Assessment of applicability of equivalent linear and nonlinear analysis methods for site response analysis in deep soil Site

抄録

Sites with deep soil layers are well-known for their propensity to significantly amplify ground motion responses in the surface soil. Moreover, the prolonged fundamental period characteristic of these sites makes structures with extended natural periods susceptible to damage induced by resonance. The focus of this study is the Eureka vertical array site in California, located within the context of deep overburden. The study utilizes both equivalent linear (EL) and Pressure-Dependent Hyperbolic (GQH) nonlinear time-domain methodologies to simulate and analyze the dynamic response of the ground surface under varying seismic excitations, including both strong and weak conditions. Following these analyses, a comparative assessment is conducted using recorded ground motion data. The findings indicate that under weak seismic conditions, both analytical methods effectively capture and reproduce ground seismic responses. However, under intense seismic forces, the nonlinear time-domain analysis method outperforms the equivalent linear analysis method significantly in predicting the dynamic response of the ground surface. Furthermore, the results obtained from the equivalent linear approach show significant deviation from the data recorded by the array, indicating its limited suitability for seismic response analysis in deep soil strata sites exposed to intense seismic events.