复合地层大直径盾构隧道侧穿既有桩基扰动影响研究  

Research on the disturbance effects of large-diameter shield tunneling side-crossing on existing pile foundations in composite strata

作　　者：刘德军 乔可可 商奇 左建平[1,2] 段抗[3] 董海洋 张成瑞 LIU Dejun;QIAO Keke;SHANG Qi;ZUO Jianping;DUAN Kang;DONG Haiyang;ZHANG Chengrui(School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 10oo83,China;National Key Laboratory for Disaster Prevention,Control,and Intelligent Construction and Maintenance of Tunnel Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;School of Civil Engineering,Shandong University,Jinan,Shandong 25006l,China)

机构地区：[1]中国矿业大学(北京)力学与土木工程学院,北京100083 [2]中国矿业大学(北京)隧道工程灾变防控与智能建养全国重点实验室,北京100083 [3]山东大学土建与水利学院,山东济南250061

出　　处：《中国矿业大学学报》2024年第6期1144-1156,共13页Journal of China University of Mining & Technology

基　　金：国家重点研发计划项目(2023YFB2390300);国家自然科学基金项目(52478423);中央高校基本科研业务费专项资金资助项目(2024ZKPYLJ03)。

摘　　要：城市隧道直径呈现大型化发展趋势,施工过程中不可避免地要在复合地层中侧穿各种类型建筑的桩基础.现有理论多集中于均质地层小直径隧道,有关复合地层大直径盾构隧道侧穿对既有桩基扰动影响的考虑较少.为此,考虑大直径盾构的特点,基于圆孔收缩理论将均质地层中隧道开挖引起的土体位移分为弹性阶段和弹塑性阶段,并考虑到计算点的连续性变化,推导了大直径盾构隧道开挖引起土体的应力、位移及塑性区半径的计算公式.进一步,将复合地层模型等效为均质地层模型与地层分层造成的附加界面力的共同作用,基于两阶段分析法,提出了复合地层中隧道开挖引起桩基水平位移和弯矩的计算方法.采用数值模拟反演,给出了附加界面应力的求解公式.通过与既有方法和数值结果的对比分析,验证了提出方法的合理性.最后将该方法应用到春风隧道工程中,分析了地层分界面位置对隧道侧穿既有桩基变形和内力的影响规律.结果表明:本文提出的方法能够考虑地层的分层效应,可以有效体现由于岩性改变而造成的位移变化;软中硬复合地层中,隧道变形量与分界面的位置有较大关系,桩基水平位移在分界面处呈现先减小后增大的趋势,桩基弯矩在分界面附近发生弯矩反向,且最大弯矩出现在软弱岩层中.本文为研究复合地层大直径隧道侧穿既有桩基的扰动影响提供了借鉴.The construction of urban tunnels is trending towards larger diameters,making it inevitable for tunnels to laterally pass through the pile foundations of various building types in composite strata.However,most existing theories focus on small-diameter tunnels in homogeneous strata,with limited attention given to the disturbance effects of large-diameter shield tunnels passing through pile foundations in composite strata.To address this gap,we consider the characteristics of large-diameter shields and divide the soil displacement caused by tunnel excavation in homogeneous strata into elastic and elastoplastic stages,based on the theory of circular hole contraction.We then derive formulas for calculating the stress,displacement,and radius of the plastic zone induced by large-diameter shield tunnel excavation,accounting for the continuous variation of calculation points.Additionally,the composite stratum model is treated as the combined effect of a homogeneous stratum model and the additional interface forces generated by stratigraphic layering.Using a two-stage analysis method,we propose a calculation method for the horizontal displacement and bending moment of pile foundations induced by tunnel excavation in composite strata.Numerical simulation inversion provides a formula for determining the additional interface stresses.The validity of the proposed method is confirmed through a comparison of existing methods and numerical results.Finally,this method is applied to the Chunfeng Tunnel project,where the influence of the stratum interface position on the deformation and internal forces of pile foundations during tunnel passage is analyzed.The results demonstrate that the proposed method effectively accounts for stratigraphic layering and accurately reflects displacement changes due to lithological variations;in soft-medium-hard composite strata,tunnel deformation is significantly influenced by the position of the interface.

关 键 词：大直径盾构 附加界面力 桩基 复合地层 位移 弯矩 

分 类 号：TU398.9[建筑科学—结构工程]