Index 1.OBJECT1 2.INTRODUCTION Report _W-B.pdf · 9.2.Net Safe Bearing Capacity: ... Preparation of...

Index1.OBJECT.............................................................................................................12.INTRODUCTION.................................................................................................13.SCOPE OF WORK:...............................................................................................24.EXPLORATION PROGRAMME:...............................................................................25.METHODOLOGY OF FIELD INVESTIGATION:...........................................................45.1.Boring:...........................................................................................................45.2.Sampling:.......................................................................................................45.2.1.Disturbed Sampling (DS):..............................................................................45.2.2.Undisturbed Sampling (UDS):.........................................................................45.2.3.Transportation and storage of samples:...........................................................55.3.Standard Penetration Test (SPT):......................................................................55.4.Drilling in rock:...............................................................................................65.5.Ground Water Level Measurement:....................................................................76.STANDARDS AND GUIDELINES FOR FIELD INVESTIGATIONS:..................................77.GEOTECHNICAL LABORATORY TESTING:...............................................................88.GEOTECHNICAL ASSESSMENT AND FOUNDATION FEASIBILITY.............................................................................................................................................................98.1.DEPTH OF FOUNDATION...................................................................................98.1.1.FOUNDATION IN SOIL...................................................................................98.1.2.FOUNDATION IN ROCK................................................................................119.OPEN/ SHALLOW FOUNDATIONS IN SOIL............................................................119.1.Net safe bearing capacity from shear consideration:...........................................119.1.1.For Clay Soils (Φ = 0):................................................................................119.1.2.For C - Φ soils:...........................................................................................119.1.3.Reduction Factors:......................................................................................129.2.Net Safe Bearing Capacity:.............................................................................129.3.Determination of Safe Bearing Capacity (SBC) from SPT 'N' value considerations...1210.PILE FOUNDATIONS........................................................................................1510.1.Capacity of Piles in Intermediate Geo-material and Rock:..................................1510.2.Ultimate Capacity of Pile in Soils:...................................................................1710.3.Lateral Capacity of Pile..................................................................................1811.SUMMARY OF FOUNDATION DETAILS:...............................................................2012.LIMITATIONS:................................................................................................25

ANNEXURE

Individual Reports of all Structures

Preparation of Detailed Project Report for Up-gradation ofAusa – Waranga & Wardha – Butibori Section of NH361 inthe state of Maharashtra.

FINAL DETAILED PROJECT REPORTFINAL DETAILED PROJECT REPORTSUB SOIL EXPLORATION &SUB SOIL EXPLORATION &

ANALYSIS REPORTANALYSIS REPORTWARDHA-BUTIBORI WARDHA-BUTIBORI

SUB SOIL EXPLORATION & ANALYSIS REPORT

1. OBJECT

Conducting detailed Subsoil Investigation and recommendation of Net Safe Bearing

Capacity (SBC) for various structures of Ausa-Waranga & Wardha - Buttibori section

of NH361 in the state of Maharastra.

The entire project awarded consists of following four packages:

• Ausa – Chakur (58.2 km)

• Chakur – Loha (61.8 km)

• Loha – Waragaphata (70.7 km)

• Wardha-Butibori (60 km)

The present report consists of detailed engineering services for Wardha – Buttibori

section (NH – 361) from Km 85+300 to Km 28+800 (i.e., Salad to Butibori).

This Report Consists of:

Introduction

Scope of work

Methodology of subsurface Investigation

Sub soil profile

Analysis & sample Design

Foundation Recommendations

2. INTRODUCTION

This report presents the results of field explorations and Geotechnical engineering

studies performed for proposed major bridges (MJB), minor bridges (MIB) and

vehicle underpasses (VUP) in various predetermined locations. The purpose of the

explorations and studies is to identify subsurface conditions and formulate

Geotechnical recommendations for design and construction.

The main text of the report includes description of field explorations, laboratory

testing, subsurface conditions, conclusions and recommendations based upon review

of existing data, engineering studies and analysis.

Field and Laboratory works are conducted based on Indian Standard specifications

and, as per the requirement of project.

1




3. SCOPE OF WORK:

The scope of subsoil Investigation is to ascertain Geotechnical and geological

properties of substratum for design and construction of various types of foundations.

It is proposed to have exploration by drilling of boreholes at various locations of

given structures. Accordingly the exploration program of boreholes are taken upto a

maximum depth of 19.5 m or 3 m into hard rock whichever occurs earlier.

Undisturbed, Disturbed and Rock samples were collected appropriate to ground

conditions and transported them to Geotechnical laboratory. Laboratory tests are

conducted to determine the Index and Engineering properties of soil, rock and

suggested the Net Safe bearing capacity of the soil on which structures are to be

constructed. Engineering analysis was carried out for recommending the location

and Net Safe Bearing Capacity of foundation for the proposed structures.

