北京地区粉质粘土土动力学参数的统计分析

土动力学参数即土的动剪切模量比和阻尼比,对土层地震反应分析结果有重要影响。本文首先选取了北京地区2001年以来,地震安全性评价报告中20份具有完整土动力学参数的实验数据,统计分析了粉质粘土的实测土动力学参数,给出了粉质粘土在不同深度下的动剪切模量比和阻尼比平均值;然后,选取了2个典型工程场地,构建土层分析模型,进行土层地震反应分析计算,并对比分析了本文得到的统计值与典型工程场地的实测值、袁晓铭的推荐值和DB001—94规范的推荐值对土层地震反应分析计算结果的影响。分析结果表明,本文得到的统计值在北京地区具有一定的代表性和适用性,对于获得原状土样困难的场地,特别是对于较薄的夹层土,本文的统计结果在实际的地震安全性评价工作中可供参考使用。

Statistical Analysis of Dynamic Parameters of Silty Clay in Beijing Area

Soil dynamic parameters, including dynamic shear modulus ratio and damping ratio, have important effects on the earthquake response of soil layer. In this paper, the parameter mean values of silty clay at different depth are obtained through statistical analysis on the experimental soil dynamic data from recent 20 reports of site seismic safety evaluation in Beijing. Furthermore, based on two typical engineering sites, the influences of four different soil dynamic parameters, mean values, experimental values, values recommend by Yuan Xiaoming, and values recommend in the code for seismic safety evaluation of engineering sites （DB001-94）, are analyzed. Our results show that mean values are applicable for the work of seismic safety evaluation of Beijing, especially for some inter-layer silty clay, for which undisturbed soil samples often are not available.