55539369-Method-Statement-of-Soil-Investigation.pdf

Soil Investigation for Vietnam Viet nam King-Whale Project

Method Statements

May, 2007

Contents Figur Fig ures............... es................................... ........................................ ........................................ ........................................ ......................................... ...................................... ................. II Tables............................................... Tables........................... ........................................ ........................................ ........................................ ......................................... ............................ ....... II 1. Introd Int roduct uction ion.................. ...................................... ........................................ ........................................ ........................................ ................................ ............ 1 2. Work Wor k Plan Pla n ...................................... .......................................................... ........................................ ........................................ ................................... ............... 2 3. Work Proced Pro cedure ure ........................................ ............................................................ ........................................ ........................................ ...................... .. 5

3.1 Soil Soi l Borin Bo ring g ....................................... ........................................................... ........................................ ........................................ ......................... ..... 5 3.2 Standard Stand ard Penetration Penetr ation Test and Sampling Sampli ng .......... ............... .......... .......... .......... .......... ......... ......... .......... .......... ..... 5 3.2.1 Sampler Sampl er ....................................... ........................................................... ......................................... ....................................... .................. 5 3.2.2  N - value valu e (Blows (B lows Count) Cou nt) Record Reco rd .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... ..... 5 3.2.4 Sampl Sam plin ing............................... g................................................... ........................................ ........................................ ......................... ..... 6 3.3 Undistur Undi sturbed bed Sampling Samp ling .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ..... 6 3.4 Core Cor e Dril Dr illi ling ng ....................................... ........................................................... ........................................ ........................................ ...................... .. 7 3.5 Field Testin Te sting....................... g........................................... ........................................ ......................................... ....................................... .................. 7 3.5.1 3.5 .1 Field Fiel d Permeabi Perm eability lity Test ....................................... ........................................................... ................................... ............... 7 3.5.2 3.5. 2 Observatio Observ ation n Well and Piezomete Piezo meterr .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... ..... 7 3.5.3 3.5 .3 Field Vane Shear Test ..................................... .......................................................... ..................................... ................10 10 3.6 Laborat Lab oratory ory Testing Test ing ....................................... ........................................................... ........................................ .............................. .......... 10 4. Quali Qua lity ty Contr Con trol................................... ol....................................................... ........................................ ......................................... ........................... ...... 11

4.1 Drilli Dri lling ng................... ....................................... ........................................ ........................................ ........................................ .............................. .......... 11 4.2 Sampling Samp ling / Storage Stor age ....................................... ........................................................... ........................................ .............................. .......... 11 5. Safety and Environmental Protection Requirement....................................13 Appendix A Relative ASTM Standards .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... .......... ..........1 .....14 4

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Figures Fi g 1

Plan Pla n Loca Lo cati tion on.................... ........................................ ........................................ ......................................... ......................................1 .................1

Fig Fi g 2

Observation Observa tion Well Details .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... .......... ......... ......... .......... .........8 ....8

Fig Fi g 3

Piezometer Piezome ter Stand Pipe Type Details .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... .........9 ....9

Tables Table Table 1

Boring Scheme for Phase 1 ...........................................................................3

Table Table 2

Boring Scheme for Phase 2 ...........................................................................4

Table Table 3

Laboratory Testing Standard Methods ........................................................10

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1.

Introduction The proposed site, as shown in Figure 1, is including two areas as Phase 1 and Phase 2. In order to

get the geological data data for detail design, the soil investigation shall be carried out. The The geotechnical investigations investigations shall be implemented according to the following description and and the specifications in this statement.

PHASE 1

PHASE PHASE 2

Figure 1 Plan Location

1

2.