4. EXPLORATION PROGRAMME:

Sub-Soil Investigation Plan

S. No. Existing chainage Proposed Chainage Type of Structure No of Boreholes

1 28+750 523+305 Half Trumpet 2

2 36+233 517+060 4 Lane VUP 1

3 38+853 514+515 MIB 1

4 39+810 513+566 MIB 1

5 43+607 509+760 MIB 1

6 43+905 509+462 MIB 1

7 44+830 508+583 MIB 1

8 45+789 507+773 2 Lane VUP 1

9 47+126 506+316 MIB 1

10 49+552 503+860 MIB 1

11

12Kelzar Bypass

501+930 2 Lane VUP 1

501+093 MIB-2 1

13 55+052 498+449 MIB 1

14 56+979 496+428 MIB 2

15 58+550 494+892 MIB 1

16

17

18

19

Seloo Bypass

493+270 Major Bridge 5

493+132 MIB-2 1

492+914 MIB-1 1

492+204 2 Lane VUP 1

20 65+961 487+542 MIB 1

2




S. No. Existing chainage Proposed Chainage Type of Structure No of Boreholes

21 67+122 486+368 MIB 1

22 67+725 485+759 MJB 9

23 72+328 477+600 2 Lane VUP 1

24 76+650 474+016 2 Lane VUP 1

25 Salod realignment 471+516 ROB 2

26 Salod reallignment 468+038 4 Lane VUP 1

Field Tests

Standard Penetration Test (SPT) was conducted at every 1.5m depth interval

in boreholes as per IS: 2131-1981.

Disturbed Samples (DS) and undisturbed Samples (UDS) were collected as

per IRC 78 – 2000 guidelines

Drilling in soft rock, weathered rock and in hard rock was carried out by

diamond core drilling method using double tube core barrels of Nx size and

obtained the rock cores.

Ground Water table was observed in each bore hole as per IS : 6935 - 1973

Following Laboratory Tests are Conducted on selected samples of Disturbed and

Undisturbed soil samples

Moisture content & Specific Gravity

Bulk Density

Grain Size Analysis

Atterbergs Limits

Free Swell Index

Triaxial Shear Properties – Cohesion, C and Friction Angle, Φ

Following Laboratory Tests are Conducted on selected Rock samples

3




Moisture content, Porosity & Density

Specific gravity

Uniaxial Compression test

5. METHODOLOGY OF FIELD INVESTIGATION:

The field exploration methods, sampling requirements, types and frequency of field

tests are performed based on project design requirements. Accordingly, we have

developed the overall investigation plan which enables us to obtain the data needed

to define subsurface conditions and perform Engineering analysis and design.

5.1. Boring:

Drilling of boreholes was carried out at specified locations to obtain information about

the subsoil profile, its nature, strength and also to collect soil samples for strata

identification and conducting laboratory tests. The sequence of boring was planned

after ascertaining preliminary nature of subsoil profile. Boring is carried out as per

the provisions given in IS: 1892-1979.

5.2. Sampling:

All the accessories used for sampling and the method of sampling adopted confirms

to IS: 2132. All the disturbed and undisturbed samples collected in the field have

been classified at the site as per IS : 1498.

5.2.1. Disturbed Sampling (DS):

Disturbed soil samples were collected from bore holes at regular intervals to

determine the soil type, grain size distribution, Atterberg limits and soil classification.

5.2.2. Undisturbed Sampling (UDS):

In each borehole, undisturbed samples are collected at every change of strata.

Undisturbed sampler tubes are made up of 100mm diameter, 450mm long MS tubes

provided with sampler head with ball check arrangement. Samples are collected in

such a manner that the structure of soil and its moisture content do not get altered.

At few locations, the sampling tubes could not be pushed into the soil because of

hard consistency. The specifications for the accessories used for sampling and the

sampling procedure adopted conforms to IS:1892 and IS:2132. Undisturbed samples

are used to determine the shear parameters, natural moisture content and unit

weight.

4




5.2.3. Transportation and storage of samples:

Undisturbed Samples are hand carried holding them in vertical. Shipping and storage

was done vertically in most of the situations. Samples are kept as near to ground

temperature during shipping. Samples are stored in a dark humid room having 90 -

94% humidity to prevent loss of moisture.

5.3. Standard Penetration Test (SPT):

Standard Penetration Test (SPT) was conducted at different depths in all boreholes.

For shallow depths SPT was conducted at close intervals of 1.5m. SPT split spoon

sampler of standard dimensions was driven into the soil from borehole bottom using

63.5kg hammer falling from 75cm height. The SPT weight was mechanically lifted to

the specified height and allowed to free fall. Blow count for each of three 15cm

penetrations was recorded and the N is reported as the blows count for the last 30cm

penetration of the sampler leaving the first 15cm penetration as seating drive. When

the number of blows exceeded 50 to penetrate the first or second 15cm length of the

Sampler, the SPT ‘N’ is regarded as more than 100 as described in IS: 2131 - 1981.

