Pyramid Ashok Mega Structure Pvt. Ltd. Nagpur. · GSR&C/0079/13- 14 Page 1 of 5 GEOsystemsTM 1....

G E O T E C H N I C A L I N V E S T I G A T I O N

R E P O R T

• Project name :

P 0066

Proposed Construction of Pyramid City Type-VI

Residential Complex at Besa, Beltarodi, Nagpur.

• Report No. :

GSR&C/0066/2013 – 14 Dt. 25/03/2014

• Client/Authority :

Pyramid Ashok Mega Structure Pvt. Ltd. Nagpur.

• Ref. Work Order /date : ---Nil--- Dtd. 05/03/2014

• Material Category : SOIL

• Sampled by : GEOsystems Research & Consultants ( I) Pvt. Ltd.

• Sample condition : Sealed

• Type of test performed : As Given in report

• Date of Start of Work /test : 05/03/2014 Onwards

• Testing Method : As per BIS

VIJAYA GROUP ENTERPRISES

GEOsystems Research & Consultants (I) Pvt. Ltd. *Geotechnical Investigation * Soil, Steel, Concrete & Material testing Laboratory

M 1 - M2 Pushpkunj Comp. 26 , Farmland Central Bazar Road , Ramdaspeth , Nagpur – 10

TEL NO.; (0712) - 6618585 / 6611855, 2423984 Fax. No. 6618585

Email : [email protected]

Project Name :

P 0066

Proposed Construction of Pyramid City

Type-VI Residential Complex at Besa,

Beltarodi, Nagpur.

Report No.: :

GSR&C/0066/2013 – 14 Dt. 25/03/2014

Client /Authority :


Geotechnical Investigation for

Proposed Construction of Pyramid City Type-VI Residential

Complex at Besa, Beltarodi, Nagpur.

C O N T E N T S

1. Introduction………………………………………………………………… Pg. no.1

2. Stratification .………………………………………………....…………… Pg. no.1 - 2

3. Investigations ……………………………………………………………… pg. no.2 - 3

4. Computation of SBC ……………………………………………………. Pg. no. 3 - 4

5. Discussion and Recommendations ………………………………….. Pg. no.4 - 5

Annexure

1. Annexure I – Borelog ……………………………………………… Sheet no.1 to 4

2. Annexure II – Summary of Results………………………………... Sheet no.1

3. Annexure III – Calculation of SBC. ……………………………... Sheet no.1 to 4

4. Annexure IV – Sample Calculation …………………………... Sheet no.1 to 2

GSR&C/0079/13- 14 Page 1 of 5 GEOsystemsTM

1. INTRODUCTION:

Pyramid Ashok Mega Structure Pvt. Ltd. Nagpur has proposed to construct the Pyramid City Type-VI, a

Residential Complex at Besa, Beltarodi, Nagpur.

M/s. GEOsystems Research & Consultants (I) Pvt. Ltd. Nagpur was awarded with the job of

geotechnical Investigations to generate the required geotechnical parameters for design of suitable

foundations.

GEOsystems Research & Consultants (I) Pvt. Ltd. has completed the work of soil investigation at 4

boreholes locations. The test locations and depth of investigation were decided by the client. Standard

penetration tests (SPT) were conducted in boreholes. Disturbed & undisturbed soil samples were collected

from boreholes for laboratory testing. UU-triaxial shear test along with other soil tests were carried out in

laboratory to ascertain the safe pressure on the encountered strata.

The Allowable Bearing Capacity is presented in clause - 5 of this report (Findings & Recommendations). All

the tests were conducted as per B.I.S. codes.

2. STRATIFICATION:

The general stratification is reported below after completing the boring work at 4 nos. of borehole locations

up to maximum 9.00m (BH-1) depth from GL and as per samples recovered from site & tested in the

laboratory.

Borehole no 1:

At the top 3.00m thick layer of black clayey soil was encountered, followed by 3.00m thick layer of yellow

clayey soil up to 6.00m depth from GL. Below this layer 3.00m thick layer of yellow clayey sandy soil was

encountered up to 9.00m from GL (depth of borehole & investigation). The shear parameters obtained from

3.00m to 4.50m from UU- Triaxial test are ranges from C = 67 kN/m2 to 62 kN/m2 and φ = 10 to 1.50 .

The SPT values noted from 6.00m to 9.00m depth were ranges from N=12 to N=19.

Borehole no 2:

At the top 3.50m thick layer of black clayey soil was encountered up to 3.50m depth from GL. This layer was

followed by 2.95m thick layer of yellow clayey soil up to 6.45m depth from GL (depth of borehole &

investigation). The shear parameters obtained from 3.00m to 4.50m from UU- Triaxial test are ranges from

C = 60 kN/m2 to 64 kN/m2 and φ = 1.50 to 20 .

The SPT values noted at 6.00m depth was N=13.

