地下结构强制反应位移法和反应加速度法的对比分析

A Comparative Analysis of Forced Displacement and Response Acceleration Methods for Underground Structures

摘要:

首先基于地震作用下地下结构的变形受周围地基土变形控制这一相互作用特征，在反应位移法的基础上讨论两种简化分析方法：一种是将土层变形施加在模型边界模拟地震作用；另一种是将土层加速度施加到整个模型上模拟地震作用。这两种简化分析方法都避免了反应位移法中弹簧刚度的取值问题，提高了计算效率。其次分析不同地震动强度、不同侧边距的计算结果，并用动力时程分析的计算结果校核，分析两种简化计算方法的精度。结果表明：随着地震动强度的增加两种简化分析方法的计算结果都令人满意，使用强制反应位移法时建议侧边距取两倍结构宽度，使用反应加速度法时建议侧边距取三倍以上结构宽度。

Abstract:

Two kinds of simplified analytical methods are discussed. Both were derived from the response deformation method based on the premise that the deformation of an underground structure depends on the deformation of the foundation soil. One method applied ground displacement to the boundary of the finite element model to simulate seismic load; the other applied ground acceleration to the integral finite element model to simulate seismic load. Both simplified analytical methods avoided calculating the value of the spring stiffness and improved the computational efficiency. Calculated results with different ground motion intensities and lateral margins were obtained and checked with the results of the dynamic time-history method. They showed that the results of the two simplified analytical methods were satisfactory as the ground motion intensity increased. The lateral margin had to be twice the width of the structure when using the forced displacement method, and needed to be more than three times the width of the structure when using the response acceleration method.