Evaluation of dynamic site response and deformation of instrumented site - Kobe

The observed dynamic response of an instrumented site at Port Island during the 1995 Kobe earthquake was utilized to demonstrate the feasibility of computer simulation of earthquake induced site response and liquefaction-induced deformations of a level ground site. Non-destructive in-situ electrical and shear wave velocity methods were used to obtain the initial state parameters and constitutive model constants representative of the site. The analysis used the fully coupled, effective stress-based, nonlinear, finite element program SUMDES with a reduced order bounding surface hypo-plasticity model to simulate the stress-strain behavior of cohesive soils and modified reduced order bounding surface hypo-plasticity model to simulate the stress-strain behavior of non-cohesive soils. The results of the dynamic analysis such as acceleration time histories and liquefaction-induced deformations agreed reasonably well with the acceleration time histories and liquefaction-induced vertical and horizontal deformation behaviors observed during the Kobe earthquake. The results of this study show that computer simulation of earthquake effects at level ground sites is possible using non-destructive in-situ testing and a verified numerical procedure.