Borehole no 3:

At the top 4.50m thick layer of black clayey soil was encountered, followed by 1.95m thick layer of yellow

clayey soil up to 6.45m depth from GL (depth of borehole & investigation). The shear parameters obtained

from 3.00m to 4.50m from UU- Triaxial test are ranges from C = 59 kN/m2 to 63 kN/m2 and φ = 1.50 .

The SPT values noted at 6.00m depth was N=10.


Borehole no 4:

At the top 3.50m thick layer of black clayey soil was encountered up to 3.50m depth from GL. Below this

layer 2.95m thick layer of yellow clayey soil was encountered up to 6.45m depth from GL (depth of borehole

& investigation). The shear parameters obtained from 3.00m to 4.50m from UU- Triaxial test are ranges

from C = 54 kN/m2 to 59 kN/m2 and φ = 1.50 to 2.50 The SPT values noted at 6.00m depth was N=13.

Water table was not encountered at all the above mentioned borehole locations.

The detailed borelogs are presented in Annexure I sheet no.1 & 2 of this report.

3. INVESTIGATIONS:

A ) Field tests

3.1 Drilling Work:

Boring was carried out using rotary drilling method. The work was in general accordance to IS: 1892-1979.

3.2 Standard Penetration Test:

Standard penetration number N is the penetration resistance in terms of number of blows for 30 cm.

penetration of split spoon sampler (test conducted as per IS: 2131: 1981).

3.3 Collection & Preservation of Undisturbed & Disturbed soil samples from Boreholes:

Undisturbed & Disturbed soil samples were collected from the boreholes for laboratory tests. These samples

were sealed and transported in the laboratory with care and stored properly. After that further tests were

carried out on the samples.

Kindly note that representing soil samples & rock samples were preserved for 3 months only from the date

of report, any query should be raised before that.

3.4 Ground Water Table:

At present ground water table was not encountered at the time of investigation, however seasonal variation

in ground water table is expected.

B) Laboratory tests

3.5 Grainsize analysis:

In laboratory, the soil samples collected were tested for soil classification, summary of grain size analysis

(IS: 2720 Part – 4) are presented in Annexure II sheet no.1 of this report.


3.6 Atterberg Limits, Free Swell Index & Classification:

Liquid limit, Plastic limits & Plasticity index (IS: 2720 Part – 5 & 6), Free swell Index (IS: 2720 Part – 40 )

tests were conducted on the soil samples collected and are classified as per IS : 1498 (1978) ,summary of

results are presented in the Annexure II sheet no.1 of this report.

3.7 Triaxial Shear Test:

Unconsolidated Undrained (UU) Triaxial shear test (IS: 2720 Part –11: 1971) was conducted on undisturbed

soil samples and C and Ø parameters were obtained. The bearing capacity has been worked out from these

values and calculated as per IS 6403:1981. The results are presented in Annexure: III Sheet no. 2.

3.8 Consolidation test:

Consolidation test were conducted in the laboratory on the undisturbed soil samples collected from

boreholes and parameters obtained from the test are reported in Annexure-III sheet no: 3 to this report.

4. CRITERIA ADOPTED FOR COMPUTATION OF SBC:

4.1 Computation of SBC by shear strength parameters (Triaxial):

The ultimate bearing capacity of soils with cohesion and angle of shearing resistance (C& Ø) as per IS:

6403: 1981 clause 5.1.2 are given in Annexure: III Sheet No.2

qd = C Nc Scdcic +q (Nq – 1) Sq dq iq + 0.5 B. γ Νγγ Νγγ Νγγ Νγ Sγ γ γ γ dγγγγ iγγγγ W` (General shear failure )

q`d = 2/3 C N’c Scdcic +q (N’q – 1) Sq dq iq + 0.5 B. γ Νγ Νγ Νγ Ν’γ γ γ γ Sγγγγ dγγγγ iγγγγ W` ( Local Shear failure )

4.1.1 : φ' = tan-1 (0.67 tan φ )

Corresponding values of Nc', Nq' & Nγ' are obtained from bearing capacity table1. (clause 5.1.1)

4.1.2: Shape factor (Sc = 1.30, Sq = 1.20, Sγ = 0.80) depth factor (dq=dγ = 1for φ <100 or dq=dγ = 1+ 0.1

Dt/B √Nφ 1for φ >100) & inclination factor is considered as 1.

4.1.3: Width of foundation B = 3 m

4.1.4: Effect of Water table W' = 0.5

4.1.5: Safe Bearing capacity qs = qd / 3 (Assuming F.S = 3)


4.2 Check for Safe bearing pressure for clayey soil by Settlement criteria based on values obtained

from consolidation test:

Net S.B.C. check for settlement for permissible settlement as per IS: 1904 – 1986 & calculated as per IS:

8009 (Part I) -1976 is presented in Annexure: III sheet no. 3 of this report.

