地震作用下抗液化碎石桩参数研究  

Parametric Analysis of Anti-liquefaction Gravel Pile in the Earthquake

作　　者：金鑫 黄鹏飞 陈必光[3] 拓勇飞[3] 肖黎[1] JIN Xin;HUANG Peng-fei;CHEN Bi-guang;TUO Yong-fei;XIAO Li(School of Civil Engineering, Wuhan University, Wuhan 430000,China;College of Civil Engineering, Tongji University, Shanghai 2000822,China;CCCC Second Highway Exploration and Design Institute Co. Ltd., Wuhan 430056,China)

机构地区：[1]武汉大学土木建筑工程学院,武汉430072 [2]同济大学土木工程学院,上海200082 [3]中交第二公路勘察设计研究院有限公司,武汉430056

出　　处：《中国农村水利水电》2020年第9期196-201,共6页China Rural Water and Hydropower

基　　金：孟加拉国吉大港出海口大直径水下盾构隧道建设关键技术研究(KJFZ-2017-071)。

摘　　要：孟加拉卡纳普里河底隧道工程存在地层条件复杂、地震液化程度高等特点,为确保工程安全,该项目采用了碎石桩复合地基加固处理方案。但目前对此工程中碎石桩的重要设计参数如桩径、桩间距的选取,以及模量的确定等没有理论依据,需结合该工程进行充分的研究,论证本工程项目中碎石桩复合地基加固处理方案的可靠性。利用FLAC3D软件建立了原状土地基模型、碎石桩单桩地基和碎石桩群桩加固复合地基数值分析模型,研究了单桩模型中桩径对碎石桩抗液化效果的影响以及群桩模型中桩体模量对碎石桩的抗液化效果的影响。研究结果表明:随着桩径的增大,场地土达到相同抗液化处理效果时,碎石桩单位截面面积处理的砂土范围减小;随着桩体模量的不同,复合地基的超孔压比震后值变化不大;通过碎石桩的施工,各埋深处的超孔压比在达到峰值之后迅速大幅下降,场地液化程度显著降低,体现了碎石桩显著的抗液化效果。研究成果为孟加拉隧道项目的地震液化处置提供了较为充分的理论支撑,也可为类似工程提供参考。Bangladesh's Kanapuri River Tunnel Project has the characteristics of complex stratum conditions and high degree of seismic liquefaction.In order to ensure the safety of the project,the project adopts gravel pile composite foundation reinforcement treatment scheme.However,there is no theoretical basis for the important parameters of gravel pile in this project,such as the selection of pile diameter,pile spacing,and the determination of modulus.It is necessary to conduct a full study in combination with the project to demonstrate the reliability of the foundation disposal measures in this project.In this paper,numerical analysis models of undisturbed soil foundation,single gravel pile foundation and composite foundation reinforced by gravel pile groups are established by using FLAC3D software.The influence of pile diameter on liquefaction resistance of gravel piles in single pile model and pile modulus on liquefaction resistance of gravel piles in pile group model are studied.The results show that with the increase in pile diameters,the foundation area treated by a unit of cross section area of gravel pile decrease when the site soil achieves the same anti-liquefaction treatment effect.With the difference in pile modulus,the excess pore pressure ratio of composite foundation changes little after an earthquake.Through the construction of a gravel pile,the excess pore pressure ratio of buried depth rapidly and substantially increases after reaching the peak value.The degree of liquefaction of gravel piles decreases significantly,reflecting the remarkable anti-liquefaction effect of gravel piles.The research results provide a sufficient theoretical support for seismic liquefaction disposal of Bangladesh Tunnel Project,and can also provide a reference for similar projects.

关 键 词：砂土液化 碎石桩加固 超孔压比 数值模拟 

分 类 号：TV6[水利工程—水利水电工程] TU435[建筑科学—岩土工程]