粉质黏土原位地震动参数测试及模型参数反演分析

In-situ ground motion parameters test for silty clay and back analysis of model parameters

为解决目前现场原位地震动参数较难获取的问题,自行研发了土体地震动参数原位试验测试系统,该系统包括可移动系统、荷载伺服系统、动力反应系统和数据采集系统四部分,利用该系统对南京某工程场地进行了土的现场非线性剪切模量试验,得到了粉质黏土的现场非线性剪切模量G-logγ曲线和G/Gmax-logγ曲线,发现当剪应变γ超过0.1%时,动剪切模量G减小的速度愈来愈快,反映了土在动荷载作用下非线性及应变累积性的特点。此外,基于Martin-Davidenkov模型,采用遗传算法对现场试验结果进行了反演分析,得到了该试验地区较浅土层内的模型参数取值范围。

In order to solve the problem that in-situ ground motion parameters are difficult to obtain,the in-situ ground motion parameters test system,which includes a mobile system,a load servo system,a dynamic response system,and a data acquisition system and has a wide range of applications,strong controllability and high reliability,was developed to carry out the test of field nonlinear shear modulus of silty clay in Nanjing and obtain the field G-logγcurve and G/Gmax-logγcurve.It is found that when theγexceeds 0.1%,the G decreases faster and faster,reflecting the nonlinearity and strain accumulation of soil under dynamic loading.In addition,the back analysis of model parameters by genetic algorithm was conducted based on the Martin-Davidenkov model to get the range of model parameters in the shallow soil layer of the test area.