SPT refusal is recorded when there is no penetration of the sampler at any stage and

also when a rebound of the sounding system is recorded. Samples from the SPT split

spoon sampler was preserved in polythene covers and transported to the laboratory.

One more polythene cover was provided to prevent the loss of moisture during the

transit.

The degree of denseness or looseness of natural deposited cohesionless soils can be

measured in terms of their relative density. SPT ‘N’ values are correlated with

relative density of non - cohesive stratum and with consistency of cohesive stratum.

Correlation for Sand/ non-plastic Silt Correlation for Clay/ Plastic soils

Penetration Value(N)

RelativeDensity

Penetration Value(N)

Consistency

0 - 4 Blows Very Loose 0 - 2 Blows Very Soft

4 - 10 Blows Loose 2 - 4 Blows Soft

10 - 30 Blows Medium Dense 4 - 8 Blows Medium

30 - 50 Blows Dense 8 - 15 Blows Stiff

>50 Blows Very Dense 15 - 30 Blows Very Stiff

>30 Blows Hard

5




5.4. Drilling in rock:

For drilling in rock, drilling was advanced by rotary core drilling method using double

tube core barrels with T.C bit or diamond bit as per the guidelines of IS:6926-1996.

The maximum length of drill run maintained is 1.0m. At the end of each run, the drill

rod string with core barrel is extracted from the Borehole and core is recovered

from the core barrel. The percentage of core recovery is recorded and the core

pieces are transferred to the core box duly numbered and labeled properly. The

selected core samples are sent to the laboratory for conducting tests. The rock core

samples are preserved and stored in wooden core boxes as specified in IS:4078 –

1980

Rock classification in terms of weathering, state of fractures and strength is carried

out in the following manner. (As per IS: 4464)

Term Description Grade Interpretation

Fresh No visible sign of rock material weathering; perhapsslight discoloration on major discontinuity surfaces

I CR > 90 %

Slightly

Weathered

Discoloration indicates weathering of rock material anddiscontinuity surfaces. All the rock material may bediscolored by weathering.

II CR between70% to 90%

Moderately

Weathered

Less than half of the rock material is decomposed ordisintegrated to a soil. Fresh or discolored rock ispresent either as a continuous framework or as corestones.

III CR between51% to 70%

Highly

Weathered

More than half of the rock material is decomposed ordisintegrated to a soil. Fresh or discolored rock ispresent either as a discontinuous framework or ascore stones

IV CR between11% to 50%

Completely

Weathered

All rock material is decomposed and / or disintegratedto soil. The original mass structure is still largelyintact.

V CR between

zero to 10%

Residual

Soil

All rock material is converted to soil. The massstructure and material fabric are destroyed. There is alarge change in volume, but the soil has not beensignificantly transported.

VICR = Zero

But N > 50

6




RELATION BETWEEN RQD AND IN-SITU ROCK QUALITY

Rock quality is further measured by frequency of natural joints in rock mass. Rock

Quality Designation (RQD) is used to define state of fractures or massiveness of rock.

Following table defines the quality of rock mass.

RQD CLASSIFICATION RQD (%)

Excellent 91-100

Good 76-90

Fair 51-75

Poor 25-50

Very Poor <25

As per IS: 13365 Part -1: 1998

CLASSIFICATION OF ROCK WITH RESPECTIVE OF COMPRESSIVE STRENGTH

Rock is also classified by strength of intact rock cores collected during drilling. Rock

Compressive strength (UCS) is used to define strength of rock. Following table

summarizes classification of rock based on strength.

5.5. Ground Water Level Measurement:

The depth of ground water level is supposed to be measured during boring and

thereafter the ground water is stabilized as per IS:6935 - 1973.

6. STANDARDS AND GUIDELINES FOR FIELD INVESTIGATIONS:

Field exploration by boring was as per below given standards:

S.No

IS Code No: Title

1 IS : 1892 - 1979Code of Practice for sub surface investigation for foundations

2 IS : 1498 - 1970Classification and Identification of Soils for General Engineering Purpose

3 IS : 2131 - 1981Method for Standard Penetration Test (SPT) for Soils

4 IS : 2132 - 1986Code of Practice for Thin- Walled tube sampling of Soils

7




S.No

IS Code No: Title

5 IS : 4464 - 1985Code of practice for presentation of drilling information and core description in foundation investigation

6 IS : 5313 - 1980 Guide for core drilling observations

7 IS : 4078 - 1980Code of practice for indexing and storage of drill cores

8 IS : 6926 - 1996Diamond core drilling-Site investigation for river valley projects-code of practice

9 IS : 6935 - 1973Method of determination of water level in a bore hole

10IS: 6065 (part-1) - 1985

Recommendations for the preparation of Geological and Geotechnical maps for river valley projects

7. GEOTECHNICAL LABORATORY TESTING:

Laboratory tests are performed on selected samples in our Geotechnical and Material

testing laboratory, Bowenpally, Secunderabad. Laboratory tests comprises of the

following tests conducted as per procedures given in relevant IS codes.

