非饱和土地基中复合多层波阻板对S波的隔离效应

Isolation effect of S-wave by composite multilayer wave impeding block in unsaturated soil

基于弹性波在非饱和多孔介质与单相弹性介质中的传播理论,考虑在非饱和土地基中设置一定厚度的复合多层波阻板(复合多层波阻板以3层为例),利用Helmholtz矢量分解定理,推导了非饱和土地基中S波通过复合多层波阻板的透射、反射振幅比的解析解。通过数值算例,分析了层间波阻板剪切模量和密度等物理力学参数对非饱和土地基中S波通过复合多层波阻板时传播特性的影响规律。结果表明:复合多层波阻板中层间波阻板材料的剪切模量和密度对透反射系数影响显著。复合多层波阻板是一种有效的隔振屏障,严格控制层间波阻板的剪切模量和密度可以获得最佳隔振效果,这为复合多层波阻板在地基振动控制领域中的应用提供理论指导。

Based on the propagation theory of elastic waves in unsaturated porous medium and single-phase elastic medium,considering that a composite multilayer wave impeding block(WIB)with a certain thickness is set in unsaturated soil(composite multilayer wave impeding block with three layers as an example),analytical solutions of transmitted/reflected amplitude ratio of S-wave passing through a composite multilayer wave impeding block in unsaturated soil foundation are derived by using Helmholtz vector decomposition theorem.The influences of physical and mechanical parameters such as shear modulus and density of interlayer wave impeding block on the propagation characteristics of S-wave passing through composite multilayer wave impeding block in unsaturated soil are analyzed by numerical examples.The results show that the shear modulus and the density of interlayer wave impeding block material have significant influences on the transmission/reflection coefficient.Therefore,the composite multilayer wave impeding block is an effective vibration isolation barrier,and a better vibration isolation performance can be obtained by strictly controlling the shear modulus and density of interlayer wave impeding block,which provides theoretical guidance for the application of composite multilayer wave impeding block in the field of foundation vibration control.