屏障隔振系统失效机理的探讨

屏障隔振是一种用来阻碍或改变外围振波向受保护区(屏蔽区)传播的工程方法，由于其机理的探讨尚不深入，工程实践中常出现隔振系统失效的现象．本假设屏障是埋入土介质的中厚弹性板，采用薄层法分析了该弹性板在振波作用下的振动响应和屏蔽区内位移变化规律；研究了影响屏障隔振效果的主要参量；发现了使屏障隔振效率降低甚至失效的入射波全透射现象．结果表明柔性屏障易发生波的全透射，并指出了避免屏障失效的措施．

RESEARCH ON THE FAILURE MECHANISM OF BARRIER FOR ISOLATING VIBRATION

Ground barrier sy stem for isolating vibration is a geotechnical engineering method used to impede or change wave propagating into protected zone. Because limited research on mechanism of the barrier, the failures of the barrier occur sometime in prectice. In this paper the theoretical analysis of soil and barrier system for isolating vibration is presented, in which the barrier is assumed to be an elastic plate of medium thickness embedded in elastic soil; and the thin layer method (TLM) is employed to examine dynamic response of the plate and ground vibration in protected zone under an incident wave. Some key parameters that influence the effect of barrier for isolating vibration are analyzed. A phenomenon of the wave completely thransmiting through the barrier and causing failur of the barrier is found, and a circular frequency of the complete wave transmission is defined to explain this phenomenon. The theoretical result shows that the complete wave transmission occurs more easily in flexible barrier system than in rigid one. At the end the recommendation for improving barrier design to avoid failure is presented.