Following tests are conducted on Undisturbed samples:

i) Sieve Analysis

ii) Atterberg Limits

iii) Free Swell Index (FSI)

iv) Triaxial test (UU)

v) NMC & Bulk density

vi) Specific Gravity

Following tests are conducted on SPT samples:

i) Sieve Analysis

Following tests are conducted on Rock Samples:

i) Water Absorption , Dry density, Porosity and Specific Gravity

ii) Uniaxial Compressive Strength (UCS)

iii) Point Load Index Test (as per requirement)

8




8. GEOTECHNICAL ASSESSMENT AND FOUNDATION FEASIBILITY

By observing the nature of subsurface strata, the type of foundation for a given

proposed structure, expected heavy loads on piers and abutment foundations, the

following types of foundations can be recommended.

a) Shallow Foundations

b) Deep/ Pile Foundations

For satisfactory performance of a foundation, the following criteria must be satisfied;

I. The foundation must not fail in shear.

II. The foundation should not settle by an amount more than the permissible settle-

ment.

The smaller of the bearing pressure values obtained according to above (I) and (II),

is adopted as the allowable bearing capacity.

8.1. DEPTH OF FOUNDATION

Depth of Analysis:

For footing resting on multilayer deposits, weighted average or average of the ‘C’ and

‘Ø’ values upto a depth of ‘H’ = 0.5 B Tan (45 + Ø/2)

8.1.1. FOUNDATION IN SOIL

A foundation must have an adequate depth from the considerations of adverse

environmental influences. It must also be economically feasible in terms of overall

structure. Depth of foundation in soil shall be decided as per Clause 705.2 of IRC 78

for open foundations and confirmed with clause 7 of IS : 1904 for special cases like;

where volume change/ scour is expected/ or when foundation is to rest on sloping

ground/ made or filled up ground/ frost action is expected etc.

Scour depth calculation:

Hydrology for the structures is calculated separately and presented whereas,

maximum scour depth based on erodible strata has been worked out and presented

in summary of borelog results itself. If the strata at which founding level arrived

based on scour depth is soil, the founding level has been arrived as explained below

(i.e Founding level = H.F.L- 2*dsm - 2 in case of piers and H.F.L – 1.27*dsm - 2 in

case of abutments) as per IRC : 78 provisions.

9




Silt Factor:

This is important factor for determining the scour depth of erodible strata. It is

calculated using following procedure as per IRC:78 (clause 703.2.2) & as suggested

in IRC: 5 (clause 110.1.3)

Where Ksf = 1.76√(dm)

Ksf = Silt Factor

dm = Mean Diameter in mm

The mean scour depth below Highest Flood Level (HFL) for natural channels flowing

over erodible bed can be calculated as per IRC : 78 (clause 703.2)

dsm = 1.34 *(Db 2/ Ksf )1/3

Where Db = The design discharge for foundation per metre width at

effective linear water way

Ksf = Silt factor for a representative sample of bed material obtained

upto the level of anticipated scour

The minimum depth of Open foundation shall be upto the stratum having safe

bearing capacity but not less than 2.0m below scour level or protected level as per

IRC:78 (Clause 705.2.1)

Floor Protection:

When high discharges are encountered in a stream water flows turbulently which

results in erosion of the bed. To prevent this, floor protection can be suggested for an

economic shallow/ open foundation. As per IRC: 78 – 2000, clause 703.3.2, for the

design of floor protection works for open foundations, the following values of

maximum scour depth may be adopted:

I) In a straight reach : 1.27 dsm

II) In a bend : 1.50 dsm or on the basis of concentration of flow

10




8.1.2. FOUNDATION IN ROCK

As per clause 705.2.2 (a) of IRC:78; for hard rock with an ultimate crushing

Strength of 12.5 MPa or above, the depth of foundation shall be 0.60m below rock

surface and 1.50m for all other cases. The embedment of the foundations shall be

decided keeping in view the overall characteristics like fissures, bedding plans,

cavities, ultimate crushing strength, proposed treatment of foundation strata etc.

9. OPEN/ SHALLOW FOUNDATIONS IN SOIL

The safe bearing capacity of soil is the net intensity of loading which the foundation

will carry, without undergoing settlement in excess of the permissible value for the

structure under consideration.

9.1. Net safe bearing capacity from shear consideration:9.1.1. For Clay Soils (Φ = 0):

The net ultimate bearing capacity immediately after construction on fairly saturated

homogeneous cohesive soils shall be calculated using following equation.

qd = C Nc Sc dc ic ; Where Nc = 5.14

The value of ‘C’ shall be obtained from unconfined compressive strength test or static

cone penetration test or triaxial shear (UU) test.

