垂直断层破碎带对Rayleigh波传播与场地地震动反应的影响

采用基于时域粘弹性人工边界的Rayleigh波输入方法，对具有不同宽度、不同剪切波速的垂直断层破碎带的场地进行了Rayleigh波作用下的动力时程反应分析，研究了垂直断层的宽度与剪切波速变化对Rayleigh波传播及场地地震动反应的影响。计算结果表明:在Rayleigh波入射一侧的中远场地表面，断层宽度与剪切波速的变化对地面峰值位移反应影响很小；在Rayleigh波入射一侧的断层角点以及距角点较近处，随着断层宽度的增大或剪切波速的减小，峰值位移反应均增大；在另一侧中远场地面的峰值位移反应随着断层宽度的增大或剪切波速的减小而减小，且水平位移峰值减小的程度略大于竖向位移峰值。由此可以看到，软弱的断层破碎带对通过的Rayleigh波有削弱作用，且破碎带越宽或剪切波速越小削弱作用越明显。

Effects of vertical fault fracture zones on the spreading of Rayleigh wave and ground motion

Dynamic time history analysis of ground motion with vertical fault fracture zones of different widths and shear wave velocities under Rayleigh wave was carried out by using the Rayleigh wave input method based on the viscous-spring artificial boundary. Influence of vertical fault fracture zones with various widths and shear wave velocities on the spreading of Rayleigh wave and ground motion was investigated. The results show variations of fault width and shear wave velocity have little effect in the mediate and far field on the incident side. Peak displacement response of the fault corner and the ground nearby on the incident side enlarges greatly with the increase of fault width or with the decrease of shear wave velocity of the fault. While in the mediate and far field on the other side, peak horizontal and vertical absolute displacements decrease gradually with the increase of fault width or with the decrease of shear wave velocity of the fault, and the horizontal displacement peak has a slighly decrease than that of vertical displacement peak. The results indicate the weak fault fracture zone weakens the Rayleigh wave and with the increase of fault width or with the decrease of shear wave velocity of the fault the weakening effect tends to be enhanced.