4.3 Computation of SBC by N value

The depth factor, shape factor and load inclination factors are mentioned below and assuming the water

table correction factor as 0.5 . The ultimate bearing capacity is calculated as per IS: 6403 Clause - 5.2.2.1

and results are presented in Annexure: III sheet no.4,

q d = q.(Nq – 1) Sq dq iq + 0.5 B. γ .Νγ γ .Νγ γ .Νγ γ .Νγ Sγ γ γ γ dγ γ γ γ iγ γ γ γ W’

Corresponding values of Nq & Nγ are obtained from bearing capacity table1. (Clause 5.1.1)

4.3.1: Shape factor ( sc = 1.30, sq = 1.20, sγ = 0.80 ) depth factor (dq=dγ = 1for φ <100 or dq=dγ = 1+ 0.1

Dt/B √Nφ 1for φ >100) & inclination factor is considered as 1.

4.3.2: Width of foundation B = 3 m

4.3.3: Effect of Water table W' = 0.5

4.3.4: Safe Bearing capacity qs = qd / 3 (Assuming F.S = 3)

4.4 Safe bearing pressure for cohesionless soil by settlement criteria based on SPT N- Value:

Net S.B.C. check for settlement for permissible settlement as per IS: 1904 – 1986 & calculated as per

IS: 8009 (Part I) -1976 is presented in Annexure: III sheet no.4 of this report.

5) FINDINGS & RECOMMENDATIONS:

5.1) The general stratification of this site was comprised of black clayey soil at the top followed by yellow

clayey soil up to the depth of investigation. The soil encountered up to the depth of investigation is

highly swelling with high plasticity classified as CH. The same stratification was encountered at the

earliest investigation beside this site at Pyramid City.

5.2) Open/ Raft foundation may be provided for this site. The foundation should be rested at minimum

3.00m depth from GL. The allowable bearing capacity of 6.00T/m2 may be considered for

foundation design at & below 3.00m depth from exist EGL.


5.3) At this site swelling clayey soil with high FSI & plasticity classified as CH was encountered at the top

layer, care should be taken to safeguard the floor cracks.

5.4) Immediately below PCC minimum 150mm thick sand/ stone dust layer should be provided for proper

leveling the uneven surface.

5.5) Soil excavated from foundation pits should not be utilised as back filling material in foundations. It must

be insured that the back filling shall be comprised of well graded strong cohesionless granular material

with good drainage properties & high compressive strength.

5.6) At founding level strata should be verified & confirmed before laying the foundation.

5.7) Report is prepared on the basis of subsoil conditions revealed at the test location of boreholes,

laboratory tests performed on the encountered & recovered samples from the site. Any discrepancy if

observed during construction shall be reported immediately to the concerned authorities & GEOsystems

Research & Consultants (I) Pvt. Ltd. Nagpur.

for GEOsystems Research & Consultants ( I ) Pvt. Ltd.

(S. M. WANKHEDE) M.tech. (Geotech) Consulting Engineer

TEST SPT (N) Type - No Depth (m)

0.00

0.50

1.00

1.50 UDS-1 1.50-1.95

2.00

2.50

3.00 UDS-2 3.00-3.45

3.50

4.00

4.50 UDS-3 4.50-4.95

5.00

5.50

6.00 SPT-1 N=12 (3/5/7) DS-1 6.00-6.45

6.50

7.00

7.50 SPT-2 N=15 (5/7/8) DS-2 7.50-7.95

8.00

8.50

9.00 SPT-3 N=19 (4/8/11) DS-3 9.00-9.45

VER :- NTS

HOR :- NTS

DS :-

WS :-

. UDS :- Undisturbed Sample

CP :- Core Pieces

S.P. :- Small Pieces

SPT :-

VST :-

WT :-

C A

S

I N

G

> >

1

50

mm

Yellow Clayey

Sandy Soil

Yellow Clayey Sandy Soil

Black Clayey Soil

3.0

0m

3.0

0m

Yellow Clayey Soil

3.0

0m

B O R E L O G

ANNEXURE - I Sheet no.1

BORE HOLE NO. :- BH-1

CLIENT :- Pyramid Ashok Mega Structure Pvt. Ltd. Nagpur.

AUTHORITY :- Pyramid Ashok Mega Structure Pvt. Ltd. Nagpur.

PROJECT :- Proposed Construction of Pyramid City Type-VI Residential Complex at Besa, Beltarodi, Nagpur.

FINAL DEPTH :- 9.00m METHOD OF BORING. :- Rotary wash method

DIRECTION OF BORING :- Vertical DATE OF START :- 05-03-2014

GROUND WATER :- Not Encountered DATE OF COMPLETION :- 07-03-2014

CA

SIN

G

DEPTH

(M)

TH

ICK

NES

S

OF L

AYE

R

LOG

25

REMARK CORE

PIECES

RECOVERY % R . Q. D. %

25 50 50 75 100

A B B R E V I A T I O N No.SCALE :-

VISUAL

DESCRIPTION OF

STRATA

FIELD TEST Type of sampleCORE DRILLING

75 100

Black Clayey Soil Disturbed Sample 3 no.