Alternatively Net ultimate bearing capacity can be determined by using the following

equation;

qd = C Nc Sc dc ; Where qd = Net ultimate bearing capacity

A factor of safety of 2.5 is used

Considering Φ = 0, Nc = 5.14

Thus the equation is simplified as

q (net safe) = 1/ 2.5 *C*5.14 Sc dc

= 2.056 C Sc dc

9.1.2. For C - Φ soils:

For General shear:

Φ ≥ 360 and C ≥ 5 t/m2

qd = C Nc Sc dc ic + q ( Nq-1) Sq dq iq + 0.5 g B Ng Sg dg ig W '

11




For Local shear:

Φ ≤ 280 and C ≤ 3 t/m2

qd = (2/3) c Nc Sc dc ic + q ( Nq-1) Sq dq iq + 0.5 g B Ng Sg dg ig

For Intermediate Shear:

Average or interpolate between Local and General Shear.

9.1.3. Reduction Factors:

Determined Bearing Capacity Factors Nc , Nq, Nγ from Table 1 of IS : 6403-1981

Shape factors Sc Sq Sγ from Table 2 of IS : 6403 - 1981

Depth factors dc dq dγ from clause 5.1.2.2 of IS : 6403 - 1981

Inclination factors ic iq iγ from clause 5.1.2.3 of IS : 6403 – 1981

9.2. Net Safe Bearing Capacity:

Net safe bearing capacity is obtained by dividing the above Net Ultimate bearing

capacity by the factor of safety of 2.5.

N et S afe Bearing C apacity =1

FOS× N et ultimate b ea ring capacity

9.3. Determination of Safe Bearing Capacity (SBC) from SPT 'N' value con-siderations

As there is neither undisturbed sample nor C, Φ values are available, but only N

values are available, Net Safe Bearing Capacity has been assessed based on SPT (N)

values. Therefore the safe bearing capacity of foundation soil at proposed founding

depth based on corrected SPT (N) value is determined using following theories.

12




I) Based on Terzaghi-Peck Theory:

qa=3 . 35∗C b∗ N−3 ∗[ B+ 0 . 32B ]

2

∗W γ∗d t

where,

qa = Allowable net increase in soil pressure (t/m2).

Cb = Correction Factor

N = Corrected SPT number

B = Width of footing (m)

wγ = Water table Correction Factor

dt = Depth Factor

II) Based on Teng’s Theory:

qa=35∗ N−3∗[ B+ 0 .32B ]

2

∗W γ∗Rd

qa = Allowable net increase in soil pressure (kN/m2).



wγ = Water table Correction Factor

Rd = Depth Correction Factor 2.01 B

D+ f

III) Based on Peck’s Theory:

q a=0 . 41∗C w∗N∗S

where,

qa = Safe settlement Pressure (kN/m2)

Cw = Water table Correction Factor =0 . 50 . 5∗D w

D f +B


S = Settlement (mm)

13




IV) Based on Meyerhof’s Theory:

q a=C b∗[ N∗S20 . 8 ]∗d m . . . . . . . . IfB<1 . 2m qa=C b∗[ N∗S

31. 2 ]∗d m . . . . . . . . IfB>1 . 2m

Where

qa = Allowable net increase in soil pressure (t/m2).



Cb = Correction Factor

dm =10 . 3∗D f

B≤1. 33

V) Based on Bowle’s Theory:

q a=0 . 73∗N∗R D1∗S . . . . . . . IfB< 1 . 2m

qa=0 . 48∗N∗RD2∗[ B+ 0. 32B ]

2

∗S . . . . . . . IfB> 1 . 2m Where

qa = Safe Bearing Pressure (kN/m2)


S = Settlement (mm)

RD1 =10 . 2∗D f

B≤1 . 20

RD2 =10 . 3∗D f

B≤1. 33

14




10. PILE FOUNDATIONS

The total vertical load carrying capacity of pile foundation is a combination of skin

friction resistance along the surface and end bearing resistance at pile tip, when Piles

are installed through layered soils. The pile design in soft soils has relatively high

skin friction resistance and granular soils have high end bearing resistance. Generally

piles resting on sound rock can be loaded to their safe structural capacity. But for the

piles resting on weathered rock it is necessary to provide Socketing depth. In the

present situation socketing depth has been considered based on IS 14593-1998,

Table 1 of Clause 6.5.1 and IRC 78-2009 amendments. The General practice of

calculating Ultimate Bearing capacity of pile socketed into the rock is of following

categories:

a) Ultimate load capacity calculated from end bearing resistance only.

b) Ultimate load capacity calculated from skin frictional resistance only.

c) Ultimate load capacity calculated from combination of both skin friction &

end bearing resistance.

d) Ultimate load capacity calculated from end bearing resistance and ultimate

side socket shear in case of piles resting on rock.

