11 soil investigation

Bina Nusantara

Session 5 – 6 SOIL INVESTIGATION

Bina Nusantara

SOIL INVESTIGATION AND LABORATORY TESTS

• SOIL INVESTIGATION• LABORATORY TESTINGS• EMPIRICAL CORRELATIONS

– CPT AND N-SPT VALUE– BETWEEN SOIL PARAMETER

Bina Nusantara

SOIL INVESTIGATION

• PURPOSE– To describe the soil condition and its stratification.– To get the soil sample for laboratory testing

• undisturbed sample• disturbed sample

– To find out the ground water level– To get the soil properties directly– In-situ Test

Bina Nusantara

SOIL INVESTIGATION

• STAGES– Site Inspection– Initial Investigation

• Cone Penetration Test (Sondir)– Advance Investigation (detail)

• Boring and sampling • Standard Penetration Test • Pressuremeter• Dilatometer

– Additional Investigation

Bina Nusantara

SOIL INVESTIGATION

• DEPTH OF SOIL INVESTIGATION– Shallow Foundation : 3 x Foundation width (min. 9m)– Raft Foundation : 2 x Foundation width– Pile Foundation : 2 x Pile width (measured from pile tip)– Pile + Raft Foundation : 2 x building width– Retaining Earth Structure : 0.7 x cutting width or 1 x cutting height (take

the biggest)– Soil Embankment : 2 x embankment width

Bina Nusantara

Bina Nusantara

SOIL INVESTIGATION

• NO. OF SOIL INVESTIGATION– Initial Investigation :

• Normal Soil : every 100 to 200 m• Soft Soil : every 50 to 100 m

– Detail Investigation :• Square structure : every 15 to 25 m• Strip structure : every 25 to 50 m

– At the important side of the structure, the number of soil investigation can be increased

Bina Nusantara

BORING INVESTIGATION

• AUGER BORING• WASH BORING• CORE DRILLING• TEST PIT

Bina Nusantara

BORING INVESTIGATION

• AUGER BORING (PENGEBORAN MANUAL)– Carried out by pushing and rotating the auger into soil– Limited application, only suitable for shallow foundation– Not suitable for boring under ground water table– Simple, easy to operate and minimum disturbance to soil

Bina Nusantara

BORING INVESTIGATION

• WASH BORING (PENGEBORAN BILAS )– Use rotary bore machine– Soil dig and washed by water circulation– Can not used for soil identification– Less suitable for rock boring– Suitable for all type of soil– Very suitable for soft soil– Disturbance to soil structure is minimum

Bina Nusantara

BORING INVESTIGATION

• CORE DRILLING (PENGEBORAN INTI)– Use rotary bore machine– Single tube without water circulation– Double or triple tube with water circulation– Can use for rock– Can identify soil directly– Not suitable for boring of soft soil– Can make a disturbance soil structure

Bina Nusantara

BORING INVESTIGATION

• TEST PIT– Carried by excavated soil manually– For shallow depth– Difficult to apply to soil with high water level– Very simple and relative cheap– Identification can be done directly by visual.– Large number of soil sample

Bina Nusantara

SAMPLING METHOD

• UNDISTURBED SOIL SAMPLING (CONTOH TANAH TAK TERGANGGU)– Sampling Technique

• Sensitive and soft to very soft clay or silt thin wall tube + piston• Soft to medium stiff clay or silt shelby thin wall tube sampler• Hard to very hard clay or silt thick wall tube sampler or Denison

or Pitcher samplers

Bina Nusantara

THIN WALL and PISTON SAMPLER

Bina Nusantara

THICK WALL and DENISON SAMPLER

Bina Nusantara

SOIL SAMPLER TUBE (ASTM D1587)

Bina Nusantara

• UNDISTURBED SOIL SAMPLE (CONTOH TANAH TAK TERGANGGU )– Storage Technique/Sample treatment

• The tube shall be covered by paraffin candle• Storage at cool place and at vertical position• Shall be labeled to facilitate soil identification• The tube shall be folded by foam during transportation• The laboratory tests shall be carried out as soon as possible

SAMPLING METHOD

Bina Nusantara

SAMPLING METHOD

• DISTURBED SOIL SAMPLE (CONTOH TANAH TERGANGGU )– Sampling Technique and Sample Treatment

• Can get from core drilling or SPT tube • Shall be folded by plastic and storage at cool place• Shall be labeled to facilitate soil identification

– Usually use for fill material

Bina Nusantara

• BASIC AND SIMPLE INSITU TEST– Standard Penetration Test (SPT)– Cone Penetration Test (CPT)

• INSITU TEST for DIRECT MECHANICAL PROPERTIES OF SOIL– Field vane shear test Soil Strength– Pressuremeter Test/Lateral Load Test (LLT) Soil Deformation– Flat Dilatometer Test Soil Deformation– Plate Bearing Test Strength and Deformation of Soil

INSITU TEST (UJI LAPANGAN)

Bina Nusantara

• PRINCIPLE OF WORKCarried out by punching the standard tube to bore hole using free fall 63.5 kg hammer from 760mm height. The number of blows required for spoon penetration of three 150mm. The number of blow counted at the last of 300mm penetration.

