Report1

PROJECT : THERMAL POWER PLANT VUNG ANG 3.1
Report on soil investigation
1 Introduction............................................................................................................................................2
2 Bases of the investigation.......................................................................................................................4
3 Quantity of geotechnical investigation...................................................................................................5
4 Equipments.............................................................................................................................................5
5 Survey method.......................................................................................................................................6
5.1 Exploration Drilling process and Sampling.......................................................................................6
5.2 Standard penetration test ...............................................................................................................7
6 Laboratory Test.......................................................................................................................................7
6.1 Moisture Content Tests...................................................................................................................7
6.2 Unit Weight Tests............................................................................................................................8
6.3 Specific Gravity Test.........................................................................................................................8
6.4 Particle Size Distribution Tests.........................................................................................................8
6.5 Liquid and Plastic Limit Tests...........................................................................................................9
6.6 Direct shear test...............................................................................................................................9
6.7 Compression test ...........................................................................................................................9
7 Photographs...........................................................................................................................................9
8 Geotechnical characteristics of the project area....................................................................................9
8.1 General............................................................................................................................................9
8.2 Strata of the investigation area......................................................................................................10
9 Conclusions and recommendations .....................................................................................................11
9.1 Conclusions....................................................................................................................................11
9.2 Recommendations.........................................................................................................................12
Appendices
Location of boreholes Appendix No1
Boring logs Appendix No2
Geotechnical profiles Appendix No3
Acceptance Minutes Appendix No4
Photographs Appendix No5
Legend
U Undisturbed sample
D Disturbed sample
N - Value Standard penetration resistance
PORT TECHNOLOGY CONSTRUCTION CONSULTING AND COMMERICAL ( JSC)
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P Particle size %
∆ Specific gravity g/cm3
ɣ Wet Density g/cm3
ɣ k Dry Density g/cm3
W Moisture content %
Wl Liquid limit %
WP Plastic limit %
IP Plasticity index %
B Consistency
e Void ratio
n Porosity %
S Saturate degree %
ϕ Angle of Internal friction in direct shear test degree
C Cohesion in direct shear test Kg/cm2
1 Introduction
In order to collect more information and characteristics of the subsurface soil layer
for thermal power plant Vung Ang 3.1, PORT TECHNOLOGY CONSTRUCTION
CONSULTING AND COMMERICAL (JSC) has signed a contract for carrying out
geotechnical investigation.
It is also intended to provide information to plan the best method of construction to
foresee and provide against any difficulties and delays during construction due to the
ground and other local conditions.
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the report represents results of geotechnical investigation including drilling, soil
sampling, standard penetration test (SPT) and laboratory testing for 9 boreholes.
Report for geotechnical investigation was made in according to ASTM standard.
Technical standard and technical requirements applicable for the geotechnical survey.
A. ASTM standard Table 1
No Tests American Standards ASTM
1 Drilling
1.1 Auger Borings ASTM D 1452-80
1.2 Field Logging ASTM D 5434-03
1.3
Classification of Soils for engineering
Purposes
ASTM D 2487-06
1.4 Descriptionand Identification of Soils
ASTM D2488-06
1.5 Core drilling
ASTM D 2113-83
ASTM D 2113-06
2 Sampling
2.1 Guide for sampling ASTM D 420
2.2 Split-Barrel Sampling (SPT) ASTM D 1586-99
2.3 Field Logging ASTM D 5434-03
2.5 Soils - Sampling, packing ASTM D 4820
2.6 transportation and curing of samples
3 Insitu tests
3.1 Standard Penetration Test (SPT) ASTM D 1586-99
4 Soil tests
4.1 Specific gravity ASTM D 854-92
4.2 Moisture content ASTM D 2216-92
4.3 Atterberg limits ASTM D 4318-93
4.4 Grain size analysis ASTM D 422-90
4.5 Unit weight ASTM D 4254-91
4.6 Direct shear test ASTM D 6528 – 07
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No Tests American Standards ASTM
4.7 Unconfinedcompression test
ASTM D 2166-85
ASTM D 2166-91
5 Rock
5.1
Suggested Methods for Determine Basic
Physical Properties of Rock
ISRM No.2, 1972
5.2
Suggested Method for Determine Shear
Strength of Rock
ISRM No.1, 1974
5.3
Standard Test Method for Unconfined
Compressive Strength of Intact Rock Core
Specimens
ASTM D 2938-95
B. Other reference standards:
British Standards
(BS)
Relevant British Standards, in particular:
− BS 1377-1990: Methods of test for soils for civil engineering
purposes – Parts 1 to 9;
− BS 5930-1999: Code of practice for site investigations.
