Topography and soil amplification for hill site when incident SH wave
ZHANG Ji;LIANG Jianwen;BA Zhenning;Department of Civil Engineering,Tianjin University;School of Civil Engineering and Architecture,East China Jiaotong University;Tianjin Key Laboratory of Civil Engineering Structures and New Materials;
At first,based on indirect boundary element method,and by adopting Ricker wavelet as incident wave,this paper studies the wave propagation characteristics of hill topography in homogeneous half-space,rock hill topography in half-space with one soil layer,soil hill topography in half-space with homogeneous soil layer,and soil hill topography in half-space with heterogeneous soil layer when incident SH wave,respectively,and compares the amplification of seismic ground motion by hill topography and soil. It is revealed that overlaying soil will enhance scattering and reflecting effects and prolong seismic ground motion duration,and soil amplification is much greater than topography amplification. Based on the above,Taft wave,El Centro wave,and Tianjin wave are selected as the incident seismic ground motions,and seismic response of soil hill topography in half-space with heterogeneous soil layer is studied. For the model considered in this paper,when the three seismic ground motions incident the maximum amplification ratio of peak of the surface acceleration response spectrum by the hill site is 102. 9%,149. 9% and 186. 7%,respectively,which are much higher than the values specified by Chinese earthquake resistant code to magnify the maximum value of horizontal earthquake influence coefficient for sake of taking local topography effect into account.