非连续群桩屏障对平面P、SV波的隔离效应:二维宽频带间接边界积分方程法模拟

发布时间：2018-04-05 06:07

本文选题：平面波　切入点：间接边界积分方程法(IBIEM)　出处：《岩土力学》2016年04期

【摘要】：采用一种高精度的间接边界积分方程法(IBIEM),对二维非连续群桩屏障对平面P、SV波的隔振效果进行宽频带计算分析。该方法基于单层位势理论,通过在非连续屏障交界面附近引入虚拟波源,分别用以构造散射体内、外散射场,继而由边界条件建立方程并求解得到虚拟波源密度,外部的总波场可由散射场和自由场叠加而得到。精度检验表明,该方法能够精确高效地求解任意排桩的宽频隔振问题。进而以圆柱实心桩为例,通过定量化频谱分析,揭示了P、SV波入射时排桩对不同频段弹性波的隔振差别,探讨了不同波速比、桩间距、桩排数对隔振效果的影响规律,研究结果表明:(1)隔振效果存在最优无量纲频段,宜优化设计桩径和桩间距以达到最佳效果;(2)场地土愈软,隔振效果愈佳。相比P波,SV波对于桩间距更为敏感;(3)低频波宜采用多排桩,但对高频波,采用三排以上的桩屏障对隔振效果的提升则不再显著。
[Abstract]:A high precision indirect boundary integral equation method is used to calculate and analyze the vibration isolation effect of two-dimensional discontinuous pile group barrier on planar Phane SV wave.Based on the theory of single layer potential, the virtual wave source is introduced near the interface of discontinuous barrier to construct the scattering field inside and outside, then the equation is established by the boundary condition and the density of the virtual wave source is obtained.The external total wave field can be obtained by the superposition of the scattering field and the free field.The accuracy test shows that the method can accurately and efficiently solve the wide-band vibration isolation problem of arbitrary piles.Then, taking solid cylindrical pile as an example, through quantitative spectrum analysis, the difference of vibration isolation between pile row and elastic wave in different frequency bands is revealed, and the influence law of different wave velocity ratio, pile spacing and pile row number on vibration isolation effect is discussed.The results show that there is an optimal dimensionless frequency band in the vibration isolation effect of 1: 1) and the optimum design of pile diameter and spacing is appropriate to achieve the optimum effect. The softer the soil is, the better the vibration isolation effect is.Compared with P wave, SV wave is more sensitive to pile spacing. Low frequency wave is more suitable for multi-row pile, but for high frequency wave, the improvement of vibration isolation effect by adopting more than three rows of pile barrier is not significant.
【作者单位】：天津城建大学土木工程学院;天津城建大学天津市土木建筑结构防护与加固重点实验室;
【基金】：国家自然科学基金项目(No.51278327) 天津市应用基础研究与前沿研究计划项目(No.14JCYBJC21900) 滨海土木工程结构与安全教育部重点实验室项目(No.2014-01)~~
【分类号】：TU473.1

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