the nonlinear time-domain modeling of earthquake …sokocalo.engr.ucdavis.edu/~jeremic/...the...

Introduction Foundation – Soil/Rock Interface Nonlinear Interface Results/Issues Summary

The Nonlinear Time-Domain Modeling ofEarthquake Soil Structure Interaction forNuclear Power Plants: Nonlinear Contact

Between Foundation and Rock

B. Jeremic, A. Kammerer, N. Tafazzoli, B. Kamrani,

University of California, Davis, CALawrence Berkeley National Laboratory, Berkeley, CAU.S. Nuclear Regulatory Commission, Washington DC

SMiRT 21, New Delhi, India, November 2011

Jeremic et al.

Nonlinear ESSI of NPPs with Contact Slip


Outline

Introduction

Foundation – Soil/Rock InterfaceThe ProblemThe Modeling

Nonlinear Interface Results/IssuesVertically Propagating Earthquake3D Synthetic Ricker Wavelet

Summary

Jeremic et al.



Introduction

I High fidelity modeling and simulation of earthquakesoil/rock structure interaction behavior of NPPs

I Reduction of modeling uncertainty

I Focus in this study are nonlinear material effects at thefoundation – soil/rock interface

I Thanks to Dr. Godoy and Dr. Kennedy for pointing out tothis issue/problem

I One of the case studies for the NRC ESSI SimulatorSystem

Jeremic et al.



Outline

Introduction



Summary

Jeremic et al.



The Problem

Foundation – Soil/Rock Interface

I The case of nonlinear, elastic-plastic zone between aconcrete slab and a foundation soil/rock.

I Layers of plastic waterproof sheets in the zone

I Reduction of capacity for horizontal shear a thefoundation-rock contact

I Possible gaping, opening and closing (hard or soft)

Jeremic et al.



The Problem

Beneficial and/or Detrimental ?

I Benefits of nonlinear contact between the foundation slaband the soil/rock

I Dissipation (significant) of seismic energy (shear)I Change of seismic motions characteristics (frequency

reduction)I "Passive" base isolation

I Detriments of nonlinear contact between the foundationslab and the soil/rock

I Gap opening with hard gap closing (high frequency load)I Change of seismic motions

Jeremic et al.



The Modeling

Contact Element

I Node to node contact element

I General, 3D element

I Gap opening/closing in normal direction

I Frictional contact in shear direction

I Viscous and/or non-viscous gap opening/closing

Jeremic et al.



The Modeling

Verification and ValidationVerification provides evidence that the model is solved correctly.

I Code verificationI Finite elementsI Constitutive simulationsI Static and dynamic solution advancement algorithmsI SolversI Wave propagationI Model/mesh verification

Validation provides evidence that the correct model is solved.

I Validate components, unit testsI Validate the system (limited data, recent earthquakes)

Jeremic et al.



The Modeling

ESSI Model, with/without Interface

Jeremic et al.



The Modeling

Model VerificationI Verification: finite element mesh, wave propagation

I Synthetic motions: Ricker, Ormsby wavelets

I Verify propagation of Body (P, SV and SH) and Surface(Rayleigh, Love) waves

2km10km

5km

x

y

xy

1

1

22

2km

0.2km

0 0 2 4 6 8 10 12

Time (s)

0.2 m/s2

z=3000m

z=3200m

z=3400m

z=3600m

z=3800m

z=4000m

z=4200m

z=4400m

z=4600m

z=4800m

z=5000m

Jeremic et al.



Outline

Introduction



Summary

Jeremic et al.



Influence of Inelastic Foundation-Soil/Rock Contact onthe NPP Response

I Soil/rock – foundation interface slip behavior

I Changes in Earthquake Soil/Rock Structure Interaction(reduction/increase in demand)

I Dissipation of seismic energy in the slip plane

I Passive (and active) base isolation

I Two examples, 1D seismic wave and 3D synthetic Rickerwavelet

Jeremic et al.



Vertically Propagating Earthquake

Incident Earthquake SV Wave

-5

-4

-3

-2

-1

0

1

2

0 0.5 1 1.5 2 2.5 3 3.5 4

Acc

eler

atio

n (m

/s2 )

Time (s)

Jeremic et al.



Vertically Propagating Earthquake

Base and Top of the Containment

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 5 10 15 20

FF

T F

unct

ion

Am

plitu

de

Frequency (Hz)

0

0.05

0.1

0.15

0.2

0.25

0 5 10 15 20F

FT

Fun

ctio

n A

mpl

itude

Frequency (Hz)

—slip —noslip

Jeremic et al.



3D Synthetic Ricker Wavelet

Incident Ricker Wavelet at 45o

Jeremic et al.




ESSI with Slip, Base, Accelerations FFT

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

FF

T F

unct

ion

Am

plitu

de

Frequency (Hz)

Slip BehaviorNo-Slip Behavior

0

0.1

0.2

0.3

0.4

0.5

0.6

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Dis

plac

emen

t (m

)

Frequency (Hz)


horizontal Acc. FFT vertical acc. FFT

Jeremic et al.




ESSI with Slip, Top, Accelerations FFT

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0.11

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

FF

T F

unct

ion

Am

plitu

de

Frequency (Hz)


0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Dis

plac

emen

t (m

)

Frequency (Hz)


horizontal acc. FFT vertical acc. FFT

Jeremic et al.



Outline

Introduction



Summary

Jeremic et al.



Summary

I Nonlinear behavior of the foundation – soil/rock interfacezone can have beneficial and detrimental effects on theseismic response of NPPs

I Beneficial or Detrimental, such nonlinear interface doesexists and has to be properly modeled

I High fidelity numerical prediction relies heavily on properverification and validation

I Information Portal:http://nrc-essi-simulator.info

I Funding by and Collaboration with the U.S.-NRC isgratefully acknowledged

Jeremic et al.


http://nrc-essi-simulator.info

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