饱和地基中二维空沟远场被动隔振研究

Two-dimensional analysis of open trench used as passive barriers in saturated soil

针对饱和地基中二维空沟远场被动隔振问题,首先,基于饱和多孔介质频域边界单元法,建立了以薄层法(TLM)基本解作为动力Green函数的饱和土半解析边界元法,该方法可有效分析饱和半空间的动力问题,是解决土-结构动力相互作用问题的一种有效工具。在此基础上,推导得到了空沟对Rayleigh波散射的二维边界元方程,对空沟的远场隔振问题进行了详细的参数分析。结果表明:设置空沟能够对地面振动起到较好的隔振作用;当空沟深度小于1个Rayleigh波波长时,提高空沟深度能够有效的提高其隔振效果;而空沟宽度对隔振效果的影响相对较小;饱和地基参数改变对空沟隔振效果影响不大。

The ground vibration isolation efficiency of open trench used as passive barriers in homogeneous saturated ground was studied.The investigation was accomplished with the aid of the semi-analytical boundary element method（BEM） in cooperation with the basic solution of the thin layered method（TLM）.Consequently,a two-dimensional（2D） semi-analytical BEM model was put forward,where the TLM basic solution was employed,to examine the performance of open trench used as passive vibration isolation device taking into account the dynamical interaction of soil-structure.Effects of the model parameters on effectiveness of vibration isolation by open trench were investigated and discussed in detail.The results show that open trenches are efficient to isolate the ground vibrations due to the incident Rayleigh wave.When the depth of the open trench is less than the Rayleigh wavelength,increasing the depth results in an increase in the screening effectiveness,while the width has less effect on vibration isolation efficiency.Furthermore,the parameters of saturated soil,as well as the drainage boundary conditions of half-space,have less effect on the screening effectiveness.