Email: [email protected]/ [email protected]

▼Water Table From GL Nil

Nil

Nil

Wash Sample Nil

CHKD BY ;- S. SURYAWANSHI

Yellow Clayey Soil

▼Borehole terminated

at 9.00m depth from

GEOsystems Research & Consultants (I) Pvt. Ltd. REFERENCE NO. GS RC /0066/ 2013-14

DATE :- 24-03-2014

3 no.

L O G

M 1 - M2 Pushp -kunj Comp. 26 , Farmland Central Bazar Road , Ramdaspeth , Nagpur - 10

TEL NO.; (0712) - 6618585 / 6611855, 2423984 Fax. No. 6618585

DRN BY:- TAHMEENA

Standard Penetration Test 3 no.

Vane Shear Test

6


0.00

0.50

1.00

1.50 UDS-1 1.50-1.95

2.00

2.50

3.00 UDS-2 3.00-3.45

3.50

4.00

4.50 UDS-3 4.50-4.95

5.00

5.50

6.00 SPT-1 N=13 (5/6/7) DS-1 6.00-6.45

6.45

VER :- NTS

HOR :- NTS

DS :-

WS :-


CP :- Core Pieces


SPT :-

VST :-

WT :-

3.5

0m

LOG

DATE :- 24-03-2014

25 50

Black Clayey Soil

Yellow Clayey Soil

L O G

Standard Penetration Test

CORE DRILLING

10025 5075 75100



Vane Shear Test Nil


TEL NO.; (0712) - 6618585 / 6611855, 2423984 Fax. No. 6618585

Black Clayey Soil 1 no.

Wash Sample

Disturbed Sample

GEOsystems Research & Consultants (I) Pvt. Ltd.

3 no.

CA

SIN

G

DEPTH

(M)

FIELD TEST Type of sample

SCALE :-

Nil

A B B R E V I A T I O N

Yellow Clayey Soil

C A

S

I N

G

> >

150 m

m

GS RC /0066/ 2013-14

▼Water Table From GL Nil CHKD BY ;- S. SURYAWANSHI

Nil

1 no.

DRN BY:-

REFERENCE NO.


REMARK CORE

PIECES

TH

ICK

NE

SS

OF L

AY

ER

VISUAL

DESCRIPTION OF

STRATA

07-03-2014


PROJECT :-


Proposed Construction of Pyramid City Type-VI Residential Complex at Besa, Beltarodi, Nagpur.


AUTHORITY :-

TAHMEENA

No.

CLIENT :-

DIRECTION OF BORING :- Vertical DATE OF START :-


at 6.45m depth from

GL.

2.9

5m

B O R E L O G



7


0.00

0.50

1.00

1.50 UDS-1 1.50-1.95

2.00

2.50

3.00 UDS-2 3.00-3.45

3.50

4.00

4.50 UDS-3 4.50-4.95

5.00

5.50

6.00 SPT-1 N=12 (3/4/8) DS-1 6.00-6.45

6.45

VER :- NTS

HOR :- NTS

DS :-

WS :-


CP :- Core Pieces


SPT :-

VST :-

WT :-

Yellow Clayey Soil

4.5

0m

Black Clayey Soil

B O R E L O G









CA

SIN

G

DEPTH

(M)

TH

ICK

NE

SS

OF L

AY

ER

LOG

VISUAL

DESCRIPTION OF

STRATA


REMARK CORE

PIECES


25 50 75 100 25 50 75 100


at 6.45m depth from

GL.

L O G A B B R E V I A T I O N No.SCALE :-

C A

S

I N

G

> >

150 m

m

1.9

5m


Wash Sample Nil DATE :- 24-03-2014

Yellow Clayey Soil 3 no.


TEL NO.; (0712) - 6618585 / 6611855, 2423984 Fax. No. 6618585

Nil

DRN BY:- TAHMEENA

Standard Penetration Test 1 no.





Vane Shear Test Nil

8

VISUAL

DESCRIPTION OF

STRATA


REMARK


CA

SIN

G

DEPTH

(M)

TH

ICK

NE

SS

OF L

AY

ER

LOG






B O R E L O G




0.00

0.50

1.00

1.50 UDS-1 1.50-1.95

2.00

2.50

3.00 UDS-2 3.00-3.45

3.50

4.00

4.50 UDS-3 4.50-4.95

5.00

5.50

6.00 SPT-1 N=13 (4/5/8) DS-1 6.00-6.45

6.45

VER :- NTS

HOR :- NTS

DS :-

WS :-


CP :- Core Pieces


SPT :-

VST :-

WT :-

C A

S

I N

G

> >

150 m

m 3.5

0m

Black Clayey Soil

2.9

5m

Yellow Clayey Soil

TEL NO.; (0712) - 6618585 / 6611855, 2423984 Fax. No. 6618585





1 no.