IRC: 78– 2009 amendments suggests the following methods for calculation

of pile capacities

10.1. Capacity of Piles in Intermediate Geo-material and Rock:

The ultimate load carrying capacity may be calculated from one of the two

approaches given below:

Where Cores of the rock can be taken and Unconfined Compressive Strength directly

established using standard method of testing, the approach described in Method 1

can be used. In situations where RQD shows highly fragmented strata (which is not

classified as granular or clayey soils), the approach described in Method 2 (Cole and

Stroud approach) can be used. Also for weak rock like Chalk, mudstone, claystone,

shale and other intermediate rocks this method is preferred.

15




Method:1

where Qu = Re + R af =Ksp qc df Ab + AsCus

Qu = Ultimate Capacity of Pile socketed into rock in Newtons

Re = Ultimate End Bearing

Raf = Ultimate Side Socket Shear

Ksp = An Empirical Co-efficient whose value ranges from 0.3 to

1.2 as per the table given below for the rocks where core

recovery is reported and cores tested for Uniaxial

Compressive Strength.

(CR+RQD)/ 2 Ksp

30% 0.3

100% 1.2

CR = Core Recovery in %

RQD = Rock Quality Designation in %

For Intermediate values, Ksp shall be linearly interpolated.

qc = Average Unconfined Compressive strength of Core below

base of pile for a depth twice the diameter /least lateral

dimension of pile in Mpa.

Ab = Cross sectional area of base of Pile

df = Depth Factor = 1 + 0.4 Length of Socket/ Diameter of

Socket. However, value of df, should not be taken more

than 1.2.

As = Surface area of Socket

Cus = Ultimate Shear strength along socket length = 0.225√qc

For calculation of Socket resistance the same should be restricted to 3 MPa.

16




Method: 2

This method is applicable when cores and /or core testing results are not available or

when geo-material is highly fragmented. The shear strength of geo-material is

obtained from its correlation with extrapolated SPT values for 300mm of penetration

as given in table below.

Shear Strength/ Consistency Moderately Weak Weak Very Weak

Approx 'N' Value 300 – 200 200 – 100 100 – 60

Shear Strength/ Cohesion in MPa 3.3 – 1.9 1.9 – 0.7 0.7 – 0.4

Qu = Re+R af = Cub Nc Ab+ As.Cus

Cub = Average shear strength below base of pile for the depth twice the

diameter / least lateral dimension of the pile

Cus = Ultimate Shear strength along socket length = 0.225√qc

For calculation of Socket resistance the same should be restricted to 3 MPa.

L = Length of Socket

Nc = 9

10.2. Ultimate Capacity of Pile in Soils:The Ultimate capacity of Pile socketed into the Rock shall be calculated using

following equation.

Qu=Qep+Q sf

Qu=A p∗(C p∗N c+q∗N q+0 . 5∗D∗γ∗N γ )+((∑ K∗PDi*tanδ )∗Asi+α∗C∗As )

Where ,

Qu = Total Ultimate capacity of pile in Soil

Qe = Ultimate End bearing resistance

Qsf = Ultimate Skin frictional resistance

Cp = Average cohesion at pile tip

Nc = Bearing capacity factor as per IS 2911(Part 1)

q = Effective over-burden pressure at pile tip

17




Nq, Nγ = Bearing Capacity factors depending on angle of internal friction 'Ø'

at toe.

= Effective Unit weight of bearing soil layer

D = Diameter of the pile.

AP = Cross sectional area of base of pile.

K = Coefficient of earth pressure

PDi = Effective overburden pressure at center of gravity of the pile

δ = Angle of wall friction between pile and soil (taken as 2/3 of Ø )

Asi = Surface area of the pile stem.

= Reduction factor as per IS 2911(Part 1)

As = Surface area of the pile shaft.

C = Average cohesion through out the length of the Pile.

Total Ultimate Safe Capacity of Pile:

Total Ultimate Safe capacity of the pile in rock is obtained from above ultimate

capacity divided by factor of safety of 3 for end bearing resistance and 6 for side

socket shear resistance. Where as In soils the total safe capacity is obtained by

dividing the ultimate capacity with a factor of safety of 2.5 for both end bearing

resistance and skin friction resistance.

Q s=Re

F . S+R af

F .S &

10.3. Lateral Capacity of Pile

The Long flexible pile, fully or partially embedded, is treated as a cantilever fixed at

some depth below the ground level. The Depth of Fixity and hence the Equivalent

Length of Cantilever are determined using the plots of Fig: 2 of 2911-Part I-2.

