FINAL REPORT ON SOIL INVESTIGATION - HPCLtenders.hpcl.co.in/tenders/tender_prog/TenderFiles/3744/Tender/SS... · final report on soil investigation for proposed construction at ss-6b

FINAL REPORT

ON SOIL INVESTIGATION

FOR

PROPOSED CONSTRUCTION AT

SS-6B AREA AT

HPCL VISAKH REFINERY VISAKHAPATNAM ANDHRA PRADESH

J.J. ASSOCIATES(VISAKHAPATNAM) AETP(P) LIMITED

#11-6-3, RockDale Layout, MaharaniPeta, Visakhapatnam – 530 002.

Table of Contents

Tables and Figures (Enclosures)............................................................................................

1 INTRODUCTION............................................................................................................... 1

2 SCOPE OF WORK ........................................................................................................... 1

3 INVESTIGATION METHODOLOGY..............................................................................1-2

4 FIELD INVESTIGATIONS ................................................................................................ 2

4.1 Standard Penetration Tests ..................................................................................................... 2 4.2 Sampling .................................................................................................................................. 2

5 LABORATORY INVESTIGATIONS ..............................................................................2-3

6 Generalised geological profile....................................................................................... 4

6.1 Geological Profile for Proposed Construction of SS-6B area .................................................. 4

7 DESIGN SOIL PARAMETERS FOR FOUNDATIONS..................................................... 4

8 SUMMARY ,ANALYSIS, CONCLUSIONS & RECOMMENDATIONS..........................4-6

Tables and Figures (Enclosures)

• Field Bore logs

• Laboratory test results

• Bore Log Details

• Site Plan

J.J.ASSOCIATES (Vskp) AETP (P) LIMITED

1

1. INTRODUCTION

M/s Hindustan Petroleum Corporation Limited proposed to conduct Soil Investigation at

SS-6B Area in DHT project at Visakha Refinery ,Visakhapatnam. Accordingly, land soil

investigations were envisaged to evolve various soil/rock parameters in order to carry

out engineering analysis and foundation design. In this connection, the soil investigation

work was awarded to M/s J.J.Associates (VSKP) AETP Pvt Ltd., Visakhapatnam vide

Purchase order No. 9000163-OQ-10004 dated 11/2/2010 to carry out the land soil

investigations at the proposed site.

Broad objectives of the investigations are as follows.

(a) To evaluate the parameters of soil/rock at the proposed site .

(b) To assess the engineering parameters and to estimate the safe bearing

capacity of soil

2. SCOPE OF WORK

The scope of work includes drilling of One(1) Land Boreholes at SS-6B Area.

Location of the boreholes is presented in the enclosed figure. “Borehole Locations”

sketch provided by M/S TOYO ENGINEERING CORPORATION / HPCL.

The scope also includes carrying out field tests like Standard Penetration Test (SPT) in

boreholes, collection of disturbed and undisturbed soil samples and carrying out the

relevant laboratory tests on collected soil samples.

3. INVESTIGATION METHODOLOGY

The details of the drilling rigs and methodology of boring are explained in the following

sections. Boreholes were terminated as per the direction of Engineer In charge.

After positioning the rig at the specified location, for drilling through soil. Borehole was

sunk by mechanically operated Cable Tool (Shell & Auger) in soil and Rotary drilling in

rock. Flush jointed steel casing tubes were provided to prevent possibility of side

collapse in boreholes. After reaching the desired depth, depending upon the soil layer

encountered, either Standard Penetration Tests & Vane Shear Tests were conducted or

Undisturbed or disturbed soil samples were collected.


2

The location of the boreholes is shown in the enclosed sketch. The field tests and sample

collections were conducted in the boreholes in accordance with the relevant Indian

Standard codes of practice and as per the following.

(a) Standard Penetration Test in soils at regular depth intervals

(b) Disturbed & Undisturbed soil samples

4. FIELD INVESTIGATIONS

4.1 Standard Penetration Tests

Standard penetration tests (SPT) were carried out in soil within boreholes to determine

strength characteristics of soil. This was carried out in accordance with IS: 2131. The

number of blows required to drive the standard split spoon sampler for penetration of

0.30 m by a 63.5 kg hammer falling freely from a height of 750 mm is recorded “N”

Value at regular intervals in the borehole. If the sampler is not fully penetrating into soil,

then the test was terminated after refusal noting the rate of penetration.

4.2 Sampling

Disturbed & Undisturbed representative soil samples were collected during investigations

and subsequently sent to laboratory for visual examination and testing. The disturbed

soil samples were also collected from split spoon sampler.

