A Study on Overall Properties of Seismic Response and Investigation Method of Counter-Measured Ground against Liquefaction and Investigation
Yumi SATO, Kenichi MAEDA, Koichi HAYASHI, Yoshinobu MURATA and Toshiyuki TAKAHARA
Abstract:Sand compaction pile, SCP, is widely adapted to reclaimed ground as a counter-measure against liquefaction of ground during earthquake. However, many case studies imply that the current design with evaluation of improvement effects by N-value is, considerably conservative. In this paper, we propose a new evaluation method for the overall dynamic properties of the improved ground in terms of a finite difference analysis and a non-linear seismic response analysis with homogenization theory. The finite-difference simulation of seismic waves shows that both share wave and surface wave propagate with constant velocity, which can be estimated by homogenization method, even if in heterogeneous improved ground. The overall evaluation including the lateral earth pressure increase around SCP showed that the improvement effects were controlled not only by an increase in liquefaction resistance, but also by an decrease in dynamic amplitude and the natural period; these results are valid for the seismic resistant design for reclaimed grounds. Key Words:Key words: Liquefaction, Composite groundCSCP, HomogenizationCFinite difference method, Wave length, Surface wave investigationCStress distribution