Where T = 5√EI/K1 for sands and normally loaded clays; R = 4√EI/K2 for Over-

consolidated Clays

T, R are the Relative Stiffness Factors

K1 and K2 are constants in kg/cm2 given in Table 1 and 2 of 2911-Part I - 2

18

Q s=Qep

F.S+Q sf

F.S−W p




E is the Young's Modulus of the Pile Material in Kg/cm2

I is the Moment of Inertia of the Cross Section in cm4.

Fig: 2 of 2911-Part I-2 is valid for Long Flexible Piles where the embedded Length Le

is ≥ 4R or 4T.

Knowing the Length of Cantilever, the Pile head deflection (Y) shall be computed

using the following Equation:

Y in cm = Q(L1+Lf)3/ 3EI, for free Head Pile

Y in cm = Q(L1+Lf)3/ 12EI, for fixed Head Pile

Where L1 is the Free standing length/ Unsupported length of pile

Lf is the Depth of fixity Q is the Lateral Load in kg.

19

Preparation of Detailed Project Report for Up-gradation of Ausa – Waranga & Wardha –Butibori Section of NH361 in the state of Maharashtra.

FINAL DETAILED PROJECT REPORTFINAL DETAILED PROJECT REPORTSUB SOIL EXPLORATION & ANALYSIS REPORTSUB SOIL EXPLORATION & ANALYSIS REPORT

WARDHA-BUTIBORI WARDHA-BUTIBORI

11. SUMMARY OF F OUNDATION DETAILS:

S.No.

Existingchainage

ProposedChainage

Type ofStructure

RL of theground

(m)

ScourLevel(m)

Type ofFoundation

RL of thefoundation

(m)

Foundationsize

L* x B* (m)

FoundationStrata

SafeBearingcapacity(t/m2)

Pilecapacity

(t)

Lateralcapacity

(t)

1 28+750 523+305 HalfTrumpet 262.952 - Raft 261.847 12.5 x 8 Stiff to Very

Stiff Sandy Clay15 - -

2 36+233 517+060 4 Lane VUP 290.444 - Raft 289.444 24 x 14.5 Soft DisintegratedROCK

40 - -

3 38+853 514+515 MIB 262.952 - Raft 261.847 12.5 x 8 Stiff to VeryStiff Sandy Clay

15 - -

4 39+810 513+566 MIB 261.967 - Raft 258.868 12 x 5 Highly WeatheredStrong Rock

50 - -

5 43+607 509+760 MIB 261.857 - Raft 257.357 12.5 x 12 Soft DisintegratedROCK

45 - -

6 43+905 509+462 MIB 258.624 - Raft 257.222 14.5 x 6Soft

DisintegratedROCK

45 - -

7 44+830 508+583 MIB 257.302 - Raft 253.91 14.5 x 12 Reddish Hard Clay 35 - -

8 45+789 507+773 2 Lane VUP 269.640 - Raft 268.640 14.5 x 12Medium DenseClayey Gravel

with Sand35 - -

20




S.No.

Existingchainage

ProposedChainage

Type ofStructure

RL of theground

(m)

ScourLevel(m)

Type ofFoundation

RL of thefoundation

(m)

Foundationsize

L* x B* (m)

FoundationStrata


Pilecapacity

(t)

Lateralcapacity

(t)

9 47+126 506+316 MIB 260.200 - Isolated 259.200 12 X 5ModeratelyWeathered

Strong ROCK50 - -

10 49+552 503+860 MIB 267.390 - Raft 263.959 14.5 X 10.0 Highly WeatheredVery Weak Rock

45 - -

11KelzarBypass

501+930 2 Lane VUP 281.631 - Raft 280.631 12 x 5

CompletelyWeathered

Extremely WeakRock

45 - -

12KelzarBypass

501+093 MIB-2 282.659 - Raft 281.65912.50 X

6.0Soft

DisintegratedRock

45 - -

13 55+052 498+449 MIB 260+191 - Raft 257.312 21 x 12.5Soft Disintegrated

ROCK40 - -

14 56+979 496+428 MIB 257.362 - Raft 253.570 36 x 14.5 Dense Silty SAND 40 - -

15 58+550 494+892 MIB 258.522 - Raft 255.030 25 x 12.5Soft Disintegrated

ROCK50 - -

21




S.No.

