考虑土体空间变异性的可液化土层圆形隧道地震响应分析

Seismic response analysis of subway tunnel in liquefiable soil layer considering soil spatial variability

引入随机场理论,研究可液化土层土体力学参数空间变异性对地铁隧道地震响应的影响.基于FLAC3D有限差分软件建立隧道下方存在可液化土层的数值模型,首先在假设土体为均质的情况下进行计算,发现隧道结构拱顶和拱腰的变形相差较大,且隧道结构在水平方向发生整体偏移;随后进行随机性计算,发现考虑土体参数空间变异性时得到的隧道结构地震响应远大于确定性计算结果,表明传统的均质土体假设高估了隧道结构在地震作用下的安全性.

The seismic response of subway tunnels is studied by introducing random field theory and considering the spatial variability of soil mechanics parameters.Based on FLAC3D finite difference software,the numerical model of a subway tunnel with liquefiable soil layer below was established.It is found that under the assumption of homogeneous soil the deformation of the tunnel is quite different from that of the arch and the arch waist,and the overall displacement of the tunnel occurs in the horizontal direction.While the seismic response of tunnel considering the spatial variability is much larger than that of the above deterministic calculation which shows that the traditional assumption of homogeneous soil overestimates the safety of the tunnel under earthquake.