Other codes or
standards
22 TCN 259 - 2000: Codes of practice for exploration drilling,
published by Ministry of Transport of Vietnam
Soil names was determined by site boring record of the boreholes and results of
laboratory test. Soil samples were tested according to ASTM, BS and Vietnamese
standard.
Soil layers were determined based on classification, state and distribution of them.
2 Bases of the investigation
The geotechnical investigation for the project was carried out based on the following
document:
• Economic contract on soil investigation for thermal power plant Vung Ang 3.1;
• Technical specification of the project;
• Method statement for Geotechnical Investigation was approved by consultant;
• ASTM – American Society for testing and Material;
• BS – 5930: 1999 Code of Practice for site investigation British Standards
instution;
• TCVN – Vietnam Construction Standard;
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3 Quantity of geotechnical investigation
• Site investigations were include drilling, taking sample, standard penetration test:
• Drilling and taking samples at 9 Borehole;
• Standard penetration tests were carries out at all above locations;
• 14 taken samples were tested in laboratory;
More details on quantity of works are shown on table 2
Table No.2: Quantity of works
No Borehole
Actual coordinates
Elevation
(m)
Undisturbed
sample
disturbed
sample
SPT
Drilling
in soil
and
rock(m)
X Y
1 BH10 1993585.1 600874.8 -1.21 1 0 3 30.0
2 BH11 1994705.1 602025.7 -12.79 2 1 6 20.0
3 BH12 1994333.7 601381.7 -10.66 1 1 7 30.0
4 BH13 1993991.5 601579.3 -10.5 2 1 7 40.0
5 BH14 1994189.5 601464.5 -10.48 1 1 7 30.0
6 BH15 1993790.0 602554.1 -12.78 1 1 3 20.0
7 BH17 1994363.0 602223.2 -12.76 1 0 7 20.0
8 BH18 1993954.2 601878.7 -11.58 0 0 3 15.0
9 BH19 1993301.2 602714.6 -12.84 0 0 4 10.0
TOTAL 9 5 47 215
4 Equipments
Using 01 drilling machines XY – 1A Made in China with maximum capacity of
150m to carry out the boring with two – merged boats and the platform (Jackup).
Following equipments were used for site investigation:
Table No.3: Equipments were used for the site investigation
No. Equip. Name Model/Manufacturer Capacity Unit Quantity
1
Rotary coring
type
XY-1A, XJ100/China 150m No. 02
2 Hydraulic pump China - No. 02
3 Positioning
Total Station/England
DGPS/France
- No.
01
01
4 Leveling Pentax/Japan - No. 01
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5 SPT Vietnam - No. 02
6
Thin walled tube
sampler
Vietnam - Set 02
7 Piston sample Japan - Set 02
8 Double tube Vietnam - Set 02
9 Drilling rod China - Meter 140
10 Casing China - Meter 60
11 Platform - - No. 01
12
Boat for worker
transportation
- - No. 01
13 Transceiver ICOM/Japan 10 km No. 03
14 Other accessories - - - -
Manpower attended in the investigation is shown in the table below.
Table No.4: Manpower
No. Job & Degree Responsibility Number Remarks
1 Qualified geotechnical
engineer
Manager & officer in
charge
01 QC
2 Geotechnical engineer Field manager and
recording
02 -
3 Worker Drilling 08 -
4 Operator Operate drilling 02 -
5 Surveyor Positioning and
leveling
02 -
6 Lab staff Lab testing 05 -
7 Geotechnical engineer Making report 02 -
5 Survey method
5.1 Exploration Drilling process and Sampling
The field Drilling engineering uses the Slurry Wall Drilling Rotary process, and
single or dual core tube collecting core, and alloy drill bits used in soil layer and rock
weathering layer, diamond drill bit used in rock. Above hole drilling technology can
achieve the drilling requirements of wall stability, clean hole bottom, more than 85%
core collection.
Undisturbed soil samples (UD sample) is collected by the thin wall Soil sampler
with the hydrostatic method to ensure the quality of undisturbed soil samples, rock
samples and regolith samples (C samples) is taken from the core tube core samples;
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disturbed soil samples (D sample) is taken from the split tube of the standard penetration
test.
5.2 Standard penetration test
Standard penetration test shall be subject to the strict implementation of standard
ASTM D 1586-99, and the mud protection will be used in the sand in the drilling, to
ensure the stability of the hole wall, clean hole bottom; test type uses 63.5kg automatic
decoupled heavy free drop hammer for hammering, the drop distance of the 76cm,
where tests need to avoid hammering eccentric and shaking, to maintain control of
penetration, drill pipe, the vertical guide rod connected degree and rate control
hammering, hammering number to ensure accurate and reliable hammering quantity.
Based on the measured standard penetration strike count (N-Value), it’s to determine the
status of soil, as described in The soil of SPT N Value and Status (Table).
