Reproducing nonlinear ground response and pore pressure variations using in-situ soil properties

Abstract

In this study, we proposed a novel method to extract pore pressure model parameters from vertical array seismic records and pore water pressure data, building upon the existing method for estimating in-situ soil dynamic parameters. Using the extracted in-situ soil properties, one-dimensional effective stress analysis is conducted in DEEPSOIL to reproduce and predict the nonlinear ground response and pore pressure variations at the Wildlife Liquefaction Array, California. Our results show that: (1) the increase and dissipation process of excess pore water pressure can be well empirically modeled using the Hill Equation and an exponential decay function, respectively; (2) the simulated ground response and pore pressure variations using in-situ soil properties are consistent with the observations, which demonstrates the feasibility and effectiveness of using in-situ soil properties to predict pore pressure variations during strong motions; (3) effective stress analysis does not outperform total stress analysis in ground response analysis when the excess pore water pressure ratio (r_u) is no greater than 0.6, but can be used to evaluate the potential for liquefaction triggering; (4) when simulated r_u > 0.9, there are clear differences between the simulated ground motions using total stress and effective stress analyses at this site.