Work Plan The quantities of boring for Phase1 and Phase 2 are shown in Table 1 and Table 2

respectively. The execution of soil investigation mainly contains two parts: field exploration and laboratory testing. The primary items are listed below and described in detail in the following section. (1) Field Exploration: (a) Boring and Sampling: Drilling, Split Spoon Sample and Thin Wall Tube Sample. (b) Field

Testing

and

Measurement:

Standard

Penetration

Test

(SPT),

Field

Permeability Test, Observation well, Piezometer and Vane Shear Test. (2) Laboratory Laboratory Testing: Testing: (a) Soil Physical Properties: Unit Weight(? t ), Water Water Content( wn), Specific Gravity(Gs), Soil Grain Size Analysis Analysi s and Atterberg Atterberg Test. (b) Soil Shear Strength Test (c) One-Dimensional Consolidation Test.

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Table 1 Boring Scheme for Phase 1

Sample Number Field Testing Propose Bore Borehole Split 3"f 3"f Thin Thin Field Vane Soil SPT Observation Hole Depth spoon Wall Permeability Piezometer shear Physical Testing Well  No. Sample Tube Test test Properties (set) (m) (set) (set) (set) (set) (set) (set) (set)

Soil Laboratory Testing Unconfined Compression Test

Triaxial 1-D UUU consolidation test Test

(set)

(set)

(set)

BH-1 BH-1

250

40

2

40

1

0

0

1

42

1

0

1

BH-2 BH-2

40

26

2

26

0

0

1(35m) 1(35m)

1

28

0

1

1

BH-3 BH-3

30

20

2

20

0

1(15m) 1(15m)

0

1

22

1

0

1

Total

320

86

6

86

1

1

1

3

92

2

1

3

*Note: The SPT tests and samples of BH-1 are executed executed from surface to GL.-60m.

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Table 2 Boring Scheme for Phase 2

Propose Borehole Bore Hole Depth  No. (m) RH-1

60

Sample Number Split spoon Sample (set) 40

Field Testing

Soil Laboratory Testing Vane shear test

Soil Physical Properties

Unconfined Compression Test

(set)

(set)

(set)

0

1

41

0

0

1

0

0 1

41 27

0 0

1 0

0 1

0 0 0

27 27 26

0 1 0

1 0 0

0 0 0

0 0 0

0 1 0

21 21 21

0 0 0

0 0 1

1 1 0

3"f Thin Thin SPT Observation Piezometer Wall Tube Testing well (set) (set) (set) (set) 1

40

0 0 0 0 0

Triaxial UUU test (set)

1-D consolidation Test (set)

RH-2 RH-3

60 40

40 26

1 1

40 26

RH-4 RH-5 RH-6

40 40 40

26 26 26

1 1 0

26 26 26

RH-7 RH-8 RH-9

30 30 30

20 20 20

1 1 1

20 20 20

1(15m) 1(15m) 0 0 0

RH-10 RH-10 RH-11 RH-11

30 30

20 20

1 1

20 20

0 0

1(25m) 1(25m) 0

0 1

21 21

0 1

1 0

0 0

RH-12 RH-12 Total

30 460

20 304

1 11

20 304

1(15m) 1(15m) 2

0 2

0 4

21 315

1 3

0 4

0 4

1(35m) 1(35m) 0 0 0

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Table 2 Boring Scheme for Phase 2

Propose Borehole Bore Hole Depth  No. (m)

Sample Number Split spoon Sample (set)

Field Testing

Soil Laboratory Testing Vane shear test

Soil Physical Properties

Unconfined Compression Test

(set)

(set)

(set)

0

1

41

0

0

1

0

0 1

41 27

0 0

1 0

0 1

0 0 0

27 27 26

0 1 0

1 0 0

0 0 0

0 0 0

0 1 0

21 21 21

0 0 0

0 0 1

1 1 0

3"f Thin Thin SPT Observation Piezometer Wall Tube Testing well (set) (set) (set) (set) 0 0 0 0 0

Triaxial UUU test (set)

1-D consolidation Test (set)

