GEOTECHNICAL SUPPORT - San Diego Regional Chapter

San Diego Regional Chapter
Liquefaction Evaluation, Mapping,
Simulation and Mitigation
September 12, 2014
Seismic Response of Stratified Sites and
Implications for Foundation Systems
Geoffrey R. Martin, Professor Emeritus, USC
&
Ahmed Elgamal, Professor, UCSD
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Workshop:
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Representative Stratified Site: Liquefaction
Design Issues
2
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Bridges – Lateral Spread Design Issues
3
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Stratified Sites: Variability of Triggering
Factors of Safety
4
Historical Developments

Cyclic Simple Shear Stress Induced by Seismic Loading
Seed et al. / Finn et al.
1960’s / 1970’s
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Laboratory Simulation of Seismic Loading
5
Historical Developments
Representative/Cyclic Triaxial
Test Results (Finn, 1971)
Representative/Cyclic Simple Shear Test
Results (Peacock and Seed, 1968)
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Laboratory Test Results
6
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Stress Controlled Cyclic Simple Shear Tests
7
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Constant Volume Strain Controlled Cyclic
Simple Shear Tests
8
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Laboratory Tests: Silty Sand – Transitional
Behavior
9
 Finn et.al 1978
: DESRA
 Matasovic 1993
: D-MOD
 Martin/Qui 1998
: DESRA-MUSC
 Pyke 2000
: TESS
 Elgamal et.al 2002
: Cyclic/Opensees
 Hashash 2009
: DEEPSOIL
 Boulanger et.al 2010 : PM4 Sand Model/FLAC
 Byrne/Beaty 2011
: UBC Sand/FLAC and PLAXIS
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Effective Stress Site Response Analysis
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Cyclic 1D Model
Elgamal et. al.
PM4 Sand Model
Boulanger et. al.
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Plasticity Based Constitutive Models
11
Fundamentals Constitutive Model – 1D Effective
Stress Site Response Analyses
Objectives:
 Time histories of pore water pressure
increases in multi layer sites
 Determine critical layer for lateral
spread analyses
 Determine effect of pore water
pressure increases on ground surface
response
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Computer Programs: DESRA (Lee and Finn, 1978)
DESRAMUSC (Qui, 1998)
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DESRA Constitutive Model Fundamentals –
Cyclic Strain Based Volume Change Parameters
13
Fundamentals Constitutive Model – 1D Effective
Stress Site Response Analyses
Input Data for Practical Applications

Nonlinear initial τ/γ backbone

Masing criteria used to
simulate hysteretic behavior

Strain hardening suppressed

Backbone curve degraded as a function of pore water pressure increase

Representative elastic rebound curves chosen based on N1 values

Volume change parameters (simplified to 2) chosen based on N1 values

Volume change/rebound parameters adjusted to match field liquefaction strength curves

