevendraK.SharmaassumesthechargeofManagingDirector 32 ofHimachalPradeshPowerCorpn.Ltd.Governing Council of indian National Group of iSrm for the Term 2011-2014 33recent Activities of indian National Group of iSrm • Seminaron“GroundControlandImprovement”,20-21September2012,NewDelhi 34• InternationalSeminaron“MinimizingGeologicalUncertaintiesandTheirEffecton 35

HydroelectricProjects”,27-28September2012,NewDelhi• Seminaron“SlopeStabilizationChallengesinInfrastructureProjects”, 38

29-30November2012,NewDelhiiSrm News 41News from indian National Group of iSrm 47Publications of indian National Group 48Guidelines for Authors 49Forthcoming Activities of indian National Group of iSrm 51

iNdiAN NATiONAl GrOuP OF iSrm

ISRM (IndIa) JouRnal Volume 2, No. 1 January 2013

Editor• Mr.V.K.Kanjlia, Member Secretary, ISRM and Secretary, Central Board of Irrigation and Power (CBIP)

Associate Editors• Mr.A.C.Gupta,Treasurer, ISRM and Director, Central Board of Irrigation and Power (CBIP)• Mr.UdayChander, Senior Manager, Central Board of Irrigation and Power (CBIP)

Allcommunicationstobeaddressedto:The Member SecretaryIndianNationalGroupofISRMCBIPBuilding,MalchaMarg,Chanakyapuri,NewDelhi–110021

Subscription information 2013/ (2issues)Institutionalsubscription(Print&Online) :Rs.900/US$75Institutionalsubscription(Onlineonly) :Rs.600/US$50Institutionalsubscription(PrintOnly) :Rs.600/US$50

ISRM (India) Journal

Volume 2 No. 1 January 2013

FRoM the edItoR’S deSk

Firstofall,ItakethisopportunitytowishallthereadersaVeryHappyandProsperousNewYear.

ConsiderableactivitiesinIndiainthefieldofrockmechanicsareinprogress,mainlyduetotheexecutionofprojectsforwaterresourcesdevelopmentforirrigation,floodcontrolandhydropowergeneration,buildingofroadsinmountainousareas,sub-surfaceexcavationsforunder-groundrailway,storageandminingpurposes,etc.

Constructionsofdams,tunnels,undergroundworks,openpitmining,deepundergroundmining,rockslopestabilityaretheworksnecessitatedfor theaforesaidstructures.Developmentofthesestructuresoftenencounterproblemsassociatedwithunfavourable

geologicalconditions.Howtheseproblemshavebeendealtsuccessfullyiswhatweshouldallshare.Theexperiencegainedduringconstructionoftheseworkswillhelpinunderstandingthemechanismorrocksupportinteraction,thusadvancingthefrontiersofrockmechanics.

Fromtheyear2013,IndianNationalGrouphasplannedanInternationalSymposiumon“RockMechanics”everyyear todeliberateon theadvances in rockengineering.Thefirsteventunder theseries “RockMechanicsIndia’2013-PresentTechnologyandFutureChallenges”willbeheldinAugust2013inNewDelhi.Ihopethatthedeliberationsatthesymposiumwillhelpinformulatingappropriatemeasuresneededforsuccessfulexecutionofprojectswhethertheyrelatetomining,tunnelling,undergroundcavernormetro.IinviteallconcernedtoactivelyparticipateintheSymposium.

Ithankalltheauthorsfortheircontributionstothisissue.IthankthemembersoftheEditorialBoardforsparingtheirvaluabletimetoreviewthepapersandoffer theircomments/suggestionsto improvethecontentsofthearticles.

ThefeebackfromallthequartershasgivenustheencouragementtoourinitiativeandIrequestallthereadersandtheircolleagues/fellowprofessionalstocontributetechnicalpapers/casestudiestofurtherimprovetheutilityoftheJournal.

V.k. kanjlia Editor and Member Secretary IndianNationalGroupofISRM

3Influence of Anisotropic Stress Conditions on Design of Development Workings in Bord and Pillar Mining


MeSSaGe

Attheoutset,asPresidentof theInternationalSocietyforRockMechanics(India), IwouldliketoconveymyHeartyGreetingsandBestWishesforaveryHealthy,Happy,ProsperousandSuccessfulNewYear–2013toalltheMembersoftheISRM(India)andallSubscribers/ReadersoftheISRM(India)Journal.IwouldalsoliketoconveymyGreetingsandHighAppreciationtoalltheMembersoftheEditorialBoard.

RockMechanicsisthetheoreticalandtheappliedscienceofthemechanicalbehaviourofRockandRockMasses.Thepresentstateofknowledgepermitsonlylimitedcorrelationsbetweentheoreticalpredictionsandempiricalresults.Themostusefulprinciplesare

basedupondataobtained from laboratoryand in-situmeasurementsandprototypebehaviour.RockMechanicsisoneofthemainfieldsofinterestinHydroPowerDevelopment,InfrastructureDevelopment,Miningetc.RockMechanicsisbecomingincreasinglyimportantinmanymorebranches,themostsignificantgloballybeingthedisposalofhazardousradioactivewasteindeeplylocatedrepositories.Itisaninter-disciplinaryengineeringsciencerequiringinteractionbetweenthePhysics,Mathematics,Geology,Civil,PetroleumandMiningEngineering.CollaborationamongdisciplinesoffersthebesthopeforsuccessindealingwiththepresentandfutureproblemsrelatedtoRockMechanics.OurEditorialBoardisdesignedtoincluderesearcherswithinter-disciplinaryexpertiseatInternationallevelinadditiontoresearcherswithexpertiseintherelevantdisciplines.

ThemainaimoftheJournalistodisseminatethedevelopmentoftechniques,newtrends,experiencegainedbyotherstoenableupdatingtheknowledgeofRockMechanics.

TheJournalispublishedHalfYearlyandavailableinbothprintandonlineversionsTheFirstIssueoftheHalfYearlyTechnicalJournalISRM(India)wasbroughtoutinJanuary2012.Thequalityofcontentsandprintinghasbeenverygood.However,thereisalwaysascopetoimproveandexcel.

IwouldrequestallthereaderstooffertheirvaluablecommentsandsuggestionstoenableustoimprovethequalityandtheutilityoftheJournal.

dr. H r Sharma President, ISRM (India)

& Chief Technical Principal – Hydro TractebelEngineeringPvt.Ltd.

4 ISRM (India) Journal

Volume 2 No. 1 January 2013 4

1. iNTrOduCTiON

Indiahasanimmensehydropowerpotentialtothetuneof84000MW,amajorchunkofwhichisinHimalayas.ThesurgeinpowerdemandinthecountryhasnecessitatedputtinganincreasedthrustindevelopmentofhydroelectricprojectsinIndia.Thepaceoftunnellingwork,whichformsamajor componentof hydroelectric development, hasanotablebearingontheimplementationoftheproject.Nowwhilethefocusisonfastercompletionofprojects,needforadvancedtechnologylikeTBMintunnellingisrequired.But unfortunatelyTBMcould not gainwider

acceptanceinthecountryduetocomplexitiesinvolvedingeologicalconditions,prevalentinIndiaespeciallyinHimalayas.ThetectonicallydeformedjointedrockmassofHimalayaposeamajorchallengetoprojectplanners.AlthoughinitialexperiencewithTBMwasnotencouragingalleffortsareontomakeTBMsuccessfulinIndia.

ThoughTBMexcavationisaveryfastmethodtunnelling,it needs meticulous planning because in case ofunpredicted/unfavourableconditions,theadverseeffectsofTBMintermsoftimeandcostarefarmoregreaterthanconventionalmethodsthusputtingahugeinvestmentat

Role oF GeoloGY and SPeCIal RoCk MeChanICS teStS In tBM tunnellInG – a PeRSPeCtIVe

V.m.S.r.murthy and Anand Gautam Department of Mining Engineering, Indian School of Mines

ABSTrACT

A growing need to switch over to the clean sources of energy, such as hydropower, is being felt in India after burning much of our coal reserves to an alarming stage. Incidentally, India has been gifted with numerous perennial rivers originating from the great Himalayas favoring hydropower generation. However, these young folded mountains with an extremely variant geology created several problematic situations delaying many tunnelling projects.

The major construction work of any hydro power project is the construction of head race tunnel (HRT) which had made use tunnel boring machine popularly known as TBM. There are number of ongoing projects of NHPC Ltd and NTPC Ltd such as Parbati Stage II and Tapovan-Vishnugad projct, etc. deploying TBMs for tunnelling. As huge amount of money is involved in deploying TBM, it is important that it should successfully complete the project. Thus, suitability of TBM needs to be established with the help of various geological and geophysical investigations coupled with insitu and laboratory tests. The role of geology, uncertainities involved and consequent hazards have an immense influence on the operational success of TBM and hence need attention.

TBM performance prediction models, namely, NTH, CSM, RMi-NTH & QTBM, are frequently used owing to their increased popularity over the years. RMi- NTH model is an empirical performance prediction method based on historical field performance of machine in certain rock types. Empirical graphs and equations obtained from regression analysis between rock properties, ground condition, machine parameters and rate of penetration are used in this. The CSM model on the other hand involves starting from the individual cutter forces and determines the overall thrust, torque and power requirement of the entire cutter head.

This paper discusses the geological problems encountered while driving tunnels with TBM, specially, with respect to Indian conditions. Different types of specialized rock mechanics tests that are carried out and available at Indian School of Mines, Dhanbad for enabling the selection of TBMs are also presented alongwith some results. Typical performance achievable in a given rock type is estimated using the RMi-NTH model. A case study of TBM drivage pertaining to Tapovan-Vishnugad Hydel project, NTPC Ltd. is considered for the analysis. The suggested approach with field corroboration could be useful for predicting the possible advance rate in a given formation.

Keywords: Geological problems, mixed face conditions, rock mechanics tests, tunnel boring machine, head race tunnel, boreability prediction models

5Role of Geology and Special Rock Mechanics Tests in TBM Tunnelling – A Perspective


risk.Theexperiencesuggeststhatmanyoftheproblemscanbeavoidedifsufficientadvanceinformationaheadof the face is available. It is essential that detailedexplorationwork is carried out before the start of theproject and exploration ahead of the face should beundertakenonaconditionbasis.Useoftunnelseismicprofilerservicescanberopedinforpredictinginadvancethegeologicalconditiontobeencountered(upto200mfromtheface).

The choice of TBM is another important aspect thatneedsaninitialanalysisatplanningstageandnoTBMcanbedesignedforeverytypeofgeologicalconditionthat is encountered in tunnelling thoughduecare canbe exercised inminimising the operational problemswithadequaterocktestingprogramsbothinlaboratoryand field. Thus, the design and special constructioncharacteristicsofeachTBMneedtobecarefullydesignedproject-specificforthesuccessfulcompletionintime.

Theconceptoftunnelboringmachinesisnotnewandits history dates back to the year 1846 in Italy.Sincethentherehavebeenrevolutionaryimprovementsinthismachine. Though it has completedmany challengingprojectsinthefieldofroad/railwaytunnels,hydropoweranddifferentotherutilitiessuccessfullybutthereareanumberofcaseswhereithasbeenprovedtobeacurseduringthemiddleoftheproject.TheTBMhadgotstuckin themidwayof theproject due to various reasons,chieflyresultingfromthevaryinggeologyofthestipulatedprojectarea,andthuscreatinghugefinanciallossestothecontractoraswellasunduedelaysintheproject.IndiaisbestowedwithhugehydropowerpotentialchieflyspreadacrossHimalayas.SomeoftheTBMprojectsenvisagedoralreadydeployingTBMsaregiveninTable1.

Table 1 :TBMprojectsenvisagedinIndia(Dubey,2008)

Hydro power projects Power generated

Status of project

ChenabBasin(HP) 2500MW Identified

Tapovanvishnugad 520MW Underimplementation

RupsiabagarKhasiabara 261MW Underclearance

Amochu(Bhutan) 500MW Identified

Kolodyne(Mizoram) 460MW Identified

Etalin&Attunli(AP) 4500MW Identified

2. rOlE OF GEOlOGY iN TBm dEPlOYmENT“For the geologist, the range of rock conditions is like a paradise but for the contractor, it is a nightmare,”byV.L.“Raja”Rajasekaran.

Thegeologyalongatunnelalignmentplaysadominantroleinmanyofthemajordecisionsthatmustbemadeinplanning,designing,andconstructingatunnel.Geologydominates the feasibility, behaviour, and cost of anytunnel.Althoughdifficulttoappreciate,theengineering

propertiesofthegeologicmediumandthevariationsofthesepropertiesareasimportantasthepropertiesoftheconcreteorsteelusedtoconstructthetunnelstructure.In a tunnel, the ground acts not only as the loadingmechanism,butalsoastheprimarysupportingmedium.Thus, it isvital that themostappropriategeotechnicalinvestigationisconductedearlyintheplanningprocessforanytunnel.Themorechallengingtheground,thegreaterthepre-planningthatisrequiredbeforetunneling.

Someofthedifficultgroundconditions,whichcanaffectTBMperformance,areboreabilitylimits,instabilityoftheexcavationwalls,instabilityoftheexcavationface,faultzonesandsqueezing.TunnelexcavationbyaTBMmayencounterotherdifficultgroundconditionsaswelldueto thepresenceofclayeysoil,softground resulting insettlementoftheTBM,stronginflowofgroundwaterandgas,rockbursting,rockandwaterathightemperatureandkarsticcavities.

Ithasbeenshownmany times that those tunnels thathavebeeninvestigatedmorethoroughlyhavefewercostoverruns and fewer disputes during construction. Theunanticipatedproblemsarethosethatcancreatecostlydelaysanddisputesduringtunnelconstruction.DetailedandthoroughexplorationsmustprecedeanytunnelingactivitymoresoincaseofTBMtechnologysothattheycan help evaluate the feasibility, safety, design, andeconomicsofatunnelproject.

2.1 Geological Uncertainties – Their Influence on Excavation by TBms in india

Uncertaintymeans“lackofknowledge”.Butstillinmanycasesthisproblemmayberesolvedsubstantiallybythemethodsofquantificationorsomeothermethodsinwhichwecanderivesomeuseful informationandreachtoadecision.Uncertaintymaybecategorizedintwoways,

1. AleatoricUncertainty(naturalvariability)

2. Epistemic(uncertaintyduetoignorance)

The former refers to thedistribution in theparametersthatinfluencethebehaviorofthestructure.Thistypeofuncertaintycannotbereducedbyextendedmeasurement.Thesecondtypeofuncertaintycanbeattributedtolackof knowledge. This includes insufficient knowledgeoftheactualgeologicalconditionincludingpoorconditionin terms of properties and geometries. This type ofuncertaintycanbereducedbyobtainingmoreinformation,i.e, from investigation,monitoring andmeasurements(Palmstrom,2010).

2.2 reasons for Poor TBm Performance in Tunnelling – Some Geological issues

In Indian scenario, it may be observed that almostall the hydro power projects are situated in themountainousregioni.e.,Himalayasorsub-Himalayantracts.Himalayas,beingyoungfoldedmountains,arestillundergoingchangesandaresubjectedtointense



compression primarily due to continent-continentcollision. This often resulted in numerous folds,faults, foliations and joints which are the commoncharacteristicoftheserocksraisingstabilityconcerns.ThepreviousstudiesonTBMapplicationsinIndiabyVishnoi in the year 2012have revealeduseful factspertaining to the uncertainties found in the projectsandtheoutcome(Table2).

Inanutshell,thefollowingaresomeoftheprimecausesofpoortunnellingratesachievedbyTBMsinIndia:

• Intenselydisturbedgrounds

• Water seepage under high pressure leading toinstability

• Supporting problems in shear zones sometimesassociatedwithintensewateringress

• Squeezingground

• Release of rock blocks due to blocky and jointedstrata

Table 2 :TBMapplicationsinIndiaandtheuncertaintiesencountered(Vishnoi,2012)

Project location uncertainties Outcome

DulhastiHydroElectricProject,NHPCLtd.

LesserHimalayasinKishtwardistrictofJammu&Kashmir,India

• Unfavourable geologicalconditions in the form ofshear zones crossing thetunnel regularly with highseepages of water andincidencesofroofcollapse.

• Tunnel’s structural failureduringconstruction.

• TBMgotburied.

• Contractual complicationsCont rac tor re fused tocontinue

• Highcostandtimeoverrun

Koteshwar Hydro ElectricProject,THDC

MiddleHimalayasinUttarakhandState,India.

• Unfavourable geologicalconditions in the form ofs lope fai lure at powerhouse locat ion dur ingconstruction.

• Majorfloodoccurredatsiteduringconstruction.

• Diversiontunnel’sstructuralfailureduringconstruction.

• Contract rates becameunviable.

• Contractor started lookingfor c la ims rather thancompletingtheworks.

• Proactive action by theOwner

ParbatiStageIIHydroElectricProject,NHPCLtd.

Located in Kullu district ofHimachalPradesh,India

• Unfavourable geologicalconditions in the form oflarge underground waterinflows.

• TBMgotburied

• ContractorwasnotreadytosharetheunexpectedRisk.

• I n o r d i n a t e d e l a y i ncompletion.

Tapovan- VishnugadHydroElectricProject,NTPCLtd.

Uttarakhand,India. • Excessivecutterwearduetoabrasiverocks,

• Unfavourable geologicalconditions in the form ofheavywateringressduetofault/geologicalfailures.

• Contractorstoppedtheworkand denied accepting thecostofrisk.

• Delayedconstruction

• Rockburstsduetocoverloads

• Highgeothermalgradients

• Cavityformation

• Hard and abrasive rocks leading to higher cutterconsumption

DeployingaTBMforaprojectinvolvesahugeinvestmentandriskfromtheemployeraswellascontractorsside.Theunfavourableconditionscanbeproducedbyeitherarockmassofverypoorqualitycausinginstabilityofthetunnelorarockmassofverygoodquality(i.e.strongandmassiverockmass)leadingtoverylowpenetrationrates.TypicalhazardsassociatedalongwiththeprobabilityofoccurrenceandriskallocationarepresentedinTable3.SomeofthehazardsassociatedwiththeTBMtunnellingaremorefrequentandthusneedspecialattentionapartfromtheirallocationweatheritistotheemployerorthecontractor.



2.3 Boreability using TBms

TheTBMperformancebasicallydependsonthethreevariables,namely,penetrationrate,machineutilizationandcuttercost.ThemainindexdescribingthecapacityofaTBMtoexcavateagivenrockisthepenetrationrateperrevolutionofthecutterheadthattheTBMisable to achieve under themaximum thrust. It is notpossibletoestablishalimitofpenetrationperrevolutionbelowwhicharockshallbeconsiderednon-boreable.Suchalimitisalsoinfluencedbytheabrasivityoftherock,thediameterofthetunnel,andthethicknessofthe rock formation. The high abrasivity, associatedwith low penetration, dictates frequent changes ofcutters,increasingthecostforeachcubicmeterofrockexcavated,inadditiontothetimelostinsubstitutingthecutters.Withincreaseinthetunneldiametertherearedifferenteffectswhichmakethesituationworse.Itmay,thus,besummarizedthatlargevariabilityingeologyistherootcauseoftheproblemsleadingtodelaysandelevated costs. Thus, considerable effort should begivenattheinitialstagesoftheprojectforconductingcomprehensiveandpropersiteinvestigationasthecostof such investigation is relatively low in comparisonwith the total contract sum. As for budgeting ITArecommends2.5%to3%oftheestimatedtotalcontractvalueshouldspentoninvestigations

2.4 mixed Face Conditions (mFC) and their Effect on TBm Performance

Hard rock tunnel boringmachines (TBMs)have todayreacheda stageof development so that a tunnel can

bebored inpracticallyanyrockmass.Howevercertaingroundconditions still present considerable challengesfortheeconomicapplicationoftheTBMmethod.“Mixedfaceconditions”,shortenedasMFC,isatermusedwhenthe tunnel face consistsof atleast two rock typeswithcompletelydifferentboreability– in simple termsamixofsoftandhardrock.Itisanormalfeatureinhardrocktunnels. It causeswell known problemswith impactsto the cutters and increased loads to the cutter headstructureandmainbearing.Aneasilyobservableresultisincreasedvibration.Thisresultinreducedpenetrationrate,increasedcutterbreakageandotherdelaysreducetheTBMutilisation. Theeffect of overall performancemaybesignificant,especiallyiftheMFCarepronouncedandprevailsoverlongtunnelsection.FailuretopredictorrecogniseMFCmaycauseselectionofnotsuitableTBMsresultinginseriouslyreducedperformance,whichmayleadtocontractualclaims(BlindheimandNilsen,2002).