RH-1

60

40

1

40

RH-2 RH-3

60 40

40 26

1 1

40 26

RH-4 RH-5 RH-6

40 40 40

26 26 26

1 1 0

26 26 26

RH-7 RH-8 RH-9

30 30 30

20 20 20

1 1 1

20 20 20

1(15m) 1(15m) 0 0 0

RH-10 RH-10 RH-11 RH-11

30 30

20 20

1 1

20 20

0 0

1(25m) 1(25m) 0

0 1

21 21

0 1

1 0

0 0

RH-12 RH-12 Total

30 460

20 304

1 11

20 304

1(15m) 1(15m) 2

0 2

0 4

21 315

1 3

0 4

0 4

1(35m) 1(35m) 0 0 0

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3. 3.1 3.1

Work Procedure Soil Boring

Soil borings are made to determine the thickness, texture and order of occurrence of the soil strata as they exist in the ground. Every effort should be made to locate and record the datum elevation at which any change in stratification occurs. The minimum diameter of the boreholes will be 100 mm when undisturbed samples are scheduled to be taken. Earth shall be removed by auger or wash wa shing ing and all samples shall be taken by driving an approved 2-in. OD split-barrel sampler. Each sample as it is removed from the ground should be packed so that it will reach the laboratory (or place of storage) in the cond ition without loss of water or damage by freezing, heating, breakage of containers or other disturbances in transit. Borings shall be the following type and sizes: uncased borings of sufficient size to accommodate a 2-in. OD split-barrel sampler, a 3-in. thin-wall tube sampler (Shelby tube), or a 3-in . piston-type piston-type sampler. The walls of uncased borings shall  be adequ a dequately ately supporte supp orted d by a suitab su itable le suspen su spension sion of drilli d rilling ng mud. mu d.

3. 3.1 3.1

Work Procedure Soil Boring

Soil borings are made to determine the thickness, texture and order of occurrence of the soil strata as they exist in the ground. Every effort should be made to locate and record the datum elevation at which any change in stratification occurs. The minimum diameter of the boreholes will be 100 mm when undisturbed samples are scheduled to be taken. Earth shall be removed by auger or wash wa shing ing and all samples shall be taken by driving an approved 2-in. OD split-barrel sampler. Each sample as it is removed from the ground should be packed so that it will reach the laboratory (or place of storage) in the cond ition without loss of water or damage by freezing, heating, breakage of containers or other disturbances in transit. Borings shall be the following type and sizes: uncased borings of sufficient size to accommodate a 2-in. OD split-barrel sampler, a 3-in. thin-wall tube sampler (Shelby tube), or a 3-in . piston-type piston-type sampler. The walls of uncased borings shall  be adequ a dequately ately supporte supp orted d by a suitab su itable le suspen su spension sion of drilli d rilling ng mud. mu d.

3.2

Standard Penetration Test and Sampling

Standard Penetration Tests shall be conducted at every change of strata and within a continuous stratum at intervals not exceeding 1.5 meters. A sample shall always be taken in the first 1.5 meters of each boring. 3.2.1 Sampler

The sampler shall shall be a two -inch outside diameter di ameter split- barrel sampler, with an inside diameter of one and three-eighth (1-3/8) inches. The dimensions of the sampler shall conform to those shown in the Method for Penetration Test and Split-Barrel Sampling of Soils, ASTM Designation D1586, the latest revision. 3.2.2 3.2.2 N - value (Blows Count) Record

The sampler shall be driven with a guided hammer or ram into undisturbed soil below the bottom of the boring after the boring has been cleaned to remove all loose and foreign material. The hammer or ram used to drive the two -inch outside diameter sampler shall weigh 140

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 pounds  poun ds and shall fall freely free ly through thro ugh a height heig ht of 30 -in. The number numbe r of blows required requi red to drive the sampler each six inches for a total depth of 18 in. shall b e counted counted and recorded. recorded. The record shall clearly show the number of blows for each six inches of penetration. Cumulative numbers of blows will not be accepted. In hard materials requiring more than 50 blows per six inches of penetration, the blows for smaller amounts of penetration shall be observed and recorded with special note of the amount of penetration actually obtained. Once the water table has been reached, particular care must be exercised to maintain the hole full of water or at a level higher than the ground water level preceding and during the standard penetration test. During the removal of the drilling rods, chopping bit and assembly, and insertion of the sampling barrel, a positive inflow of water at the top of the casing shall be maintained. 3.2.3 Sampling

