In situ Testing and Soil Properties Correlation

135 Pages·2016·9.58 MB·English

by  Rahardio Paulus P.

n situ Testings and
Soil Properties
Correlations
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in conjunction with
International Conference on In Situ Measurement of
Soil Properties and Case Histories
Bali-Indonesia, May 21-24,2007
Iniitu Testing and Soil Properties Correlation
P r e f a ce
The use of in situ testing has been widely gained popularity to establish general soil profile and
to derive soil parameters to be used in design and geotechnicai analysis. The use of CPT, SPT,
DMT and PMT for ground improvement control has also been accepted by practical engineers.
Nowadays the addition of sensors and testing technology has caused -even positive development
in the practice of geotechnicai engineering.
The main advantages of the present use of in situ testing derives its favor from the fact that
empirical correlation has been so much developed and may be used to accurately estimate the
parameters. These publications of correlation are scattered everywhere, in the seminar and
conference proceedings, in journals, and research reports. By effort of the graduate students of
the Parahyangan Catholic University, they have tried to put all these together to make the most
practical and handy application of the in situ testing results.
This publication is nothing but the first embryo of the effort. Although many other publications
have not been included in this book, we believe that the present collection is advantageous as
reference for every geotechnicai engineer. Comprehensive examples rather than simple
interpretation has been added in the final chapter to enable further thought towards a more
rational application of the empirical correlations.
Finally we expect that this book will be beneficial for everyone who use it and for students who
want to go deeper into the geotechnicai engineering practice. We apologize for incompleteness
of the published correlation which has not been included in the book. In the future this effort
will be continued to update with the state of the art so that this book will be more acceptable
and more useful.
Bandung, May 12, 2001
Paulus P. Rahardio
Geotechnics Laboratory
Parahyangan Catholic University
In SFtli Z001 I
Itiiitu Testing and Soil propertie Correlation
T A B LE OF C O N T E NT
PREFACE
CHAPTER 1. IN SITU TESTING DEVICE AND TEST PROCEDURE 1-1
1.1. Vane Shear Test (VST) 1-1
1.2. Bore Hole Shear Test (BST) 1-2
1.3. Standard Penetration Test (SPT) 1-3
1.4. Cone Penetration Test (CPT) 1-4
1.5. DilatometerTest (DMT) 1-6
1.6. Pressuremeter Test (PMT) 1-7
CHAPTER 2. ENGINEERING PROPERTIES OF SOILS 2.1-1
2.1. Soil Classification and Weight Volume Relationship 2.1-1
2.2. Soil Plasticity 2.2-1
2.3. Permeability 2.3-1
2.4. In Situ Stress and State Parameter 2.4-1
2.5. Shear Strength 2.5-1
2.5.2. Undrained Shear Strength of Clays 2.5-4
2.6. Compressibility and Consolidation Characteristics 2.6-1
2.7. Stiffness and Shear Rigidity 2.7-1
2.7.1. Applicability of Strains in Various Construction 2.7-1
2.8. Expansive Soils 2.8-1
CHAPTER 3. USE IN SITU TESTING TO IDENTIFY SOIL TYPES AND SOIL
BEHAVIOUR TYPES 3-1
CHAPTER 4. IN SITU TESTING FOR PREDICTION OF DENSITY OF SOILS
AND STATE PARAMETERS 4-1
CHAPTER 5. IN SITU TESTING FOR PREDICTION OF IN SITU STRESS AND
STRESS HISTORY 5-1
5.1. Prediction of Preconsolidation Pressure or Yield Stress 5-1
5.2. Prediction of Overconsolidation Ratio (OCR) 5-3
5.3. Prediction of Horizontal Stress and K 5-7
0
