Effects of Spatial Variability of Soil Properties on Liquefaction Behavior of Horizontally Layered Ground

Kyohei Ueda ； Vargas Tapia Ruben Rodrigo ； Susumu Iai

《Geotechnical Hazard Mitigations: Experiment, Theory and Practice—Proceedings of the 5th International Conference on Geotechnical Engineering for Disaster Mitigation and Rehabilitation》 2017年 (2017/10) Pp. 75-87

https://doi.org/10.6140/9789864371419.201710.0007

摘要

Effective stress analyses based on the finite element method are often used to predict liquefaction occurrence in soil-structure systems during earthquakes. In the analyses, the soil properties are typically specified by using a deterministic model although they intrinsically have spatial variability. In this study, nonlinear finite element analyses are performed to investigate the effects of soil heterogeneity on the liquefaction behavior of stochastically heterogeneous soil deposits through a Monte Carlo simulation approach. The material nonlinearity of soils is expressed by using a strain space multiple mechanism model. In the simulation, the spatial distribution of the SPT N value, shear wave velocity, and internal friction angle is independently taken into account by using sample functions of discretized Gaussian, triangular, and exponential stochastic fields. A series of analyses has revealed that the heterogeneity of the shear wave velocity has no significant effect on the distribution of the computed excess pore water pressure (EPWP), while the maximum value of EPWP ratio is partially influenced and becomes less by considering the spatial variability in the internal friction angle and the N value. In particular, the heterogeneity of the internal friction angle has a possibility to reduce the mean value (i.e. averaging over all the finite elements) of the computed EPWP ratio to about 80% of that in the case of homogeneity.

關鍵字

Liquefaction ； Spatial variability ； Numerical analysis