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
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.
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J.J.ASSOCIATES (Vskp) AETP (P) LIMITED
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.
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J.J.ASSOCIATES (Vskp) AETP (P) LIMITED
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.
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J.J.ASSOCIATES (Vskp) AETP (P) LIMITED
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 Gravel content Sand content
0.00 to 1.00m Filled
%
material
%
Silt and Clay content
%
1.00m to 2.50m
2.50m & below Highly
up 7 to 11
Weathered
rock
31 to 43 46 to 62 CL-SC
Soil Classification as per IS
Note : A layer of Clay with pebbles observed from 6.00m to 6.50m
7.Suggested Design Soil Parameters Layer
Depth Below GL
No.
1
Soil type
(m) FROM
TO
0.00
1.00
Filled up
Average
Cu 2
Ф
γ
N-Value
t/m
degree
t/m3
-
-
-
-
-
-
-
2.10
material 2
1.00
2.50
Clay with sand 13 & pebbles 3 2.50m & below Highly 50 weathered rock 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.
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J.J.ASSOCIATES (Vskp) AETP (P) LIMITED
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 S No.
Depth (m)
Width (m)
Net safe Bearing Length (m)
Capacity in t/m2 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.
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J.J.ASSOCIATES (Vskp) AETP (P) LIMITED
S No.
Depth of
Width of
Settlement
Allowable bearing
Foundation
Foundation
Pressure for
pressure for 25mm
(m)
(m)
10t/m2
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., 6
J.J.ASSOCIATES (Vskp) AETP (P) LIMITED
J.J. ASSOCIATES(VISAKHAPATNAM)AETP(P) LIMITED 11-6-3,RockDale Layout, Maharanipeta, Visakhapatnam – 530 002.
Project : Proposed DHT project at Visakh Refinery. Location : SS-6B Bore hole : 7 Ground Water Table : 1.93m
Date of Commencement : 1/4/2010 Date of completion : 6/4/2010 Ground RL : +5.497 Coordinates : N 556.394 E 1673.212
BORELOG
Ground R.L.
From
To
+5.497
Depth Below G.L. (m) From
+4.497 +2.997
1.00
DS-1
+4.497
1.00
1.00
1.50
2.50
Reddish clay with pebbles
SPT-1 DS-2
+2.997
2.50
Highly weathered rock
3.50
SPT-2 DS-3 SPT-3 DS-4
+1.497
4.00
-0.503
6.00
Reddish clay with pebbles
0.50
-1.003
6.50
2.50
-0.503 -0.503
6.00 6.00
-1.003 UDS – Undisturbed Sample
Type of sample
Filled up soil & boulders
1.00 +2.997
Thickness of Strata (m)
To
0.00 +4.497
Visual Description of strata
RL & Depth at which sample collected (m) GL GRL (m)
6.50
DS – Disturbed Sample
DS-5
SPT – Standard Penetration Test
RL & Depth at which SPT conducted (m)
SPT
NValue
GRL
GL (m)
15 cm
30 cm
45 cm
+3.997
1.50
3
5
8
+2.497
3.00
8 49 52(5 cm pen.)
>50
+0.997
4.50
58(5cm pen.)
>50
pen. – Penetration
Core recovery %
RQD %
Remarks
13
1
J.J. ASSOCIATES(VISAKHAPATNAM)AETP(P) LIMITED 11-6-3,RockDale Layout, Maharanipeta, Visakhapatnam – 530 002.
Project : Proposed DHT project at Visakh Refinery. Location : SS-6B Bore hole : 7 Ground Water Table : 1.93m
Ground R.L.
