Reproducing ground response using in‐situ soil dynamic parameters

Abstract

AbstractIn this study, we extracted the in‐situ soil dynamic parameters that contains shear wave velocity, shear modulus degradation curve and damping ratio from seismic data recorded at the Delaney Park Digital Array (DPDA) during the 2018 Mw 7.0 Anchorage earthquake. Based on these parameters, a one‐dimensional finite element model in DEEPSOIL is constructed to simulate the propagation of seismic waves in near‐surface, and the simulated pseudo‐spectral accelerations with 5% damping from the in‐situ soil dynamic parameters are compared with those from different velocity profiles and damping models. The results show that: (1) it is necessary to consider the effects of downward waves on the estimation of shear strain when extracting the modulus degradation curve, otherwise the shear strain will be overestimated by several times at this site; (2) the validity and reliability of the use of the in‐situ soil dynamic parameters in reproducing and predicting nonlinear ground response are verified, in which the Pearson correlation coefficients between the simulated and observed spectral accelerations at different depths for five selected events are generally higher than 0.95; (3) the ground response analysis exhibits relatively high sensitivity to both velocity profiles and damping models, where the velocity profile extracted from vertical seismic data obviously outperforms other velocity profiles, and the Rayleigh damping provides an alternative to the constant damping model in this study.