浅埋三维夹杂及空腔对SH波地面运动的研究

采用基于显示集中质量有限元与透射边界结合的波动问题求解方法,对软硬不同的浅埋夹杂和空腔进行了三维有限元数值模拟,研究了不同软硬的夹杂和空腔对地震动特性(包括峰值加速度和反应谱)的影响,分析了夹杂的软硬程度对地面运动的放大效应的影响。结果表明:空腔对地面运动以及地震动特性影响最大,软弱夹杂次之,硬质夹杂对地震波主要表现为一种强烈的屏障作用;软弱夹杂或空腔存在时,PGA、反应谱峰值都会变大,加速度反应谱峰值周期变小。

ANALYSIS OF THE GROUND MOTION BY SUBSURFACE THREE-DIMENSIONAL INCLUSION AND CAVITY UNDER INCIDENT PLANE SH-WAVE

The terrain effects on ground motion characteristics (such as the peak acceleration and acceleration response spectrum) is studied by the three-dimensional finite element numerical simulation about shallow buried soft or hard inclusion and cavity based on the method to solve the wave propagation problem of the combination of the explicit lumped mass finite element and transmission boundary,and the amplification of ground motion is also analyzed in different degrees of soft and hard inclusions.The results show that the cavity has the greatest influence on the ground motion and the ground motion characteristics,the soft inclusion is the second and the hard soft inclusion mainly shows a strong barrier effect to the earthquake wave;the value of PGA and the peak value of acceleration response spectrum increase and the peak response spectra period decrease when there are soft inclusions and cavity under the surface.