From
To
-1.003 -2.003 -3.003 -4.503 -6.003 -6.503 -7.503 -9.003
Depth Below G.L. (m) From
Visual Description of strata
Thickness of Strata (m)
To
6.50 -2.003 -3.003 -4.503 -6.003 -6.503 -7.503 -9.003 -9.853
7.50 8.50 10.00 11.50 12.00 13.00 14.50
Type of sample
7.50 8.50 10.00 11.50 12.00 13.00 14.50 15.35
Highly weathered rock
9.03
SPT-4 DS-6 DS-7 SPT-5 DS-8 DS-9 SPT-6 DS-10 SPT-7 SPT-8
Date of Commencement : 1/4/2010 Date of completion : 6/4/2010 Ground RL : +5.497 Coordinates : N 556.394 E 1673.212 RL & Depth at which sample collected (m) GL GRL (m) -2.003 -3.003 -4.503 -6.003 -7.503
RL & Depth at which SPT conducted (m)
SPT
NValue
-1.003
GL (m) 6.50
15 30 45 cm cm cm 53(10cm pen.)
>53
-3.003
8.50
56(5cm pen.)
>50
-6.003
11.50
73(10cm pen.)
>73
-7.503 -9.853
13.00 15.35
81(8cm pen.) 100(no pen.)
>81 >100
GRL
7.50 8.50 10.00 11.50 13.00
Core recovery %
RQD %
Nil
Nil
Nil
Nil
Nil
Nil
3 2 Nil Nil Nil
Nil Nil Nil Nil Nil
Remarks
Borehole terminated at 15.35m below G.L. (i.e.) at R.L -9.853
UDS – Undisturbed Sample
DS – Disturbed Sample
SPT – Standard Penetration Test
pen. – Penetration
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J.J. ASSOCIATES(VISAKHAPATNAM) AETP(P) LIMITED #11-6-3, RockDale Layout, MaharaniPeta,
Visakhapatnam – 530 002. IDENTIFICATION & ENGINEERING PROPERTIES OF SOIL Project : Proposed DHT project at HPCL, Visakh Refinery at Visakhapatnam Location : Proposed SS-6B Site.
Sl No.
BH No
Sample No.
1
7
1
2
7
2
3
7
3
Type of sample
RL & Depth at which sample collected GRL
GL (m)
SPT
+3.997
1.50
DS
+2.997
2.50
DS
+1.497
4.00
Gradation Analysis Natural moisture content (%)
Bulk Density (g/cc)
9.76
-
16.22 -
Dry Density (g/cc)
Consistency Limits
FINES
Triaxial Test UU Specific gravity
ISC
-
-
CL
-
-
2.64
SC
-
-
-
Clay
Liquid Limit (%)
Plastic Limit (%)
Plastici ty Index (%)
C (kg/cm²)
φ degree
42.00
13.00
34
19
15
-
32.00
7.00
24
13
11
Gravel (%)
Sand (%)
Silt
-
10.00
35.00
-
-
0.00
61.00
-
-
0.00
90.00
10.00
◄▬NP▬►
-
J.J. ASSOCIATES (VISAKHAPATNAM) (P) LIMITED #11-6-3, Rock Dale Layout, Maharanipeta,
Visakhapatnam – 530 002. Project Location
: Proposed DHT Project at Visakh Refinery. : SS-6B Area.
CHEMICAL ANALYSIS OF SOIL
S.No.
BH No.
1
7
Depth at which sample collected G.L G.R.L. (m) +2.997 2.50
Pн 7.20
Sulphates Chlorides % % 0.002
0.005
Organic Matter % nil
CHEMICAL ANALYSIS OF WATER
S.No.
BH No.
1
7
Depth at which sample collected G.L G.R.L. (m) +3.567 1.93
Pн 7.40
Sulphates Chlorides mg/l mg/l 320
118
Organic Matter mg/l 11
J.J. ASSOCIATES(VISAKHAPATNAM) AETP (P) LIMITED #11-6-3, Rock Dale Layout, Maharanipeta, Visakhapatnam – 530 002. BORE LOG DETAILS
Project Location
: Proposed DHT Project at Visakh Refinery. : At Proposed SS-6B Site. BH-7
0.00
+5.497 Filled up soil & boulders
1.00 Reddish clay with pebbles 2.50 Highly weathered rock 6.00
+4.497 N=13@+3.997 +2.997 N>50@+2.497 N>50@+0.997 -0.503
Reddish clay with pebbles 6.50 Highly weathered rock
15.35
-1.003 N>
[email protected] N>
[email protected] N>
[email protected] N>
[email protected] N>
[email protected] -9.853