Pore water pressure dissipation/re-distribution during analyses a program option

1
(Note 𝑚𝑚𝑣𝑣 = � )
𝐸𝐸𝑟𝑟
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curve matched to G/Gmax curve
14
Fundamentals Constitutive Model – 1D Effective
Stress Site Response Analyses
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Example illustrating effects of pore water pressure redistribution and sequential liquefaction
15
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Stratified Soil Condition at a Bridge Site
16
Fundamentals Constitutive Model – 1D Effective
Stress Site Response Analyses
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Example illustrating effects of large strain liquefaction
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8th WCEE, 1984
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Elgamal et al. 1989
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Site Liquefaction (Soil Liquefaction)
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Site Liquefaction (Soil Liquefaction)
Adalier and Elgamal 1992
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Kokusho et al. (2000)
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Site Liquefaction (Soil Liquefaction)
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Site Liquefaction (Soil Liquefaction)
(Verification of Liquefaction
Analyses by Centrifuge
Studies)
Simple Configurations
Few sensors
Bonnie Silt!
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Project VELACS (1993)
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Fiegel and Kutter 1994
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Boulanger et al. and Kutter et al. 2001-2004
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Figure 4. Geotechnical cross-section for
WLA developed from CPT data.
Youd and Holzer 1994
Steidl and Seale 2010
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Site Stratification (Wildlife Array, Imperial County, CA)
25
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Cyclic mobility at large shear strain (Zeghal and Elgamal 1994)
26
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Cyclic mobility at large shear strain (Zeghal and Elgamal 1994)
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Soil Constitutive Model
Shear stress-strain and effective
Conical yield surfaces for granular stress path under undrained shear
soils (Prevost 1985; Elgamal et al. loading condition (Parra 1996, Yang
2003; Yang and Elgamal 2008)
2000, Yang and Elgamal 2002)
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 Multi-yield surface plasticity model (based on Prevost 1985)
 Incorporating dilatancy and cyclic mobility effects
28
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Permeability is a critical parameter for the estimation of
liquefaction-induced lateral deformations
Yang, Z. and Elgamal, A. “Influence of Permeability on Liquefaction-Induced Shear
Deformation,” Journal of Engineering Mechanics, ASCE, 128, 7, July 2002.
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Before
After
1m of Lateral Spreading ( > 3 pile diameters)
NIED, Tsukuba, Japan
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
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NIED, Tsukuba, Japan
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
31
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
32
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
33
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
34
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
35
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
36
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Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
37
Plan-view
shear
around the pile
(depends on pile
stiffness)
Side-view shear
EERI_San Diego_Sept_2014_Martin_Elgamal
Shaking Table Tests: US-Japan Research (UCSD, NSF, NIED, PEER, CALTRANS)
5m height: Liquefaction-Induced lateral Spreading Effects on Piles (NIED, Tsukuba)
Professor Kohji Tokimatsu, Dr. Masayoshi Sato, and Dr. Akio Abe
38
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OpenSees FE Model
39
2 degrees
3.8 m
----------------------------------LVDT
Accelerometer
3.9 m
11.6 m
3.9 m
------------------------------
Pore pressure sensor
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0. 5
5.0 m
Instrumentation Layout/Experimental Data
Strain gage
40
Recorded and computed free-field displacement profile at 10 seconds
Free-Field Displacement Profile at 10 seconds
0
0.5
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Numerical
Experimental
k= 5 e-5 m/sec
1
1.5
Depth (m)
2
2.5
3
3.5
4
4.5
5
0
0.1
0.2
0.3
0.4
0.5
Ground Lateral Displacement (m)
0.6
0.7
0.8
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Influence of permeability on free-field displacement profile
at 10 seconds
Free-Field Displacement Profile at 10 seconds
0
2
3
k
k
k
k
1
1.5
=5
=5
=5
=5
e
e
e
e
-5
-4
-3
-2
m/s
m/s
m/s
m/s
Depth (m)
2
2.5
1
4
3
2
3
3.5
4
(undrained) k1<k2<k3<k4 (drained)
4.5
5
0
0.1
0.2
0.3
0.4
0.5
Ground Lateral Displacement (m)
0.6
0.7
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1
4
0.5
0.8
42
Influence of permeability on stiff pile moment profile at 10 seconds
Stiff Pile Moment Profile at 10 seconds
-1
Free-Field Displacement Profile at 10 seconds
k=5
k=5
k=5
k=5
0
0.5
4
1
0
1
2
3
k
k
k
k
1.5
=5
=5
=5
=5
e
e
e
e
-5
-4
-3
-2
m/s
m/s
m/s
m/s
e
e
e
e
-5
-4
-3
-2
m/s
m/s
m/s
m/s
2.5
3
1
3.5
Free-Field Displacement
Depth (m)
4
4.5
5
2
0
0.1
0.2
0.3
0.4
0.5
Ground Lateral Displacement (m)
0.6
0.7
0.8
1 2
4
3
3
(undrained) k1<k2<k3<k4 (drained)
4
3
2
1
4
5
-20
0
20
40
60
80
100
Moment (kN·m)
120
140
160
180
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Depth (m)
2
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Conclusion
liquefaction-induced lateral deformations
- Permeability is a critical parameter for the estimation of pile
moments due to liquefaction-induced lateral ground deformation
- Larger ground displacement is not always proportional
to higher moment in piles
Yang, Z. and Elgamal, A. “Influence of Permeability on Liquefaction-Induced
Shear Deformation,” Journal of Engineering Mechanics, ASCE, 128, 7, July 2002
EERI_San Diego_Sept_2014_Martin_Elgamal
-Permeability is a critical parameter for the estimation of
44
Shear resistance depends on:
1) N1(60) , CPT qc1 , Vs
2) Soil/System Permeability k
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For Saturated Cohesionless soils…
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http://soilquake.net/openseespl/
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OpenSeesPL: http://soilquake.net/openseespl/
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OPENSEESPL Example Input Files
(http://soilquake.net/openseespl/example_input_files/
Pile in Ground Strata
3-D Shear Beam Site Amplification
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Ground Modification by Stone Columns. Pile-pinning, Earthquake Drain,
or Deep Soil Mixing Grids
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OPENSEESPL Example Input Files
(http://soilquake.net/openseespl/example_input_files/
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OPENSEESPL Example Input Files
(http://soilquake.net/openseespl/example_input_files/
Pile Groups and Piled Rafts
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