The soil of SPT N Value and Status Table
Clay Soil Sandy Soil
SPT N Value Consistency SPT N Value Compactibility
0～2 Very Soft
2～4 Soft 0～4 Very Loose
4～8 Med Stiff 4～10 Loose
8～15 Stiff 10～30 Med.Dense
15～30 Very Stiff 30～50 Dense
>30 Hard >50 Very Dense
6 Laboratory Test
Physical properties of soil (moisture content, wet density, specific gravity) are
determined in accordance with Vietnamese standard and American standard ASTM
D2216, TCVN 4202:1995, ASTM D 854.
6.1 Moisture Content Tests
The moisture content of the soil was determined by oven drying for 24 hours at a
constant temperature of 105°C. The loss in mass of the sample due to the drying
represents the moisture of the soil. The moisture content of the soil is presented as a
percentage of the dry weight of the soil.
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6.2 Unit Weight Tests
Unit weights were computed from the wet and dry weights of a standard volume of
soil. The dry weight was obtained after the wet standard volume of soil had been dried
for 24 hours at a temperature of 105°C.
Unit weights were routinely determined from direct measurement of sample weight
and volume. However, soils that were fully saturated in-situ may have expanded and
become partially saturated as the overburden pressure was relieved or as dissolved gas in
the pore water came out of solution during sample retrieval. For these reasons, the unit
weights determined in this manner could be less than the actual in-situ unit weights.
6.3 Specific Gravity Test
The specific gravity of soil solids that pass the 4.75mm was determined by mean
of a water pycnometer. The pycnometer was calibrated and the water content of a
portion of the sample was determined. The soil was dispersed using a blender to agitate
the water until a slurry was formed. The pycnometer was filled with de-aired water.
After achieving thermal equilibrium, the mass of the pycnometer, soil and water was
measured and recorded.
6.4 Particle Size Distribution Tests
Particle size distributions were performed by means of sieving, hydrometer tests,
or both. The percentage weight of the various particle sizes in excess of 63 microns were
determined by sieving through a set of various standard sieves in an electric shaker with
horizontal and vertical motion. Wire sieves were used up to and including a sieve
opening of 4.75mm.Plate sieves with a sieve opening up to 9.5mm were used when more
than 5% of the weight of the specimen was retained on the 2 mm sieve. When there
were more than 50% of particles smaller than 63 microns, the sieving was
complemented by a hydrometer test, in which the sample was mixed with water and
stirred for about 15 minutes. An additive prevents flocculation of the soil particles. After
mixing, the density of the water-soil slurry was measured at fixed time intervals. With
this information the particle size distribution of the sediment particles was determined.
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6.5 Liquid and Plastic Limit Tests
Tests to determine the Atterberg Limits (Liquid and Plastic Limits) were performed
on selected samples of cohesive material. The soil was first dried and then ground in a
mortar into separate grains. All soil grains larger than a sieve size 0.425mm were then
removed. The soil was then thoroughly mixed with different quantities of distilled water.
6.6 Direct shear test
The direct shear tests are carried out in compliance with Vietnamese standard
TCVN 4199-9 with rapid shear and unsaturated method. Load applied is selected
depending on soil type and its state. The tests are performed with load applied at 0.25,
0.5, 0.75 kg/cm for soft to very soft soil; 0.5, 1.0, 1.5 kg/cm2 for sand and firm in state,
and 1.0, 2.0, 3.0 kg/cm2 for other soil. From direct shear test results, the values of
internal friction angle φ and cohesion c are calculated using least mean square method.
6.7 Compression test
The compression tests are carried out for undisturbed samples of soil layers in
investigated strata and performed in accordance with Vietnamese standard TCVN
4200-95 with rapid compression and saturation. The load applied at 0.125, 0.25, 0.5,
1.0, 2.0 and 4.0 kG/cm². For each applied load, the settlement of soil specimen is
monitored continuously in 2 hours. For the end applied load, the settlement of soil
specimen is monitored continuously in 24 hours.
Based on compression test results, the graph of void ratio against applied load
is plotted for calculation compression coefficient a and compression Modulus E
7 Photographs
All the field investigation such as boring, sampling, SPT testing have taken
photographs. More details in photograph can be see in appendix No 5
8 Geotechnical characteristics of the project area
8.1 General
The area of the proposed construction site for Thermal power Vung Ang 3.1 is
around 10 square kilometers, in Ky Anh district, Ha Tinh province VN. The
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geotechnical investigation consists of drilling, sampling, standard penetration test and
laboratory testing.
8.2 Strata of the investigation area
Based on results of the site investigations & laboratory tests carried out by PORT
TECHNOLOGY CONSTRUCTION CONSULTING AND COMMERICAL JSC in
August and September 2014, 05 geotechnical profiles was made for illustration
stratigraphical structure of the project area.
