Numerical Procedures for Simulating Earthquake Fault Rupture Propagation

Abstract

Numerical simulations of earthquake fault rupture propagation can be used to design structures to resist damage from induced ground deformations. Several researchers have developed numerical models for analyzing the responses of soil and structures to underlying fault movement. Often, however, a relatively simple Mohr-Coulomb constitutive model that is modified to incorporate strain softening or other material nonlinearity is used. In this work, a modification of the UBCSAND soil constitutive model, one that has been shown to capture well the nonlinear shear response of soil for many stress paths, was used. The UBCSAND model was modified to add postpeak strain softening with a response that is dependent on the mode of fault rupture, a nonlinear failure envelope that is stress dependent, and a modified flow rule that is dependent on the mode of shear deformation. The numerical simulations captured well the observed trends in carefully performed geotechnical centrifuge experiments. The Modified-UBCSAND models developed herein can be used to evaluate boundary-deformation problems.