Existingchainage

ProposedChainage

Type ofStructure

RL of theground

(m)

ScourLevel(m)

Type ofFoundation

RL of thefoundation

(m)

Foundationsize

L* x B* (m)Foundation Strata


Pilecapacity

(t)

Lateralcapacity

(t)

16Seloo

Bypass493+270

MJB – A1 258.955 254.210 Pile 240.955 1.20Completely

Weathered VeryWeak Rock

- 350 30

MJB – P1 259.050 251.620 Pile 240.050 1.20 Highly WeatheredRock

- 300 30

MJB – P2* 255.890 251.610 Pile 235.890 1.20 Highly WeatheredRock

- 300 30

MJB – P3 252.940 250.640 Open 248.440 10 x 5Highly WeatheredExtremely Weak

Rock55 - -

MJB – A2 258.012 253.230 Pile 246.012 1.20Moderately

Weathered StrongRock

- 450 30

17 SelooBypass

493+132 MIB-2 256.477 - Raft 255.477 12.5 X 6 Stiff Sandy Claywith Gravel

15 - -

18 SelooBypass

492+914 MIB-1 264.267 - Raft 263.267 12.5 X 6 Very Stiff SandyClay

18 - -

19 SelooBypass

492+204 2 Lane VUP 265.208 - Raft 263.708 14.5 x 12 Medium DenseSilty Sand

15** - -

20 65+961 487+542 MIB 248.545 - Raft 246.722 14.5 X 8 Stiff Sandy Clay 12/20** - -

21 67+122 486+368 MIB 241.729 - Raft 240.729 12.5 X 10Reddish Medium

dense ClayeySand

20 - -

22




S.No.

Existingchainage

ProposedChainage

Type ofStructure

RL of theground

(m)

ScourLevel(m)

Type ofFoundation

RL of thefoundation

(m)

Foundationsize

L* x B* (m)Foundation Strata


Pilecapacity

(t)

Lateralcapacity

(t)

22 67+725 485+759

MJB – A1 241.868 241.868 Open 236.868 10 x 5Moderately

Weathered WeakRock

45 - -

MJB – P1 241.795 241.795 Open 238.295 10 x 5 Highly WeatheredWeak Rock

45 - -

MJB – P2 240.733 240.733 Open 237.733 10 x 5 Slightly WeatheredStrong Rock

80 - -

MJB – P3 236.349 234.849 Open 233.349 10 x 5 Slightly WeatheredStrong Rock

100 - -

MJB – P4 236.175 234.675 Open 233.175 10 x 5Slightly WeatheredModerately Strong

Rock60 - -

MJB – P5 238.337 236.337 Open 234.837 10 x 5Moderately

Weathered Rock50 - -

MJB – P6 240.231 237.231 Open 235.231 10 x 5Highly Weathered

Rock45 - -

MJB – P7 240.895 237.895 Open 235.895 10 x 5Slightly Weathered

Strong Rock70 - -

MJB – A2 241.684 238.684 Open 236.684 10 x 5Highly WeatheredVery Weak Rock

45 - -

23




S.No.

Existingchainage

ProposedChainage

Type ofStructure

RL of theground

(m)

ScourLevel(m)

Type ofFoundation

RL of thefoundation

(m)

Foundationsize

L* x B* (m)

FoundationStrata


Pilecapacity

(t)

Lateralcapacity

(t)

23 72+328 477+600 2 Lane VUP 276.811 - Raft 275.311 14.5 x 12Brownish MediumDense Sand With

Gravelly Clay40 - -

24 76+650 474+016 2 Lane VUP 286.204 - Raft 285.204 12 x 5Highly WeatheredModerately Strong

ROCK 50 - -

25Salod

realignme-nt

471+516

ROB – A1 266.885 - Open 264.885 10 x 5Moderately

weathered andstrong rock

60 - -

ROB – P1 267.175

- Open 265.175 10 x 5Moderately


50 - -

- Pile 261.275 1.20Moderately


- 350 20

ROB – P2 267.338

- Open 265.338 10 x 5 Highlyweathered rock

50 - -

- Pile 261.438 1.20 Highly weatheredrock - 350 20

ROB – A2 268.306 - Open 266.306 10 x 5 Highly weatheredrock 50 - -

24




S.No.

Existingchainage

ProposedChainage

Type ofStructure

RL of theground

(m)

ScourLevel(m)

Type ofFoundation

RL of thefoundation

(m)

Foundationsize

L* x B* (m)

FoundationStrata


Pilecapacity

(t)

Lateralcapacity

(t)

26Salod

reallignme-nt

468+038 4 Lane VUP 253.699 - Raft 252.699 24 X 14.5Soft

DisintegratedROCK

40 - -

Note: CWR=Completely weathered Rock, MWR=Moderately weathered Rock, DSS= Dense Silty Sand, DCG= Dense Clayey Gravel, SSC= Stiff Sandy Clay, VSC= Very Stiff Clay, DCS = Dense Clayey Sand* Along with 0.5 m replacement below foundation level with granular material.

Note : All Individual bridge reports along with calculations are enclosed in the Annexure.

12. LIMITATIONS:

Recommendations contained in this report are based on our field observations, subsurface exploration, laboratory tests and some assumptions.It is possible that soil conditions could vary between or beyond the points explored. If soil conditions encountered during construction differsfrom those described herein, concerned person at construction is requested to notify the same immediately in order that a review may be madeand any supplementary recommendations be provided.

For aarvee associates architects engineers & consultants pvt. ltd.

25

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