中文摘要：

结合＂分区契合＂技术,采用间接边界元方法研究了地铁列车振动诱发的层状地基振动问题。方法首先将模型划分为含隧道的层状半空间和轨道下垫层两个区域。然后求解振动荷载作用于垫层表面时轨道下垫层区的自由波场,同时在两个区域的边界上分别施加单位虚拟荷载来模拟两个区域内的散射波场。最后契合两个区域,由边界条件求得虚拟荷载的幅值,进而求得地基的动力响应。文中进行了数值计算,着重分析了土层厚度、基岩与土层刚度比等地基动力特性参数对地表振动的影响,同时针对天津一典型地基和其等效单层土地基进行了比较研究,得出了一些有益的结论。

英文摘要：

Combining with the region matching technique, the indirect boundary element method （IBEM） is used to study the vibration of layered foundation under the dynamic load induced by train. Firstly, the model is decom- posed into the region of layered half-space including the tunnel and the region of cushion. Then, the free wave field is calculated, which is defined as dynamic response induced by dynamic load acting on the surface of the cushion, and the scatter fields in the two regions are constructed by applying virtual distributed loads on the boundaries of the two regions. Finally, the two regions are matched to determine the amplitudes of the virtual loads and the dynamic response on the surface of the foundation can be calculated. Numerical calculations are performed and influence of the layer thickness ratio and stiffness ratio of the bedrock to layer on the vibration is studied in detail, and the com- parison between results of one typical layered site in Tianjin and its equivalent single layer site is made, and some useful conclusions are drawn.