饱和地基水泥土复合桩近场主动隔振的BEM-FEM耦合分析  

BEM-FEM coupled analysis of near-field active vibration isolation of SDCM piles on saturated foundation

作　　者：时刚[1] 郜新军[1] 张浩[1] SHI Gang;GAO Xinjun;ZHANG Hao(School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学土木工程学院,郑州450001

出　　处：《振动与冲击》2024年第1期252-264,282,共14页Journal of Vibration and Shock

基　　金：国家自然科学基金面上项目(52078469)。

摘　　要：人工振动污染是当前城市发展过程中面临的一个难题,单排或多排桩是人工振动污染防治的一种重要方式。传统基桩施工容易造成泥浆污染、振动等各种负面环境问题,而水泥土复合桩是一种低振动、低噪声、无挤土、少排泥浆的新型基桩,特别适合在城区构建排桩屏障。针对饱和地基中单排水泥土复合桩的近场主动隔振问题,建立了动力机器基础环境振动影响的半解析BEM方程;在此基础上,分别采用半解析BEM对饱和地基、FEM对水泥土复合桩进行建模,根据饱和地基-水泥土桩接触面的平衡和相容条件,建立了水泥土复合桩近场主动隔振的半解析BEM-FEM耦合方程,给出了耦合方程稀疏矩阵的存储策略,并对单排水泥土复合桩的近场主动隔振效果进行了计算分析。研究结果表明:单排水泥土复合桩能够有效地对动力机器基础引起环境振动进行隔振;等长芯桩复合桩的隔振效果要优于短芯桩。单排水泥土复合桩的隔振效果随着桩数的增加而逐渐提高;较小桩间距并不一定取得更好的隔振效果,建议相邻桩桩间净距取2.0~2.5λ_(R)(Rayleigh波波长)。随着单排水泥土复合桩距振源距离的增加,屏障隔振效果逐渐降低,但降低幅度相对较小。此外,对水泥土复合桩而言,当内插预制桩的外轮廓尺寸相同时,预制芯桩型式对水泥土复合桩隔振效果影响相对较小,可根据实际工程条件选择合适的芯桩类型。Artificial vibration pollution is a challenge faced in the current urban development process,and single or multiple row of piles are important way to prevent or control artificial vibration pollution.Traditional pile construction can easily cause various negative environmental problems of mud pollution and vibration,while stiffed deep cement mixing(SDCM)pile is a new type of pile with low vibration,low noise,no soil squeezing and less mud discharge,especially,suitable for building pile barriers in urban areas.Here,aiming at near-field active vibration isolation problem by using single row of SDCM piles on saturated foundation,a semi-analytical BEM equation for effects of environmental vibration due to dynamic machine foundation was firstly established.Then,semi-analytical BEM was used to model saturated foundation and FEM was used to model SDCM piles.Based on equilibrium and compatibility conditions of contact surface between saturated foundation and SDCM piles,a semi-analytical BEM-FEM coupled equation for near-field active vibration isolation of SDCM piles was established.The storage strategy for sparse matrix of the coupled equation was given,and the near-field active vibration isolation effect of single row of SDCM piles was calculated and analyzed.The study results showed that single row of SDCM piles can effectively isolate environmental vibration caused by dynamic machine foundations;the vibration isolation effect of composite piles with equal length core piles is better than that of composite piles with short core piles;the vibration isolation effect of single row of SDCM piles gradually increases with increase in number of piles;smaller pile spacing may not necessarily achieve better vibration isolation effect,it is recommended to take 2.0-2.5λ_(R) which is Rayleigh wave length as a clear spacing between adjacent piles;with increase in the distance between single row of SDCM piles and vibration source,the vibration isolation effect of barrier gradually decreases but this decrease is relatively smaller;f

关 键 词：饱和地基 水泥土复合桩 近场主动隔振 隔振效果 半解析BEM-FEM 

分 类 号：TU435[建筑科学—岩土工程]