以绵竹清平波作为输入地震波,采用ANSYS-FLAC3。相结合的方法对2层2柱3跨软土典型地铁车站结构进行强震响应的三维数值模拟。土体采用D-P本构模型,车站结构采用弹性模型,并选用瑞利阻尼和Hardin/Drnevich模型的滞后阻尼实现土在循环动荷载下的滞回和非线性特性。计算结果表明:下层中柱的相对水平变形主要由水平方向加速度引起,而受竖直方向加速度的影响甚微;下层中柱轴力主要受水平方向和竖直方向加速度共同作用的影响,在发生汶川地震级别的地震时,将可能发生车站下层中柱坍塌的现象;土压力以及侧墙对土体的挤压力均较大;下层中柱柱顶的水平方向加速度响应大于柱底的水平方向加速度响应,而两者的竖直方向加速度反应相差不大。由此可知:发生地震时,下层中柱是地铁车站最为薄弱的构件,并且中柱的破坏系由水平方向加速度和竖直方向加速度共同作用的结果。
With Qingping wave of Mianzhu as the input earthquake wave, 3D numerical simulation was carried through on the strong earthquake response for the typical structure (2-layer 2-column 3-span) of the underground railway station in soft soil by adopting the combined ANSYS-FLAC3D method. The D-P constitutive model was employed to simulate the model soil, and the elastic model was employed to simulate the station structure. The Rayleigh damping and the hysteretic damping of Hardin/Drnevich model were used to simulate the hysteretic and nonlinear characteristics of the model soil under cyclic dynamic load. The calculation results show that the relative horizontal deformation of the central column on the lower layer is caused by the horizontal acceleration, and the effect of the vertical acceleration on it is very little. The axial force of the central column on the lower layer is mainly affected by the interaction of the horizontal and the vertical acceleration. The central column on the lower layer of the station may collapse if Wenchuan same level of earthquake occurs. The soil pressure and the side wall produce greater extrusion force on the soil mass. The horizontal acceleration response at the top of the central column on the lower layer is greater than that at the bottom, while the vertical acceleration response is almost the same at both the top and the bottom of the central column. Thus it is clear that the central column on the lower layer is the weakest component of the station structure under strong earthquake, and the damage of the central column is caused by both the horizontal acceleration and the vertical acceleration.