Vane Shear Test Nil


DATE :-

Standard Penetration Test

24-03-2014

Yellow Clayey Soil 3 no.

Nil

DRN BY:- TAHMEENA


Wash Sample Nil


at 6.45m depth from

GL.

L O G A B B R E V I A T I O N No.SCALE :-

75 100 25 50 75 100

VISUAL

DESCRIPTION OF

STRATA


REMARK CORE

PIECES


25 50

CA

SIN

G

DEPTH

(M)

TH

ICK

NE

SS

OF L

AY

ER

LOG

9

Fre

e S

we

ll

Ind

ex

Gravel SandSilt &

ClayWL WP IP

FSI

(%)

0.00-1.50 gs-079/BH-1/01 DS 0.00 7.13 92.87 40.35 57.00 25.32 31.68 70 CH � �

1.50-1.95 gs-079/BH-1/02 UDS 0.50 10.70 88.80 21.58 58.00 24.69 33.31 70 CH 14.81 12.18

3.00-3.45 gs-079/BH-1/03 UDS 4.40 6.96 88.64 22.93 57.00 24.33 32.67 70 CH 15.02 12.22

4.50-4.95 gs-079/BH-1/04 UDS 4.48 6.08 89.44 30.53 59.00 25.91 33.09 80 CH 15.01 11.50

6.00-6.45 gs-079/BH-1/05 DS 2.86 7.20 89.94 20.31 57.00 23.25 33.65 70 CH � �

7.50-9.00 gs-079/BH-1/06 DS 0.00 59.33 40.67 32.78 35.00 19.66 15.34 40 SC-CI � �

0.00-1.50 gs-079/BH-2/01 DS 0.46 7.87 91.67 26.53 53.00 24.32 28.68 60 CH � �

1.50-1.95 gs-079/BH-2/02 UDS 1.38 6.32 92.30 23.96 57.00 24.68 32.32 70 CH 15.11 12.19

3.00-3.45 gs-079/BH-2/03 UDS 0.70 11.62 87.68 22.70 57.00 23.54 33.46 70 CH 14.79 12.05

4.50-4.95 gs-079/BH-2/04 UDS 0.38 3.62 96.00 32.96 60.00 26.52 33.48 80 CH 14.85 11.17

6.00-6.45 gs-079/BH-2/05 DS 0.00 4.12 95.88 32.62 60.00 26.41 33.59 80 CH � �

0.00-1.50 gs-079/BH-3/01 DS 0.44 5.82 93.74 39.26 56.00 24.18 31.82 70 CH � �

1.50-1.95 gs-079/BH-3/02 UDS 0.00 5.92 94.08 21.13 55.00 22.86 32.14 70 CH 14.67 12.11

3.00-3.45 gs-079/BH-3/03 UDS 0.58 5.58 93.84 20.16 55.00 21.07 33.93 70 CH 15.19 12.64

4.50-4.95 gs-079/BH-3/04 UDS 0.00 2.60 97.40 27.11 61.00 26.15 34.85 80 CH 15.23 11.98

6.00-6.45 gs-079/BH-3/05 DS 0.00 5.64 94.36 24.98 62.00 26.99 35.01 80 CH � �

0.00-1.50 gs-079/BH-4/01 DS 0.00 6.14 93.86 32.44 56.00 22.98 33.02 70 CH � �

1.50-1.95 gs-079/BH-4/02 UDS 0.42 5.52 94.06 22.68 56.00 23.70 32.30 70 CH 15.07 12.28

3.00-3.45 gs-079/BH-4/03 UDS 1.12 6.06 92.82 22.59 56.00 23.67 32.33 70 CH 15.21 12.41

4.50-4.95 gs-079/BH-4/04 UDS 0.00 3.22 96.78 31.36 61.00 26.11 34.89 80 CH 14.92 11.36

6.00-6.45 gs-079/BH-4/05 DS 4.72 5.14 90.14 31.01 62.00 27.45 34.55 80 CH � �

CH

SC-CL

Clayey Soil With High Plasticity

Clayey Sandy soil With Low Plasticity

Depth (m) Sample No.

Sa

mp

le Grain Size Analysis (%)

ABBREVIATIONS

BH-1

BH-2

BH-3

BH-4

Annexure: II

Sheet no.1

SUMMARY OF THE TEST RESULTS

Atterberg Limit (%)

Cla

ssific

atio

n

Bu

lk D

en

sity

(kN

/m3

)

Dry

De

nsi

ty

(kN

/m3

)

WC (%)Bore

No.

