不同岩性组合下的斜坡地震动力响应研究

本文采用大型有限差分软件FLAC3D, 建立上硬下软, 上软下硬, 含软弱基座和不含软弱基座4种斜坡的数值分析模型, 输入阪神地震波, 分析总结斜坡的动力响应规律。计算结果表明:(1)从加速度动力响应规律来看, 无论是水平向还是竖直向, 上软斜坡均比上硬斜坡大。并且, 两种斜坡的水平向放大系数均比竖直向放大系数大, 基本在1.52.0倍之间。(2)从位移规律上来看, 软岩相比于硬岩, 其对地震波更加敏感, 上硬下软岩性组合在强震动力作用下更易失稳。(3)从速度、位移的动力响应规律来看, 有软基斜坡地震动响应程度明显大于无软基斜坡。但是从边坡的应力变化来看, 软弱基座的存在, 一定程度上起到了吸收入射地震波能量的作用, 反而有利于边坡稳定性。

THE ANALYSIS OF DYNAMIC RESPONSE OF COMPLEX SLOPE

This paper built four kinds of numerical analysis models of slope, inputting Ban Shen seismic waves. Summarizes the dynamic response of the law. Calculated result shows that: 1 the hardness-upward slope demonstrates larger amplification effect of acceleration than the softness-upward slope basically according to acceleration dynamic responses. Forthermore, vertical excitation concentrate than those in horizontal excitation, the largest amplification of horizontal acceleration is 1.5 to 2.0 times than the vertical acceleration.2 Soft rock is more sensitive to seismic waves than hard rock, under the strong earthquake, the hardness-upward slope is apt to fail according to the displacement.3 Rock slope with soft foundation demonstrates larger amplification effect of acceleration than the rock slope with no soft foundation according to acceleration and displacement dynamic responses. However, evolution of stress field shows that before the failure of the slope, the existence of soft foundation can reduce the role of earthquake dynamic effect to a certain extent, which is positive to slope stability.