ThedegreeofMFCdependsonboth themechanicalpropertiesofthegeologicalformationsandthegeometryofsuchformations.Inahorizontaltunnelaverticaldykecrossingthetunnelperpendicularlywillnormallynotgivemuchproblems.Asthegeologicalformationsarealignedmoreparallelo the tunnelaxis, thesituationbecomesincreasinglyunfavourable.ThisisthecaseforinstanceinIcelandicbasaltformations,asshowninFigure1,wherethedifferentvolcanicandsedimentarylayersareusuallydipping2°-10°.

Itisevidentthatalargepartofanearhorizontaltunnelin such geological conditionswould be excavated inMFC.This couldaffect theboreability of the rockand

Table 3 :TypicalhazardsassociatedwithTBMtunnelingwithrelativeprobabilityofoccurrence

Hazard Probability of Occurrence risk AllocationHighwaterpressure Medium EmployerSwellingpressure Medium EmployerStucking,clampingofTBM Medium ContractorFacecollapsebygroundwaterflow Medium ContractorGasdetection Medium ContractorOverstressedliningbygroundwaterpressure Low ContractorExcavationmaterialnottransportablethroughconveyorbelt Medium ContractorExceptionalhighwearingofexcavationtools High ContractorBoulderswithinsoilformation Medium ContractorNaturalCaverns Medium EmployerApproachingfaultzone High ContractorWaterinflowthroughsegments Medium ContractorContaminatedground VeryLow ContractorTreatmentofexcavationmaterial Verylow ContractorThermalImpact High Contractor



stabilityoftheface.Forexplainingthisseveralphysicalandmechanical parameters that are expressing theboreabilitymayberelevantfordescribingMFC.ForthisUniaxialcompressivestrength(UCS)istheparameterthatoftenisputinfocusindiscussionsconcerningMFC.TheUCSmaynotbethebestparameterforTBMboreability,but its availabilitymakes it a useful reference.NextparameterthatusedisDrillingRateIndex(DRI)maybemorerelevantas it includes theresistanceto impacts,whichsimulatesthedynamicloadingofrockfromthedisccutters.FurtherparametersincludeelasticityorabrasivitymayalsobeofrelevancetodescribeMFC.

2.4.1 Effects of MFC

The effects ofMFCwith respect to boreability areconnected to impacts on the cutters, vibrationsof thecutterheadand theTBM, uneven loading of themainbearing,andincreasedcutterbreakage.Thedisccuttersexperiencearapidlyvaryingloadfromclosetozerotopeakloadsof5-10timestheaverage.Ifthishardnessvariationissharpbetweentworocks,thecutterwillexperienceanimpact,rollingfromtheweakerintothestrongermaterial,theaverageandpeakloadsalsojumpuptoahigherlevel.Ifthisimpactislarge,thecutteredgesmaychiporbreak.If the rocksareabrasive, theabrasivewearmayalsoresultasthecontactstressesareincreasing.Overtime,thecutterbearingswilltakemoreandhighershockloadsper revolution, and bearing breakagewill occurmoreoften.Andifthebearing“freezes”,thecutterringwillbedestroyedaswell.Intotalincreasedcutterconsumptionwillresult.TheeffectisTBMutilisationisreducedduetoincreasedcutterchangetime,aswellasincreaseofotherscheduledandunscheduledstoppages.

2.4.2 Effects on TBM Operation

DuringoperationofTBM ifoperatorobserves that thevibrationsare increasing fromthenormal level tohighleveloriftheTBMdeviatesduetounevenhardnesshis

immediate reactionwill be to lower the applied thrustforce to the cutter headsand to reduce theRPM.Towhich level the thrust andRPMshould be reduced isinfluencedbymany factors such as boreability of therockandrockmass,thesizeofcutters,thetypeandageoftheTBM,thelengthandexpectedconditionsontheremainingdrive,etc.

2.4.3 Dealing with MFC

MFCwithdifferentrocktypeswouldnormallyhavelessimpact thanamedium tovery fractured rockmass. Infracturedrocks,therocksmayfalloutorpushedoutofface leavingopengapsor voids.Thevoids left in thefacewill cause impactswhen the cutters passing thevoidshitstherockonthesideofthevoid.InMFCcaseswithveryhighstrengthratiossayabove5-10,itmaybenecessarytoreduceby50%.Thiswouldobviouslyhavealargeimpactontheoverallperformance.

2.5 models for Predicting the TBm Performance

Two popular approaches for the calculation of TBMpenetration are available though a fewmodels arerecently added to this. Themost popularmodels areCSMandRMi-NTHmodels. Input in the formof rockcharacterstics andmachine parameters are providedandafternumerouscomputationstheoutputintheformof certain useful performance parameters is provided(Table4).

3. rOCk mECHANiCS TESTS ViS-A-ViS TBm SElECTiON

Itmaybeobservedfromtheabove-mentionedtwoTBMperformancepredictionmodels(Table4)thatseveralrockparametersareneededtobeusedasinputparametersfortheintroductionofTBMswhichareessentiallyobtainedfrombothlaboratoryandfieldinvestigations.ConsideringthisneedrelevanttestsetupwascreatedatIndianSchoolofMines,Dhanbadandtestsarebeingcarriedoutsince2001.ThefollowingsectionspresenttherockmechanicstestsrequiredtobecarriedoutforTBMselection,designandoperation(Murthyetal,2005).

• Brittleness Index (BI)

ThebrittlenessvalueS20 isan indirectexpressionofthenecessaryamountofenergyittakestocrushtherock.About500gmcrushedrocksample(basedonthedensityofrock)between16and11.2mmsievesizeistakenandpoundedwitha14kgweightfromaheightof25cmfor20times.TheBIvalueisthepercentageof thematerial that passes the 11.2mmsieve after20dropsand isdeterminedas themeanvalueof3to4paralleltests.Higherthebrittlenessbetteristherelativeboreability.

Fig. 1 :MixedfacedconditionsoftenencounteredinTBMtunnelling(BlindheimandNilsen,2002)



• Sj Value

TheSeiver’s J value expresses indirectly the surfacehardnessoftherock.Theholedepthmeasuredin10-1 mmunitsafter200revolutionbytheminiaturedrillwiththrustof20kgisknownasSjvalue.Thedrillbitusedis8.5mminwidthwith110gbevelangle.HighertheSjvaluebetteristheboreability.

• Drilling Rate Index

TheDRIvaluesareobtainedusinganomogramshowninFigure3.d.HighertheDRIbetteristheboreability.

• Cerchar Abrasivity Index

Abrasiveness is one of the properties of rocks thatismeasured in order to assess their suitability formechanicalexcavation.Thisparameterhasbeenfoundtostronglygoverntheperformanceofdisccutters,theirrateofreplacementandthereforethecostofthetunneling.The test isconductedbyabradingasteelpinundera

staticloadof7kgbymovingthepin1cmontherockin1sec.Thepinismachinedfromsteelhavingatensilestrengthof2kN/mm2 (Rockwellhardness54-56).Thepin is shaped tohavea sharp900 conical point.Aftereachabrasiontestthewearflatontheendofthepinismeasuredusingamicroscopeequippedwith a lengthscale.Theaveragediameterofthewearflat,measuredin10-1mmunitsgivestheTheCercharAbrasivityIndex.Thescalerangesfrom0to6,one-indexpointcorrespondingtoaconicbluntsurfacediameterof0.1mm.Rockswithanabrasivenessvaluegreater than4maygiverisetohighratesofwearonTBMcutters.

• Uniaxial Compressive Strength

Theuniaxial compressive strength of rock samples isdeterminedusingastifftestingmachine(servocontrolled)undercontrolled loadingrate.TestsarecarriedoutasperthenormslaiddownfortestinginISRMsuggestedmethods.

Table 4 : ParametersusedinCSMandNTHmodelsforTBMdesign(Palmström,A.1995,Bruland1998)

CSM Model RMi-nth ModelParameters units Parameters units

iNPuTCutterradius (in) Fracturing Class(0-iv)

Tipwidth (in) Brittleness S20Index

Spacing (in) Drillability Sievers‘Jindex

Penetration (in) Abrasiveness AVindex

RockUCS (psi) Porosity %

TensileStrength (psi) CutterDia mm

TBMDiameter (ft) CutterLoad kN

RPM (rev/min) Spacing mm

No.ofCutters (#) MachineDiameter m

OuTPuTThrust (lbs)

Torque (ft-lbs)

Power (hp)

CuttingForce (lbs) No.ofCutters #

Normal-Thrust (lbs) RPM rev/min

Rolling/Torque (lbs/ft-lbs) Thrust Ton

Power (hp) Power kW

BasicPenetration (in/rev) BasicPenetration mm/Hr

RateofPenetration (ft/hr) RateofPenetration m/Hr

HeadBalance (force/moments) Torque (kN-m)

MachineSpecification (th,tq,hp,etc) Utilization %

PerformanceCurve (Graph(rop-vs-thtqvsts) AdvanceRate (m/Day)

UtilizationCurve (%) Cutterlife (Hr/Cutter)

Advancerate (Ft/day)

Cutterlife (Hr/cutter)



• Brazilian Tensile Strength

ThetensilestrengthofrockisdeterminedusingBrazilianmethod.Bothparallelandperpendiculartofoliationaredeterminedsoastofixthecutterstotakethisadvantage.Values are higher when the samples are loadedperpendiculartofoliations.

• Young’s Modulus of Elasticity & Poisson’s RatioThe Young’s Modulus of elasticity (tangent) wasmeasured inMTS stiff testingmachine using straingauges(balanced).Thedatawereacquiredbyadataacquisitionsystem(SPIDER8).• Thin section analysis

Mineralogicalstudieswerealsodonetounderstandthehardmineralspresentalongwiththeirtexture,orientationetc.Microphotographsof two rock typesareshown inFigure2a&2b.

Fig. 2a :ThinSectionofMetabsicrock Fig. 2b :ThinSectionofQuartzite

DifferenttestsetupandtheresultsondifferentrocksuitssuppliedfromTapovan-VishnugadprojectareprovidedinFigure3andTable5respectively.

Table 5 :Rockpropertiesofdifferentrocksuits,Tapovan-VishnugadHydelProject(Murthy,2005)

Name of rock Bi Sj dri CAi uCS (mPa) BTS (mPa) mOE (GPa) Poisson’s ratioMetabasicrock 69.5 53.2 79 2.40 84(52-107) 6.7-8.3 7.8

(5.8-9.5)0.26

(0.16-0.33)AugenGneiss 52.4 31 58 3.42 91(61-125) 8.4-8.7 27.9

(24-29)0.23

(0.18-0.30)CoarsegrainedGneiss 63.2 28.6 69 4.35 77(63-88) 7.3-7.9 35(23-48) 0.27

(0.10-0.40)FoliatedGneiss 63.5 5.5 62 3.50 98(84-114) 7.3-10.1 36.7

(34-40)0.24

(0.17-0.34)FinegrainedGneiss 58.7 16 61 3.00 196

(143-236)6.9-8.4 36.1

(29-42)0.14

(0.11-0.16)Quartzite 55.6 3.83 52 5.62 184

(103-254)7.8-8.7 55.5

(45-63)016

(0.15-0.18)MicaSchist 70.3 107.5 86 2.28 Regularcoresamplecouldnotbeobtained

3.1 Summary of Laboratory InvestigationsOf the seven rock types tested, the quartzite rockshave the lowestDRI value (52).MetabasicRock andMicaSchisthavethehighestDRIvalue,i.e.,morethan79.LowDRIvalues indicatedifficultboreability for theTunnel BoringMachine, in general, where as higherDRI values indicate easier boreability. TheCercharAbrasivityIndex(CAI)fortheQuartziterockwasfoundtobe5.62whichindicatesthattherewillbehighrateofwearinTBMcutterswhencomparedtootherrocktypesmentioned above.Higher abrasivity of quartzite andcoarse-grainedgneiss,weakstrengthofmetabasicrockaresomeofthetypicalobservationsintheserocksuits.TheYoung’sModulusofelasticitywas thehighest forquartzite (55.5GPa)and the lowest for themetabasic rocks(7.8GPa).



(g)SetupforthedeterminationofYoungModulus (h)AnalysisforcomputingMOEandPoisson’sRatioFig. 3 :LaboratorytestsetupforTBMapplication,ISM,Dhanbad

(a)Siever’sJvalue(Sj) (b)Brittlenessindex(BI)

(c)CercharAbrasivityIndex(CAI) (d)NomogramforestimationofDRI

(e)UniaxialCompresssivestrength (f)BrazilianTensileStrength



Table 6 : TBMspecificationsusedinTapovan-Vishnugad HydelProject,NTPCLtd.(S.K.Sengupta,2008)

machine parameters ValueModel Herrenknecht’sdoubleshield

hardrockTBM

Frontshielddia 6480mm

Cutterhead 6550mm

Disccutters(54nos) 432mm(17”)

Maxthrustpercutterring 267kN

Max recommended cutter-headthrust

14,418kN

Cutterheadpower 6x350KW

Maxtorque 4590kNm

Grippingforcebygrippers(2nos)

2x18465kN

CutterTipwidth 19.05mm

4.1 Estimation of Penetration rate

Thebasicpenetrationcanbeestimated,foragivengrossthrustperdiscandcutterdiameter,fromthestudyconductedbyMovinkel&Johannessenin1986(Figure5).

4. PErFOrmANCE PrEdiCTiON OF TBm

TBMisinoperationinTapovan-VishnugadHydelProjectofNTPCLtd. TheTBMadit betweenCh. 130.00and371.08mwasexcavatedbyadoubleshieldedtunnel-boringmachine(Figure4).Therockmasswasobservedfrom themuck either on the conveyor belt or in thedumpingyard,throughtheholesforpeagravel,groutinganderectorintheprecastsegments,infrontofthecutterheadandthroughthetelescopicshield.TherockmassinTBMaditarepredominantlyquartzmicagneisswithmicaschistandquartzitebands,andquartzite(JoshimathFormation),whicharehighlytoslightlyweatheredand/ordisintegrated(Weatheringgrade:W3toW1).

Therockmassischaracterizedbyprominenttwoormorejointsetsandfewrandomjointswithsiltyorsandy-claycoatings and small clay fraction (non-softening), andnon-softeningminerals, sandyparticles, and clay-freedisintegrated rocks, etc. along them. The rockmassis completely dry in general andwet at someplaces.Judgingfromthetotalthrustforceofthecylinders,whichliesmostly below 5000 kN, the rockmass conditionappears to be poor to fair. Based on the estimatedQ-values,permanentrocksupport(acombinationofrockbolts,steelfiberreinforcedshotcreteandsteelribs)wasrecommendedforHRT.(Adhikarietal.,2009).

Fig. 4 : LayoutoftheHRT,Tapovan-VishnugadHydelProject,NTPCLtd.(Murthy,2005)

The headrace tunnel driven using TBMat Tapovan-VishnugadHydroPowerProjectwouldintersect,mainly,mediumtohighgrademetamorphicrocks.TheprojectareaformingapartofDhauligangaandAlakhnandavalleyexposesrockclassedascentralHimalayancrystalline.The tunnel isproposed tobedrivenbyTunnelboringmachine(TBM.)tonegotiatethehighcoverreach.ThelengthofthetunneltobeboredbyTBMfromDhauligangatoAlakhnandawouldbearound11.975kms,andlikelytocoverMetabasicrock,AugenGneiss,CoarsegrainedGneiss,FoliatedGneiss,FineGrainedGneiss,QuartziteandMicaschistformationsthroughoutitslength.TheTBMspecificationsusedareprovidedinTable6.

Fig. 5 : BasicpenetrationasafunctionofDRI,(fromMovinkelandJohannessen,1986)

Fromtheabovesuggestedmethod,foraDRIvalueof52andgrossthrustpercutterat210kN,thepenetrationcanbe foundas5.32mm/rev.Fora thrustof267kN(for theTBMbeing used inTapovan), this couldwellbe extrapolated close to 9mm/rev. Considering thelimitationoftheaboveapproachforhigherthrustvalues,theRMi-NTHmodelhasbeenused forestimating thebasicpenetration.

TheRMi-NTHmodel,forestimatingthedailyadvanceofTBMforHRTdriveninParbatiStageIITBMtunneling,waspresentedearlier(Murthyetal,2011).AccordingtotheRMi-NTHModel,theinstantaneouspenetrationrateisgivenbythefollowingrelation,andtheunitismmperrevolution.



Io=(MEQ/M1)b ...(1)

where,MEQrepresentstheTBMproperties,and‘M1’and‘b’dependsontherockmassproperties.Therockmasspropertiesareinturnrepresentedbythefactor‘KEQ’.

Thevalueof ‘MEQ’and ‘KEQ’canbedeterminedbytherelations(equation2&3)givenbelow:

MEQ=MBxKDxKA=267*1.15*1.02=313.2kN ...(2)

KEQ=KSxKDRIxKPOR=1.0*1.04*1.02=1.06 ...(3)

Where,MBisappliedthrustperdisc(inkN),KDisthecorrectionfactorforcutterdiameter,(refer Fig. 6)KAisthecorrectionfactorforcutterspacing,(refer Fig. 7)KPORisthecorrectionfactorforPorosity.(refer Fig. 8)KDRIisthecorrectionfactorforDRI,(refer Fig. 9)KSisthecorrectionfactorforjointing/fractures,(refer Fig. 10)

M1andbvaluesforobtainedKEQvaluesareobtainedfromFigure11andFigure12.Thepenetrationrateiscalculatedusingtherelation(1)asfollows:

Io=(MEQ/M1)b=(313/80)1.7=10.16mm/rev

Thenetadvancerate(m/h)isfoundfromrelation(4):I=(IO)x(RPM)x60/1000=10.16*4*60/1000=2.44m/h ...(4)

DailyAdvance(DA)=(I)x(W)x(U)=2.44*12*0.4=11.7 ...(5)

Where,

IOistheinstantaneouspenetrationrate(mm/rev).

RPMisrotationperminute.

Wisworkinghoursavailableperday(twoshiftswith6hoursatface) Uistheutilizationfactor(%) DAisadvanceperday(m/day)

Fig. 6 Fig. 7

Fig. 8 Fig. 9



5. CONCluSiON

FeasibilityofaTBMisverymuchbasedontheabilityof TBMand its other back up equipment to performefficientlyundertheaveragesobtainedfromthedifferentlab and field investigations defining the favorable orthe adverse geological condition. Previous tunnellingexperienceinIndiahasprovedthatgeologyhasoftenplayedadecisiveroleindecidingthesuccessorfailureof theproject.TBMstobeusedfor tunnelling inhardrock terrain have to be designed and selected to beable to sustainmixed faced conditions (MFC) also.Thus, it is very important that planning, design andpreparationofcontractdocumentstaketheresponsibilityofMFCintoconsiderationapartfromthevariationsinrock properties. All the TBMdrivagesmust take intocognizance the variations in geology and this canbe best achieved through a careful sample selectionfollowed by a comprehensive testing programme.

Fig. 10

Fig. 11 Fig. 12

This datawill be immensely useful in designing theTBMsystemsmayitbeusingNTHorCSMorQTBMorRMi-NTHmethods. Specialised tests, namely, DRI,CAI andBrittlenesswere found to relate reasonablywell with the penetration rate achieved. Thin sectionanalysis and identification ofmicrostructure has alsohelpedunderstandthereasonsforpoorboreabilityandhigher cutter rate consumption. Physico-mechanicalproperties help in designing the overall system. TestdatageneratedforTapovan-VishnugadHydelProjectbyISMhasbeenutilizedtoestimatethebasicpenetrationratewithRMi-NTHmodel.Thiscanbeused,rocksuit-wise,forarrivingatthedailyadvance(assumingsuitableutilizationofmachine).Consideringtheestablishedutilityoflabtests,itisneedlesstore-emphasizetheneedforextensive laboratory studiesduringplanningstageoftunnellingwithTBM.However,thepredictedpenetrationratesindifferentrocksuitsneedtobecorrelatedwith

RMi-NTHModel



Fig. 12

actual penetration achieved in the field for the betterappreciationof theentireprocessanddevelopusefulguidelinesinIndianscenarioasTBMtunnellingisgoingtocatchupfurther.