10

11

Annexure: III

Sheet No. 1 Allowable Bearing Capacity

Bore hole No. Depth (m)

Allowable Bearing Capacity

T/m²

BH-1

3.00 6.00

4.50 7.50

6.00 8.00

BH-2

3.00 6.50

4.50 7.50

6.00 8.50

BH-3

3.00 6.50

4.50 7.00

6.00 8.00

BH-4

3.00 7.00

4.50 8.00

6.00 8.50

12

Annexure: III Sheet No. 2

CALCULATION OF SBC FROM UU- TRIAXIAL SHEAR TEST

Borehole

No.

Depth

(m) Sample No.

Cohesion -

C (kN/m² )

Angle of Sharing

Resistance Ø

(deg)

qd F.S S.B.C T/m²

BH-1 3.00 gs-079/BH-1/03 67 1.0 38.39 3 12.80 ≈ 12.50

4.50 gs-079/BH-1/04 62 1.5 39.83 3 13.28 ≈ 13.00

BH-2 3.00 gs-079/BH-2/03 64 1.5 37.61 3 12.54 ≈ 12.50

4.50 gs-079/BH-2/04 60 2.0 39.56 3 13.19 ≈ 13.00

BH-3 3.00 gs-079/BH-3/03 63 1.5 37.04 3 12.35 ≈ 12.00

4.50 gs-079/BH-3/04 59 1.5 37.96 3 12.65 ≈ 12.50

BH-4 3.00 gs-079/BH-4/03 59 1.5 34.73 3 11.58 ≈ 11.50

4.50 gs-079/BH-4/04 54 2.5 36.73 3 12.24 ≈ 12.00

Note:

1. Bulk unit weight - γ = 15.00 kN/m3

2. Factor of safety of 3 has been used for calculating qs. 3. Width of foundation (B) =3m , Dilatancy Correction value N’’ Assuming load inclination factors as unity(1) shape

factor ( sc = 1.30, sq = 1.20, sγ = 0.80 ) depth factor ( dq=dγ = 1+ 0.1 Dt/B √Nφ for φ > 10) and assuming the water

table correction factor W`= 0.5 (During Rainy season) 4. Calculations and B.C factors as per IS 6403 Clause 5.1.2

13


CONSOLIDATION TEST RESULTS AND COMPUTATION OF SETTLEMENT

BH.

No.

Depth

- from

GL (m)

Sample No.

Initial

voids

ratio eo

Compressi

on Index

(Cc)

Pressure

Intensity

(T/m2)

Initial

settlem-

ent (mm)

Consolidation

settlement

(mm)

Total

settlement

(mm)

Total settlement

after applying

correction

factor (mm)

Remarks

BH-1

3.00 gs-079/BH-1/03 0.961 0.153 12.50 6.18 78.50 84.68 61.82

Consolidation settlement is on

higher side for 12.50 T/m2

6.00 2.96 45.34 48.31 35.26 Consolidation settlement is within

permissible limit for 6.00 T/m2

4.50 gs-079/BH-1/04 0.958 0.161 13.00 6.94 68.51 75.45 50.55





BH-2

3.00 gs-079/BH-2/03 0.964 0.147 12.50 6.47 75.31 81.77 59.70





4.50 gs-079/BH-2/04 0.958 0.164 13.00 7.17 69.79 76.96 51.57





BH-3

3.00 gs-079/BH-3/03 0.969 0.148 12.00 6.31 73.49 79.79 58.25





4.50 gs-079/BH-3/04 0.945 0.167 12.50 7.01 69.48 76.49 51.25





BH-4

3.00 gs-079/BH-4/03 0.980 0.139 11.50 6.45 66.59 73.05 53.32





4.50 gs-079/BH-4/04 0.968 0.153 12.00 7.36 61.06 68.37 45.81





Note: 1) The above settlement is checked for corresponding allowable pressure with respect to the corresponding depth.

2) For pressure intensity the total settlement is within the permissible limit as per IS: 1904 -1986. To keep the differential settlement within

the limit the size of the footing must be proportionate.

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Summary of Bearing Capacity based on settlement & shear criteria from SPT N Value

Borehole No. Depth - (m) Allowable Bearing Capacity T/m2

Recommended Allowable Bearing Capacity T/m2

BH-1 6.00 8.00

8.00 BH-2 6.00 8.50

BH-3 6.00 8.00

BH-4 6.00 8.50

CALCULATION OF SBC FROM SPT- N VALUE

BH. NO. Depth (m) SPT –N Value

N’’ φ φ φ φ

(deg) Nq Nγγγγ S.B.C. T/m2

BH-1 6.00 12 12 30.5 7.71 7.08 36.16

BH-2 6.00 13 13 31 8.04 7.51 38.08

BH-3 6.00 12 12 30.5 7.71 7.08 36.16

BH-4 6.00 13 13 31 8.04 7.51 38.08

� Factor of safety of 3 has been used for calculating qs.

