土层分层厚度对场地地表地震动参数的影响

Effect of Soil Layer Thickness on the Ground Motion Parameters of Site Surface

以江淮地区典型场地资料为原型,选取不同的土层分层厚度,构造多种场地土层计算模型,选择Taft、Kobe和El Centro三条强震记录作为地震输入,采用一维频域等效线性化波动方法分析了分层厚度对场地地表地震动参数的影响。研究表明:土层分层厚度对场地地震动参数存在影响,主要表现为采用较大分层厚度计算得到的地表峰值加速度A_(max)和反应谱特征周期T_g相对偏低,应采用尽可能小的土层分层厚度;分别采用1.0m和2.0m分层厚度计算得到的地表加速度反应谱形状基本重合,A_(max)和T_g也基本一致,最小选取2.0m土层分层厚度可以满足工程精度的要求。

Based on the data from typical sites in Jianghuai Region, many kinds of soil layer sites for the seismic response was modeled by choosing different layer thickness. The layer thickness effect on ground motion parameters was analyzed with the one dimension equivalent linear method in frequency domain by choosing the Taft, Kobe and El Centro strong motion records as the earthquake input. The results have shown that the soil layer thickness has effect on the ground motion parameters. The peak ground acceleration Amax and the characteristic period of response spectrum Tg calculated by the larger layer thickness are relatively low, the soil layer thickness should be divided as small as possible. The shape of ground acceleration response spectrum obtained by 1. 0m and 2. 0m layer thickness calculation are basically coincident, and the Amax and Tg are also basically consistent, the minimum soil layer thickness of 2. 0m can satisfy the requirement of engineering precision.