Acknowledgement – Authors thankfully acknowledgeall the concerned officers andmanagement ofNTPCLTd. and NHPC Ltd. for assigning rockmechanicsinvestigations pertaining to variousHydel Projects ofthe country andalso for their continuous involvementthrough various executive development programmeson drilling, blasting and tunnelling.Support of ISM inprovidingneedfulsupportandfacilitiesisalsothankfullyacknowledged. Special thanks toMr. Jerrin Jose,PGscholar for helping to prepare thepaper andShriB.Munshi,STA to support the laboratory studies. Theviewsexpressedareoftheauthorsandnotnecessarilyoftheorganizationstheyrepresent.

rEFErENCES

1. Adhikari,G.R,,R.KSinha,SandeepNelliat,sagayaBenady&G.HKotnise (2008-2009)NIRM report,pp1-3

2. Blindheim,O.T.,E.Grv,B.Nilsen(2002):Theeffectofmixedfaceconditions(MFC)onhardrockTBMperformance,AITES-ITAWorldTunnelCongress,Sydney,March2002,pp1-7.

3. Bruland,A.,(1998).Hardrocktunnelboring.Ph.D.Thesis, Norwegian University of Science andTechnology,Trondheim.

4. Dubey,K.B.(2008),WorldTunnelCongress&34th GeneralAssembly,September,Agra

5. Murthy, V.M.S.R. et al.(2004), A study into themechanical properties of rock for the selectionof tunnel boringmachine in Tapovan-Vishnugadhydropowerproject,Joshimath,ProjectNo.:PCE/CONS/1735/2004, Indian School of MinesDhanbad.

6. Murthy, V.M.S.R, Anoop Shukla and NikeshSrivastava(2011),Tunnellingusinghardrocktunnelboringmachines-Somedesignandperformanceaspects,Intl.ConferenceonUndergroundSpaceTechnology,17-19January,Bangalore,India,ppLI-04-1to10.

7. Palmström, A.(1995), RMi –a rock masscharacterization system for rock engineeringpurposes.Ph.D.Thesis,UniversityofOslo,p.400.

8. Palmstrom&Stille(2010),Rockengineering,pp43-54

9. Sengupta,S.K,P.K.Saxena&S.S.Bakshi.(2008),Tunnel boring in India- Experience, prospectsand challenges.World TunnelCongress 2008 –UndergroundFacilitiesforBetterEnvironmentandSafety-India,pp1544-1551

10. VishnoiR.,(2012),Challenges inContracting andProcurementofLargeHydroProjects,Washington,Seminar onRiskManagement from anOwner’sPerspective.



1. iNTrOduCTiON

Thedistributionandmagnitudeofin-situstressesaffectthegeometry,shape,dimensions,excavationsequenceandorientationof undergroundexcavations (AnireddyandGhose 1994). Themain goals when designingunderground openings in rock / coal (where stressesare likely to be a problem) are tominimize stressconcentrations, create a compressive stress field asevenlyaspossible (theharmonicholeconcept) in theexcavationwalls andavoid tensile regions (HoekandBrown1980).Thiscanbedonebychangingtheshapeandgeometryoftheopeningsaswellastheirorientationwithrespect to theknownprincipal in-situstress. Theknowledgeofin-situstressdirectionplaysapivotalroleindecidingtheorientationandpillaringplanincoalmines(Doliner2001,Dolineretal.2001,Bigbyet.al.1992).Oncetheoptimalorientationofthepanelisdecided,thesizeoftheslicesinbord&pillarminingcanbeoptimizedinordertopreventpossiblelossofcoalinthegoaf.StratacontrolproblemassociatedwithTandsimine,WesternCoalFields,Indiaisdiscussedinthispaper.

2. SAliENT FEATurES OF THE miNE

TandsiMineliesintheinChindwaradistrictofMadhyaPradesh. Damua thenearest town is connectedwithDungaria(headquarterofKanhanarea,WCL)andParasia(headquarterofPencharea,WCL)byametaled road(Figure1).ThedetailedexplorationinTandsiblockhasprovedtheexistenceofthreecoalseamsdesignatedfromtoptobottomasseam–III,IIandI.SeamIIIispersistentinnatureaswellasattainedworkablethicknessintheentireminearea.Thisisthemainpotentialseam.Seam

IIhasnotattainedworkablethicknessof1.2mandaboveanywhereintheexploredarea,whileseamIhasattainedworkablethicknessof1.2mandaboveinsomepartoftheareaexplored.Thepresentminingisconcentratedat3.5mthickseamIIIwhichisatadepthof230mbelowthegroundlevel.ThestrikeofthecoalseaminmajorpartoftheareaisgenerallyEWwithlocalizedswingsandanaveragegradientof1in15.Theimmediateroof(3.5mthick)ofseamIIIismadeoffinetomediumgrainedgreywhite,moderatelyhardsandstonewithoccasionalbandsofshaleandcarbonaceousshalestreaksatplaces.Thefloorconsistsofsandstonefrequentlyinterbeddedwithshaleandcarbonaceousshale.Therearenooverlyingorunderlyingworkableseamsinthemine.

InFluenCe oF anISotRoPIC StReSS CondItIonS on deSIGn oF deVeloPMent woRkInGS In BoRd and

PIllaR MInInG

r.k. Sinha, m. Jawed and S. Sengupta National Institute of Rock Mechanics, India

ABSTrACT

The knowledge of in-situ stress plays a vital role in design of any underground structure in rock. In mining context, the knowledge of in-situ stress becomes necessary at many stages of mine planning, viz. while deciding about the appropriate layout, designing the ground support and establishing a proper and efficient extraction sequence etc. In today’s numerical analysis based problem solving approach, the state of subsurface stress or in-situ stress forms the basic input parameter for analysis of any rock mechanic problem. This paper discusses the directional role of high horizontal stress in Tandsi mine, of Western Coal Fields (WCL). An approach based on wedge analysis and stress analysis of the layout for bord and pillar mining is discussed in this paper. This helps in understanding the design requirements for proper layout plan.

Fig. 1 :LocationMapoftheTandsiMine, MadhyaPradesh,India

16



Fig. 2 :KeyplanshowingtherooffallproblemsencounteredatTandsimine

3. miNiNG PrOBlEm uNdEr iNVESTiGATiON

Inordertoachievetroublefreeminingoperationandsufficientventilationtotheworkingfacesitisdesirablethatallthegalleriesbestableenoughtoprovideaccesstothemanandmaterialaswellasthepassageoffreshair to theworking faces. During development, rooffallswereencounteredindipgalleriescloseto12th,14thand16thlevels(Figure2),ellipseportionshowslocationoftherooffalls). Insomeinstancestherooffalls were extended up to theRider Seam. Thoughtherewas no change in the geometry of theminingandthephysicalpropertiesof therockandcoal, thepatternofrooffallwerenotcontinuousandrestrictedin tocertainareas. Theroofconditionsdeterioratedupondevelopmentevenafter immediate supporting,duetoshearbreaksintheroofabutments(Figure3).Thesamesetoflevelgalleries/dip-riseshavingsimilarrocktype,strikeofthebedandjointpatterndidnothavecontinuousroofproblems.Theroleofre-orientationofthein-situstressduetoinfluenceofdiscontinuitieswas

The factors such as the effectiveness of roof boltingsystem,method of blasting and structural instabilitynegated thecauseof roof failures.Detailednumericalanalysis of the stress induced failure (Senguptaet al.2011)provedthedominantroleof the influenceof thedirectionof the in-situstressandpossible influenceofthestressperturbationduetofaults.Thepresentpaperinvestigatesindetailtheroleofstructuralinstabilityduetoformationofwedgesintheroofandthedirectionalroleofin-situstressthroughnumericalmodelingfororientationofsaferandtroublefreegalleries.

Prior to the stressmeasurement at TandsiMine, themanagementofthemineshadmademanytrialanderrorcombinationsbyreducingthewidthofthegalleriesto3.6mfromaninitialwidthof4.5m.Thedetailsofdifferentcombinations forsupportsystemresortedby theminemanagement isgivenin Table1,howevernoneofthemethodswerefoundeffective.

Theaccess to themine is through four inclinesdrivenuptothecoalseam.Thedevelopmentoftheminewascarriedoutbydrivingmutuallyperpendicularheadingsataspacingof45mcenter tocenter, therebycreatinganarrayofpillarsofsize45mx45mcentertocenter(Figure2).Thesetofheadings(almostEWdirection)drivenalongthestrikeofthecoalseamarecalledlevelgalleries and the other set of headings perpendiculartothelevelgalleriesarethedip-risegalleriesorsimplydip galleries. Theheadingshada rectangular crosssectionof3.6mwidthand3.0mheight.TheexcavationwascarriedoutusingdrillingandblastingusingClassVpermittedexplosivesanddelaydetonatorstominimizeblastdamagetoexcavations.

suspectedincaseofTandsimine.Theotherprobablefactorscausingrooffailurecanbe:

(i) The effectiveness of the roof bolting system.Boththelevelanddipgalleriesweresupportedsystematically and no delay in supporting thefaceswerereported.Theanchoragetestsoftheboltsindicatedloadbearingcapacityof10T.

(ii) Methodofblasting.Noblastdamagewasreportedinthemine,asClassVpermittedexplosiveanddelaydetonatorswereused for blasting.Overbreakswerealsonotreported.

(iii) Structuralinstabilityduetowedgeformationinroofofthegalleries.Adetailedanalysisofthewedgeformationanditsstabilityisdiscussedinsection4.0ofthispaper;thisalsonegatesthe cause of roof failure due to structuralinstability.

Fig. 3:Natureofroofinstabilityin14thLevelatTandsiMine.



18

Table 1 :Summaryofthedifferentsystemofsupport,triedbytheminemanagement, fordevelopmentgalleriesatTandsimine

Parameter Option 1 Option 2 Option 3 Option 4Roofspan(m) 4.5 3.6 3.6 3.6Systemofsupport roofbolt roofbolt roofstitching roofboltwithW-strapLengthofbolt(m) 1.5 1.5 1.8and1.5mlong

eyebolts1.8

Noofboltsinarow 3 3 2 4Spacingbetweenrows 1 1 1 0.9Distance from pillar sideandangleofthebolt

0.75 0.3 0.3 0.3

PerformanceofSupport Massiverooffallsatnumberofplaces

Rooffallsatnumberofplaces

Rooffallsinlevelanddipgalleries

Frequentrooffallsreduced

Table 1 :(Contd.)

Parameter Option 5 Option 6 Option 7Roofspan(m) 3.6 3.6 3.6

Systemofsupport roofboltwithW-strap resinboltingwithwstrap resinboltingstaggeredpattern

Lengthofbolt(m) 1.8 2.1 2.1

Noofboltsinarow 4 5 4/5

Spacingbetweenrows 0.5 0.6 0.6

Distance from pillar sideandangleofthebolt

0.3 0.3 0.2

Performance of support Rooffallsatnumberofplaces Rooffallsatnumberofplaces Rooffallsatnumberofplaces

Note:Pillarshavenosignof loadinghowever crackswereobserved in the roofof thegallery, inall theoptionsat someplaces

4. Determination of the normal forces on eachwedgeplane.

5. Computation of the joint shear strength, andtensilestrength(ifapplicable)

6. Calculationoffactorofsafetyagainstslidingoftheblock.

Wedgesareformedbytheintersectionof3–jointplanesandexcavation.Thewedgessoformedaretetrahedralin shape (in general the three joint planes forms thethree sides of the tetrahedron and the fourth side isformed by the excavation boundary). In anUnwedgeanalysistherearefairchancesofformationofprismaticwedges,thisoccursiftwoofthejointplanesstrikeinthesamedirectionresultinginaprismaticshaperatherthanthe tetrahedral shape of thewedge. The geometricalpropertiesofeachwedgearedescribedbyitsvolume,wedge face area and the normal vectors for each wedgeplane.

Theforcesactingonthewedgearecategorizedintotwotypes,viz.theactiveandpassiveforces.Theseforcesareutilizedinthecalculationofthefactorofsafetyofthewedges.Alldriving forcesare treatedasactive forces

4. WEdGE ANAlYSiS OF THE diSCONTiNuiTiES ENCOuNTErEd AT TANdSi miNE

RMRreportoftheTandsimine,preparedbyWCLNagpur,providedbytheminemanagement,revealstwosetsofpredominantvertical jointsobserved in thesandstone.OneofthejointsetstrendingN-SandtheotherN1500. The joint along the seam is another obvious joint set,whichhasbeenconsideredforthewedgeanalysis.

Thewedge analysis of Tandsiminewas carried outusingtheSoftware‘Unwedge’SuppliedbyRocscienceInc.Canada.ThesoftwareUnwedgecarriesoutaseriesofcalculationsbasedontheinputprovidedbytheuserin termsof thegeometry of theopening, the joint setinformation,thejointpropertyandthesupportinformation.Thecalculationstepsinclude:

1. Determinationofwedgegeometry usingblocktheory(GoodmanandShi,1985)

2. Determinationoftheindividualforcesactingonawedgeandthencalculationoftheresultantactiveandpassiveforcevectorsforthewedge.

3. Determination of the sliding direction of thewedge.



andallresistiveforcesaretreatedaspassiveforces.Theactiveforcevectorisgivenbyequation(1):

...(1)

Where, = resultant active force, = vectorrepresentingwedgeweight, = vector representingtheweight of shotcrete on thewedge, = activepressure(Support)forcevector ,waterforcevectorand =seismic forcevector.Thepassive forcevector is

givenbyequation(2):

...(2)

Where, = resultant passive force vector, = shotcrete shear resistance forcevector, =passivesupport pressure force vector and = resultant boltforcevector.

Oncetheactiveforcesarecomputed,thisisutilizedfordeterminationofthedirectionoftheslidingofwedge.Itisworthnotingthatthepassiveforcesdonotinfluencetheslidingdirection.Foranytetrahedron,therecanbe7–possibledirectionsofsliding .Thevectorrepresentsthemodeoffallingorliftingofthewedge.The and vectors represent themodeofslidingonasingleplane.The and vectorsrepresent themodeof slidingof thewedgealong thelineofintersectionoftwojointplanes.Theequationsfortheslidingdirectionvectorsaregivenbyequations(3),(4)and(5).

...(3)

...(4)

...(5)

Where, =fallingorliftingdirectionofwedge,â=unitdirectionof active force, = resultant active force, =slidingdirectionon joint ‘i’,ni =normal to joint face ‘i’directedintowedge,nj =normaltojointface‘j’directedintowedgeand =slidingdirectionon joint ‘I’and ‘j’(intersectionofjoints).

Aftertheevaluationoftheslidingdirection,theevaluationof normal force on each of the three joint planes ofthe tetrahedron isaffected.Theequations (6), (7)and(8) describe the normal forces on the planes of thetetrahedron.ForfallingorliftingwedgeNi=0,Nj=0,Nk =0...(6)

Forslidingonasinglejoint‘i’Ni=–FA,ni,Nj=0,Nk =0...(7)

Forslidingalongjoint‘i’and‘j’

...(8)

Now, for thecomputationof the resisting forceon thewedge, thenormal forceactingoneach joint plane isevaluated.Thenormalstressiscomputedbasedontheactiveandpassivenormalforcecomputedonthejointplaneandisgivenbyequation(9).

...(9)

Where,σniistheithjointplane,Niisthenormalforceon

theithjointandaiistheareaoftheithjoint.Theresisting

stressduetotheshearstrengthofthejointisrepresentedbytheMohr-coulombfailurecriteriagivenby

...(10)

Eventually the resisting forcedue toshearstrengthofthejointisgivenby

...(11)

Where, =themagnitudeoftheresistingforceduetoshearstrengthofthejoint =theshearstrengthofthejoint theareaofthejoint thecohesionofthejointplane theangleofinternalfrictionofthejointstrengthandtheanglebetweentheslidingdirectionandthe joint.

Theresistingforceduetothetensilestrengthofthejointistakenaszerofortheanalysisinthispaper.

Finally the factor of safety for the three cases viz., (i)thefallingfactorofsafety- (ii)unsupportedfactorofsafety- and(iii)thesupportedfactorofsafety- iscalculated.Themaximumamongstthethreeisreportedasthefactorofsafetyofthewedge.

As per the development carried out at Tandsimine,fourdirectionsofgalleries(Table2)willbesufficienttorepresentthedrivageofthemine.Table3liststhedetailsofthejointsetspresentintheroof.

Table 2 :DirectionofgalleriesatTandsimine.

Sl. No. location Gallery Trend Plunge

126D/9L

Level 078 00

2 Dip/Rise 171 04

310D/14L

Level 120 01.7

4 Dip/Rise 033 03.7



20

Table 3 :ListofpredominantjointsetsintheroofatTandsimine.

Joint Set No.

Strike of joint set

dip of the joint set

dip direction

1 N–S 78 090

2 N150E 85 040

3 N145E 04 055

Thesizeortheweightofthewedgeformedifanyinthe roofwill dependon the sizeof thegallery.Onlyroof wedge formed in the upper part of the galleryis considered from theoutputprovidedbyUnwedgesoftware,asthejointsetsconsideredhereisforroofstrataonly,notinthecoalseamorthefloorrock.Withtheworstpossiblescenario,consideringnosupport,thewedgeanalysisfordifferentsizeofthegallerywascarriedout.ThisistabulatedinTable4.TheinputtotheUnwedge software is fromTables 2 and3whichliststhedirectionofthegalleriesandthethreesetofjointsprevalentintheroofofthemine.Intheabsenceof the proper joint propertymeasurement, themostrepresentative values of joint shear parameters forcoalmeasure rocks as suggested by Barton (1974)have been used. The cohesion is taken as 0.012MPa and the angle of internal friction is consideredas16degreesforallthejointsets.Anoutputfromthe

Table 4 :SummaryofroofwedgeanalysisforTandsiMine

Gallery Trend / Plunge

FOS and roof wedge information in 3.6m wide and 3.0 m high gallery without support

FOS and roof wedge information in 4.2 m wide and 3.0 m high gallery without support

FOS and roof wedge information in 4.5m wide and 3.0 m high gallery without support

26D/9LLevel 078/00

FOS=0.682

Weight=0.071ton

Slides along Jset1 in thedirection090/78

FOS=0.593

Weight=0.113ton

Slides along Jset1 in thedirection090/78

FOS=0.558,

Weight=0.139ton.

Slidesalong Jset 1 in thedirection090/78.

26D/9LDipRise 171/04

FOS=1.12,

Weight=0.492ton.SlidesalongJset2inthedirection040/85

FOS=0.963,

Weight=0.782ton.Slidesalong Jset 2 in direction040/85.

FOS=0.901,

Weight=0.962ton.SlidesalongJset2inthedirection040/85.

10D/14LLevel 120/01.7

FOS=0.626,

Weight=7.922tonwedgeinroof.slidesalongJset2inthedirection040/85

FOS=0.502,

Weight=12.269tonwedgeslides along Jset 2in thedirection040/85.

FOS=0.456.

Weight=14.948tonwedge.slides along Jset 2 in thedirection040/85.

10D/14LDipRise 033/03.7 Nowedge formed in theroof.

Nowedge formed in theroof.

No wedge formed in theroof.

Fig. 4 : Stereographicplotofjointvis-a-visthegallerydirections

UnwedgeSoftwareshowingthestereographicplotofthejointsetsvis-a-visthegallerydirectionsisgivenin Figure4.TheresultsofUnwedgeanalysisissummarizedin Table 4. Representative output from the UnwedgeSoftwareisgiveninFig.5.



Asobserved from the stereographicplot of the jointsvis-avis thegallerydirectionsasshown inFig.4andsummaryoftheresultsofUnwedgeanalysisinTable4,thefollowingobservationsaremade:

1. Forthegallery078/00,wedgeisformedintheroofandtendstodrivethewedgealongJointset1.Thewedgeweightincreasesasthewidthofthegalleryisincreases.Thefactorofsafetyfor4.5mgalleryis0.558withoutanysupportorshotcrete.Thewedgeweight being 0.139 ton and extends barely highenoughintotheroof,thismeansaminimalsupportof less than 1 ton capacity can support the roofeffectively.

2. Forthegallery171/04,wedgeisformedintheroofandtendstodrivethewedgealongJointset2.Thewedgeweightincreasesasthewidthofthegalleryisincreases.Thefactorofsafetyfor4.5mgalleryis0.901withoutanysupportorshotcrete.Thewedgeweight being 0.962 ton and extends barely highenoughintotheroof,thismeansaminimalsupportof less than1.5 ton capacity can support the roofeffectively.

3. Forthegallery120/01.7,wedgeisformedintheroofandtendstodrivethewedgealongJointset2.Thewedgeweightincreasesasthewidthofthegallery

isincreases.Thefactorofsafetyfor4.5mgalleryis0.456withoutanysupportorshotcrete.Thewedgeweight being 14.98 ton and extends barely highenoughintotheroof,thismeansaminimalsupportofthreeboltsoflength0.5mwithcapacity6toneachcansupporttheroofeffectivelytoafactorofsafety2.0.