� Width of foundation (B) =3m, Dilatancy Correction value N’’ Assuming load inclination factors as unity(1) shape

factor ( sc = 1.30, sq = 1.20, sγ = 0.80 ) depth factor ( dq=dγ = 1+ 0.1 Dt/B √Nφ for φ > 10) and assuming the water

table correction factor W`= 0.5

� Calculations and B.C factors as per IS 6403 Clause 5.2.2.1

SAFE BEARING PRESSURE BY SETTLEMENT CRITERIA BASED ON SPT N- VALUE (Net S.B.C check for settlement as per IS: 1904 – 1986 for cohesion less soils from fig.9 of IS: 8009

(Part I) -1976)

BH. NO. Depth (m) SPT –N Value

N” Permissible settlement

(as per IS:1904-1986)

(mm)

Safe Bearing Pressure T/ m

2

BH-1 6.00 12 12 50 8.33 ≈ 8.00

BH-2 6.00 13 13 50 8.62 ≈ 8.50

BH-3 6.00 12 12 50 8.33 ≈ 8.00

BH-4 6.00 13 13 50 8.62 ≈ 8.50

Dilatancy Correction value N’” and assuming the water table correction factor W`= 0.50. The above calculation is for 50mm permissible settlement. The safe bearing pressure can be provided for other permissible settlement if required.

15

Annexure: IV

Sheet No.1

SAMPLE CALCULATIONS

SAFE BEARING CAPACITY FOR CLAYEY SOIL BY SHEAR FAILURE CRITERIA: BH-1

Depth (Dt) = 3.00m

For width of foundation B = 3m

As per the report C = 67 kN/m2 & φ = 1 0 φ' = 0.670 Bulk unit weight (γ) = 15.00 kN/m3

q = γγγγ x Dt = 15.00 x 3.00 = 45.00 kN/m2

Based on φ' value N’c = 5.32 N’q = 1.08 N’γγγγ = 0.06

Assuming the depth factor, shape factor and load inclination factors as unity (1) & assuming the

water table correction factor as 0.5.Since φ = 1 0 local shear failure is considered. The ultimate bearing capacity is calculated as under: IS 6403 Clause -5.1.2

q`d = 2/3 C x N’c x Sc x dc x ic +q (N’q – 1) Sq x dq x iq + 0.5 x B x γ γ γ γ x ΝΝΝΝ’γ γ γ γ x Sγ γ γ γ x dγ γ γ γ x iγ γ γ γ x W`

= 370.697 + 4.32 + 0.54

= 376.65 kN/m2

= 38.39 T/m2

Considering factor of safety = 3

qs = 12.80 ≈ 12.50 T/m2

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CHECK FOR SAFE BEARING PRESSURE FOR CLAYEY SOIL BY SETTLEMENT CRITERIA:

(As per IS 8009 (Part – I)-1976)

The SBC work out by shear failure criteria to be check for settlement as per IS:1904-1986 for

foundation resting on clayey soil.

Sample Calculation for BH. No.1 (Depth-3.00m

Total Settlement St= Sc + Si (As per clause 9.2)

I) Immediate Settlement for clays – Si (As per IS 8009 (Part – I)-1976)

Si = P x B (1 – µ2) x I

E

P = Intensity of pressure = 12.50 T/m2

B = Width of foundation = 3m

µ = 0.5 (for clays)

I = Influence factor as = 0.30

(From fig. 11 of IS 8009 (Part I) 1978)

L = Length of foundation = 3.00m

E = modulus of elasticity as per Bowles 100 qu to 500 qu

E = 100 qu

qu = Undrained shear strength

qu = 2C

C = Cohesión = 67 kN/m2 = 6.8298 T/m2

qu = 2 x 6.8298 = 13.6595 T/m2

E = 100 qu = 100 x 13.2518 = 1365.95 T/m2

Using above equation:

Si = 6.18 mm

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II) Consolidation Settlement-Sc

D = 3.00m

q = 12.50 T/m2 (Intensity of pressure)

W = 3.00m L = 3.00m

3a 3b

a = 1 b = 1

Ht = 0.5m

Cc = 0.153 (Compression Index)

eo = 0.961 (Initial Voids Ratio)

Sc = 1 Ht 0 Cc log10 [Po + ∆ P] (1 + eo) Po

Layer No

Effective depth

(m)

Overburden Pressure

P0 (T/m2) z

m = a/z

n = b/z

Newmark’s Constant

K 4k

Pressure increment

∆ P =4 k x q

Settlement (mm)

1. 3.25 4.88 0.25 4.00 4.00 0.2463 0.9852 12.315 21.35

2. 3.75 5.63 0.75 1.33 1.33 0.1941 0.7764 9.705 16.99

3. 4.25 6.38 1.25 0.80 0.80 0.1461 0.5844 7.305 12.94

4. 4.75 7.13 1.75 0.57 0.57 0.0999 0.3996 4.995 9.00

5. 5.25 7.88 2.25 0.44 0.44 0.0700 0.2800 3.5000 6.23

6. 5.75 8.63 2.75 0.36 0.36 0.0511 0.2044 2.555 4.40

7. 6.25 9.38 3.25 0.31 0.31 0.0397 0.1588 1.985 3.25

8. 6.75 10.13 3.75 0.27 0.27 0.0316 0.1264 1.58 2.46

9. 7.25 10.88 4.25 0.24 0.24 0.0257 0.1028 1.285 1.89

Total Consolidation Settlement in mm 78.50 *Note: K = Influence factor for uniformly loaded rectangular area by After Newmark’s 1935.

