1. Soil Property Characterization by In-Situ Tests
Session 1.2
Soil Property Characterization by In-Situ Tests
ISSMGE
August 28, 2001
Georgia Tech

2. Session 1.2 - Soil Property Characterization by In-Situ Tests
Chair: Max Ervin (Australia)
Discussion Leader- Paul W. Mayne (USA)
Panel Members:
Martin Fahey (Western Australia)
Ranier Massarsch (Sweden)
An-Bin Huang (Taiwan)
Georgia Tech

3. Session 1.2 - Soil Property Characterization by In-Situ Tests
Use of Enhanced In-Situ Tests, notably hybrid devices.
Importance of small-strain measurements in geotechnical deformation analyses
Reliability and Variability Issues
Repeability of soundings
Class ratings for equipment.
Georgia Tech

4. Session 1.2 - In-Situ Tests Question from Topic 1
Is it time to retire the Standard Penetration Test (SPT) ?
To consider this prospect
Let us go back - back in time
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5. Session 1.2 - In-Situ Tests Question 1
Telephone 1909
Cell phone
2001
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6. Session 1.2 - In-Situ Tests Question 1
Wright Plane 1903
Boeing 717
2001
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7. Session 1.2 - In-Situ Tests Question 1
Oldfield Auto 1903
BMW
2001
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8. Session 1.2 - In-Situ Tests Question 1
Geotech Test 1902
Geotech Test 2002 ?
Colonial Charles Gow
of Raymond Pile Company
Georgia Tech

9. N Is One Number Enough??? p' = preconsolidation SAND CLAY
cu = undrained strength
gT = unit weight
IR = rigidity index
' = friction angle
OCR = overconsolidation
K0 = lateral stress state
eo = void ratio
Vs = shear wave
E' = Young's modulus
Cc = compression index
qb = pile end bearing
fs = pile skin friction
k = permeability
qa = bearing stress
CLAY
DR = relative density
gT = unit weight
LI = liquefaction index
' = friction angle
c' = cohesion intercept
eo = void ratio
qa = bearing capacity
p' = preconsolidation
Vs = shear wave
E' = Young's modulus
 = dilatancy angle
qb = pile end bearing
fs = pile skin friction
SAND N
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10. Numerical Simulations
Use of In-Situ Tests
Numerical Simulations
Finite Elements
Strain Path
Finite Differences
Discrete Elements
PLAXIS, FLAK, SEEP3d,
ABAQUS, CRISP, ADINA,
GEOSLOPE
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11. Enhanced In-Situ Tests
Cone Pressuremeter
Seismic Piezocone
Dilatocone
Seismic Dilatometer
Resisitivity Cone
Georgia Tech

12. SCPTu Sounding, Memphis, Tennessee
Real-Time readings in computer screen
Penetration at 2 cm/s
Sand
Clay
Crust
Georgia Tech

13. Shear Wave Velocity, Vs
Fundamental Measurement in all Solids (steel, concrete, wood, soils, rocks)
Initial small-strain stiffness represented by shear modulus: G0 = r Vs (alias Gdyn = Gmax = G0)
Applies to all static & dynamic problems at small strains (gs < 10-6)
Applied to undrained & drained cases
Need Reduction Factor for Relevant Strain Levels.
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14. Modulus Degradation Schemes
Kondner (1963)
Ramberg-Osgood
Duncan & Chang (1970)
Seed & Idriss (1971)
Hardin & Drnevich (1972)
Jardine, et al. (1986)
Prevost & Keane (1990)
Vucetic & Dobry (1991)
Tatsuoka & Shibuya (1992)
Fahey & Carter (1993)
Whittle & Kavvadas (1994)
Puzrin & Burland (1996, 1998)
Tatsuoka, et al. (2001)
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15. PreFailure Deformation Characteristics of Geomaterials
SPECIALTY CONFERENCES
Sapporo (1995): Edited by Shibuya, Mitachi, & Miura.
London (1997): Edited by Jardine, Davies, Hight, Smith, & Stallebrass.
Torino (1999): Edited by Jamiolkowski, Lancellotta, & LoPresti.
Lyon (Sept , 2003)
Georgia Tech

16. Enhanced In-Situ Tests SCPTu with Dissipation at Amherst Test Site
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17. Enhanced In-Situ Tests SCPTu Prediction for DSS at Amherst Site
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18. SCPTu at Opelika Test Site, Alabama
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19. Axial Load Test at Opelika, Alabama
Q (total)
Drilled
Shaft 01
(cased)
d = 0.91 m
L = 11.0 m
Q shaft
Q base
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20. Topic 3: Reliability, Repeatability, Calibration, & Interpretation Issues
Prior Comparative Studies:
Lunne, et al. (In-Situ'86)
Tanaka (CPT'95)
Electric vs. Electronic Penetrometers
Subtraction vs. Tension Cones for fs
Smooth vs. Rough Steel - Interface affecting fs measurements.
Lunne, Robertson, & Powell (1997): Recommend different Class I to Class IV penetrometers for CPT work.
Georgia Tech

21. Effective Strength Parameters
Bearing Capacity Theories
Durgunoglu & Mitchell (1975); Vesic (1977); Robertson & Campanella (1983); Salgado et al. (1994); Jamiolkowski & LoPresti (2000)
CSSM Dilatancy Approach using DR from CPT (Bolton, 1986)
Effective Stress Method (Senneset, Janbu & Sandven, 1989)
y-f’ (psi-phi)
“Sci-Fi”
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22. Session Summary
Geotechnical Investigations need to Employ Modern Technologies: Seismic Piezocone, Flat Dilatometer, Cone Pressuremeter, Geophysical Methods
Small-Strain Stiffness (G0) is Relevant to Monotonic (Static) and Dynamic Geotechnical Problems
Address issues of Calibration,Equipment, Reliability, and Interpretation.
Georgia Tech

23. Georgia Tech

24. Enhanced In-Situ Testing
Recommendations for Geotechnical Research
Need more consistent methods for interpretation of in-situ tests:
Vane - Limit Equilbrium
Pressuremeter - Cavity Expansion
Piezocone - Strain Path
Pile Foundations - Limit Plasticity
Georgia Tech

25. Enhanced In-Situ Testing
Recommendations for Geotechnical Research
Need additional numerical & analytical simulations of multiple tests using
Finite Elements
Strain Path Method
Discrete Elements
Finite Differences
Georgia Tech

26. Enhanced In-Situ Testing
Recommendations for Geotechnical Research
Develop additional sensors + channels
New digital cone systems
Seismic Piezocone Pressuremeter
Dielectric-Resistitivity Seismic Piezocone
Gamma-EM-Dilatocone
Better use of statistical methods
Georgia Tech

27. Georgia Tech