FromtheresultsoftheTable4andtheobservationsoftheUnwedgeanalysis, it is quiteevident that the rooffallsasreported inTandsiMine isnotbecauseofanystructural instability (Wedge failure), rather it indicatestowardstheroleofhighhorizontalstressesthatmaybecreatingtroubleintheroofstrata.

5. investigation of Stress redistribution due to mining Geometry

InvestigationconductedinAustraliancoalmines(GaleandFabjanczyk,1991)hasestablishedarelationbetweenroof failure in the roadways and the angle betweenthe roadway axis and themaximumhorizontal stressdirection. Actualmeasurement of stress in vicinity ofthefaultzoneprovedtherotationofthestressdirectionalongoneofthegalleries(Senguptaet.al2011),whilethe regional stressdirectionaway from the fault zonewas at 45 degrees to galleries. In a typical bord andpillarminingmethodthedipdrivesandlevelgalleriesare

Fig. 5:Viewofthewedgesformed,withgalleryorientation120/01.7,OutputfromUnwedgesoftware.



22

drivenperpendiculartoeachother.Nowinaparticularsetofdirectionofmaximumhorizontalstressoneofthesemaybeorientedunfavorablywiththeorientationofthemaximumhorizontal stress.Adetailed investigation iscarriedoutbynumericalmodelingtoestablishthemostfavorabledirectionofthedipdrives/levelgalleriesvisavisdirectionofmaximumprincipalhorizontalstressfromthestabilitypointofview.Forthestudyofredistributionofstressesduetochangeinmininggeometrythreecaseswereconsidered.

Case 1:OrientationofMax.HorizontalPrincipalStress(σH)isperpendiculartoorientationoflevelgallery.

Case 2:OrientationofMax.HorizontalPrincipalStress(σH)isparalleltoorientationoflevelgallery.

Case 3:OrientationofMax.HorizontalPrincipalStress(σH)is45

otoorientationoflevelgallery.

Theobjective of the study is to estimate effect of theabove three conditions on the stability of roof so thatpropermeasurecanbetakentoreducetheroofstabilityproblembychangeingeometryoftheworkingsandalsotoestimatethesupportrequirement.

5.1 model Setup for Evaluating re-orientation of development Working

To investigate the effect of in-situ stress direction onworkingofadevelopedbordandpillarpanel,apanelof 3x3pillarswasmadeinEXAMINE3Dprogram.Pillarsizeof45mcentertocenterandthegallerysizeof4.5mx3mwereselected.Developmentexcavationsweremadebyuseofpolylinesandnodelines.Betweenthetwonodelinestheskinoftheexcavationwasextruded.Theskinofexcavationwasdiscretizedusingthedefaultdiscretizationschemeoftheprogramwithameshdensityfactorofunity.The crossingof excavationwasmadebydeleting therequiredelementsfromthecrossingpoints;anodelinewasdrawnalongthedeletedportionoftheexcavation,thisnodelinewasextrudeduptothenextcrossingpointtoformaleakageproofexcavationFig.6.

5.2 initialization of in-Situ stress in Examine 3d

Examine3Dhasanoptionofusingthegravityaswellasthein–situstressdata.Thein–situstressvaluescanbe fed in the formof principal stresseswith theirrespective dip anddip direction. Themeasured valueoftheregionalstressforTandsimine(Senguptaetal.2004)wasutilized,whichistabulatedintheformofinputrequiredbyExamine3D.

Table 5 :In-situstressvaluesofTandsiMine,used inExamine3D,whenthemajorprincipalstressisalonglevelgalleries

major Principal

Stress (σH)

intermediate Principal

Stress (σV)

minor Principal

Stress (σh)Magnitude(MPa)

9 4.5 5

Direction(degrees)

90 0 0

Dip(degrees) 0 0 90

Toevaluatethesecondoptionwhenthemajorprincipalstress is perpendicular to the level gallery, the stressdirections ofσH andσh as given in Table 5 above isinterchanged.

Forevaluatingthethirdoptionofthecasewhenthemajorprincipalstressisatanangleof45°fromthelevelgalleryandstillhorizontal.TheStressdirectionswerechangedintheinputasgiveninTable6.

Table 6: In-situstressvaluesofTandsiMine,used inExamine3D,whenthemajorprincipalstressisatanangleoffromthelevelgalleries.

major Principal

Stress (σH)

intermediate Principal

Stress (σV)

minor Principal

Stress (σh)

Magnitude(MPa)

9 4.5 5

Direction(degrees)

135 45 0

Dip(degrees)

0 0 90

Thusoverallthestressorientationinthethreecasesisasfollows:

Case 1 : themajorprincipalstressactsalongeast–westdirection.Thegalleriesaredrivennorth–southandeast–west.

Case 2 : themajorprincipalstressactsalongnorth–southdirection.Thegalleriesaredrivennorth–southandeast–west.

Case 3 :themajorprincipalstressactsalongNortheast–Southwestdirection.Thegalleriesaredrivennorth–southandeast–west.

Fig. 6 :Discretizedmodelfora3x3pillardevelopment panelinExamine3D



5.3 rock mass Property and Failure Criteria for Evaluating the Factor of Safety

Therockmasselasticmoduluswastakenas5.0GPaandPoisson’sratioof0.25wasutilizedinthemodel.ForIndiancoalmeasurerocks,theSheorey’sFailurecriterionhasbeenfoundsuitablebyresearchersinIndia(MuraliMohan2001). This criterion uses the 1976 version ofRMRofBieniawskiforreducingthelaboratorystrengthparameterstogivethecorrespondingrockmassvalues.ThebasicCMRI–ISMRMRisdirectlyusedhereinsteadof Bieniawski’sRMR, since this procedure has beenfoundtobeacceptableafterapplicationin18-coalminecases(Kushwahaet.al2010).Sheorey’scriterionforrockmassesisdefinedas:

...(12)

Thesubscriptmreferstorock-mass,whereσ1 isthetriaxial strength of rockmass (MPa),σ3 is theminorprincipalstressortheconfiningstress(MPa),bmistheexponentofthefailurecriterionthatcontrolsthecurvatureofthenon-linearSheorey’sfailurecriterionσcmandσtm andσtmisthecompressivestrengthandtensilestrengthoftherockmassrespectively,whichisdefinedas:

...(13)

...(14)

...(15)

Thesymbolswithoutthesubscriptmarethelaboratorydeterminedvaluesforintactrock.

As the programExamine 3Dhas no facility for usingdifferentfailurecriteriaotherthantheMohrcoulombandtheHoekandBrownfailurecriterion;theMohrCoulombEquivalent (best fit) ofSheorey’s failure criterionwasused.Therockmassshearstrength(orcohesion)τsm,thecoefficientmOmandtheangleofinternalfrictionϕOm areobtainedfromSheorey’scriterionas

...(16)

...(17)

Itis,however,foundthatthevaluesofrockmasscohesionτsmandfrictionangleϕOmhastobechangedslightlytoaccountforthefactthattheSheorey’sFailurecriterion

isnonlinear(Figure7)intheform ,where

,whereas theMohrCoulomb criterion islinear.ThevalueofτsmobtainedfromSheorey’scriterionwas increased by 10%and that ofϕOmwas reducedby5°foruseasMohrCoulombcriterion.ConsideringlargenumberofIndiancasestudies,MuraliMohanetal(2001)prescribedthatthevaluesdeterminedbyabovementionedmethodcanbesafelytakenformodelling.

Usingthecompressivestrengthofintactcoalspecimenas42MPa,tensilestrengthof5MPaandRMRof56,theMohrCoulombequivalentcohesioniscalculatedas1.33MPaandangleofinternalfrictionas29.38degrees.

5.4 model result of re-orientation of development Working

Plot of the factorof safety contourson the skinof theexcavations during development showsmajor roofproblems,whenoneofthestressesisparalleltoeitherofthegalleries(seethestressblockinFigure8);theareaoftheroofiscompletelyfilledwiththeFOScontoursfallingintherangeof0to0.7(Figure8)indicatingdirectionalfailure.ThissituationisapplicabletoboththeCase1andCase2.

Fig. 7:SchematicofusingequivalentMohrCoulombCriterionoftheSheorey’sCriterion.

Fig. 8 :Plotoffactorofsafetycontoursontheskinofexcavations duringdevelopment,forthecase,whenoneofthemajorhorizontalstressisparalleltotheeast–westgallery.



But in theCase3,when themajor principal stress isorientedattotheworking,theroofproblemdiminishesrapidlyasseeninFig.9.

6. CONCluSiON

ThewedgeanalysisoftheTandsiminerevealsthattheexistingjointsetshaveminimaleffectontheinstabilityoftheroof.Infactthewedgesextendintotheroofupto0.38mandminimal roofboltingcanprovidesufficientstabilityoftheroof.However,inactualtheroofisfoundtobequiteunstableeven for rockboltsof lengthupto1.8minlength.Thereisnoreportofblastingdamageorthedelayinsupportinstallation.Thiscallsforattentiononother factor i.e. the stress related instability of thegalleriesatTandsimine.DetailednumericalmodelingoftheTandsiminerevealsthefollowing:

(a) Plot of factor of safety contours on the skinof excavations during development, for thecasewhenoneof themajor horizontal stresscomponents isparallel to the levelgallery, thedip–risegalleryexperiencemajorroofproblems(Figure8).

(b) Plotoffactorofsafety,contoursontheskinofexcavationsduringdevelopment, for thecase,whenoneofthemajorhorizontalstressisat450 tothelevelgallery.Showsreducedroofproblemsin both level as well as dip – rise galleries (Fig.9).

Re-orientationofthedevelopmentworkingsoftheminewith respect to the direction of the in-situ stress canresolve the stress governed failure in the roof of thegalleries.

rEFErENCES1. Anireddy,H.R. andGhose, A.K.(1994). Determination

of In-SituHorizontalStressesbyHydraulicFracturing inUndergroundCoalMines, Journal ofMinesMetals andFuel,July1994,pp145-155.

2. Barton,N.R.(1974).AReviewoftheShearStrengthofFilledDiscontinuitiesinrock.NorwegianGeotech.Inst.Publ.No.105.Oslo:NorwegianGeotech.Inst.

3. Bigby,D.N.;Cassie,J.W.andLedger,A.R.(1992).AbsoluteStressandStressChangeMeasurementsinBritishCoalMeasures, Proceedings of ISRMConference onRockCharacterization,Eurock’92,pp390-395.

4. Dolinar,D.R.(2001).VariationofHorizontalStressesandStrains inMines inBeddedDeposits in theEasternAndMid-WesternUnitedStates,22ndInternationalConferenceonGroundControlinMining,pp178-185.

5. Dolinar,D.R.;Mucho,T.P.andOyer;D.C;(2001).AdvanceandRelieve”Mining,aMethodtoMitigate theAffectsofHighHorizontalStresses in theMineRoof,SMEAnnualMeeting,Feb26-28,Denver,Colorado,Preprint01-113.

6. Goodman,R.E.andShi,Gen-hua.(1985).BlockTheoryanditsapplication.PrenticeHallInc.,EnglewoodCliffs,NewJersey.ISBN0–13–078189–7.

7. Gale,W.J. andFabjanczyk,M.W. (1991).Strata controlutilizingrockreinforcementtechniquesinAustraliancoalmines,Symposiumonroofbolting,Poland,pp.362–373.

8. Hoek,E.andBrown,E.T.(1980).UndergroundExcavationsInRock,InstitutionofMiningandMetallurgy,1980,pp100,183-241.

9. Kushwaha,A.;Singh,S.K.;Tewari,S.;SinhaA.(2010).EmpiricalApproach forDesigningofSupportSystem inMechanizedCoalPillarMining. International Journal ofRockMechanicsandMiningSciences,47(7).pp.1063-1068.

10. Murali,MohanG.; Sheorey, P. R. and Kushwaha, A.(2001)Numerical Estimation of Pillar Strength inCoalMines.InternationalJournalofRockMechanicsandMiningSciences,38(2).pp.1185-1192.ISSN1365-1609

11. ReportonRMRTandsiMine,WCLNagpur.12. Sengupta, S., Sinha, R.K., Subrahmanyam,D.S. and

Joseph,D.(2011)‘InvestigationintotheCausesofSevereRoofProblemsinsomeIndianCoalMinesandformulationof Guidelines to ReduceGround Control Problems’,Int. J.Mining andMineral Engineering, Vol. 3, No. 4, pp.290–302.

13. Sengupta,S.;Chakrabarti,S.;Gupta,R.N.;Subrahmanyam,D.S.;Joseph,D.;Sinha,R.K.;Kar,A.;Sanyal,K.;Prasad,B.; andWanarey, R.M. (2004). Measurement of in-situStress byHydrofracMethod and Investigations onRedistributionofin-situstressduetolocalTectonicsandmethodsofworkingatTandsiandThesgoramines,WCLtodeviseasuitablesupportplanSSR.ACoalS&TProject,fundedbyCoalS&TgrantofMinistryofCoal,Govt.ofIndia,Projectno.MT–117.

14. Sheorey,P.R.(1997).EmpiricalRockfailurecriteria,A.A.Balkema,Rotterdam.

15. Venkateswarlu,V.;Ghose,A.K.;Raju,N.M.(1989).Rock-massClassificationforDesignofroofSupports-AStatisticalEvaluationofParameters,MiningScienceandTechnology,Volume8,Issue2,March1989,Pages97-107,ISSN0167-9031,DOI:10.1016/S0167-9031(89)90507-0.

Fig. 9 :Plotoffactorofsafety(FOS)contoursontheskinofexcavationsduringdevelopment,forthecase,whenoneofthemajorhorizontalstressisattooneofthegallery.Shows

reducedroofproblemsinbothgalleries.

24


1. iNTrOduCTiON

InIndia,thegrossreservesofcoalarepresentlyestimatedataround293.49Billiontonnes(Bt)uptothemaximumdepth of 1200mwith proven reserves of 118.14Bt,sufficient to last thenext century at anannual rate ofproductionofover1180Mtatpresentlevelofextraction(Anon, 2012). The demand of coal in the country isincreasingyearbyyearasenergysourcesfromdifferentindustries.With the increasing demandof coal,moremechanizedopencastminesarecomingup.However,atpresentonly38%ofIndiancoalreservesismineableby opencastmining within economic limit whereasthe remaining62% is to beexploitedbyundergroundmining(Singhetal.,2004).Theshareofundergroundcoalproductioninthecountryhasdeclinedfrom73%in1974-75to10%in2011-2012.Forahealthyandbalancedgrowthofcoalminingindustryinthecomingdecade,itisessentialthatundergroundproductionshouldincreaseatamorerapidrate.Thisispossibleonlybyintroducingextensivemechanization in undergroundmines andadoptingnewtechnologies.

About50%ofcoalreservesinIndiaareinseamsthickerthan4.5m,whichcomeunderthecategoryofthickseams,theexploitationofwhichisconsistentlyposingchallengesto theminingengineers.Extractionof thick seamsbyconventionalhandsectionmethodisneitherproductivenor effective from the conservationpoint of view.Thepercentageofextractionbyhandsectionmininginthick

StRata MonItoRInG StudIeS In BlaStInG GalleRY Panel duRInG dePIllaRInG BaSed on FIeld

InStRuMentatIonS. kumar reddy

National Institute of Rock Mechanics

V.r. Sastry National Institute of Technology Karnataka, India

A challenging task for mining professionals is to extract natural resources like coal from underground with utmost safety. The challenge becomes more when the thickness of coal seam is high. Blasting Gallery (BG) method of depillaring thick coal seam is one of the productive method with favourable economics, high production and productivity. In this method, stability of workings and easily cavability of goaf is very important for safely extraction of pillars, safety of men and machinery. In this paper, strata monitoring data of a blasting gallery panel is analyzed for the stability of pillars and workings in a Blasting Gallery panel during depillaring in specific geo-mining and working conditions of a underground mine in Southern part of India.

Keywords: Underground coal mining, Thick seam mining, Blasting Gallery method, Strata monitoring studies.

seamsisaslowas25-30%.Lotofgoodgradecoalhasbeen lost andmillion tonnes of coal are standing onpillars.Sandstowingforworkingofthickseamscannotbeconsideredasanoptionbecausethecostisprohibitive.Sand has becomean increasingly scarce commodityalongwith timber.At thesame time, thecoal industrywasinsearchofaneconomicmethodtoachievehigherpercentageofextraction(70–85%)andneedsasuitabletechnologytoovercometheproblemsintheextractionofthickseamsbyconventionalbordandpillarmethod.

Charbonnage de France (CdF) suggested BlastingGallery(BG)methodforextractionofvirginthickseamsaswellasdevelopedpillarsinthickseams.ThefirstBGpanelwasstartedinthecountryatEastKatrasCollieryinJhariaCoalfield(BCCL)andChora-10PitCollieryinRaniganjCoalfield(ECL)intheyear1987incollaborationwithFrance.Duetostrataproblems,themethodwasnotsuccessful atEastKatrasCollierywhereoverridingofthepillarsoccurredinonepanel.WhereasatChora-10PitColliery, themethodwaspartiallysuccessfulgivingencouragingresults.However,theexpectedproductionandpercentageofextractioncouldnotbeachieved inboth themines (Pandey et al., 1992). TheSingareniCollieriesCompanyLtd.(SCCL)adoptedthismethodintheyear1989atGDKNo.10Inclineforextractionofcoalinvirginarea.Themethodwasverysuccessfulresultingin85%ofextractionwithhighproductivity(SCCLinternalreport,2005).Realizingtherateofsuccess,BGmethodofextractionisgearingupitsfuturepotentiality.

25



The soft nature of coalmass and presence of easilycaveableoverlyingroofstrataplayacrucialroleforthesingleworking of a thick coal seam.However, both,the coalmassand the roof strata of Indian coalfieldsare, relatively, strong andmassive.Here location ofa prominent parting planewithin the roof strata playsan important role in estimating the void between thecavedwastes and overhanging roof inside the goaf.For these strata conditions, the valueof limiting spanof the overhang, generally, remains high,whose fallmanifestsdynamicloadingoverpillarsfacinggoafline.Due to increased height of the void to be filled, theproblems associatedwith the dynamic loading needspecialattention forsuccessofsingle liftworkingofathickcoalseam.So,BGpanelsneed tobemonitoredwithinstrumentsforcompleteextractionofpanelswithsafetywithout any strata problemby takingprotectiveand precautionarymeasures beforehand. This paperdiscusses stratamonitoring experiences ofBGpanelduring depillaring in a given geo-mining andworkingconditions.

2. BlASTiNG GAllErY mETHOd (BG)

In brief themethod involves splitting along level ofdevelopedpillarsinthebottomsection,intotwoorthreerectangular stooks (Fig. 1) andadequately supportingwidenedgalleries byhydraulic propsand roof bars atleasttwopillarsaheadofthepillarunderextraction.ThestooksareextractedbydrillingaringoflongholesuptothefullseamthicknessbyJumbodrillsandblasting.Theblastedcoal from thegoaf is loaded through the levelgalleries/splitsbyremotecontrolled load-haul-dumpers(LHD).LHDsdischargethecoalintothearmouredchainconveyorssetwithin100m from theextraction line foronwardtransporttoasmallbunker.

2.1 Preparatory Work

The galleries in the panel arewidened to 4.8mandheightenedto3mforefficientmanoeuvrabilityofLHDsand drill jumbos, and galleries upto two pillars of thelineofextractionaresupportedby40tonneopencircuithydraulicprops.Thepropsaresetatanintervalof0.7msuchthataclearspaceof4.2mwasavailableforafreemovementofthemachines.ThemethodofsupportofgalleriesandjunctionsinthepanelisshowninFig.2.Onechainconveyorinlevelisinstalledforcoaltransporttoabunker.

Fig. 1:TypicallayoutofBlastingGallerymethodinundergroundcoalmine.

2.2 method of Extraction

Initially,thepillarsaredividedbydriving4.8mx3mlevelsplitgalleries.Thesplittingofpillarsisrestrictedtotwopillarsaheadofthelineofextraction.Adiagonallineoffaceismaintainedatabout600.

Whileretreating,thegalleriesarewidenedonboththesidesbydrillinglongholesinaringpatternuptothefullthicknessoftheseamandblasting.Holes(42mm)aredrilledatanangleof300towardsthegoaf.Theringsofholesarespacedat1.4m.Onlyoneringisdrilledandblastedatatime.Drillingisdonewiththeroofsupportbutthesupportsarewithdrawnjustbeforetheblasting.ThepatternofdrillingisshowninFig.3.

