场地地震反应的比较研究

The effect of seismic responses of sites on input motions and numerical methods and models

用数值分析方法计算分析了场地地震反应。针对几种典型场地,分别采用频域等效线性化波动法(以下简称波动法)和有限元法,分析比较了在6种地震波作用下场地土的地震反应特性、有限元法和波动法间的数值差异、盆地模型和水平分层模型的地表地震反应特性及差异,并用Drucker-Prager模型模拟盆地沉积物介质的非线性。结果显示,有限元法求得的土层表面加速度峰值大于波动法;盆地的松散沉积物对地震波有明显的放大作用,盆地中部区域的最大地震反应与水平分层模型相应结果接近;在El-Centro波作用下,盆地表面的非线性位移反应较线性情形增大明显。

In this paper,we study the effect of seismic responses of sites on input motions and numerical methods and models. We compare the seismic responses of typical construction sites to six differont input motions using the frequency domain method,the seismic responses of two construction sites using two different numerical methods - the finite dement method and the frequency domain method, and the seismic responses of a basin modal with a horizontally layered model using the finite element method. Moreover,we analyze the nonlinear seismic responses of the basin based on Drucker-Prager modds. Our study reveals that： the acceleration responses of the sites surfaces are larger using the finite dement method than those using the frequency domain method; the seismic responses are significantly enlarged due to loose soft in the basin, the peak seismic responses of the basin surface are closdy approximated by the horizontally layered model; and the nonlinear displacement responses of the basin surfaces are larger than the linear ones on the El- Centro input.