5. LABORATORY INVESTIGATIONS

All collected soil samples from the boreholes were brought to laboratory for necessary

testing and rechecking the preliminary borelogs. The laboratory tests comprised of

a. Grain Size distribution of all samples collected from boreholes

Grain size distribution was determined in two stages. The soil fraction retained on 75

micron IS Sieve was analysed by Sieve analysis using standard set of IS Sieve as

prescribed by IS 460 – 1962. Sieve analysis is again done in two stages. The oven dried

samples of soil was separated into two fractions by passing it through 4.75mm IS Sieve.

The portion passing through the sieve was analysed by fine analysis using the IS Sieve

Nos. 2mm, 1mm, 500, 425, 300, 212, 150 and 75 microns. The portion retained on this

sieve was analysed by coarse analysis using IS Sieve Nos. 100, 60, 20, 10 and 4.75mm.


3

b. Atterberg Limits on all clay fractions

Liquid limit of the soil was determined by Casagrande method using Casagrande type

mechanical liquid limit apparatus. Plastic limit was determined as per the standard

procedure.

c. Natural moisture content

Natural moisture content of the soil was determined by oven drying method as per IS :

2720 Part – II, 1969. Weights were taken to an accuracy of 0.001gr.

d. Bulk & Dry density

Bulk density and dry density of the undisturbed soil samples were evaluated as per

IS:2720

e. Triaxial Test.

The encountered strata was stiff in consistency, careful attention is made to extract

sample from the tube. The test is conducted as per part of IS 2720.

f. Specific Gravity Tests

Specific gravity test was conducted on the soil fraction passing through 425 micron

I.S.Sieve by density bottle method or by pycnometer. All weights are taken to an

accuracy of 0.001 gr. and the tests were conducted at 27°C.

g. Chemical Analysis of soil & water

Chemical Analysis for soil and water were carried out for PH value chlorides, sulphates

and organic matter and the results are enclosed in the report.

h. Consolidation tests

Consolidation tests were conducted on vertical drainage using Fixed ring cell type

consolidometer. The soil specimens were allowed to consolidate under pressure

increments of 0.01, 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 kg/cmª . The pressures were

unloaded through increments of 4.00, 2.00, 1.00, 0.50, 0.25 and 0.01 kg/cmª. Each

pressure increment was maintained constant per 24 hours. The vertical compression was

measured after the application of each pressure increment after the following elapsed

times, 0, 0.25, 1.00, 2.25, 4.00, 6.25, 9.20, 12, 25, 16.00, 20.25, 25, 36, 49, 64, 81,

100, 225, 400, 720 and 1440 minutes.

Note : The Possible tests are only conducted if samples were collected. In some case soil

samples could not be collected as rock is met at shallow depth.


4

6.GENERALISED GEOLOGICAL PROFILE

A generalised geological profile is prepared for individual boreholes. The description of

the various layers is based on the laboratory test results based on IS classification. For

the purpose of clarity, existing ground level is considered as 0.0m, datum for boreholes

in the individual geological profile.

6.1 Geological profile of proposed SS-6B Area(Bh-7).

Bore logs at proposed SS-6B Area shows the soil strata as per Field observation & bore

log . The geology of the proposed site is varying with respect to the thickness of each

layer. The top over burden predominantly consists of Filled up material from 0.00 to

1.00m followed by Clay with Sand, Highly Weathered rock . The ground water Level is

observed in the bore hole at shallow depth.

Soil Properties 0.00 to 1.00m 1.00m to 2.50m 2.50m & below

Gravel content % 7 to 11

Sand content % 31 to 43

Silt and Clay content % 46 to 62

Soil Classification as per

IS

Filled up

material

CL-SC

Highly Weathered

rock

Note : A layer of Clay with pebbles observed from 6.00m to 6.50m

7.Suggested Design Soil Parameters

Depth Below GL

(m)

Layer

No.

FROM TO

Soil type Average

N-Value

Cu

t/m2

Ф

degree

γ

t/m3

1 0.00 1.00 Filled up

material

- - - -

2 1.00 2.50 Clay with sand & pebbles

13 - - -

3 2.50m & below Highly weathered rock

50 - - 2.10

8. SUMMARY, ANALYSIS, CONCLUSIONS & RECOMMENDATIONS

8.1 General

The summary of the investigation is given below.

Total One (1) borehole is conducted in the proposed site.


