INFLUENCE OF SEISMIC POREWATER PRESSURE INCREASE AND LIQUEFACTION ON SITE RESPONSE ANALYSIS
Description
Seismic site response analysis is a technique used to predict the ground’s response to local soil conditions. Recent advancements in understanding the generation of shear-induced excess pore pressure have led to the development and implementation of pore pressure response models in site response analysis that take effective stress into consideration. This research focuses on developing recent approaches to calculate site response analysis using the nonlinear effective stress method. The research specifically examines the impact of Porewater Pressure (PWP) buildup, soil softening, potential liquefaction, and post-liquefaction effects on site response. The study is divided into two stages: (1) The performance of a Porewater pressure generation model coupled with constitutive models is tested to compute stress-strain response during shaking using effective stresses, and to solve dynamic site response problems. (2) A parametric study using 2D elements is conducted to determine the principal variables that affect site response analysis. In the first stage, the study evaluates the performance of nonlinear effective stress constitutive models, commonly known as advanced constitutive models, used in one-dimensional (1D) site response analysis for assessing stress-strain behavior, porewater generation, and liquefaction potential in soft soil deposits at the element level. Three constitutive models are combined with the porewater pressure generation model to develop coupled models called PDMY 02, PM4SAND, and PDMY 03. The study also proposes protocols for selecting model input parameters.