软土地基中软土厚度及刚度对地表地震响应影响研究

为研究深厚软土地层的软土层厚度和刚度对地表地震响应的影响，以某高速公路工程勘察钻孔为基础，考虑了软土层的厚度和刚度变化，研究了14个计算剖面。计算剖面分为两组，一组的软土层厚度由18.8 m逐渐变化至2.8 m，另一组的软土层剪切波速由105 m/s变化至185 m/s。将集集、El Centro和汶川地震记录调幅至0.05 g，0.10 g和0.20 g，形成9组输入。利用一维场地动力分析程序Deepsoil对计算剖面在输入下的动力反应进行分析，统计计算剖面的地表峰值加速度和放大系数。结果表明:在各计算剖面下，随着软土层的厚度增大，地表峰值加速度和放大系数变小；随着软土层刚度提高，地表峰值加速度和放大系数变大。

Study on Influence of Thickness and Stiffness of Soft Soil on Seismic Response of Ground Surface in Soft Soil Foundation

In order to study the influence of thickness and stiffness of soft soil on the seismic response of ground surface in deep soft soil stratum, 14 calculated sections were studied with thickness and stiffness of soft soil layer being considered, which is based on the drilling information of a highway survey. There are two groups of calculated sections. In one of these, the thickness of soft soil varied from 18.8 m to 2.8 m and the shear wave velocity of the soft soil was changed from 105 m/s to 185 m/s in the other. The Chichi, El Centro and Wenchuan records were scaled to 0.05 g, 0.10 g and 0.20 g, which made 9 input motions. A one-dimensional field dynamic analysis program Deepsoil was used to analyze the dynamic response of the calculated section under the input, and the surface peak acceleration and amplification coefficients of the section were statistically calculated. The results show that the ground peak acceleration and amplification coefficients decreased with the increase of the thickness of soft soil and these two indicators increased with the increase of the stiffness of the soft soil.