5

8.2 Analysis

SAFE BERING CAPACITY FROM SHEAR CRITERIA IN BOREHOLE – 7

Safe Bearing Capacity from shear criteria at a depth of 2.50m

Qns = (2/3 CNC SC DC IC + r Df (NQ-1) SQ DQ IQ + 0.5r BNr Sr Dr Ir Wr| ) / FS

C = Cohesion intercept = 0 kg/cm2

ø = 36°

ø IF(ø <=28,(TAN-¹ (0.67*TAN ø )Else ø) = ׳

NC NQ Nr = Bearing capacity factors which are obtained by interpolation

Here NC = 51.96 NQ = 39.48 Nr = 60.31

SC SQ Sr = Shape factors which are 1.00 for Strip and 1.30 for Square

IC IQ Ir = Inclination factors

Nø = tan2(((22/7)/4) + (ø/2) )

DC = 1 + ( 0.2 x (Depth / Width) x √Nø) here it is 1.491

DQ = Dr = 1 for ø > 10˚

DQ = Dr = 1 + ( 0.1 x (Depth/Breadth) x √Nø) for ø > 10˚

Here Dr = DQ = 1.246

Qns = Safe Bearing Capacity

Factor of safety : 3.00

Safe Bearing Capacity from shear criteria at a depth of 2.50m

Net safe Bearing

Capacity in t/m2

S No. Depth (m) Width

(m)

Length (m)

Strip Square

1 2.50 2.00 2.00 115.42 126.94

2 2.50 3.00 3.00 120.46 128.76

3 2.50 4.00 4.00 128.26 133.90

4 2.50 5.00 5.00 137.16 140.36

5 2.50 6.00 6.00 146.61 147.48

Taking N = 50,

SBC Calculation as per IS:8009 (Part-I)-1976 from Settlement Criteria at a

depth of 2.50m below G.L(i:e) at R.L +2.997 in Bore Hole-7.


6

S No. Depth of

Foundation

(m)

Width of

Foundation

(m)

Settlement

Pressure for

10t/m2

Allowable bearing

pressure for 25mm

settlement(t/m2)

1 2.50 2.00 4.70 53.19

2 2.50 3.00 5.20 48.08

3 2.50 4.00 5.50 45.45

4 2.50 5.00 5.60 44.64

Recommendations: Considering the subsoil conditions prevailing at the site and based

on field and laboratory investigation results, the following recommendations have been

made for foundations of proposed constructions.

1. Shallow Foundations

a) As Hard strata is met at shallow depth and taking both shear criteria & settlement

criteria into consideration raft foundation/ isolated column footings should be

adopted at the depths mentioned below with the following safe bearing capacities.

BH No. Location Depth of foundation (m) SBC from shear

criteria (t/m2)

7 SS-6B Area 2.50m & below 30

Note:

1. Filled up material if any should be removed and foundation should be from

the natural ground level

2. Plinth beams are to be provided to safeguard the structure against differential

settlements if any.

b ) Due to presence of sulphates in water necessary precautions should be taken as

per IS 456-2000.

c) Back Filling material should be Rubble Soling and well compacted in layers of

150mm below PCC.

For J.J.ASSOCIATES(VSKP) AETP (P) LTD.,

J.J. ASSOCIATES(VISAKHAPATNAM)AETP(P) LIMITED 11-6-3,RockDale Layout, Maharanipeta,

Visakhapatnam – 530 002.

Project : Proposed DHT project at Visakh Refinery. Date of Commencement : 1/4/2010 Location : SS-6B Date of completion : 6/4/2010 Bore hole : 7 Ground RL : +5.497 Ground Water Table : 1.93m

Coordinates : N 556.394 E 1673.212

UDS – Undisturbed Sample DS – Disturbed Sample SPT – Standard Penetration Test pen. – Penetration 1

BORELOG

Ground R.L. Depth Below

G.L. (m)

RL & Depth at which sample

collected (m)

RL & Depth at which SPT

conducted (m) SPT

From To From To

Visual Description

of strata

Thickness of Strata

(m)

Type of

sample GRL GL

(m) GRL GL (m)

15 cm

30 cm

45 cm

N-Value

Core recovery

%

RQD % Remarks

+5.497

+4.497

0.00

1.00 Filled up soil & boulders 1.00 DS-1 +4.497 1.00

+4.497

+2.997

1.00

2.50

Reddish clay with pebbles 1.50 SPT-1

DS-2

+2.997

2.50 +3.997

1.50

3

5

8

13

+2.997

-0.503

2.50

6.00

Highly weathered

rock 3.50

SPT-2 DS-3 SPT-3 DS-4

+1.497

-0.503

4.00

6.00

+2.497

+0.997

3.00

4.50

8 49 52(5 cm pen.)

58(5cm pen.)