Total settlement S = immediate settlement Si + consolidation settlement Sc

= 6.18 + 78.50

= 84.68 mm > permissible settlement (50mm)

For pressure intensity of 12.50t/m2 the total settlement is exceeding the permissible limit. Hence pressure intensity is reduce to 6.00 T/m2

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For :

P = Intensity of pressure =6.00 T/m2

Si = 2.96 mm

II) Consolidation Settlement-Sc

Sc = 1 Ht 0 Cc log10 [Po + ∆ P] (1 + eo) Po

Layer No

Effective depth

(m)

Overburden Pressure

P0 (T/m2) z

m = a/z

n = b/z

Newmark’s Constant

K 4k

Pressure increment

∆ P =4 k x q

Settlement (mm)

1. 3.25 4.88 0.25 4.00 4.00 0.2463 0.9852 5.9112 13.45

2. 3.75 5.63 0.75 1.33 1.33 0.1941 0.7764 4.6584 10.22

3. 4.25 6.38 1.25 0.80 0.80 0.1461 0.5844 3.5064 7.43

4. 4.75 7.13 1.75 0.57 0.57 0.0999 0.3996 2.3976 4.91

5. 5.25 7.88 2.25 0.44 0.44 0.0700 0.2800 1.6800 3.28

6. 5.75 8.63 2.75 0.36 0.36 0.0511 0.2044 1.2264 2.25

7. 6.25 9.38 3.25 0.31 0.31 0.0397 0.1588 0.9528 1.64

8. 6.75 10.13 3.75 0.27 0.27 0.0316 0.1264 0.7584 1.22

9. 7.25 10.88 4.25 0.24 0.24 0.0257 0.1028 0.6168 0.93

Total Consolidation Settlement in mm 45.34 *Note: K = Influence factor for uniformly loaded rectangular area by After Newmark’s 1935.

Total settlement S = immediate settlement Si + consolidation settlement Sc

= 2.96 + 45.34

= 48.31 mm

Correction for depth factor = 0.73 (as per fig. 12 of IS: 8009)

Total Settlement after Correction = 35.26 < permissible settlement (50mm)

For pressure intensity of 6.00t/m2 the total settlement is within the permissible limit. To keep the differential settlement within the limit the size of the footing must be proportionate. Hence the allowable bearing capacity at 3.00m for footing size of 3m is 6.00 T/m2

19

Annexure: IV

Sheet No.2

SAMPLE CALCULATIONS

SAFE BEARING CAPACITY FOR COHESIONLESS SOIL BY SHEAR FAILURE CRITERIA FROM SPT N-VALUE:

BH-3 Depth (Dt) = 6.00m

For width of foundation B = 3m

As per the report N= 12 N’’ = 12 φ = 30.5 Bulk unit weight (γ) = 15 kN/m3

q = γγγγ x dt = 15 x 6.00 = 90.00 kN/m2

Based on φ' value N’q = 7.71 N’γγγγ = 7.08

Assuming the depth factor, shape factor and load inclination factors as unity (1) & assuming

the water table correction factor as 0.5.Since φ = 30 local shear is considered. The ultimate bearing capacity is calculated as under: IS 6403 Clause -5.2.2.1

q`d = q (N’q – 1) Sq x dq x iq + 0.5 x B x γ γ γ γ x ΝΝΝΝ’γ γ γ γ x Sγ γ γ γ x dγ γ γ γ x iγ γ γ γ x W`

= 978.26 + 86.02

= 1064.28 kN/m2

= 108.49 T/m2

Considering factor of safety = 3

qs = 36.16 T/m2

SAFE BEARING PRESSURE BY SETTLEMENT CRITERIA:

The SBC work out by shear failure criteria to be check for settlement for foundation resting on

cohesionless soil.

Permissible settlement = 50mm

N = 12 N’’ = 12

As per IS -8009 from fig. 9

Settlement -28.00 mm for 10 T/m2

Applying water table correction of 0.50

Settlement= 30/0.5=60 mm

Hence for permissible settlement of 50 mm

SBC= 10/60 x 50 = 8.33 ≈ 8.00 T/m2 at depth 6.00m.

Hence allowable bearing capacity at 6.00m depth for footing size of 3m is 8.00 T/m2 for isolated footing.

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