Immediately upon removal from the hole, the sampler shall be carefully disassembled and the the soil classified. The most representative and least disturbed disturbed portion of the sample, shall be tightly sealed sealed and kept in Engineer approved containers. The depth of the change shall be recorded. The containers shall be securely sealed to prevent evaporation of the soil moisture. The jar shall be properly labeled as to boring number, depth of sample, number of sample, and number of blows for each six inches of penetration, or as otherwise stipulated above. The project identification and date of sampling shall be clearly shown on the label. If a soil sample is lost or is found unsatisfactory as to size or condition, a second attempt shall be made to obtain a satisfactory soil sample before advancing the casing to a lower elevation. 3.3

Undisturbed Sampling

The undisturbed samples of cohesive materials shall be obtained by thin-wall tube sampler (Shelby tube). The tube to be used shall confo rm to ASTM D1587, its area ratio shall be no more than l0% and its inside clearance ratio shall be between l.0% and l.5%. Samples shall be obtained by forcing the tube into the soil with continuous pressure. Driving will not be permitted. The hole shall be thoroughly cleaned to its bottom prior-to sampling and all samples shall be taken below the bottom of the casing or below the  bottom  bot tom of o f the th e hole, ho le, if i f uncase un cased. d.

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When very soft soils are encountered and a thin-wall tube sampler is not able to recover an undisturbed smap1e, a piston sampler, with a stationary piston, shall be used; the dimensions of the sample tube remaini remaini ng the same as above. 3.4 Core Drilling

When bedrock is encountered, perform continuous core sampling utilizing triple tube core barrel and diamond bits of diameter not less than 50 mm. The individual coring runs shall be limited to a maximum length of 2.0 m.

Each coring recovery shall shall be recorded.

All significant actions of the bit, water return and reasons for loss of core shall be recorded in the boring log. Core recovery, RQD and rock logging shall be carried out. 3.5 Field Testing 3.5.1 Field Permeability Test

Field permeability test is performed to realize the mobility of water flow through aquifer encountered in BH-1. Water is added to an open-ended pipe casing sunk to desired depth. With constant head tests, constant rate of gravity flow into hole and size of casing of pipe are measured. Pipe casing must be carefully cleaned out just to the bottom of the casing. Clear water must be used or tests may be grossly misleading. The testing procedure should be followed NAVFAC DM7.1. The variation of flow rate with time was monitored and the data were used to obtain soil's permeability k value. 3.5.2 3.5.2 Observation Well and Piezometer

The observation wells and piezometers are installed to monitor the distribution and variation varia tion of groundwater level and piezometric pressure. The detailed installations are shown in Figure 2 and Figure 3. After installation, the groundwater and piezometric  pressure  pressu re shall be measured measu red constantly. consta ntly. During Du ring the period peri od of field work, work , the measurem meas urement ent shall be once every day. After the field work finishes, the measurement shall be twice a week lasting lasting one mo nth.

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Figure 2 Observation Well Details

8

Figure 3 Piezometer Stand Pipe Type Details

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3.5.3 Field Vane Shear Test

Vane Shear Test is performed in order to obtain the in-situ undrained shear strength and sensitivity sensitivity of cohesive cohesive soil. Because th e test is carried out on site, the prob lems of sample disturbance and the change of stress condition from field to laboratory can be eliminated. The testing procedure shall shall be followed ASTM D-2573-94 -2573-9 4 as shown in Appendix A.

3.6

Laboratory Testing

For present planning, planning, the lab test include soil property test and shear strength parameters test. Soil property tests include the unit weight, specific gravity, Atteberg test, water content content and soil soil gr ain size analysis. analysis. The test results are used for soil soil classification according to Unified Soil Classification System(USCS). According to the nearby investigation information, the soil layer is mostly cohesive soil layer. The undrained shear strength strength parameters are very important to design. The shear strength parameters can be obtained from Unconfined Compression Test and Tri-axial UUU Test. The consolidation consolidation test is planned to obtain the consolidation coefficient coefficient and coefficient of volumetric compression. Laboratory test work items and method are listed as Table 3. The laboratory testing shall follow the standard methods of testing given below.

