Modeling and Simulations for Geotechnical Problems

Modeling and Simulations for GeotechnicalProblems

Boris Jeremic

Department of Civil and Environmental EngineeringUniversity of California, Davis

http://sokocalo.engr.ucdavis.edu/ ˜jeremic/

JHU Workshop, November 2005,

Modeling and Simulations for Geotechnical Problems

Overview of Features

Systems Approach

I Elasticity (small and large deformation, linear, nonlinear,isotropic, cross anisotropic...)

I Elasto–plasticity (small and large deformations, isotropic,anisotropic, deterministic, stochastic

I Solid elements (small and large deformations)I Single and multi–phase formulations (u–p–U for small def.,

u–p for large def.)I Parallel computations using Plastic Domain Decomposition

MethodI Seismic analysis using Domain Reduction Method (with

above features)

Modeling and Simulations for Geotechnical Problems

Stochastic Elasto-Plasticity

Low OCR Cam Clay withRandom G, M and p0

0.1

0.2

0.3

00.010.020.030.040

200

400

Stress (MPa)

0

Time (s)

Strain (%)

0

1.62

ProbDensity

0

200

400

0 0.05 0.1 0.15 0.2 0.25 0.3

0

0.01

0.02

0.03

0.04

Time (s)

Strain (%)0 1.62

Std. Deviation Lines

Mean LineDeterministic Line

Mode Line

Stre

ss (M

Pa)

50

30

10

Modeling and Simulations for Geotechnical Problems

Stochastic Elasto-Plasticity

High OCR Cam Clay withRandom G and M

0.1

0.2

0.3

00.010.020

200

400

Stress (MPa)

Time (s)

Strain (%)

0

2

0

ProbDensity

0.37

0

200

400

0 0.05 0.1 0.15 0.2 0.25 0.3 0.37

0

0.005

0.01

0.015

0.02

0.025

0.03

Strain (%)

Mean Line

Std. Deviation Lines

Time (s)

0 2.0

Stre

ss (M

Pa)

3050

100

Deterministic LineMode Line

Modeling and Simulations for Geotechnical Problems

Soil–Foundation–Structure Interaction

Beneficial orDetrimental?

5 10 15 20−10

−5

0

5

10

Time [s]

Mom

ent [

MN

m]

Structure 1Fixed BaseSFSImax/min(Fixed Base)max/min(SFSI)

0

2

4

6

8

Nat

ural

Fre

quen

cy [H

z]

5 10 15 20−4

−2

0

2

4

Time [s]

Mom

ent [

MN

m]

Structure 2 Fixed BaseSFSImax/min(Fixed Base)max/min(SFSI)

0

4

8

12

16

Nat

ural

Fre

quen

cy [H

z]

5 10 15 20−3

−2

−1

0

1

2

3

Time [s]

Mom

ent [

MN

m]

Structure 3 Fixed BaseSFSImax/min(Fixed Base)max/min(SFSI)

0

2.5

5

7.5

10

12.5

15

Nat

ural

Fre

quen

cy [H

z]

5 10 15 20−10

−5

0

5

10

Time [s]

Mom

ent [

MN

m]

Structure 4Fixed BaseSFSImax/min(Fixed Base)max/min(SFSI)

0

4

8

12

16

Nat

ural

Fre

quen

cy [H

z]

I NEHRP–94 seismiccode states thatommiting SFSI ison safe side

I Reality andsimulations showdifferent picture

Modeling and Simulations for Geotechnical Problems

Conclusions

There are many parts to succesfull simulations forgeotechanical and structural problems

I Systems approach to model building (discovery),simulations, and results interpretation

I Education , practice and research : need to overcomeempirical (historical) approach

I Great oportunity and challenge to advance modern(good!) methodology to practice

I Economic forces (not cheaper but better design) andlitigation threat can actually help!

Modeling and Simulations for Geotechnical Problems

Invitation to WCCM

Consider submitting an abstract to the WorldCongress on Computational Mechanics, L.A. ’06

I Computational GeomechanicsI Organized by:

I Stein StureI Fusao OkaI Ronaldo BorjaI Richard RegueiroI Boris Jeremic

I Follow link from my web site to WCCM