Fig. 2 :Junctionandgallerysupportinbottomsectionattheworkingface(Guptaetal.,1990).

Aspecial lowstrengthexplosive isused in longholeshavingtherequirementofupto2kgperhole.Aspecialnon-incendive detonating cord is used in long holes.HallowPVC tube spacers, 50 cm long, are used toseparate the charge in the shot holes.A hollowPVCsleevecontaininganexplosivecartridgewasinsertedat

Fig. 3 :Ringholeblastingpatternandchargedistribution

27Strata Monitoring Studies in Blasting Gallery Panel During Depillaring Based on Field Instrumentation


onemetreinsidetheholefromthemouthwhichcontainedtheendofthedetonatingfuseattachedwithanelectricdetonatorasshowninFig.4.About1mlongclayplugwasprovideduptothemouthoftheholeintheconventionalway.Aftercharging,blastingiscarriedout.Theblastedcoalinthegoafwasloadedbyelectro-hydraulicremotecontrolledLHDs.Theremotecontrolwaspneumaticallyoperated.TheLHDtravelledfromgoafedgetotheloadingpointanddischargedontoarmouredchainconveyor.

40mandbetweenNo.3SeamandNo.4Seamis4.5mto5.5m.Blastinggallerytechnologyisintroducedandpractisedin3Seam.Theseamno.3isdippingatabout1in5.2liesat321to348mdepth.The10.97mthick3seamisbeingworkedinthebottomsectiontoaheightofabout3malongthefloor,leaving1.5mthickcoalinthebottom,andareaofthepanelis17369m2consistsof6pillarswith50x60msize.Itisoverlainbyamediumgrainedwhitesandstoneby23.16mthickformsthemainroof.TheunderlyingNo.4seamwasunmined.Thepanelworkingswereobservedfreeofwater.Otheroverlyingseamswerefoundtobenon-commercial(Fig.5).TheBGpanel-3B,isselectedforthepresentinvestigations.

2.3 Advantages with BG method

TheadvantagesofBGmethodinclude;

1. Extractionof5-12mthickseamsinasingleslicebycaving.

2. Extractionofsmallsizepanelsnotsuitableforlongwallmethod.

3. Extractionofhardcoalsnotsuitableforploughsandshearers.

4. Higherproductionandproductivity.5. Lesscapitalintensivecomparedtolongwall.6. Lessskilledmanpower isneededascomparedto

longwall.7. IncaseofBGfailure,theequipmentcanbeusedfor

headingdrivages.8. The workers/operators are always under the

supportedroof.

3. FiEld iNVESTiGATiONS

The investigationswerecarriedout inanundergroundcoalminewithcoal formationsofKamthiandBarakarseries located in Southern India. Three seams areoccurringinthemineviz.,3ASeam,3Seamand4Seam.ThepartingbetweenNo.3ASeamandNo.3Seam is

Fig. 4 :Chargingdetailsinringholes(SCCLinternalreport,2005).Analready-extractedpanelwas lying towardsnorthernandwesternsideofPanel-3B,whereastowardsthesouthsideandeastern,therewasavirginpanel(Fig.6).Theimmediateoverlyingstratawereobservedtobestrongandmassivewithacaveabilityindexofmorethan2915(NIRM,1999).Thepresenceofadifficultroofoverthenearly11mhighvoidinthegoafcreateddifficultconditionsforpillarminingthetotalthicknessoftheseaminasinglelift.TheincreaseingoafheightduetoroofcoalextractionbyBGmethodwasobservedtobeofconsiderableimportanceforstabilityofthepillars.Therewasaremarkablechangeinthewidth/heightratioofthepillarswhichfacedthegoafoftheadjacentminedpillars(RajendraSingh,2004).

Fig. 5 :BoreholesectionNo.441,GDK-10Incline,SCCL.

Fig. 6 :PlanofPane-3B



Initially,50mx60mpillarsweredividedintothreehalvesbydriving4.8mx3mlevelsplitgalleries.Thesizeofstooksaftersplittingwas15.2mx50m.Thesplittingofpillarswasrestrictedto2pillarsaheadofthelineofextraction.A diagonal line of facewasmaintained atabout600.

3.1 Safety Factor of the Pillars

Under normal pillar extraction condition, the localminestiffnessremainsmoreorlessconstantwhilethereductioninpillarstrengthwiththereductioninpillarsizegeneratesasituationconducivetoviolentfailure.Here,increasingtheextractionratiobysplitting/stokingofpillarsaheadofthefacemaybedangeroustotheworkingarea.Laboratoryscalespecimensbecomeelasto-plasticwhenwidth/heightratiosapproach8(Das1986).Inaccordancewith the field data available for the actual failure of apillars(Sheorey1993),thepostfailuremodulusofapillarwithwidth/heightratioabout4becomespositiveanditsbehaviourchangesfromstrain-softeningtoelasto-plastic.Fortunately, theBG does not involve the process ofsplitting/stokingaheadoftheface,exceptforsplittingandslicingthepillarsbeingextracted.Undertheseconditions,thechanceoftheviolentfailureofapillarbecomeslowand is limited to thepillar beingextracted.The safetyfactorofthepillarsofpanel-3Bremainsnearly2.33fornormalheight(3m)pillarextraction,whilethesameforfull-heightworkingoftheseambytheBGmethod(11m)withdoublesplittinggoesbelowone.

Table 1: Pillarsizevariationasperregulation99ofIndianCoalMiningRegulations,1957(CMR1957).

depth cover (m)

Pillar size (center to center) for different gallery widths (m)

3.0 m 3.6 m 4.2 m 4.8 m

<60 12.0 15.0 18.0 19.5

60-90 13.5 16.5 19.5 21.0

90-150 16.5 19.5 22.5 25.5

150-240 22.5 25.5 30.5 34.5

240-360 28.5 34.5 39.5 45.0

>360 39.0 42.0 45.0 48.0

Pillars formed (Table 1) in accordancewith theCoalMiningRegulations possess adequate safety factorsandahighw/h ratiowhich sustain thevariousminingconditions resulting from pillar extraction at normalheights.However, there is an indirect increase in theheightofpillarsduetothewinningoftheroofcoalbytheBGmethod(Singhetal.,2007).TheprocessofroofcoalwinningaffectsthestabilityofpillarsdesignedfornormalheightworkingsdevelopedinaccordancewiththeCoalMiningRegulations.

3.2 Strata monitoring

Field instrumentationwas carried out in panel-3B tostudystressdistributioninthepanel,loadonhydraulicpropsingalleries,convergenceingalleries,rooflayersmovementandstresschangeinthepanel.Detailsoffieldinstrumentationprogrammearegivenhere(Fig.7):

• Stress measurements in BG workings.Fivevibratingwirestresscells,S1at66BLN/39D,S2at67LS/39D,S3 at67ALS/39D,S4at68ALS/39DandS5at68BLS/39D,wereinstalledintheBGpanel.

• Load over O.C. props in galleries.VibratingwireloadcellswereinstalledontheO.C.hydraulicprops,till10maheadofworkingfaceingalleries.Recordingsfromloadcellswereobtainedatevery10minterval.Loadcellswereshiftedtonewstationsafterevery10moffaceretreatinthegalleries.

• Convergence in gate roads.Rooftofloorconvergencewasmonitoredatevery10mintervalingalleriesusingtelescopicconvergenceindicators.

• Immediate roof layers movement. Three Tell-taleextensometers,T1at66L,T2at67LandT3at68L,wereinstalledinthejunctionsoftheBGpanel.

4. rESulTS ANd diSCuSSiON

4.1 Stress Variation Over the Pillars

Themeasurementsobtainedfromvibratingwirestresscells at 66BLN/39D (S1), 67LS/39D (S2), 67ALS/39D(S3),68ALS/39D(S4)and68BLS/39D(S5)arepresented

Fig. 7:Locationofdifferentmonitoringinstruments.



inFig.8and9.Variationofstresswasfoundinallcellsanditsmagnitudeincreasedastheareaofextractionincreasesandthefaceretreatedclosertothestation.Itcanbeseenthatthestresscell(S1) recordedhigherstresscomparedtootherstresscellsinstalledinthepanel-3B.Thereasonscouldbethelargeoverhangsingoaftowards66ALNorth,66BLNorthand67LNorthandnearertothegoafedgedistancecomparetotheotherstresscellsinthepanel.

observedonO.C.propsindicatedtheoccurrenceofrooffallinthegoaf,duetoinducedblastingpractices.Afterthat, increase in loadwasobservedwith respective toareaofextractionof27tfor7000m2,28tfor8000m2,32tfor8600m2and39tfor10060m2.Theserecordingsshowedregularincreaseinload,indicatingperiodicbuild-upofloadongalleries,andincreaseinloadmaybeduetonon-cavingofgoaf.O.C.

FurtherO.C props experienced higher loads in 66ALNorth, 66BLNorth, 67L and 67AL South, and loadvariesfrom30t-39t.Thepanelexperiencedsupportsdisplacements ingalleriesof66ALNorth,66BLNorth,67Land67ALSouth.

0

1

2

3

4

5

3500 5500 7500 9500 11500

Incr

ease

in st

ress

(MPa

)

excavation area (m2)

66BLN/39D

67LS/39D

67ALS/39D

68ALS/39D

68BLS/39D

0

1

2

3

4

5

020406080100

Incr

ease

in st

ress

(MPa

)

Goaf edge distance (m)

66BLN/39D

67LS/39D

67ALS/39D

68ALS/39D

68BLS/39D

Fig. 8 :Stressrecordingswithrespectivetoareaof exxtractioninPanel-3B.

Fig. 9 :Stressrecordingswithrespectivetogoafedge distanceinPanel-3B.

4.2 load Variation in the Galleries

The loadoverO.C. propswas recordedduring panelextraction.Initialloadinalltheloadcellswasmaintained5t.Thechangeinloadwascalculatedbasedonfinalloadrecordedbefore the removalofO.C.propas faceapproached it. ThechangeinloadofO.C.propswithrespectivetoareaofextractionofPanel-3BispresentedinFig.10.Therewasanincreaseinloadof22toverO.C.propsfortheinitialareaofextractionofabout4000m2and32tforfurtherareaofextractionofabout5300m2inthepanel.

Subsequently,noticeabledecreaseinloadof25toverO.C.propswasobservedforfurtherareaofextractionabout 6200m2. Thus, the sudden decrease in load

Page 11 of 15

0

10

20

30

40

0 2000 4000 6000 8000 10000 12000

Max

. cha

nge

in lo

ad (t

)

area of extraction (m2)

with respective to area of extraction of Panel-3B is presented in Fig. 10. There was an

increase in load of 22 t over O.C. props for the initial area of extraction of about 4000 m2

and 32 t for further area of extraction of about 5300 m2 in the panel.

Subsequently, noticeable decrease in load of 25 t over O.C. props was observed for

further area of extraction about 6200 m2. Thus, the sudden decrease in load observed on

O.C. props indicated the occurrence of roof fall in the goaf, due to induced blasting

practices. After that, increase in load was observed with respective to area of extraction of

27 t for 7000 m2, 28 t for 8000 m2, 32 t for 8600 m2 and 39 t for 10060 m2. These

recordings showed regular increase in load, indicating periodic build-up of load on galleries,

and increase in load may be due to non-caving of goaf. O.C.

Further O.C props experienced higher loads in 66AL North, 66BL North, 67L

and 67AL South, and load varies from 30 t - 39 t. The panel experienced supports

displacements in galleries of 66AL North, 66BL North, 67L and 67AL South.

Fig. 10 load recordings in galleries in Panel-3B.

4.3 Convergence in galleries

Roof to floor convergence was monitored at 10 m intervals (i.e. station C1, C2, C3, C4, C5,

C6, C7, C8, C9 and C10) from goaf edge in each level of Panel-3B during depillaring.

The convergence in galleries with respective to area of extraction analysed during

depillaring in Panel-3B are shown in Fig. 11. Convergence is increasing with area of

extraction increased. Results revealed that all the stations that recorded cumulative

4.3 Convergence in GalleriesRooftofloorconvergencewasmonitoredat10mintervals(i.e. stationC1,C2,C3,C4,C5,C6,C7,C8,C9andC10) fromgoafedge ineach levelofPanel-3Bduringdepillaring.

Theconvergenceingallerieswithrespectivetoareaofextractionanalysedduringdepillaring inPanel-3BareshowninFig.11.Convergenceisincreasingwithareaofextractionincreased.Resultsrevealedthatallthestationsthatrecordedcumulativeconvergencehigherthan100mmwere experiencing large overhangs in goaf eventhoughinducedblastingpracticesingoaf.

Fig. 10:LoadrecordingsingalleriesinPanel-3B.

0

40

80

120

160

200

0 2000 4000 6000 8000 10000 12000

Con

verg

ence

(mm

)

excavated area (m2)

Fig. 11:Convergencerecordingsingallerieswith respectiveareaofextractioninpanel–3B.



4.4 immediate roof layers movementThetrendofimmediaterooflayerbedseparationchangerecordedinthepanel-3B.Themaximumbedseparationrecorded at 68L/39D junctionwas 3mmand 0mm,respectively,intheanchorplacedat7mand2m.Thisindicatesthattherewasnodeformationoftheimmediatecoal roof which forms themain roof, whereas, highdeformationswererecordedinconvergencestationsmaybeduetomassivesandstonelayersoverhang.

4.5 relationship between Change in Stress, load in Galleries and Convergence in the Panel

The recordings obtained from stress cells installed inpillars,convergenceingalleriesandloadcellsoverO.C.props in galleries of Panel-3B are shown in Fig. 12.All the instruments recordingvaluesshown increasingwith respective area of extraction in the panel-3B.Generalisationofrelationshipbetweenstresschangeinthepanel,convergenceingalleriesandloadsonsupportsmayrequirefurtherstudies.Establishingsuchrelationshiphelpsinsafelyworkingofthepanel.

0

20

40

60

80

100

0 2000 4000 6000 8000 10000 12000

Perc

enta

ge (

%)

area of excavation (m2)

Convergence in galleries Load on supports Stres change in the panel

Furtherstudyrevealedthatthepanelexperiencedheavyspalling and supports displacements in galleries of66ALNorth,66BLNorth,67Land67ALSouthasshown inFig.13(a,b,c&d).

Fig. 12 :Stresschangeinthepanel,convergenceingalleriesandloadsonsupportsinpercentagewiseinthepanel–3B

Fig. 13 :(a,b,c&d)Pillarspallingandsupportdisplacementsat66ALto67LNorthPillar

(a) (b)

(c) (d)



5. CONCluSiONS

PlanningandexecutionofBGpanelsrequiresdetailedaccounting for rockmass characterisation to be inputinitiallyandpredicttheactualbehaviourofpanelextraction.Fieldinstrumentationprovidesvitalinformationduringtheextractionprocess for takingnecessarydecisionsandprecautionstoavoidmajorobstaclesduringproduction.Thoughplanningbyvariousmodellingstudiesprovidesaninsightintothebehaviourofpanelduringextraction,the real-timemonitoring facilitates retrievalofvaluableinformationaboutthebehaviourofgalleries,pillarsandgoaf.Thisstudyinvolvedextensivefieldinstrumentationtounderstandthebehaviourofstrataatdifferentlocationswithinthepanel.

Resultsrevealedthattheareaofextractionwashavingan influenceon front abutment stresses, convergencein galleries and loadson supports aheadof the face.Further, it was observed that, total increase in frontabutmentstress,about3.04MPawasnoticedwhentheareaofexcavationwas6200m2 inthepanel.LoadonO.C.props increasedup to39 t, indicating transferofload ahead of face.Galleries experiencedmaximumcumulativeconvergenceof151mm.Convergenceinthegalleriesincreaseswithrespectivetoareaofexcavation.Tell-tale extensometers indicates that therewas nodeformationoftheimmediatecoalroofwhichformsthemain roof,whereas,highdeformationwasrecorded inconvergencestationsmaybeduetomassivesandstonelayersoverhang.

Itmaybe concluded thatwhen the largeoverhang ingoafispresent,highstressinpillars,highconvergenceingalleries,highloadsingalleriesandspallinginpillarsisexpected.TheresultsobtainedfromfieldmonitoringstudieswerequitecomparablewiththefieldconditionsinBGpanel,likespallinginpillarsanddisplacementofsupportsingalleries.Adoptionoffieldinstrumentationinpanelscould,therefore,beofsignificantvalueinassessingthebehaviourofBGpanelsduringextraction.

Acknowledgement: Author is thankful to SCCL forcarryingout theprojectandsincere thanksaredue toDirector,NIRM, for permission to submit the paper injournal.

rEFErENCES

1. Anon, 2012. Coal reserves statistics, CentralMinePlanning & Design Institute Limited (CMPDI), http://www.cmpdi.co.in/.

2. CMR,1957.TheCoalMinesRegulations.InKaku(ed.),Dhanbad,Lovelyprakashan.

3. Das,M.N.1986.Influenceofwidth/heightratioonpostfailurebehaviourofcoal.InternationalJournalofMiningandGeologicalEngineering.4:79-87.

4. Gupta,R.N.,Garg,A.K.,Mukherjee,K.P.,andSingh.B. 1990. Strata control problems associated duringextractionofdevelopedPillarsinThickSeambyBlastingGallerymethod.RockMechanicsContributions andChallenges,Hustrulid&Johnson(ed.)ISBN9061911230.109-117.

5. SCCLInternalReportonBGmethod,2005.

6. NIRMfinalreport.1999.Studyofcavabilityofroofof3seamatGDK-10Incline,RG-111Area,SCCL.

7. Pandey,B.N.,Prasad,S.N.,Mukherjee,K.P.,Tiwary,S.,Samanta,S.,andSaxena,N.C.,1992.ExperiencesofBlastingGallerymethodofThickSeammininginJhariaandRanigunjCoalfield.ProceedingsofSymposiumonThickSeamMining,India,409-421.

8. RajendraSingh,2004.Staggereddevelopmentofathickcoalseamforfullheightworkinginasingleliftbytheblastinggallerymethod.InternationalJournalofRockMechanicsandMiningSciences, 41,January,pp745-759.

9. Sheory,P.R. 1993.Designof coal pillar arrays andchain pillars. InHudson (ed.),ComprehensiveRockEngineering.Oxford:PergamonPress,vol.2,pp.631-670.

10.Singh,R.,Ahuja,B.P.,Guruvaiha,K.,andRamesh,M.,2004.Geo-technical considerations for full heightextraction of a developed Thick Coal seam withstaggeredbottomsectionbyBlastingGallerymethod.MGMITrans.100:102-116.

11.Singh.R.,andKumar.R.2007.Pillar stabilityduringundergroundminingofthecompletethicknessofathickcoalseaminasinglelift-Indianexperiences.Eberhardt,Stead&Morrison(ed.),pp.1463-1468.



MR. deVendRa k. ShaRMa aSSuMeS the ChaRGe oF ManaGInG dIReCtoR oF

hIMaChal PRadeSh PoweR CoRPn. ltd.Mr.DevendraKumarSharma, has takenover asManagingDirector ofHimachalPradeshPowerCorporationLtd.(AGovt.ofHimachalPradeshUndertaking)inSeptember,2012.AsManagingDirectorofHimachalPradeshPowerCorporationLtd.,heisresponsibleforplanning,development,engineering,constructionandorganizingfundingfor20hydroelectricprojectshavingaggregateinstalledcapacityof3025MW.

AftergraduatinginCivilEngineeringfromtheUniversityofIndorein1981,hewasawardedtheNetherlandsGovt.fellowship,in1982,topursueMasterofEngineeringinWaterResourcesfromtheAsianInstituteofTechnology,Bangkok,Thailand.Hehasdonetraininginhydropowerplanning anddesign engineering fromCanada (1987),Sweden (1989) and Japan (1994).During theyear1991,hewasawardedUNESCOfellowship tocomplete InternationalPost

GraduateCourse inHydrology from theWaterResourcesResearch Institute (VITUKI),Budapest,Hungary.HedidcoursesfromtheInternationalCentreforHydropower,Trondheim,NorwayasNORADScholarin‘HydropowerandtheEnvironment’during1999and‘HydropowerDevelopmentintheContextofIntegratedWaterResourcesManagement’during2003.