More details on geotechnical profiles is shown in Appendix No4
Stratum of the investigation area can be divided into layers from top to bottom
described in details as follows:
 Layer No.1(1S1): Very loose to loose, blackish grey, grey, somewhere mixed
shells. Fine Sand .
This soil layer distributes in all most boreholes (not BH 10), the thickness of layer
has changed range from 5.0m (BH 12) to 10,7m (BH 13), the average thickness’one is
about 7.0m with the main composition are blackish grey, grey, fine sand somewhere
mixed shell, very loose to loose.
 Layer No.1(1S2): Loose to medium dense, whitish grey, yellowish grey,
medium sand and sandy gravel mixed little shells.
This layer distributes below layer No I, the thickness of layer has changed in
boreholes as BH 10 (7.0m), BH 14 (17.0m), BH 17 (5.9m) and BH 19(8.0m). The
average thickness’ one is about 9,0m, the elevation of bottom layer is -32,98 (BH 14)
with the main composition are whitish grey, yellowish grey, medium sand and sandy
gravel mixed little shells.
 Layer No2 (1M): Hard, reddish brown, yellowish grey, grey, sandy clay, silty
clay mixed gravel.
This layer distributes below layer No1 at all most boreholes. The thickness of layer
has changed from 0.8m (BH11) to 6.5m (BH12). This one is thin, the average thickness
of layer is about 3.0m with main composition: sandy clay, silty clay mixed gravel.
 Layer No3 (2): Zone of Completed weathered rock: Hard, brown, yellowish
brown, sandy clay little gravel (content about from 20 to 40% gravels)
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This layer distributes in all most boreholes (not BH19). The elevation of surface
layer has changed range from -11.91m(BH10) to -32,98m(BH14) and the elevation of
bottom layer has changed from -24.79m(BH11) to -42.0m(BH13), the average thickness
of layer is about 8.0m. The main composition of layer is Sandy clay mixed gravel,
structural and texture composition of rock had changed, value index SPT of layer is
quite high (>50).
 Layer No4(3): Zone of Highly weathered rock: hard, fissured and soft rock,
blackish grey, light grey.
This layer is encountered in all most boreholes (not BH17, BH19), some boreholes
has finished but indefine the thickness of layer. The main composition of layer is highly
weathered quartz schist, blackish grey, light grey, Gravel mixed clay, in the zone
materials has changed into soil, texture anh structure intact. Small fragments formed
when crush in hand or immerse in water. SPT index of this one is highly.( ≈100).
 Layer No5(4): Moderately weathered quartz schist: hard fissured, light grey,
relative strong.
Layer No5 is defined as moderately weathered quartz schist and ecounterd in four
boreholes are BH 10, BH12, BH13, BH14. In this one, color changes relatively in all
rock of materials (ogiginal color increases) whole texture and structure of rock is
unchanged. The fragments of rock are hard to break by hand, the rock is relatively hard
but unconfined compression strength is low due to a lot of close fractures contained
inside, drilling speed is this layer slow. SPT index is over 50. The elevation of surface
layer is encounterd in borehole from -30.71m(BH10) to -48.8m(BH13). However
boreholes finished we was undefine bottom of layer.
9 Conclusions and recommendations
9.1 Conclusions
Based on the results mention above, some conclusions can be given, as follows:
• Stratum of investigation area consists of 05 layers.
• Layer No1(1S1): Very loose to loose, blackish grey, grey, somewhere mixed
shells. Fine Sand with thickness changed from 5.0m to 10,7m.
• Layer No1(1S2): Loose to medium dense, whitish grey, yellowish grey, medium
sand and sandy gravel mixed little shells.has infinitely small load with thickness
changed relatively.
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• Layer No2(1M): Hard, reddish brown, yellowish grey, grey, sandy clay, silty clay
mixed gravel. Has medium capacity but the thickness of layer is small.
• Layer No3(2): Zone of Completed weathered rock: Hard, brown, yellowish
brown, sandy clay little gravel (content about from 20 to 40% gravels) have
bearing capacity. Thickness of layer 3 varies from 2.0m to 8.0m, accept borehole
BH11 separated with thickness up to 8.0m.
• Layer No4(3): Zone of Highly weathered rock: hard, fissured and soft rock,
blackish grey, light grey has bearing capacity with average thickness is about
8m. Some boreholes finished we was undefine bottom of layer.
• Layers No5(4): Moderately weathered quartz schist: hard fissured, light grey,
relative strong, have high bearing capacity. The thickness of layers are
undefined.
• In general, this investigation results consistent with the result of Feasibility study.
9.2 Recommendations
• For medium loading capacity work items, it is possible to place foundation at the
layer No2 or layer No3
• For high loading capacity work items, it should be used pile foundation. Head of
pile would be placed in layer No 5.
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