CHAPTER 6. MEASUREMENT OF SHEAR STRENGTH BY IN SITU TESTINGS 6-1
6.1. Drained Shear Strength of Sand 6-1
6.1.1. Prediction of Ф' by SPT 6-1
6.1.2. Prediction of ф' by CPT 6-4
6.1.3. Prediction off by Dilatometer 6-6
6.2. -Effective Friction Angles of All Soils 6-7
6.3. Undrained Shear Strength of Clays 6-8
6.3.1. Shear Strength of Clays by SPT 6-8
6.3.2. Shear Strength of Clays by CPT 6-8
6.3.3. Shear Strength of Clays by Dilatometer Test 6-11
6.3.4. Shear Strength of Chalk by CPT ^-11
In Situ zooi ii
imitu letting and Soil propertie Correlation
CHAPTER 7. IN SITU TESTING TO ESTIMATE SOIL STIFFNESS AND
SHEAR RIGIDITY 7-1
CHAPTER 8. IN SITU TESTING TO ESTIMATE CONSOLIDATION
CHARACTERISTIC 8-1
CHAPTER 9. IN SITU TESTING FOR EVALUATION OF LIQUEFACTION
POTENTIAL 9-1
CHAPTER 10. COMPARISON BETWEEN THE RESULTS OF IN SITU TEST 10-1
CHAPTER 11. COMPREHENSIVE EXAMPLE 11-1
11.1. SPT and CPT Interpretation on Clays 11-1
11.2. SPT and CPT Interpretation of Sand Layer 11-6
11.3. CPTU Interpretation in Soft Alluvial Soils 11-11
REFERENCES
InSituzooi • " iii
CHAPTER 1
1№ШТ№Т^ШЙ@ ВЕЙ
AND TEST PROCEDURE
Chapter! in Situ Taring Device and Tat Procedure
CHAPTER 1
IN SITU TESTING DEVICE AND TEST PROCEDURE
1.1. VANE SHEAR TEST (VST)
Device :
• Four-bladed rectangular vane
(Normally H/D = 2)
• Rotating rod
• Torque measuring device
Test Procedure :
Test carried out in a borehole or directly pushing
the vane into the ground. It is important that the
vane is pushed ahead of disturbance caused by
vane housing or drilling operations. The vane rod
is then rotated at a rate of 6°/min., while the
torque is read at interval of 30 s. After maximum
torque isachieved, the^ yane is rotated at higher
rate to Obtainг thef remolded-strengthof the^soiis.
Measured Parameters:
fir,
peak
• Peak torque (т к) => греак=~ч
Fig. 1.1.1 Swedish Vane Borer реа
6Т
Г1
• Residual torque (^residual) =>
Muastmng irii
Factors Affecting Results:
1. Disturbance due to vane insertion
2. Blade thickness
3. Rate of rotation
-Squortlw
4. Time lapse between insertion of the vane and
the beginning of the test
5. Strength anisotropy
6. Type of soils
.-Casing
7. Possible friction of the rod and surrounding
soils
8. Failure planes around the vanes
■Bdbtwring spacer
Corrections for Interpretation:
■Ffietafttfiminoioc <Ь5и
Skempton recommended multiplying the vane
diameter by 1.05 for interpretation of strength
and Bjerrum has used plasticity index to
•Vane
incorporate field strength to vane shear strength
(see chapter 6).
Fig. 1.1,2. Details of VST
(Ortigao & Collet, 1988)
1.2. BOREHOLE SHEAR TEST (BST>
Device:
• Shear head
• Pressure source
• Pulling Yoke
• Cabling
• Control/measuring unit
Test Procedure:
Shear head is lowered in a borehole to perform
the test. At the required position the two shear
plates are expanded until seated in a borehole
walls at preselected pressure. Some time is
allowed for consolidation to occur. When
consolidation is complete the shear head is either
pulled upward, or pushed downwards at a steady
rate of 2 mm/ min. Thje required forces for
shearing are measured, and the shearing stress
:,pjs£ted=aga!ns£^he^^aki3^^^
the shear plates may be contracted, the shear
head lowered to its original position, rotated 90°
and the test repeated. The shear head is then
returned to the original position, another seating
pressure selected and the test repeated.
Tranducers
Factors affecting results :
• Drainage condition
— Deairing Ports • Disturbance and size of drilling hole
Porous Stones
100 kPa
D_£i
Shear Head
Fig. 1.2.1. The Iowa Borehole Shear Device (BSH
fWineland. 1975^
I.