Table 3 Laboratory Testing Standard Methods Test

Approved Standard

Soil Moisture Content and Density

ASTM D22l6-98 D22l6-9 8

Soil Specific Gravity

ASTM D854-92

Particle Size Analysis of Soil

ASTM D422-63 D422 -63

Classification Classification of Soils

ASTM D2487-98

Soil Atterberg Limits

ASTM D4318-95

Soil

Unconfined

Compressive ASTM D2166-91

Strength Soil

Unconsolidated

Undrained ASTM D2850-95

Triaxial Compressive Strength Soil Consolidation Test

ASTM D2435-96 D2435-9 6

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4. 4.1

Quality Control Drilling

The written record referred to as boring logs or field logs form the basis for determining the soil profile and contributed to an estimate of the quality of the samples and the in-situ conditions. Written records should be accurate, clear, concise, and account for the full depth of the boring. The field logs should contain information and the materials encountered, the number and type of samples obtained, the depth and length of the samples, the percentage of core recovery or recovery ratio, etc. Conditions to be recorded include the following. Ÿ

Difficulties in drilling, such as squeezing or caving formations.

Ÿ

The date, depth, and any condition change of drilling fluid during boring operations.

Ÿ

The name of project and its location.

Ÿ

The name and positions of members of the field party.

Ÿ

Describe the methods of advancing the borehole and the methods for stabilizing the boreholes.

4.2

Ÿ

Record all major changes of soil strata.

Ÿ

Record the number of the sample and its depth.

Ÿ

Record of groundwater table before commencing every day.

Sampling / Storage

(1)

Removal of sample from sampling device

After the sampling device has been withdrawn from the borehole, the sampling tube was disconnected from the sampler without shocks or blows. For open-tube samplers, sludge which has accumulated on top of the sample will be removed before the length of the sample is determined. (2)

Labeling samples

As samples are removed from the respective respective borings, they should be numbered by boring and consecutive order, order, such as S-1 ~ S- n, for split spoon samples and T-1 ~ T-n for thin-walled shelby tube samples, and by the depth of the respective samples. At the same time, the samples will be identified

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with labels labels and glue d to the outside of the container with waterproof plastic tape. The field engineer must ensure that each sample is labeled consistency with the data in the field log. (3)

Preservation of samples

Undisturbed samples shall shall be preserved in sample tubes, and coated with wax and sealed in sturdy containers to protect from changes of water content, shock and vibration. The plastic or rubber caps will be placed over the end of the thin-walled tube and sealed with waterproof plastic tape. After the sample has been placed in a suitable container, such as a wooden box, the annulus shall be between the sample and the cont ainer packing material for additional  protect  pro tection ion for the sample. samp le. All the samples samp les shall sh all be stored stor ed in certain cert ain space spac e away from from sunlight, sunlight, vibration. vibration.

After collection of certain certain amount, amount, the

samples samples shall be transported to the laboratory. (4)

Transporting ranspor ting samples

The distributed samples can be transported in almost any type of container and by any available mode of transportation. The undistributed samples, as a minimum requirement, should be transported in wood container that provides cushioning cushioning and insulation for each sample. Samples should fit snugly in each container to prevent rolling, bumping etc., and should be protected against vibration, shock, and temperature extremes.

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5.

Safety and Environmental Protection Requirement Requirement The local laws of safety and environment protection shall be followed. All  persons  person s on site and in works work s areas sh all wear appropriate appro priate personal perso nal protective prote ctive equipment. The personal protective equipment includes at least the safety helmet with with chin strap.

The site site shall be kept in a clean, clear clear and and

uncluttered unclutte red condition, condition , free of obstructions and hazards, at all times.

All

material and equipment shall be set up properly, particularly on access routes. There will be warning signals around the drilling rigs where necessary.

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Appendix A Relative ASTM Standards

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