非连续屏障对Rayleigh波宽频散射三维快速边界元模拟

3-D simulation for broadband scattering of Rayleigh wave by discontinuous barrier based on FMP-IBEM

基于单层位势理论,将快速多极子-间接边界元方法(FMM-IBEM)拓展到弹性半空间群桩对弹性波的宽频散射求解,进而研究了Rayleigh波入射下多排桩屏障体系的隔振效果。数值试验表明该方法能够大幅度降低常规IBEM计算所需的存储量和计算量。针对典型算例,讨论了单排桩净距、排桩桩长、场地波速、排桩排数及多排桩之间净距对Rayleigh波的屏障效应。结果分析表明:排桩排数是影响多排桩隔振效果的主要因素,而多排桩之间的排距对隔振效果影响较小;桩间净距和桩长是影响单排桩隔振效果的重要参数,桩距在0.1倍~0.3倍Rayleigh波波长,桩长大于1倍波长时即可取得较好的隔振效果;对于不同的场地,场地土越软,排桩隔振效果越好。对低频波隔振宜采用多排桩进行隔振。

Here,based on the single-layer potential theory,the fast multi-pole indirect boundary element method(FMP-IBEM)was extended to solve broadband scattering of elastic wave by group of piles in an elastic half-space.Then,vibration isolation effect of multi-row piles barrier on incident Rayleigh wave was investigated.Numerical simulation showed that this method can greatly reduce storage amount and computational one of conventional IBEM calculation.A typical example was given to discuss barrier effects of single row piles’spacing,pile length,site wave velocity,row number of multi-row piles and spacing between rows on Rayleigh wave.The results showed that the row number of multi-row piles is the main factor affecting vibration isolation effect of multi-row piles,while the spacing between rows of multi-row piles has smaller effect on their vibration isolation effect;the spacing between piles and pile length are important parameters affecting vibration isolation effect of single-row piles;if the pile spacing is 0.1-0.3 times of the wavelength of Rayleigh wave and the pile length is larger than one wavelength,good vibration isolation effect can be obtained;for different sites,the softer the site soil,the better the vibration isolation effect of row piles;multi-row piles barrier is suitable for vibration isolation of low-frequency wave.