• RULES– Dimension of SPT tube according to ASTM D1586– The hammer type is conventional or automatic

STANDARD PENETRATION TEST (SPT)

Bina Nusantara

• ADVANTAGES– Could be used to identify soil types visually– Could be used to get qualitative soil properties by empirical

correlation• LIMITATION

– The soil strength profile can not be measured continuously– The high accuracy is needed during investigation in case of weight

and falling height of hammer

STANDARD PENETRATION TEST (SPT)

Bina Nusantara

SPT HAMMER

Bina Nusantara

DIMENSION OF SPT TUBE

Bina Nusantara

EXAMPLE OF BORING LOG AND SPT

Bina Nusantara

SPT EXECUTION

Bina Nusantara

• TYPE OF PENETROMETER AND PRINCIPLE OF WORK– Mechanical friction-cone penetrometer

by pushing a cone with projection area 10 cm2 and 60o angle and standard velocity 20 mm per-second.

2 measurement parameters each 20 cm of depth:• Cone Resistance (qc)• Local Friction (fs)

– Electric friction-cone penetrometermeasure the cone pressure and continuously friction with better accuracy level

CONE PENETRATION TEST (CPT)

Bina Nusantara

CONE PENETRATION TEST (CPT)

• ADVANTAGES– Continuous Soil strength profile– Give fast description of soil– Simple

• LIMITATIONS– Bad accuracy for soil with some stones– Mechanical friction-cone penetrometer is less sensitive when

applied in very soft clay

Bina Nusantara

CPT CONE SIZE (ASTM D 3441)

Bina Nusantara

ELECTRIC FRICTION-CONE PENETROMETER TIP

Bina Nusantara

EXAMPLE OF CPT GRAPH

Bina Nusantara

FIELD VANE SHEAR TEST (FVT)

• Measure undrained shear strength of soil• Suitable for very soft clay to medium stiff clay• Principle of equipment operation : vane pushed and rotated• The vane shear equation :

• Correlation between vane shear and shear strength of soil

H3D1x

2HDx

10

Ts2

6

fv

fvu s.s

Bina Nusantara

FIELD VANE SHEAR TEST (FVT)

Bina Nusantara

PRESSUREMETER TEST (PMT)

• Measure the strength and deformation of soil• Recommended use for the soil which need elastic settlement prediction• Equipment mechanism : expanding the rubber cylinder of water by using

air pressure

Soil Types Limit Pressure (kN/m2) EM/pl

Soft clay 50 – 300 10

Firm clay 300 – 800 10

Stiff clay 600 – 2,500 15

Loose silty sand 100 – 500 5

Silt 200 – 1,500 8

Sand and gravel 1,200 – 5,000 7

Till (Tanah liat berbatu) 1,000 – 5,000 8

Old fill 400 – 1,000 12

Recent fill 50 – 300 12

Bina Nusantara

PRESSUREMETER TEST (PMT)

Bina Nusantara

DILATOMETER TEST (DMT)

• Have similar purpose and equipment mechanism with Pressuremeter

• The difference is in the pressure direction :– DMT one direction– PMT radial

Bina Nusantara

DILATOMETER TEST (DMT)

Bina Nusantara

PLATE LOAD TEST

• Measure strength and deformation of soil• Use to determine bearing capacity of soil and its settlement especially for

shallow foundation• Work mechanism : push the circle/square plate at the certain depth with

load of 2 – 3x design load until rupture• Loading influence : 1.5 – 2x plate width• Relationship to undrained shear strength:

Su = (qu - t.H)/Nc

qu = rupture load t = unit weight of soil H = thickness of soil on the sample surface Nc = bearing capacity factor

Bina Nusantara

• Purpose:– Ground water elevation– Seepage behaviour

• Method:– Ground water elevation

• Observation at bore hole• Observation at observation

well (standpipe)• Measure using piezometer

– Seepage behaviour• Seepage test at bore hole• Pump test at bore hole• Large scale of pump test

GROUND WATER INVESTIGATION

Bina Nusantara

PIEZOMETER

Bina Nusantara

PUMPING TEST

Bina Nusantara

LABORATORY TESTS

• Soil Index (, , e, GS etc.)– Measurement of soil volume and mass– Sieve analysis test– Atterberg test

• Shear Strength (c, )– Triaxial Test (UU, CU, CD)– Direct Shear– Unconfined Compression Test

• Compresibility (Cc, Cv)Consolidation test

• Permeability (k)– Constant Head– Falling Head

Bina Nusantara

EMPIRICAL CORRELATION

• N-SPT value

Sandy Soil Clayey or Silty SoilN-SPT Value Relative Density N-SPT Value Consistency

0 – 4 Very loose 0 – 2 Very soft

4 – 10 Loose 2 – 4 Soft

10 – 30 Medium 4 – 8 Medium stiff

30 – 50 Dense 8 – 15 Stiff

> 50 Very dense 15 – 30 Very stiff

> 30 Hard

Bina Nusantara

EMPIRICAL CORRELATION• CPT value

Bina Nusantara

• Between soil properties– Cc = 0.009 (LL – 10)– C = qu/2– C = (19 – 23) CBR (C in kN/m2)

EMPIRICAL CORRELATION