Normal Stress, psi
Fig. 1 -? о Typical Results
tettezwi- 1-2 -i*
Спарил. In Situ Tating Dora and let Procedure
1.3. STANDARD PENETRATION TEST (SPT)
Device =
• Split spoon sampler
$
• Hammer (63.5 kg)
• Rods
Test Procedure :
Automatic
63.5 kg free drop trip
hammer ('Monkey! Test carried out in a borehole by lowering the split
spoon sampler and driving it using repeated blows
Striker plate by the hammer freely dropped at falling height of
762 mm at the top of the borehole. Blow count is
Connector to
32mm rods recorded 3 times, each 150 mm penetration and the
N value is the sum of the blow count of the last 300
Round 'A' tods mm penetration as blows/300 mm.
or square 32mm
boring rods
Measured Parameters:
Spill spoon
N blows/30 cm
—.—"О*- Standard
cutting shoe Corrections for blow count:
60* cone (0( gravel.
0i) and overburden pressure (С )
ы
Fig. 1.3.1. Equipment For The Ni(60) «TJ.CN-N
Standard
Penetration Test
Factors Affecting Results:
1. Variations in the test apparatus
2. Disturbance and size of drilling hole
3. Type and consistency or density of soils
4. Confining pressure or overburden pressure
5. Energy
6. Drainage condition
7. Disturbance and size of drilling hole
Types of Hammers :
1. Automatic Trip Hammers
2. Slip-Rope-Hammers (pin weight hammer, safety
and donut hammer)
Fig. 1.3.2. Sections through
American SPT slip-
rope hammers
(a) pin weight hammer
(b) safety hammer
(c) donut hammer
(Riggs, 1986)
in Situ zoo) 1-3
flapttn. In Situ feting Device and Tes tProcedure
1.4. CONE PENETRATION TEST fCPT>
Device :
• Cone
D=15
• Friction sleeve
• Pore pressure transducer (for piezocone)
.D-12.5
.D-30 • Other sensors (if any)
• Rods
fl
• Control/ measuring device
E=2p Types of Cone :
D-36-
• Mechanical cone
tei • Electric cone
Test Procedure :
Test is carried out by mechanically or
D-23
«rf hydraulically pushing a cone into the ground at a
constant speed (2 cm/s) whilst measuring the tip
and shear force, for piezocone, pore pressure is
measured along depth of penetration and a
d isslpa" ^ -^| Y; an =№=perfcWi^~ara"n"yiTe"q u i red
n s C
D=32.5 depth by stopping the penetration and measuring
the decay of pore water pressure with time. It is
recommended that the dissipation be continued to
D=35.7;
at least 50% degree of dissipation.
Measured Parameters :
(Dimensions are in mm)
Fig. 1.4.1, Begemann Mechanical • Tip resistance, q (kg/cm2)
c
Friction Cone fMeiah, • Friction resistance, f (kg/cm2)
s
1987) • Pore pressure, u (for piezocone)
Factors Affecting Results :
Water seal Soil seal
Type and consistency or density of soils
Confining pressure or overburden pressure
Verticality
Rate of penetration
S load cell
Calibration of sensors
Wear of the cone
Temperature changes
Water seal^ r Soil seal
A rigid pore pressure measuring system and a
fully saturated system (for piezocone)
Rate of dissipation of pore pressures (for
*Г<^ \j > >r4nf*tJ/7 piezocone)
X T
Location of the filter and axial load on the cone
C + S load cell С load cell
(for piezocone)
Variations in the test apparatus
Fig. 1.4.2. Electric Friction Cone
(Meigh. 1987)
In Situ кип 1-4
Chapter], to Situ Toting Device and Test Procedure
Correction for Interpretation :
3 major area of cone design that influence
interpretation are :
1. Unequal area effects
2. Piezometer location, size and saturation
3. Accuracy of measurement
Additional sensors :
In recent year, the CPT or CPTU is supplemented
Local side Iriciion.
by additional sensors, such-as geophone arrays
(seismic cone), lateral stress sensing,
pressuremeter module behind cone-penetrometer,
electrical resistivity or conductivity for estimating
in situ porosity or density and has also been used
as an indicator of soil contamination, heat flow
measurement, radioisotope measurement,
acoustic noise, and other geo-environmental
devices.
Fig. 1.4.3. Typical Result