Mr.Sharmahasmorethan31yearsofexperienceinthefieldofhydropowerinIndiaandabroad.HeworkedwithHimachalPradeshStateElectricityBoardinvariouscapacitiesforapproximatelytwentyfourandhalfyearsfrom1982to2006wherehewasresponsibleforplanning,investigation,designandmonitoringofnumberofhydroelectricprojectslikeChameraStageII(300MW),KolDam(800MW),DhamwariSunda(70MW),GhanwiStageI(22.5MW),Gaj(10.5MW),Baner(12MW)andThirot(4.5MW).HehasworkedondeputationwithSJVNL(formerlyNJPC)forNathpaJhakriHydroelectricProject(1500MW)from1994to1997.HeworkedinBhutanonTalaHydroelectricProject(1020MW)forconstructionofdam,diversiontunnel,cofferdamsandpowerintakesfor6yearsfrom1997to2003wherehewasawarded“ManoftheYear1999”awardforexcellenceinperformanceofduties,dedicatedservicesandmeritoriouscontributioninthefieldofhydropower.AfterreturningfromBhutanduringtheyear2003,hewasresponsibleforSawraKudduHydroelectricProject(111MW)inPabbarValleyPowerCorporationinHimachalPradesh.

Inordertogainexperienceofworkinginprivatesector,heworkedwithL&Tfrom2006toMay,2010,wherehecompletedworksofParbatiStageIII(520MW)andAllainDuhangan(192MW)HydroelectricProjectsinHimachalPradesh.FromMay2010toSeptember,2012,hewasresponsibleforDevelopmentofHydroelectricProjectsonBOTbasisinIndiaandtheneighbouringcountries.

Mr.Sharmahaspresented26 technicalpapersandreports in InternationalConferences/Seminars in Indiaandabroad.HehasvisitedhydropowerplantsinThailand,Norway,Sweden,Canada,Japan,Hungary,Austria,Spain,Portugal,BhutanandNepal.

Mr.SharmaislifememberofvariousNationalandInternationalbodiesworkinginthefieldofhydropowerdevelopment.HeisamemberofGoverningCouncilofInternationalSocietyforRockMechanicssince2008andisVicePresidentofIndianSocietyofRockMechanicsandTunnellingTechnology.HeisGoverningCouncilmemberofTunnellingAssociationofIndiafortheyear2011-13.HehasrepresentedinTechnicalandOrganizingCommitteesofvariousInternationalandNationalConferencesorganizedinthefieldofhydropower.

ISRM(India)wisheshimallsuccessforhisnewassignments.

32



GoVeRnInG CounCIl oF IndIan natIonal GRouP oF ISRM

FoR the teRM 2011-2014

President

• Dr.H.R.Sharma,ChiefTechnicalPrincipal–Hydro,TractebelEngineeringPvt.Ltd.

Vice President

• Dr.R.K.Goel,ChiefScientist,CentralInstituteofMiningandFuelResearch,RegionalCentre,Roorkee

immediate Past President

• Dr.K.G.Sharma,Professor,DepartmentofCivilEngineering,IITDelhi

members

• Dr.A.K.dhawan,ChiefConsultant,FugroGeotechPvt.Ltd.

• Mr.D.P.Goyal,Director,JaiprakashPowerVenturesLtd.

• Mr.R.Jeyaseelan,FormerChairman,CentralWaterCommission

• Mr.PawanKumarkohli,GeneralManager(CivilDesign),HimachalPradeshPowerCorporationLimited

• Mr.D.M.kudtarkar,ChiefTechnologyOfficer,HindustanConstructionCompanyLtd.

• Mr.P.K.mahajan,VSM,ChiefEngineer,DirectorateGeneralBorderRoads

• Mr.Ganeshmanekar,DeputyGeneralManager(Mines),MOILLimited

• Mr.R.N.misra,Director(Civil),SJVNLimited

• Dr.A.Nanda,DeputyGeneralManager,EngineersIndiaLimited,SubSurfaceProjectsDivision

• Mr.A.B.Pandya,Member(D&R),CentralWaterCommission

• Dr.RajbalSingh,JointDirector(RockMechanics),CentralSoilandMaterialsResearchStation

• Dr.T.ramamurthy,VisitingProfessor,DepartmentofCivilEngineering,IndianInstituteofTechnologyDelhi

• Dr.S.Sengupta,Scientist–V&HOD(GeotechnicalEngineeringDepartment)andScientist-in-Charge-BangaloreUnit,NationalInstituteofRockMechanics

• Mr.D.K.Sharma,ManagingDirector,HimachalPradeshPowerCorporationLimited

• Dr.T.G.Sitharam,Professor,IndianInstituteofScience,DepartmentofCivilEngineering

• Dr.ManojVerman,TechnicalDirector,GEODATAIndia(P)Limited

• Mr.R.K.Vishnoi,GeneralManager(DE&S–Civil),THDCIndiaLtd.

member Secretary

• Mr.V.K.kanjlia,Secretary,CentralBoardofIrrigation&Power

Treasurer

• Mr.A.C.Gupta,Director(WR),CentralBoardofIrrigation&Power

33



Aspart of its activities,CBIP,with the support of theIndian National Group of International Society forRockMechanics (ISRM, India) and IndianChapter ofInternationalGeosyntheticsSociety(IGS,India)organizedaSeminaron“GroundControlandImprovement”atCBIPConferenceHall,MalchaMarg,Chanakyapuri,NewDelhiduring20-21September2012.

TheobjectiveoftheproposedSeminarwastoprovidea forum for discussion and interaction amongst theparticipants about the potentially applicable groundimprovementmethodsforcivilworksstructures.

Lectures/CaseHistories on the following topicswerepresentedduringtheSeminar:

• CharacterizationofGround

• PreloadingandVerticalDrains

• InsitureinforcementTechniques

Recent Activities of Indian National Group of ISRM

SeMInaR on “GRound ContRol and IMPRoVeMent”, 20-21 SePteMBeR 2012, new delhI

• GeosyntheticsandtheirapplicationsinGeotechnical&GeoenvionmentalEngineering

• DeepExcavationSupportSystems

• Grouting Techniques: Permeation, Compaction,Infiltration,JetGrouting,etc.

• Landslides&SlopeStabilisationMethods

• Soil&RockAnchors

• Liquefaction&MitigationMethods

The Seminar was sponsored by PANASIA ProjectConsultancyPvt.Ltd.&Wassaraandco-sponsoredbyTechFab(India)IndustriesLtd.

TheSeminarwas attended by 61 delegates from24organisations.

The Seminar was inaugurated byMr. S.P. Kakran,Chairman,CentralWaterCommission. The inaugural

34

35Recent Activities of Indian National Group of ISRM


sessionwaspresidedoverbyDr.H.R.Sharma,ChiefTechnicalPrincipal-Hydro,TractebelEngineeringPvt.Ltd.andPresident,IndianNationalGroupofISRM.Dr.G.V.Rao,FormerProfessor,DepartmentofCivilEngineering,IITDelhiandPastPresidentoftheIndianChapterofIGS,addressedthegatheringtoo.

Lectureswere delivered by the following prominentexpertsduringtheSeminar:

• Mr.MichaelBeas,Wassara,Sweden

• Mr.Shadab.A.Gadhiya,TechFab(India)IndustriesLtd

• Dr.M.R.madhav,JNTUniversity&IITHyderabad

• Dr.K.Pathak,IITKharagpur

• Dr.V.M.Sharma,AIMILLimited

• Mr. R.K. Sinha , National Institute of RockMechanics

In this context, NHPC Limited, in association withCentralBoardofIrrigationandPower(CBIP),organizedan International Seminar on “MinimizingGeologicalUncertaintiesAndTheirEffectOnHydroelectricProjects”,on27and28September2012atCBIPConferenceHall,MalchaMarg,Chanakyapuri,NewDelhi.

Theprimeobjectiveoftheseminarwastodiscussissuesrelatedtoimprovingupongeologicalinterpretationsandsupplementationbygeotechnicalexplorations towardsformalizingacomprehensive investigationprogramaswellastobring-forthawarenessaboutthetechnologicaladvancementsandtheirapplications.

• Prof. G.L.Sivakumar Babu, Indian Institute ofScience

• Dr.G.V.ramana, Indian Institute of TechnologyDelhi

• Dr.G.Venkatappa rao,SaiMasterGeoenvironmentalServicesP.Ltd.

Itwas concluded that asmoreandmorepoor groundconditions were being encountered atmany of theinfrastructural development project sites, and posinggeotechnical challenges, theSeminar on the subjectof “Ground Control and Improvement” was aptlychosen. Itwas stressed that to keep pacewith rapidinfrastructure development, the concerned had tobe prepared to meet the emerging geotechnicalchallenges and provide superior and cost effectivesolutions,besidescompletingtheprojectsintimebound manner.

InteRnatIonal SeMInaR on “MInIMIzInG GeoloGICal unCeRtaIntIeS and theIR eFFeCt on hYdRoeleCtRIC PRoJeCtS”,

27-28 SePteMBeR 2012, new delhI

Thereisabroadfeelingthathydroelectricprojectstakelongertimethanthescheduleandthedelaysarecommonlyattributedtouncertaintiesingeologicalprognostication,withoutconsideringtheinherentlimitationsofsuchstudiesand the appliedmethodologies.Accordingly, in ordertominimizedelays, it ismandatory that thegeologicalandgeotechnical assessments aremadewith greaterreliability & precision towards establishment of safeandeconomicprojects.Itisthereforeimportanttoholdtechnicalforumtodeliberateuponthecriticalissuesinaddressingproblemsrelatedtogeological&geotechnicalconcerns towards finding appropriate solutions toovercomethechallenges.



The seminar focused on the issues and challenges inintegration of exploratory techniques for improving thereliability of geological assessment, and provided a forumto discussmatters of adoption of appropriate constructionmethodologies supplemented by contractual provisionrelated to geological information and sharing of risks thatare generally issues of concern. During the Seminar,issues related to generating structural geological modelsfor mechanized tunneling sites as well as the selectionof TBM types, specific for the site conditions, werediscussed.

Followingwere the topics proposed for discussions duringthe Seminar:

• Integrating Exploratory Techniques for ReliableGeological Assessment

• Provisions for Looking Ahead in Critical Areas inConstruction

• Importance of Slope Stability in HydroelectricProjects

• Role of Geology in Deployment of TBM

More than 140 delegates from India and abroadparticipated in the Seminar.

Lighting of Lamp by V.K. Kanjlia

During the Inaugural Session, Mr. D.P. Bhargava, Director(Technical), NHPC Limited, welcomed the dignitaries onthe dais and the participants.

Mr. A.S. Bakshi, Chairperson, Central ElectricityAuthority, in his address mentioned that geologicaluncertainties and unexpected strata encountered duringconstruction of tunnels and underground works ofhydropower projects, especially the large ones, result inunforeseen problems, increased quantities of execution,and time & cost overruns. He expressed the hope thatproject developers, contractors, consultants, engineers,suppliers, researchers who were attending the seminarwould be greatly benefited from deliberations regardingthe state-of-art technology and modern methodologyin overcoming challenges occurring due to geologicaluncertainties during the construction of hydroelectricprojects and thus minimize the cost overruns.

Mr. Devendra Chaudhry, Additional Secretary toGovernment of India, Ministry of Power, mentioned thatHydro Electric Projects having about 6000 MW potentialwere affected by geological problems at present, andexpressed the hope that the very purpose of the Seminarwould be not just to address a very large interesting andwider range of issues, but the focus should be to addresswhat were the problems in those projects.



Mr. R.P. Singh, Chairman and Managing Director, SJVNLimited in his address mentioned that when we look backupon the development of Hydro Power in general inour country in the past, it is observed that barring a fewprojects, all of them have suffered significant time andcost over-run and the major reason cited for it is widevariance between geology predicted at the DPR stageand as actually encountered during the construction ofunderground works, and expressed hope that the elitegathering present in the Seminar would be sharing thelatest development in the geological exploration fieldwhich would definitely help all the developers in havingbetter understanding of geology.

The keynote address on “Minimizing GeologicalUncertainties and their Effects on Hydroelectric Projects”wasdeliveredbyMr.M.Gopalakrishnan, FormerSecretaryGeneral, ICID, before the commencement of the technicalsessions. Mr. M. Gopalakrishnan emphasized need forissues like cost of investigations, time frame required forplanning to Design stage nature of tender documents.He mentioned that the Hydro Power sector should notbe singled out for failures as failures had been observedall over the world and in case of tunnels in other sectorssuch as transportation sector.

The presentations on the following topics were made anddiscussed during the Seminar:

• Geological Investigations – Challenges & Success -Mr. A.S. Walvekar, Executive Director (Geo-Tech),NHPC Limited

• Geotechnical Monitoring-Contribution to RiskManagement - Dr. Florian Krenn, Managing Director,Geoconsult India Pvt. Ltd.

• Optimum Exploration for a Bankable Detailed ProjectReport - Mr. Prasanta Mishra, Director, GeologicalSurvey of India

• Importance of Rock Mechanic Studies in SiteCharacterization towards Minimizing Uncertainties -

Dr. V. M. Sharma, Director, AIMIL Ltd.

• P rognos t i c Geo log i ca l Exp lo ra t i ons fo rMinimizing Geological Uncertainties - Dr. GopalDhawan, Chairman and Managing Director, MineralExploration Corporation Limited

• Minimizing Geological Uncertainties during theExecution Phase - Mr. Wolfgang Holzleitner, COO,Bernard Gruppe, Germany

• Integrating Exploration and Preparation of BaselineReport - Dr. Dinesh Sati, Consulting Geologist, THDCIndia Limited

• Geological Assessment through Integrated Approach– Mr. Umesh.V. Hegde, Executive Director-Engg.Geology & Geotech, Lanco Infratech Limited

• Geological Uncertainties-Site Specific Challenges andits Management - Mr. Manoj Basu, General Manager(Geology), NHPC Limited

• Contractual Problems due toGeological UncertaintiesandPossible Remediation throughContract –Mr. V.K.Kapoor, President-Projects, Bhilwara Energy Ltd.



• ManagingRisk due toGeologicalUncertainties inHydropowerProjects -Mr.EckhardKleine,SalesEngineer,HerrenknechtAG,Germany

• Geological Prognostication duringMechanizedTunneling–Dr.G.W.Bianchi,SeniorEngineeringGeologist,SEAConsultings.r.l.

• ApplicationofTunnelSeismicPrediction inVariedGeological Conditions - Dr. T. Dickmann, UnitManager-Geophysics, AmbergTechnologiesAG,Switzerland

• Minimizing Geological Uncertainties throughMitigatingMeasuresatNathpa-JhakriProject–Mr.DeepakNakhasi,GeneralManager (CivilDesign),SJVNLimited

• GeotechnicalPrognosticationduringConstruction–Dr.RajbalSingh,Scientist,CentralSoilandMaterialsResearchStation

• RoleofGeologyandSpecialRockMechanicTestsinTBMTunnelling-APerspective–Dr.V.M.S.R.Murthy,Professor,DepartmentofMiningEngineering,IndianSchoolofMines

• ConcurrentEvaluation&MeasuresAdoptedWhileTunnelingThroughTBM–Mr.MicheleA.Sposetti,IndiaProjectsCoordinator,S.E.L.I.Tunnelling(India)PrivateLimited

• ImportantAspectsforGeologicalAssessmentinTBMSelection-Casehistory-Mr.M.M.Madan,Director,GVKGroup

• CurrentPracticesinGroundImprovementandsupportMeasures inTBMdrivenTunnels throughDifficultGeologicalConditions -Mr. JamesClark,ProjectsManagerIndia,TheRobbinsCompany

• SlopeStability-IssuesandManagement–Mr.BalrajJoshi,GeneralManager,NHPCLimited

• IdentificationofPotentialSlidesandSupportSystems–Dr.R.Chitra,Scientist,CentralSoilandMaterialsResearchStation

TheSeminar concludedwithPanelDiscussions,withfollowingpanelofexperts:

• Dr. H.R. Sharma (Chairman), Chief TechnicalPrincipal-Hydro,TractebelEngineeringPvt.Ltd.

• Dr.V.M.Sharma,Director,AIMILLtd.

• Dr.PrabhasPande,FormerADG,GeologicalSurveyofIndia

• Mr.R.N.Misra,Director(Civil),SJVNLtd.

• Dr. FlorianKrenn,ManagingDirector,GeoconsultIndiaPvt.Ltd.

• Mr.A.S.Walvekar,ExecutiveDirector (Geotech.),NHPCLtd.

The panel of experts after having an overview of alltechnicalsessionsinitiateddiscussionswithinthehouse.Subsequenttovariousdeliberationsintheopenhouse,draftrecommendationsweremade.

SeMInaR on “SloPe StaBIlIzatIon ChallenGeS In InFRaStRuCtuRe PRoJeCtS”,

29-30 noVeMBeR 2012, new delhI

Aspartofitsactivities,theCentralBoardofIrrigation&Power (CBIP),with the support of the IndianNationalGroupofInternationalSocietyforRockMechanics(ISRM,India)andIndianChapterofInternationalGeosyntheticsSociety (IGS, India) organised aSeminar on “SlopeStabilizationChallenges in InfrastructureProjects” atCentral Board of Irrigation andPower,MalchaMarg,Chanakyapuri, NewDelhi on 29 and 30November2012.

TheobjectiveoftheproposedSeminarwastoprovideaforumfordesignandconstructionengineersforanalyzingthestabilityofslopesofearthandrock-filldams,slopesofother typesofembankments,excavatedslopes,andnaturalslopesinsoilandsoftrock,methodsforanalysisofslopestability,strengthtests,analysisconditions,andfactorsofsafety,useofgeosyntheticsforslopestability,etc.

TheSeminarwas inaugurated byMr.R. Jeyaseelan,Former Chairman, CentralWater Commission. TheInauguralSessionwaspresidedoverDr.T.Ramamurthy,VisitingProfessor,DepartmentofCivilEngineering,IITDelhi.

Mr.A.C.Gupta,Director (WR),CBIP, in hiswelcomeaddress stressed on the need to provide adequatedrainagewhich,ingeneral,shallhelpinminimizingfailureof soil/rock slopes.He requestedparticipants to haveusefulinteractionduringtheSeminar.

Dr.A.K.Dhawan,ChiefConsultant,FugroGeotechPvt.Ltd., andFormerDirector,Central Soil andMaterialsResearch Station and Seminar Coordinator brieflydescribed the objectives of the Seminar during theInauguralSession.



A view of the dais during inaugural session (L to R): Dr. A.K. Dhawan, Dr. T. Ramamurthy, Mr. R. Jeyaseelan

and Mr. A.C. Gupta

Panel Discussions (L to R): Mr. S.K. Raina, Mr. J.N.L. Das, Dr. T. Ramamurthy, Mr. R.K. Vishnoi and Mr. A.C. Gupta

Intotal,40participantsfrom26organizationsparticipatedintheSeminar.

FollowingpaperswerepresentedanddiscussedduringtheSeminar:

• SlopeStability-LessonfromFailuresEncountered–Mr.R.Jeyaseelan,FormerChairman,CentralWaterCommission

• StabilityProblemsinNaturalandManmadeSlopes–Dr.A.K.Dhawan,ChiefConsultant,FugroGeotechPvt. Ltd., and FormerDirector,Central Soil andMaterialsResearchStation

• RoleofGeoinformaticsinSlopeStabilityAssessmentandMonitoring –Dr. P.K.Champati Ray,Head,GeosciencesandGeohazardsDepartment, IndianInstituteofRemoteSensing,ISRO,Dehradun

• SlopeStabilityinOpenPitMines-TheoryandPractice–Dr.V.K.Singh,DeputyDirector&Head,SlopeStabilityDivision,CentralInstituteofMining&FuelResearch

• GeosyntheticHybridDrain System for ImprovingFineGrainedSoil–Dr.ChandanGhosh,Professor&Head(Geohazards),NationalInstituteofDisasterManagement

• SlopeStability usingGabionsand relatedFlexibleEngineeringMaterials–Ms.MinimolKorulla,ChiefTechnicalOfficer,MaccaferriEnvironmentalSolutionsPvt.Ltd.

