Evaluation of seismic stability of critical facilities to earthquake-induced failure of rock foundations based on ground displacement is considered to be crucial. In this study, a constitutive model was developed to consider the effects of both shear and tensile failure of rock on the stress–strain relation derived from the multiple shear spring model. This model was then used for dynamic nonlinear analysis that considers progressive failure. The applicability of this analysis method to a dynamic centrifugal model test of a rock foundation was evaluated. The amounts of residual displacements of the analysis results were comparatively close to the model test results although the vibration step, which begins after the occurrence of residual displacements, was slightly faster than that of the model test.
The occurrence of fatal, large-magnitude earthquakes in the recent past has led to increased attention on earthquake ground motion during the design phase of modern structures. Accordingly, quantitative assessment of seismic resistance of critical facilities to earthquake-induced failure of rock foundations has become important.
In Japan, the seismic stability of rock foundations has conventionally been evaluated in terms of their bearing capacity, inclination, and sliding (JEAG 4601-1987 1987). In terms of the sliding motion during an earthquake, a slip safety factor based on an equivalent linear analysis is conventionally used to evaluate the stability of rock foundations. However, a slip safety factor value of less than 1 does not necessarily indicate immediate ground instability (Ishimaru et al. 2018a). Therefore, the evaluation of seismic stability based on ground displacement is considered to be a more effective approach.
In this study, therefore, the applicability of a nonlinear analysis method that considers progressive failure to evaluate the seismic stability of rock foundations (including post-earthquake residual displacement) was investigated. This paper explains the proposed nonlinear analysis method. The applicability of this nonlinear analysis method to a dynamic centrifugal model test of rock foundation is presented.
