地下结构抗震设计中的静力弹塑性分析方法

首先介绍目前地下结构抗震分析方法存在的主要问题,在借鉴地上结构静力弹塑性分析方法思想的基础上,提出一种适用于地铁等地下结构抗震分析与设计使用的静力弹塑性方法。详细介绍该方法的实施步骤与特点,给出水平等效惯性加速度的求解方法。该方法概念清晰、操作简单,能够在不需要计算相互作用系数的情况下较好地模拟土-结构之间的动力相互作用;能够进行结构在地震作用下的全过程分析,给出地下结构在输入地震波作用下的峰值变形与内力,避免对土-结构整体模型进行复杂的动力相互作用分析。结合实际工程与基于黏弹性静-动力统一人工边界的静-动力联合分析方法进行对比研究,验证地下结构静力弹塑性分析方法的可靠性及良好的模拟精度,可以应用于地下结构的抗震分析与设计中。

A static elasto-plastic analysis method in seismic design of underground structures

Main problems of the methods currently used for seismic response analysis of underground structures are discussed. Then based on the static elasto-plastic methods for seismic analysis of superstructures, a similar method for seismic response analysis and design of underground structures is proposed. The implementation procedure and special features of the method are introduced in some details. Also included in the paper is a solution method of equivalent horizontal inertial acceleration which can analysze the soil-structure interactions under dynamic loading. The method presented is clear concept and easy for application. In fact, dynamic soil-structure interactions can be simulated well by the method without calculating the interaction coefficient. In addition, the method is capable of performing a whole range analysis of the super-structure, then provide the data input in terms of peak response and internal forces needed for the subsequent analysis of an underground structure under seismic loading. By doing so, one can avoid the complicated analysis of dynamic soil-structure interactions. Taking an actual subway station project as an example, the validity and good simulative accuracy of the method are verified by comparing with the static-dynamic coupling analysis method based on a unified viscous-spring boundary. The analysis results have shown that the method is suitable for seismic response analysis and design of underground structures.