• Slope StabilizationChallenges - Significance ofAnalysisforEffectiveSolutions–Mr.R.K.Vishnoi,AGM,THDCIndiaLimited

• StabilityAnalysisofSlopes–Dr.R.Chitra,ScientistE,CentralSoilandMaterialsResearchStation

• DesignandDevelopmentof ImprovedVarietiesofOpenWeaveJuteGeotextilesforErosionControl–Mr.P.K.Choudhury,In-Charge,GeotechCell,IndianJuteIndustries’ResearchAssociation

TheSeminarconcludedwiththepaneldiscussionson30November 2012 under theChairmanship of Prof.T.Ramamurthy.Mr. S.K.Raina, ExecutiveDirector,ChenabValleyPowerProjects(P)Limited,Mr.J.N.L.Das,Chief TrackEngineer,Ministry ofRailwaysMr.R.K. Vishnoi, AGM, THDC India Ltd. andMr. A.C.Gupta,Director(WR),CBIP,participatedinthePanelDiscussionsaspanelist.Duringthesession,participantsdiscussedtheproblembeingfacedintheprofessionalengagements and provided their feedback about theSeminar.

SomeofthepointswhichemergedduringthedeliberationsoftheSeminarareasunder:

• Constructionofanyinfrastructureinaslideproneareashould be carriedout only after gatheringenoughgeological data of that area.Apowerful databasecomprisingof informationaboutdisasterpronehillrangesshouldbemaintained

• KeepinginviewthatatDPRstageitmaynotpossibletodotherequisiteoradequateinvestigationofsoil/rockmassdue tovarioussiteconstraintsorsomeother reasons, it isdesirable thatduringexecutionwhereverthereiselementofdoubt,rockstrataorsoilmassistobetestedfortherequisitepropertiessoastotakemidcoursecorrectionforslopestabilizationmeasures.

• Surfaceaswellassub-surfaceDrainagearethebestpreventivemeasureformitigationrock/soilslide



• Deepdrainageholesarepreferredoverweepholesinretainingwallsforeffectiveslopestabilization.Providingproperdrainagemeasureiskeytosuccess.

• RootsofVegetationformananchorforsoilandhelpreduceamountofwaterinporespaces.Aforestationshould be encouraged to as it can help in slopestabilization.underallconditions.

• Mappingofoldslidezonesusingremotesensingdatashallbeusefulfortakingpreventiveactionasthese

slidescanactivateanytimeandmaycauseheavydamagetomanandproperties.Geoinformaticstoolsand technique(GIT) cansupplement the traditionalmethods of observation by providing timely andreliableinformationatrelativelylowercost

• Flexibleretainingwallsusinggabionsareusefulandoftenpreferableovernonflexibleretainingwallsforslopestabilization.

• HYBRIDsystemconsistingofthinsandmatatbothsidesofgeocompositeisfoundtobeefficientagainstclogging.

• Jute Textile (JGT) plays amore effective role inrestrainingsurfacesoilerosionthantheconventionalvarietiesofOpenWeaveJuteGeotextile(OWJGT)ofidenticalweights.

• Man-madeGTsappearstobelesseffectivebecauseof its thinness apart from its inability to create acongenialmicro-climate that facilitates vegetationgrowth.

• ForOpen castmining, it is desirable from slopestabilityconsiderationstodumpthewastematerialatasafedistanceratherthanatthetoplevelnearthecutslope.

A view of the participants

iSrm SPONSOrEd FOrTHCOmiNG EVENTS

20-22May, 2013,Brisbane,Australia -• Effective and Sustainable Hydraulic Fracturing - anISRMSpecializedConference

18-20June2013,Shanghai,China-SINOROCK2013-• Rock Characterization, Modelling and Engineering Design Methods –anISRMSpecializedConference

20-22August2013,Sendai,Japan-• The 6th International Symposium on Rock Stress -anISRMSpecializedConference

21-26September2013,Wroclaw,Poland-• EUROCK 2013 - Rock Mechanics for Resources, Energy and Environment -the2013ISRMInternationalSymposium

26-28 May 2014, Vigo, Spain -• EUROCK 2014 - Rock Engineering and Rock Mechanics: Structures in and on Rock Masses –anISRMRegionalSymposium

15-17October2014,Sapporo,Japan-• ARMS 8 - 8th Asian Rock Mechanics Symposium -The2014ISRMInternationalSymposium

10-13May2015,Montréal,Canada-ISRM13thInternationalCongressonRockMechanics•7-9October2015,Salzburg,Austria-• EUROCK 2015 – Geomechanics Colloquy -anISRMRegionalSymposium

41


iSrm 50-years anniversary celebrations closed in October in Salzburg, at the Geomechanics Colloquy

The celebrations of the 50-years anniversary of theISRMstarted inOctober 2011 inBeijing, during the12thISRMCongress,hadapeakduringtheEUROCK2012inStockholm,lastMay,andsymbolicallyclosedinOctober2012duringthe61stGeomechanicsColloquyinSalzburg,thesamecitywhereISRMwasfounded,in1962.

A number of activities took place during this year ofcelebrations:

• Acompetition,opentoISRMmembers,tocreatethe50thanniversarylogo,whichwasusedthroughouttheyearof2012,wonbyourmemberDrLudgerSuarez-Burgoa.

• AcompetitionopentoyoungmembersoftheISRMtopresenttheirvisionof“TheFutureDirectionsforEngineeringRockMechanics”,wonbyDrRicardoResende.

• A 50th anniversary commemorative banquetheld during the ISRMCongress in Beijing on 21October2011,whereDrNunoGrossmannmadeapresentationonthelifeoftheSocietyduringitsfirst50years.

• The publication of the “ISRM 50th AnniversaryCommemorative Book - 1962-2012”, edited byProf. John Hudson and Dr Luís Lamas. Thisbook has been compiled to celebrate ISRM’s50-year anniversary by outlining the backgroundto the formation of the ISRM and the mostsignificantactivitiesduringthe50years.ItincludescontributionsfromthelivingPastPresidentsoftheISRMandfromtheRegionalVicePresidents.Thisfullcolourbook,with200pages,canbepurchasedfromtheISRMSecretariat.

• AHistoricalExhibitionincludingsixpanelsdescribingthemainmilestonesinthedevelopmentoftheISRMduringthese50years,startingwiththeconstitutionalmeeting on 25 May 2012 in Salzburg and theFirst Congress in Lisbon in 1966. Reference ismade to themain technicalachievements,namelythrough the ISRMCommissions andCongresses,to themost importantpublicationsandto themaintechnical concernsof theSocietyalong theyears.Theevolutionofthemembershipandthelocation

of the venues of the ISRM conferences are also presented.

• The Commemorative Book and the HistoricalExhibitionweredisplayedatalltheISRMconferencesof2012,atthe46thU.S.RockMechanicsSymposiumand also at the 61stGeomechanicsColloquy, inSalzburg.

• A commemorative session at theGeomechanicsColloquyinSalzburg,withthepresenceofDrFranzPacher,oneofthefoundersoftheISRM,

Closing session of the 50th anniversary celebrations in October 2012, in Salzburg, during the 61st Geomechanics

Coloquy: addresses by Prof. Wulf Schubert, Dr Nuno Grossmann and Prof. Xia-Ting Feng.

Dr Franz Pacher—that together with Prof. Leopold Müller put forward the idea of creating the ISRM—gave an interview allusive to the foundation of the ISRM and was present

at the commemorative ceremony.

ISRM newS



A Tribute to John Franklin, 1940-2012ProfessorJohnFranklinpassedawayon6July,afteraprolongedillnessthathefoughtwithunparalleledstrengthandcourage.ThosewhoattendedtheISRMCongressinBeijing,lastOctober,whereJohnreceivedhisFellowshipoftheISRM,canconfirmhisperseveranceanddedicationtoourSocietyuntilthelimitofhiscapacities.

FortheGeo-engineeringcommunityandfortheISRMinparticularthisisaverysadmoment.Geo-engineeringat large is poorer. John Franklinwas a top scientist, a successfulpractitioner, a strong leaderandamarvelousperson.Thosewhohadtheprivilegetoknowhimwillneverforgethisdedication,hiscapacityto

motivatepeople,hisbrilliantmindandhisinsurmountablecapacitytodiscovernewresearchthemes,ornewworkingmethods.Hewasandwill remainaguide foryoungergenerations.

Ofhislifetimeaccomplishments,hewasmostproudofhisassociationwiththeISRM.HeservedasISRMPresident(1987-1991)andChairmanoftheISRMCommissionsonTestingMethods(1975-1987)andEducation(1991-1995).AmonghisuncountablecontributionstoourSociety,JohnhasorganisedanddirectedthepreparationofmostoftheISRM“SuggestedMethods”forrocktesting.

iSrm Franklin lecture instituted to honour the memory of late Past President Professor John Franklin

TheISRMBoarddecidedtoinstitutetheISRMFranklinLecturetohonourthememoryofProfessorJohnFranklin(1940-2012), President of the International Societyfor RockMechanics from 1987 to 1991. Among hisuncountablecontributionstoourSociety,JohnFranklinhasorganisedanddirectedthepreparationofmostoftheISRM“SuggestedMethods”forrocktesting.

ThepurposeoftheISRMFranklinLectureistorecogniseamid-careerISRMmemberwhohasmadeasignificantcontribution toaspecificareaof rockmechanicsand/orrockengineering.Itwillbegivenineveryyear,attheISRMInternationalSymposium,exceptforthoseyearswhenthe4-yearlyISRMCongressisheld.ThislecturewillreplacetheexistingISRMannuallecture.

Click here to read the Guideline for the FranklinLecture.

The ISRMFranklin Lecturer will be selected by theBoard.HeshallbebasedintheregionwheretheISRMInternationalSymposiumisbeingheldthatyear,andwill

berequiredtogiveakeynotepresentationonthesubjectofhis/herexpertise.

TheISRMFranklinLecturewillbepublishedintheISRMNewsJournal.

The2013ISRMFranklinLecturewillbegiveninWroclaw,Poland, during the 2013 InternationalSymposium, by Dr.AndreasGorickifromAustria.

A massive Global Energy Assessment Study involved Experts from Around the World

TheInternationalInstituteforAppliedSystemsAnalysis(IIASA) in Austria has completed amassiveGlobalEnergyAssessmentstudyinvolvingexpertsfromaroundtheworld.Thereportisavailablefordownloadingatthefollowingsite:http://www.iiasa.ac.at/web/home/research/researchPrograms/Energy/Chapters_Home.en.html.

OneofourISRMMembers,DrMauriceDusseault,andhis graduate studentAliShafiei, contributed importantsections related to non-conventional petroleumenergysources,withafocuson viscous oil productionmethodsandenvironmentalissues. Dr Dusseault ist he P res iden t o f t hePetroleumGeomechanicsCommission of the ISRM,and the contributions thathe hasmade to heavy oildevelopment engineeringhave been related to histraining and experience inRockMechanics.

DrDusseaultandAliShafieialsorecentlycontributedanewChapteronOilSandsforthewell-knownUllmann’sEncyclopedia of Industrial Chemistry, an industrystandardknowledgebasepublishedbyWiley:Dusseault MB, Shafiei A. 2011. Oil Sands. Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. 52 pages.Thischapterevaluatesworldoil sand resources and summarizesmany aspects ofresourcemagnitudeandproductionapproaches.

MauriceDusseault

GotothetopoftheNewsletter

iSrm Online lectures Series: A New initiative to Start in February 2013

TheISRMBoardhasdiscussedanumberofinitiativesto be implemented in the short term, in order to givemorebenefits to themembersand toservebetter the

43


rockmechanicscommunity.Oneofthem,whichwillstartverysoon,isthe ISRMOnline LecturesSeries.Experts in different fields of rockmechanicswill be invited to givea lectureonaspecific topic.Eachlecturewill be broadcast from theISRMwebsiteatapredefineddateand time, and the attendeeswillbe able to ask questions to the

lecturerbye-mail,onthetopicofthelecture,duringthesubsequent 48 hours. The ISRMOnline Lectureswillremain available on the ISRMwebsite in a dedicatedwebpage.

OurplansaretoorganisefourOnlineLecturesperyear.Thefirstonewillbebroadcaston19February,at10a.m.GMT,anditwillremainonlinesothatthosethoseunabletoattendatthistimewillbeabletodoitlater.InordertoknowwhatisthecorrespondencebetweenGMTandyourlocaltime,justlookforGMTinyourInternetsearchengine.

ForthefirstOnlineLecturetheISRMPresidentdecidedthatitwouldbeagoodopportunitytolistentothedevelopmentsinthewell-knownNewAustrianTunnellingMethod,nowthat it formally completed 50 years of existence. TheinvitedspeakerwillbeProf.WulfSchubertfromAustria,andthetitleofhislecturewillbe“50yearsNATM-fromaconstructionmethodtoasystem”.

Prof.SchubertisheadoftheInstituteforRockMechanicsandTunnelling at theGrazUniversity of Technology,whereheteachesintheBachelorandMasterprogram,aswellasinthepost-graduatecourse“NATMEngineer”.Underhisguidanceabout70Masterthesesand20PhDtheses have been prepared. Besides theUniversityactivitiesheconsultsoninternationalprojectsasapartnerof3G-GruppeGeotechnikGrazConsultingEngineers.HeservedasVicePresidentatLargefortheISRMfrom1999to2003andisPresidentoftheAustrianSocietyforGeomechanicssince2007.

New delhi Asian rock mechanics Symposium keynote lectures Now Online

Thevideosandpresentationsofthekeynotelecturesofthe2010ARMSheldinNewDelhi,Indiaarenowonline.ISRMmemberscanwatchthefulllengthlectures,whichareaccompaniedbythepowerpointpresentations:

• JanChristerAndersson,RochaMedalWinner-ÄspöPillarStabilityExperiment

• JohnA.Hudson-UndergroundRadioactiveWasteDisposal:TheRockMechanicsContribution

• Maurice Dusseault - Deep Injection Disposal: Environmental and Petroleum Geomechanics

• Shinichi Akutagawa -OnSite Visualization as aNew Paradigm for FieldMeasurement in RockEngineering

• HerbWang-DeepUndergroundInstrumentationandMonitoring

• GiovanniBarla -Progress in theUnderstandingofDeep-SeatedLandslidesfromMassiveRockSlopeFailure

• YossefH.Hatzor-ModellingDynamicDeformationinNaturalRockSlopesandUndergroundOpeningswithNumericalDDAMethod

• Claus Erichsen - Challenges in the Design andConstructionofTunnelsinJointedRock

• GuoweiMa and Yingxin Zhou - RockDynamicsResearch in Singapore: Fundamentals andPractices

• Xia-Ting Feng - Application of Intelligent RockMechanicsMethodologytoRockEngineering

• JohnRead-TheLargeOpenPitProject

Wudongde Hydropower Station - A New 10,200 mW Hydropower Project

• TheWudongdehydropowerstation, locatedat thedownstreamsegmentofJinshaRiverhasaninstalled10,200MWelectriccapacity.Itconsistsofonedamand two underground cavern hinges. The dam isa typicalhyperboloidalarchconcretedamwith themaximumheightin265m.Therearefivetableholes,sixmidholesandtwospillwaytunnelsinthisdam.

• The left underground hydraulic caverns includemain powerhouse,main transformers cavern, sixbusbartunnels,tailwaterlockchamber,sixpressurepipes, and six tailwater tunnels. The size ofmainpowerhouseisabout321.0minlength,31.8minwidth



and86.9minheight.Themaintransformerscavern,whichisparalleltothemainpowerhouseandis45mindistancewithmainpowerhouse,isabout255.6minlength,18.5minwidthand34.5minheight.TheaxesdirectionofmainpowerhouseandmaintransformerscavernisNE42ºintrend,whichintersectsthetrendofrockstratumwith45º.Theundergroundhydraulichinge in right bank has the same structure of leftundergroundhydraulic.TheaxesdirectionofmainpowerandmaintransformedcavernisNE70º,whichintersectsthetrendofrockstratumwith10º.

• The rock stresses around the left and groundunderground caverns is shown in the followingtable. Fig. 1 :LayoutofWudongdehydraulicproject

underground caverns Statistic

Principal stress Principal stress

Value (mPa)

dip angle (°)

Trend angle (°)

Value (mPa)

dip angle (°)

Trend angle (°)

Left

Range 11.3-14.9 40-70 210-270 5.2~8.2 300-340

120-140

Max. 14.9 68 9.6 41

Min. 11.3 7 5.2 5

Average 13.3 41.4 6.8 24.6

Right

Range 5.6-13.0 290-340 120-180

50-100 300-360

Max. 13.0 88 6.4 80

Min. 5.6 4 2.9 2

Average 7.2 56.9 4.0 12.9

• Thefoldedstratuminthisregionisslightmetamorphiclimestoneandmarbleandsedimentarydolomitewiththedip angle of 50~80º, as canbe seen inFig.3.

Fig.2:TheJinshaRiverandbankscollapse in the diversion tunnel

Fig.3:Steepdipstratumindiversiontunnel

Fig.4:Rock

Thus,duringtheexcavationofundergroundtunnelsorcaverns,fallingofsurroundrockoccurredfrequently,asshowninFig.4.

45


The 2014 iSrm international Symposium will take place in Japan

The ISRMCouncil has selectedSapporo, Japan, asthevenueofthe2014ISRMInternationalSymposium,followingavotebysecretballotbetweenEurock1014inVigo,Spain,andARMS8.

iSrm rocha medal 2013

The ISRM Board decided at its Tokyomeeting inSeptember 1981, to institute an annual prizewith aview to honour thememory of Past-President Prof.Manuel Rocha. Profiting from the basis establishedbyProf.Müller,Prof.Rochaorganized thefirst ISRMCongressandhewastheleaderthatwasresponsiblefortransformingtheinternationalcollaborationcarriedout in an amateurish way into a real internationalscientificassociation,havingforthepurposesettledthefundamentallinesthathaveguidedandsupportedtheISRMactivityalongtheyears.

The Rocha Medal is intended to stimulate youngresearchers in the field of rock mechanics. Theprize, a bronzemedal and a cash prize, have beenannually awarded since 1982 for an outstandingdoctoral thesisselectedbyaCommitteeappointed for thepurpose.

TheISRMBoardhasdecidedtoawardtheRochaMedal2013 toDrMathewPierce fromCanada for the thesis“Amodel for gravity flowof fragmented rock in blockcavingmines”presentedattheUniversityofQueensland,Australia.Hewill receive theawardat the2013 ISRMInternationalSymposiuminWroclaw,Poland.

Two runner-up certificateswere also awarded toDrHeLei, fromChina, for the thesis “Threedimensionalnumerical manifold method and rock engineeringapplications” presentedat theNanyangTechnologicalUniversity,Singapore,andtoDrAndreaPerino,fromItaly,forthethesis“Wavepropagationthroughdiscontinuousmediainrockengineering”presentedatthePolitecnicodiTorino,Italy.

“Hydrogeology for rock Engineers” by Gunnar Gustafson publ ished by BeFo wi th iSrm sponsorshi

Thebook“HydrogeologyforRockEngineers”byGunnarGustafson,originalywritteninSwedish,wastranslatedinto English and published by BeFo, the SwedishRock EngineeringResearch Foundation, with ISRMsponsorship.ThebookcanbepurchasedfromBeFo.

Groundwaterhasbecomeaprobleminconstructionoftunnelsandotherundergroundfacilitiesinawayithas

never been before. Tighter environmental regulationsmean that documentation of a completely differentcalibreisnowrequiredwhenapplyingforpermissiontoconstructanundergroundfacility.Greaterrequirementsfor a dry environment in road and railway tunnelshave increased demands on sealing and drainage.Existing tunnels inmetropolitan areas largely draintherockoftheavailablegroundwater,andnewunder-ground constructions and tunnels canexacerbate thesituation.Naturally, the traditionalproblems relating togroundwater remain,making construction difficult inwater-conductingzonesinpoor-qualityrock,andinvolvingthe risk of settlement if clay layers overlying the rock aredrained.

Thisbookprovidesa reviewofourcurrentknowledgeaboutthehydro-geologyofthecrystallinebasement,andexplainshowthiscanbeappliedinpracticalmethodsforuseinsiteinvestigations,layoutanddesign,aswellasin theoperationof tunnels andunderground facilities.Theworkisbasedonresearchandpracticalexperienceofhydrogeologicalproblemsandphenomena.MuchoftheknowledgebasecomesfromtheSKBresearchandpre-investigation studies relating to final disposal forspentnuclearfuel.However,theaimisnottodescribetheresearchfrontassuch,butrathertoexplainwhatisimportantandusefulfortherockconstructioncommunityingeneral.

iSrm Communication

The website continues to be the main source ofinformation about theSociety andmost benefits areofferedtothemembersinapasswordprotectedmembers’area.Members can nowdownload theirmembershipcertificatesinpdfformat.

The digital newsletter issenttoallISRMmembersandsubscribersevery3months.Itincludesnewsaboutthesocietyandothernewsof interest to rockmechanics.Contributionsarewelcomewithshortnewsonissuesofgeneralinterest.

