高速铁路CFG桩-土复合地基减振性能研究  

Investigation on vibration mitigation performance of CFG pile reinforced subgrade for high-speed railway

作　　者：高广运[1,2] 张继严 毕俊伟 GAO Guangyun;ZHANG Jiyan;BI Junwei(College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Shanghai 200092,China;School of Civil Engineering&Transportation,South China University of Technology,Guangzhou 510641,China;Institute of Geotechnical and Underground Engineering,Guangzhou Design Institute Group Co.Ltd.,Guangzhou 510620,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]华南理工大学土木与交通学院,广东广州510641 [4]广州市设计院集团有限公司岩土与地下空间院,广东广州510620

出　　处：《中南大学学报（自然科学版）》2023年第6期2209-2219,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51978510,42277130)。

摘　　要：为系统研究高铁运行引起的CFG桩-土复合地基环境振动特性及其自身减振性能,首先基于2.5维有限元计算理论,利用等代桩墙对CFG桩-土复合地基进行等效,建立轨道-路堤-CFG桩-土复合地基系统的2.5维有限元模型;其次,与高速铁路环境振动既有实测研究成果进行对比,验证所建模型的正确性;最后,考虑高速列车的不同运行速度,以竖向振动加速度为评价指标,分析桩径、桩间距和桩体刚度对CFG桩-土复合地基减振性能的影响。研究结果表明:相较于无桩地基,CFG桩-土复合地基对高速列车运行引起的地面环境振动具有良好的减振效果,距轨道较远处减振效果优于轨道近处减振效果;距轨道较近处,CFG桩-土复合地基的减振效果由列车运行速度和共振条件共同主导;增大桩径d、增大桩体刚度或减小桩间距s均能提高CFG桩-土复合地基的减振效果。然而,当桩径d≥1/4s或桩间距s≤4d或桩土刚度比R_(PS)≥138.9时,继续改变CFG桩设计参数将难以进一步显著提高减振效果。CFG桩-土复合地基可提高地基的临界速度,当车速接近该临界速度时减振效果较差。For investigating ground vibrations and mitigation performance of the CFG pile-soil composite subgrade under high-speed train loading,firstly,based on the 2.5-dimensional finite element method(2.5D FEM)and equivalent pile walls approach,the 2.5D FE model for track-embankment-CFG pile-soil composite subgrade system was established.Secondly,the reliability of the model was validated by comparing with the field measurements.Finally,by taking the vertical vibration acceleration as a primary indicator and considering various vehicle speeds,the influence of CFG pile design parameters on vibration mitigation performance was investigated by comparing the ground vibration at different pile diameters,pile spacing,and pile stiffness.The results show that,compared with the unreinforced subgrade,the CFG pile-reinforced subgrade exhibits favorable vibration mitigation performance,and this performance is better at a distance from the track than near it.In the near track zone,the vibration mitigation performance depends on both the vehicle speed and resonance conditions.The vibration mitigation performance increases with the increase of pile diameter or the increase of pile stiffness or the decrease of pile spacing.However,it is hard to further improve the vibration mitigation performance when d(pile stiffness)≥1/4s(pile diameter),or s≤4d,or RPS(pile-to-soil stiffness ratio)≥138.9.The CFG pile-reinforced subgrade increases the critical speed,and the vibration mitigation performance deteriorates when the train runs at the critical speed.

关 键 词：高速铁路 2.5维有限元法 CFG桩-土复合地基 竖向振动加速度 减振性能 

分 类 号：TU435[建筑科学—岩土工程]