>50

>50

-0.503

-1.003

6.00

6.50

Reddish clay with pebbles 0.50 DS-5 -1.003 6.50

J.J. ASSOCIATES(VISAKHAPATNAM)AETP(P) LIMITED 11-6-3,RockDale Layout, Maharanipeta,


Project : Proposed DHT project at Visakh Refinery. Date of Commencement : 1/4/2010 Location : SS-6B Date of completion : 6/4/2010 Bore hole : 7 Ground RL : +5.497 Ground Water Table : 1.93m

Coordinates : N 556.394 E 1673.212

UDS – Undisturbed Sample DS – Disturbed Sample SPT – Standard Penetration Test pen. – Penetration 2

Ground R.L. Depth Below

G.L. (m)


collected (m)

RL & Depth at which SPT

conducted (m) SPT

From To From To

Visual Description

of strata

Thickness of Strata

(m)

Type of

sample GRL GL

(m) GRL GL (m)

15 cm

30 cm

45 cm

N-Value

Core recovery

%

RQD % Remarks

-1.003 -2.003

6.50 7.50

SPT-4 DS-6

-2.003

7.50

-1.003

6.50

53(10cm pen.)

>53 Nil Nil

-2.003 -3.003 7.50 8.50 DS-7 -3.003 8.50 Nil Nil -3.003

-4.503 8.50

10.00 SPT-5 DS-8

-4.503

10.00

-3.003

8.50

56(5cm pen.)

>50 Nil Nil

-4.503 -6.003 10.00 11.50 DS-9 -6.003 11.50 3 Nil -6.003 -6.503 11.50 12.00 SPT-6 -6.003 11.50 73(10cm pen.) >73 2 Nil -6.503 -7.503 12.00 13.00 DS-10 -7.503 13.00 Nil Nil -7.503 -9.003 13.00 14.50 SPT-7 -7.503 13.00 81(8cm pen.) >81 Nil Nil -9.003 -9.853 14.50 15.35

Highly weathered

rock 9.03

SPT-8 -9.853 15.35 100(no pen.) >100 Nil Nil

Borehole terminated at 15.35m below G.L. (i.e.) at R.L -9.853

J.J. ASSOCIATES(VISAKHAPATNAM) AETP(P) LIMITED #11-6-3, RockDale Layout, MaharaniPeta,


IDENTIFICATION & ENGINEERING PROPERTIES OF SOIL

Project : Proposed DHT project at HPCL, Visakh Refinery at Visakhapatnam Location : Proposed SS-6B Site.

Triaxial Test

Gradation Analysis Consistency Limits UU

FINES


collected Sl No. BH No

Sample No.

Type of sample

GRL GL (m)

Natural moisture content

(%)

Bulk Density (g/cc)

Dry Density (g/cc) Gravel

(%) Sand (%) Silt Clay

Liquid Limit (%)

Plastic Limit (%)

Plasticity

Index (%)

C (kg/cm²)

φ degree

Specific gravity ISC

1 7 1 SPT +3.997 1.50 9.76 - - 10.00 35.00 42.00 13.00 34 19 15 - - - CL

2 7 2 DS +2.997 2.50 16.22 - - 0.00 61.00 32.00 7.00 24 13 11 - - 2.64 SC

3 7 3 DS +1.497 4.00 - - - 0.00 90.00 10.00 ◄▬NP▬► - - - -

J.J. ASSOCIATES (VISAKHAPATNAM) (P) LIMITED #11-6-3, Rock Dale Layout, Maharanipeta,


Project : Proposed DHT Project at Visakh Refinery. Location : SS-6B Area.

CHEMICAL ANALYSIS OF SOIL

Depth at which sample collected S.No. BH

No. G.R.L. G.L (m)

Pн Sulphates %

Chlorides %

Organic Matter

%

1 7 +2.997 2.50 7.20 0.002 0.005 nil

CHEMICAL ANALYSIS OF WATER

Depth at which sample collected S.No. BH

No. G.R.L. G.L (m)

Pн Sulphates mg/l

Chlorides mg/l

Organic Matter

mg/l

1 7 +3.567 1.93 7.40 320 118 11

J.J. ASSOCIATES(VISAKHAPATNAM) AETP (P) LIMITED #11-6-3, Rock Dale Layout, Maharanipeta,


BORE LOG DETAILS

Project : Proposed DHT Project at Visakh Refinery. Location : At Proposed SS-6B Site.

BH-7

0.00 +5.497 Filled up soil &

boulders

1.00 +4.497 Reddish clay

with pebbles N=13@+3.997

2.50 +2.997 Highly

weathered rock N>50@+2.497 N>50@+0.997

6.00 -0.503 Reddish clay

with pebbles

6.50 -1.003 Highly

weathered rock N>[email protected] N>[email protected] N>[email protected] N>[email protected] N>[email protected]

15.35 -9.853

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FINAL REPORT ON SOIL INVESTIGATION - HPCLtenders.hpcl.co.in/tenders/tender_prog/TenderFiles/3744/Tender/SS... · final report on soil investigation for proposed construction at ss-6b