The latest issueof theNews Journal,editedbyProf.JohnHudsonandProf.Xia-TingFeng, has80pagesandcontainstheannualreviewoftheSociety’sactivityalong2011and technical articles suchasa summaryof the 6thMüller Lecture. It has been posted on thewebsitewhere it cannowbe readonlineor it canbe downloaded.

Thedigital library,hostedbyOnePetro.org,continuestobeupdatedwithpapersfrommoreISRMsponsoredconferences.Ithasnow22conferences,withover25,000pages.Memberscandownload100papersperyearatnocost.



recipients of the rocha medal

1982 A.P.Cunha PORTUGAL MathematicalModellingofRockTunnels

1983 S.Bandis GREECE ExperimentalStudiesofScaleEffectsonShearStrengthandDeformationofRockJoints

1984 B.Amadei FRANCE TheInfluenceofRockAnisotropyonMeasurementofStressesinSitu

1985 P.M.Dight AUSTRALIA ImprovementstotheStabilityofRockWallsinOpenPitMines

1986 W.Purrer AUSTRIA CalculationModelfortheBehaviourofaDeep-LyingSeamRoadwayinaSolid(butcutbyBeddingPlanes)SurroundingRockMass,takingintoConsiderationtheFailureMechanismsoftheSoftLayerDeterminedIn-SituonModels

1987 D.Elsworth UNITEDKINGDOM LaminarandTurbulentFlowinRockFissuresandFissureNetworks

1988 S.Gentier FRANCE MorphologyandHydromechanicalBehaviourofaNaturalFractureinaGranite,underNormalStress–ExperimentalandTheoreticalStudy

1989 B.Fröhlich GERMANY AnisotropicSwellingBehaviourofDiageneticallyConsolidatedClaystones

1990 R.K.Brummer SOUTHAFRICA FracturingandDeformationattheEdgesofTabularGoldMiningExcavationsandtheDevelopmentofaNumericalModeldescribingsuchPhenomena

1991 T.H.Kleine AUSTRALIA AMathematicalModeloftheRockBreakagebyBlasting

1992 A.Ghosh INDIA FractalandNumericalModelsofExplosiveRockFragmentation

1993 O.ReyesW. PHILIPPINES ExperimentalStudyandAnalyticalModellingofCompressiveFractureinBrittleMaterials

1994 S.Akutagawa JAPAN ABackAnalysisProgramSystemforGeomechanicsApplication

1995 C.DerekMartin

CANADA TheStrengthofMassiveLacduBonnetGranitearoundUndergroundOpenings

1996 M.P.Board USA NumericalExaminationofMining-InducedSeismicity

1997 M.Brudy GERMANY DeterminationofIn-SituStressMagnitudeandOrientationof9kmDepthattheKTBSite

1998 F.MacGregor AUSTRALIA TheRippabilityofRock

1999 A.Daehnke SOUTHAFRICA StressWaveandFracturePropagationinRock

2000 P.Cosenza FRANCE CoupledEffectsbetweenMechanicalBehaviourandMassTransferPhenomenainRockSalt

2001 D.F.Malan SOUTHAFRICA AnInvestigationintotheIdentificationandModellingofTime-DependentBehaviourofDeepLevelExcavationsinHardRock

2002 M.S.Diederichs

CANADA InstabilityofHardRockmasses:theRoleofTensileDamageandRelaxation

2003 L.M.Andersen

SOUTHAFRICA ARelativeMomentTensorInversionTechniqueappliedtoSeismicityInducedbyMining

2004 G.Grasselli ITALY ShearStrengthofRockJointsbasedontheQuantifiedSurfaceDescription

2005 M.Hildyard UNITEDKINGDOM WaveInteractionwithUndergroundOpeningsinFracturedRock

2006 D.Ask SWEDEN NewDevelopmentsoftheIntegratedStressDeterminationMethodandApplicationtotheÄSPÖHardRockLaboratory,Sweden

2007 H.Yasuhara JAPAN Thermo-Hydro-Mechano-ChemicalCouplingsthatDefinetheEvolutionofPermeabilityinRockFractures

2008 Z.Z.Liang CHINA ThreeDimensionalNumericalModellingofRockFailureProcess

2009 LiGang CHINA ExperimentalandNumericalStudyforStressMeasurementbyJackFracturingandEstimationofStressDistributioninRockMass


47

2010 J.ChristerAndersson

SWEDEN RockMassResponsetoCoupledMechanicalThermalLoading.ÄspöPillarStabilityExperiment,Sweden

2011 D.Park KOREA ReductionofBlast-InducedVibrationinTunnellingUsingBarrierHolesandAir-deck

2012 M.T.Zandarin ARGENTINA Thermo-Hydro-MechanicalAnalysisofJoints-ATheoreticalandExperimentalStudy

Rocha Award Runner Up Certificates

2010 YoonJeongseok KOREA Hydro-MechanicalCouplingofShear-InducedRockFracturingbyBondedParticleModeling

2010 AbbasTaheri IRAN PropertiesofRockMassesbyIn-situandLaboratoryTestingMethods

2011 BoLi CHINA CoupledShear-flowPropertiesofRockFractures

2012 B.PWatson SOUTHAFRICA RockBehaviouroftheBushveldMerenskyReefandtheDesignofCrushPillars

2012 J.Taron USA GeophysicalandGeochemicalAnalysesofFlowandDeformationinFrac-turedRock

newS FRoM IndIan natIonal GRouP oF ISRMNOmiNATiON FrOm iNdiA FOr iSrm COmmiSSiON ON EduCATiON

ISRMCommissionon"Education"isoneofthecommissionsonvarioussubjects.ThepurposeoftheCommissionistoorganizeactivitiesandenhanceteachingandtraininglevelofeducationonrockmechanics.

Prof.MeifengCai,CollegeofResourcesEngineering,UniversityofScience&TechnologyBeijing,isthePresidentoftheCommission.Theothermembersofthecommissionare:

= M.A.Kwasniewski(Poland)

= N.F.Grossmann(Portugal)

= M.U.Ozbay(USA)

= J.P.Harrison(Canada)

= J.A.Wang(China)

= F.Pellet(France)

= L.Jing(Sweden)

= J.Zhao(Switzerland)

= Xia-TingFeng(exofficio),ISRMPresident

= YingxinZhou(exofficio)ISRMVicePresident(Asia)

ISRMrequestedtheIndianNationalGrouptonominateakeypersonwhoisworkingatIndianUniversitytobeamemberofISRMCommissiononEducation.

Prof.K.G.Sharma,DepartmentofCivilEngineering,IITDelhi,hasbeennominatedasmemberoftheCommissionfromIndiaconsideringhisexposuretoteachingofrockmechanics,bothatUndergraduateandPostgraduatelevels.



PuBlICatIonS oF IndIan natIonal GRouP oF ISRMProceedings of the 6th Asian rock mechanics Symposium on “Advances in rock Engineering”

Indiaisafastdevelopingeconomyrequiringlargescaleinfrastructure.SuccessivefiveyearplansofGovernmentofIndiahaveprovidedthepolicyframeworkandfundingfor building up itswide infrastructure andmanpower RockEngineeringdoesplayan important role inmostof infrastructure developmental activities related tocivilengineeringworks.Theneed therefore is tokeepourselvesabreastwiththelatestdevelopmentinthefieldofrockengineeringanditsrelatedfieldssuchasdesignand constructionof undergroundworks, foundationofdams,slopestabilityetc.

Keepingthisinview,ISRMInternationalSymposiumandthe6thAsianRockMechanicsSymposiumon“Advances in rock Engineering” wasjointlyorganizedbytheIndianNationalGroupofISRMandCentralBoardofIrrigationandPower,inNewDelhiduring25-27October2010.

TheproceedingsoftheSymposiumcontainsextendedabstractsof166papersfrom27countriesselectedfororalandposterpresentationsonthefollowingtopics:

• TestingandModellingofRocks&RockMasses

• SlopeStability:Analysis&Design• Foundations• Underground Structures: Analysis, Design &

Construction• ArtificialIntelligence• FlowandContaminantTransport• RockDynamics• Techniques for Improvement ofQuality of Rock

Mass• InstrumentationandMonitoring

Inaddition,theproceedingscontainsthefulltextsofthefollowingkeynotelecturesdeliveredbyrenownedexpertsfromAustralia, Canada, China, Israel, Italy, Japan,Singapore,U.K.andUSA:

• OnSiteVisualizationasaNewParadigmforFieldMeasurementinRockEngineering

• Progress in theUnderstandingof Landslides fromMassiveRockSlopeFailure

• Deep Injection Disposal: Environmental and

PetroleumGeomechanics• ApplicationofIntelligentRockMechanicsMethodology

toRockEngineering• ModellingDynamicDeformation inNatural Rock

SlopesandUndergroundOpeningswithNumericalDDAMethod

• UndergroundRadioactiveWasteDisposal--TheRockMechanicsContribution

• RockDynamicsResearchinSingapore:FundamentalsandPractices

• TheLargeOpenPitProject• DeepUnderground InstrumentationandMonitoringThefulltextsareavailableinelectronicversionwiththeextendedabstractsinprint.

PricedatIndianRs.1500/US$50+PostageCharges,theproceedingswould be very informativeandusefulreference to the concerned agencies/individuals.MembersofCBIPandISRMwillbeoffered10%discount.Theproceedingscanbepurchasedbypaymentthroughdemanddraft/chequepayable at par inNewDelhi, infavourof“CentralBoardofIrrigationandPower”.

manual on rock mechanics

ThefirstManualonRockMechanics,whichwaspreparedundertheguidanceofanExpertCommittee,wasreleasedbyCentralBoardof Irrigation&Power (CBIP) inearly1979.Themanualwasverywellreceived.

Themanualwas revised in 1988, to reflect the thenstate-of-artknowledgeofIndianEngineersinthefieldofRockMechanicsandcontained17Chapters,coveringbasicconceptsofRockMechanics,FieldandLaboratoryTestsonRockMassandRockSpecimen,GeophysicalInvestigations, Interpretation of Test Data and theirApplicationtovariousproblemsofFoundationofDams,Tunnelling,etc.

TheGoverningCounciloftheIndianNationalGroupofISRMfeltthattherewasaneedtoupdatethemanual,as more than 20 years had passed since its lastpublication.

Accordingly,themanualwasupdatedandreleasedduringtheISRMInternationalSymposium2010and6thAsianRockMechanicsSymposiumheld inNewDelhiduring23-27October2010.


GuIdelIneS FoR authoRS

TheauthorsshouldsubmittheirmanuscriptinMS-Word(2003/2007)insinglecolumn,doublelinespacing.Themanuscriptshouldbeorganized tohaveTitlepage,Abstract, Introduction,Material&Methods,Results&Discussion,Conclusion,andAcknowledgement.Themanuscriptshouldnotexceed16pagesindoublelinespacing.

Submission of manuscript:

ThemanuscriptmustbesubmittedindocandpdftotheEditorasanemailattachmenttouday@cbip.org. The author(s) should send a signed declaration formmentioning that, thematterembodiedinthemanuscriptisoriginalandcopyrightedmaterialusedduringthepreparationofthemanuscripthasbeendulyacknowledged.

Peer review Policy:

review System: Everyarticle isprocessedbyamaskedpeer reviewofdoubleblindorbythreerefereesandeditedaccordinglybeforepublication.Thecriteriausedfortheacceptanceofarticleare:contemporary relevance, updated literature, logical analysis, relevance to the global problem, sound methodology, contribution to knowledge and fairly good English. Selectionofarticleswill bepurelybasedon theexperts’ viewsandopinion.Authorswill becommunicatedwithinTwomonthsfromthedateofreceiptofthemanuscript.TheeditorialofficewillendeavortoassistwherenecessarywithEnglishlanguageeditingbutauthorsareherebyrequestedtoseeklocaleditingassistanceasfaraspossiblebeforesubmission.Paperswithimmediaterelevancewouldbeconsideredforearlypublication.Thepossibleexpectationswillbeinthecaseofoccasionalinvitedpapersandeditorials,orwhereapartialorentireissueisdevotedtoaspecialthemeundertheguidanceofaGuest Editor.

The Editor may be reached at:[email protected]



dR. BhandaRI awaRded PReStIGIouS VaRneS Medal FoR 2012

dr. V.k. Singh,ChiefScientist&Head,SlopeStabilityDepartment,CentralInstituteofMiningandFuelResearch,Dhanbad,andanactivelifememberIndianNationalGroupofISRM,hasbeenawardedwithSociety of Geoscientists and Allied Technologists (SGAT) Award of Execellence-2012,inrecognitionofhisoutstandingcontributiononGeotechnicalServicestotheMiningIndustryforbettermanagementofsafetyandmineralconservationthrougheco-friendlymining.

Dr.V.K.SinghhasbeeninstrumentalinconfidencebuildingtothecivilconstructionprojectsinHimalayanRegionandcontroloflandslides.HisprolificcontributiontowardsdevelopmentofindigenoustechnologyandgeotechnicalcontributionstoIndianMiningIndustryispraiseworthy.Hisnumberofscientificpublications in reputed internationalandnational journals,different

booksontechnology,hasbroughtoutstandingrecognitiontoDr.V.K.Singhasatruescientistinthefieldofearthsciencewithspecialreferencetogeotechnicalinvestigationsandslopestabilitystudies.

Dr.V.K.Singhhasinitiated,motivatedandguidedtoestablishgeotechnicallaboratories/slopestabilitycellinvariousminingorganizationsofreputeinthecountry.

IndianNationalGroupofISRMcongratulatesDr.V.K.SinghforhisoutstandingcontributiontotheMiningIndustry,andwisheshimtocontributemoreinfuture.

ReCoGnItIonS

DrR.K.BhandariwasawardedtheprestigiousVarnesMedalfortheyear2012attheUNESCOHeadquartersinParison23November2012forexcellenceinresearchonLandslides.ItisthehighestawardoftheInternationalConsortiumofLandslides(ICL)andDr.BhandariisthefirstIndianrecipient.TheICLrepresents51memberinstitutionsfrom32countries;anditsInternationalProgrammeonLandslides(IPL)wasjointlyestablishedbyUNESCO,WMO,FAO,UNISDR,UNUICSU,IUGSandWFEO.DrBhandariisseenintheabovepicturewithProfessorPaoloCanuti,thePresidentofICL(extremeright),ProfessorKyojiSassatheExecutiveDirectorofICL(extremeleft)andDr.SalvanoBriceno,ChairofScienceCommitteeofIntegratedResearchonDisasterRisk.


FoRthCoMInG aCtIVItIeS oF IndIan natIonal GRouP oF ISRM

International Symposium“RoCk MeChanICS IndIa’ 2013 –

PReSent teChnoloGY and FutuRe ChallenGeS” and PRe-SYMPoSIuM woRkShoP on “oPen PIt MInInG”

3-5 JulY 2013, new delhI, IndIa

iNTrOduCTiON

Thestudyofrockmechanicshasassumedconsiderableimportance because of its wide application in civilengineering,more predominantly inwater resources,miningengineeringandundergroundstructures.Fortheexecutionofmultipurposewaterresourcesprojectslocatedincomplicatedgeologicalsettings,thesignificanceofrockmechanicsinthedesignandconstructionwasrealisedinlate1950s.Despitetremendousalroundadvancementintechnology,afullunderstandingofnaturalforcesandphenomenaeludesthedesignengineer.Thedetailsofthechallengesencounteredduringconstructionofwaterresourcesprojectsinadversegeologicalconditionsandthemethodology/approachfollowedtoreducethemhavelotofsignificancetoconstructionanddesignengineers.Similarexperiences for thedesignandconstructionofroad tunnels,metro tunnel, rail tunnels in complicatedconditions alongwith stability of slopeswill also beveryuseful.Miningisanotherfieldwherebesidesopenpitmining, deep seated oremining is also providingchallenges to engineers. Besides providing support,instrumentation is also gaining importanceas it helpsstudying themomentof rockmassandprovide timelywarningtotakeappropriateaction.

Bothdesignand constructionengineerswouldalwaysbekeentoknowwhatadvancementsaretakingplaceintheirrespectivefields.Therefore,thereisaneedforupgradationofonesknowledge.

Liberalisationof economyhas facilitatedplanningandexecution ofmany exciting and complicated projectsin India. Theseprojects require applicationofmodernprinciplesofrockmechanics,whichwarrantsdeliberationsand collaboration to facilitate flow of appropriatetechnologytoenablesuccessfulimplementationofsuchprojectsunderatime-boundprogrammeinacost-effectivemanner,conformingtoenvironmentalrequirements.

Todeliberateontheadvancesinrockengineering,theIndianNationalGroupof ISRMand theCentralBoard

ofIrrigation&Power(CBIP)areorganizingthepresentInternationalSymposium–rock mechanics india’ 2013 on“PresentTechnologyandFutureChallenges”andPre-SymposiumWorkshopon“OpenPitMining”.

SYmPOSium SuB-THEmES

1. Advancements in Testing andCharacterisation ofRocksandRockMasses

2. ModellingandAnalysisofRockStructures

3. Preservation and Restoration of Ancient RockMonuments

4. UndergroundConstructionandMininginProblematicGeologicalConditions

5. UtilisationofUndergroundSpaceincludingStorageofWaterandGas

6. FractureandFragmentation

7. StabilityofUndergroundandSurfaceOpenings

8. EnvironmentalIssues

• SpecialSessiononUndergroundMining

- UndergroundMininginNarrowandWiderOreBodieswithDifferentRockMassConditions

- UndergroundMining atDeepSeatedOreBody

- UndergroundDevelopment&MininginWeakRockMassConditions

- Instrumentation inUndergroundMining forBetterSafety&Productivity

PrE-SYmPOSium WOrkSHOP - OPEN PiT miNiNG

Topicsproposedfordiscussions:

• InstrumentationandSlopeMonitoring

• PitSlopeStabilityinOpenCastMines

• BlastingPracticesforSafeOpenPitmining

• GroundwaterManagement



CAll FOr PAPErS / CASE STudiES

Papers/Casestudiesonthetopicsproposedandalliedtopicsareinvited.Thefulltextofthepapers/casestudies,not exceeding 08 pages of A4 size,insinglespace,bothinMSWordandPDF,[email protected] last date for the receipt of full texts of the case studies is 15 June 2013.

Thepapers/casestudieswillbereviewedbytheTechnicalCommitteeas to theirsuitability forpresentations.Thepapers/casestudiesacceptedforpresentationswillbenotifiedby22June2013.Aconditionofacceptanceofthepapers/casestudieswillbethat theauthor,oroneoftheauthorsincaseofmultipleauthors,willattendtheSymposiumandmakethepresentation.

Thepaper/casestudyshallcontain:

• adescriptive,butbrieftitle

• title,name(s)andaffiliationoftheauthor(s)

• addressforcorrespondence(includingfaxnumbersande-mailaddresses)

• detailed information about the objective,methods,resultsandconclusion,toenableacorrectappraisalofthesuitabilityoftheproposedpaper/casestudyfortheSymposium

Onlyoriginalcontributionsthathavenotbeenpublishedorpresentedatanyotherforumareacceptable.

rEGiSTrATiON FEE

A. Pre-Symposium Workshop (3 July 2013)

MembersofCBIP/ISRM/ITA/ICOLD/IGS

IndianRs.4,500/- [email protected]%

Non-Members IndianRs.5,000/- [email protected]%

Researchers/Academicians/Students/AccompanyingPersons

IndianRs.2,500/- USD65+ServiceTax @12.36%

B. Symposium (4-5 July 2013)MembersofCBIP/ISRM/ITA/ICOLD/IGS


Non-Members IndianRs.10,000/- [email protected]%

Researchers/Academicians/Students


C. Combined Fee for the Pre-Symposium Workshop and Symposium (3-5 July 2013)

MembersofCBIP/ISRM/ITA/ICOLD/IGS


Non-Members IndianRs.13,500/- USD340+ServiceTax @12.36%

Student/AccompanyingPerson


Incaseof03ormorenomineesfromanorganization,onenominationwillbeallowedfreeregistration.

Toavail thestudentconcessionintheregistrationfee,the registration form/requestwill have tobesubmittedalongwithacertificatefromtheheadoftheDepartment/institute.

SYmPOSium SECrETAriAT

Central Board of Irrigation & Power MalchaMarg,Chanakyapuri,NewDelhi110021,India

ContactPerson:V.K.Kanjlia,MemberSecretary,IndianNationalGroupofISRM

Phone :+91-11-26115984/26111294Fax :+91-11-26116347E-mail :[email protected];[email protected] :http://www.cbip.org

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