上覆黏土层条件下考虑空间变异的砂土地基地震液化可靠度研究

Study on reliability of seismic liquefaction under the condition of overlying clay layer considering the spatial variability of sandy soil

基于FLAC3D有限差分软件,对上覆黏土层的砂土地基地震液化响应动力可靠度进行研究,建立了黏土-砂土地基平面应变模型,通过模拟土体剪切模量的空间变异性,利用蒙特卡洛模拟方法并结合生成的非高斯随机场评估液化区面积、超孔隙水压力和地表位移,研究了不同剪切模量变异系数(COV)对地基地震液化可靠度的影响。结果表明:剪切模量变异系数越大,液化范围缩小越困难,液化范围峰值的分布范围越分散;地表水平位移和地表最大差异沉降均随剪切模量变异系数的增大而增大。

Based on the FLAC3D finite difference software,the dynamic reliability of seismic liquefaction response of sandy soil foundation covered with clay layer was studied,and a plane-strain model of clay-sandy soil foundation was established.By simulating the spatial variability of soil shear modulus,the area of liquefaction zone,excess pore water pressure and surface displacement were evaluated using the Monte Carlo simulation method and the generated non-Gaussian random field.The influence of different coefficient of variation(COV)on the reliability of seismic dynamic liquefaction of foundation was studied.The results show that the larger the COV of shear modulus,the more difficult it is to reduce the liquefaction range and the more dispersed the distribution range of peak liquefaction range;the horizontal displacement and maximum differential settlement of the surface increase with the increase of COV of shear modulus.