群桩加固可液化地基的地震响应特性研究  

Study on seismic response of a liquefiable foundation reinforced by group piles

作　　者：林宇亮[1,2] 李澳华 邢浩 李丽华 宋宣儒 杨果林 LIN Yuliang;LI Aohua;XING Hao;LI Lihua;SONG Xuanru;YANG Guolin(School of Civil Engineering,Central South University,Changsha 410075,China;China Railway Group Limited,Beijing 100039,China;The Fourth Engineering Co.Ltd.,the Seventh Bureau Group of China Railway,Wuhan 430074,China;School of Civil Engineering Architecture and Environment,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中国中铁股份有限公司,北京100039 [3]中铁七局集团第四工程有限公司,湖北武汉430074 [4]湖北工业大学土木建筑与环境学院,湖北武汉430068

出　　处：《中南大学学报(自然科学版)》2025年第1期123-137,共15页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51878667,51678571);湖南省自然科学基金资助项目(2021JJ30830)。

摘　　要：可液化场地高速铁路路基通常采用群桩加固地基+加筋路堤的结构形式,而地基液化往往是导致路基结构丧失服役性能的主要因素,揭示可液化场地群桩加固地基的地震响应特性是保障高速铁路路基安全运行的重要内容。本文以某可液化场地高速铁路群桩加固地基+加筋路堤为研究对象,通过振动台试验和三维数值仿真手段实现不同强度的地震动激励工况模拟,得到可液化地基超孔隙水压力和桩身应变;将振动台试验结果与数值模拟结果进行对比和验证,研究地震动激励下群桩加固可液化地基的孔隙水压力、超孔压比、桩身内力的变化规律,分析地震动强度对群桩加固地基地震响应的影响,得到不同地震动持时下群桩加固地基的液化区域发展规律。研究结果表明:在不同强度的地震激励下,孔隙水压力和超孔压比响应随输入地震动加速度峰值增加而增加,但增幅随地震动加速度峰值减小;孔隙水压力和超孔压比沿地基深度增大呈现出减小的趋势,地基土液化区深度逐渐加大;地基液化主要发生在地震动激励强烈的时段;当地震结束时,大部分地基土体单元从液化状态转变为非液化状态;在高强度地震动激励下,加固桩的桩身弯矩变化显著,但桩身内力分布合理,其值在允许范围内,桩身不会遭到破坏。可将群桩加固地基方案应用于可液化场地。The structural form of group-pile foundationcombining reinforced embankment is often adopted for high-speed railway subgrade in liquefiable site.Commonly,the foundation liquefaction is a main factor leading to the loss of service performance of subgrade structure.It is an important aspect to reveal the seismic response characteristics of group-pile reinforced foundation in order to ensure the safety of high-speed railway subgrade.The group pile foundation combining reinforced embankment of a high-speed railway in a liquefiable site was taken as the research object.The excitations of seismic ground motion with different intensities were simulated by means of shaking table test and three-dimensional numerical simulation,to obtain the excess pore water pressure in the liquefiable foundation,and strain of pile body were monitored.By comparing and verifying the results of numerical simulation and shaking table test,the variation rules of pore water pressure,excess pore pressure ratio and pile internal stress under seismic excitation were investigated.The effect of intensity of seismic ground motion on the seismic response of group-pile reinforced foundation was analyzed.The development of liquefaction area in the group-pile reinforced foundation was obtained subjected to seismic motion with different durations.The results show that,the pore water pressure and excess pore water pressure ratio increase with the increase of the peak acceleration of input seismic ground motion regardless of intensity of seismic excitation.Nevertheless,the increasing amplitude of those responses decreases when the peak acceleration of seismic ground motion increases.The pore water pressure and excess pore water pressure ratio tend to decrease along the depth of subgrade,and the liquefaction area of subgrade grows gradually.The liquefaction mainly occures during the intensive period of seismic excitation,and most of the foundation soil elements change from the liquefied state to the non-liquefied state at the end of earthquake.The bending m

关 键 词：可液化场地 群桩 地基 振动台试验 数值模拟 液化区分布 

分 类 号：TU435[建筑科学—岩土工程]