Design and Construction of Shaft

7/24/2019 Design and Construction of Shaft

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Design and Construction

of Shaft

Zubair Nizamani

2015250284


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Outline

Introduction

Locating Shaft

Designing of Shaft

Construction ethods !"ca#ation ethod

Soft and $et %round

!"ca#ation &um' Chamber

Summar(


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Introduction

Shafts are the door)a(s to the underground ost of the shafts for tunne* construction are #er( sha**o)

com'ared to mine shafts+

an( of the ci#i* shafts ma( be in the range of 100 ft, but It)ou*d be c*assi-ed a sha**o) shaft as *ess than .00 ft+

/he( a*so, on some occasions ma( be uiet a *ot *arger, sa(50 to 5 ft in diameter+

/he man con#e(ance is ust a crane )ith an attachedbuc3et,

ore of the ci#i* shaftsseem to be sun3 in #er(soft ground, #er( )etground or e#en througha bod( of )ater, )hich

brings about entire*(


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/here are genera**( t)o )a(s to access the tunne* *e#e* forconstruction through a 'orta* 'ro#iding direct accessat the

surface or through a shaft 'ro#iding #ertica* access to the *e#e* oftunne* o'erations+

6sua**( )hen the tunne*ing is in a rura* setting, a 'orta*7dec*ine isthe best so*ution, if the tunne* is under about 00 800 ft+ 9ut,since urban *and is #a*uab*e and interference )ith e"isting ser#icesmust be minimized, most tunne*s bui*t through urban areas reuire

shafts to reach the )or3ing area and to 'ro#ide for remo#a* oftunne* muc3+

/unne* shafts can be tem'orar( or 'ermanent

tem'orar( shafts are for the contractor:s use during construction;tem'orar( shafts norma**( are bac3-**ed at the end ofconstruction


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Locating a Shaft

/he *ocation of shafts is critica* in '*anninge>cient construction+ Locating a shaft at themid'oint of a tunne* )i** 'ermit tunne* dri#ing

in t)o directions= a*so, a sing*e com'ressor'*ant, hoist, sho', and o>ce can ser#e bothheadings+ 9ut there ma( be o#erriding s'ace*imitations, )hich )i** dictate *ocating a shaft

near #acant *and that )i** faci*itate theerection of tem'orar( bui*dings+ /he 'ro"imit(of muc3 dis'osa* *ocations and routes shou*da*so be considered+


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Designing ?f Shaft

$hen designing a shaft, these four 3e( uestionsdictate

$here is the ground)ater tab*e@

$hat t('e of ground )i** be e"ca#ated@

Ao) much )or3ing s'ace is needed@

Ao) dee' is the tunne* horizon@

/he ans)ers to these uestions determine )hichshaft construction methods are feasib*e and best touse on (our 'roect+


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9efore determining (our shaft construction method,decide (our minimum shaft size+

During design, the minimum dimensions are t('ica**(

determined b( the 'h(sica* *a(out of the -na* structureto be constructed or s'ace needed for *aunching atunne* boring machine ;/9cu*t to determine e"act*( )hat size shaft the

contractor )i** need because (ou )i** not 3no) the'ro'osed means and methods and the e"acteui'ment that )i** be used+

$hen surface s'ace a**o)s, assume the contractorma( need to increase the foot'rint of the shaft+


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/he big design uestion is Can the shaft be circu*ar@ circu*ar shaft isstructura**( stab*e+ /he earth *oads on a circu*ar shaft '*ace the shaftsu''ort in ring com'ression+ /he bene-t of a circu*ar shaft is that thereinforcement in the structura* e*ements can be reduced and the need forinterna* su''ort is e*iminated+


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Construction Method

Timber Sheet andPiling/imber 'i*ing is

ine"'ensi#e and, onceinsta**ed, #er( eas( to)or3 )ith

/he method can be

economica* to starte"ca#ating in soft materia*,not dee'er than about 20ft of soi* o#er*(ing roc3+


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Steel Sheet Piling Inter*oc3ing stee* sheet 'i*es, rather

than timber sheet 'i*es are common*(used to brace soft, )aterbearing groundif the e"ca#ation e"ceeds about 20 ft+

!"ca#ation usua**( begins after the 'i*edri#ing o'eration is com'*eted, un*essthe shaft is unusua**( dee'+


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Soldier Piles and Laggings Stee* A 'i*es, ca**ed so*dier 'i*es, usua**(

s'aced from E to 10 ft a'art, are dri#en tothe reuired de'th+

s the e"ca#ation 'roceeds, horizonta* timber*agging, usua**( . or 4in+ hard)ood, is

'*aced against the face of the e"ca#ation and)edged bet)een the Fanges of the A 'i*es+


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Liner Plates/he main ad#antage

of *iner '*ates is thattheir sma** size'ermits ease ofo'eration in *imited

)or3ing s'aces, and itis not necessar( toha#e s'ecia*

eui'ment to *ift or'*ace the *iner '*ates+


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Slurry Walls S*urr( )a**s are a series of e"ca#ated

'ane*s+ 'ane* is e"ca#ated andremains stab*e and o'en )ith the use ofs*urr(+

fter 'ane* #ertica*it( is chec3ed, areinforcement cage is *o)ered into thee"ca#ated 'ane*7s*ot+

/he s*urr( is dis'*aced )ith tremie

concrete and a**o)ed to harden+ &rimar('ane*s are insta**ed -rst+


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So*dier &i*esandLaggings

S*urr(


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Excavation Methods

Con#entiona* dri**, b*ast G remo#e stone(muc!out< to surface )ith a )inder+ If the shaft is to be*ined ;i+e+ sides to be co#ered )ith a concrete ore#en a stee* *ining


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"aise boring a 'i*ot ho*e is dri**ed-rst and in this case reamed out to

the fu** shaft diameter b( a *argereaming bit 'u**ed u')ards from thebottom of the shaft+


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#rilling $lindShafts %ith& Moles

/he J mo*e isa horizonta*

/9 modi-edfor shaft

boring+


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Shaft 9oring achine ;S9

Design and Construction of Shaft

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