盾构隧道正交侧穿既有桥梁桩基临界安全距离研究  

Critical safe distance of shield tunnels crossing pile foundation of existing bridges at orthogonal side

作　　者：王超[1] 邹金锋[1] 舒丹 伍钦铧 WANG Chao;ZOU Jinfeng;SHU Dan;WU Qinhua(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《岩土工程学报》2025年第4期779-791,共13页Chinese Journal of Geotechnical Engineering

基　　金：南昌轨道交通集团2020年度科研计划项目(2020HGKYB002)。

摘　　要：为探究盾构隧道穿越既有桥梁桩基的安全施工距离,以正交侧穿施工为例,考虑桩基剪切效应的影响,利用Pasternak双参数地基模型,构建既有桥梁桩基与在建隧道中间土体水平位移的平衡微分方程,进而推导桩-隧中间土体的水平位移解析解。在此基础上,基于尖点突变理论确定桩-隧中间土体势函数的标准表达式及其系统突变失稳的充分必要条件,据此建立盾构隧道正交侧穿既有桥梁桩基临界安全距离计算方法,通过数值模拟和现场实测验证其工程适用性,并基于该方法分析盾构隧道正交侧穿既有桥梁桩基临界安全距离的主要影响因素。结果表明:临界安全距离与桥梁桩基桩径比之间近似为指数函数关系,且二者呈正相关;临界安全距离与盾构隧道深径比呈二次函数关系,随深径比增大,临界安全距离先增大后减小,且在盾构隧道深径比为8.1时达到最大值。理论值与数值模拟所得估测值拟合良好,且现场测量结果及相关规范也进一步验证了方法的工程适用性。本研究为类似隧道穿越工程设计和施工方案优化提供了理论依据。In order to investigate the safe construction distance of shield tunnel crossing the pile foundation of the existing bridges,taking the crossing construction at the orthogonal side as an example and considering the influences of the pile shear effects,we use the Pasternak two-parameter foundation model to establish the equilibrium differential equations for the horizontal displacements of the soil in the middle of the pile foundation of the existing bridges and the tunnels under construction,and the analytical solutions for the horizontal displacements of the pile-tunnel intermediate soil are derived.Based on the cusp catastrophe theory,the standard expression for the potential function of the pile-tunnel intermediate soil and the sufficient and necessary conditions for its system to be suddenly destabilized are determined.Accordingly,the method for calculating the critical safe distance of the pile foundation of the existing bridges is established,and its engineering applicability is verified through the numerical simulations and field measurements.The method is used to analyze the main influencing factors for the critical safe distance of the pile foundation of an existing bridge.The results show that the critical safe distance is approximately an exponential function with the diameter ratio of the pile foundation of the bridge,and the two parameters are positively correlated,while it follows a quadratic function of the shield tunnel depth ratio,and first increasing and then decreasing as the depth ratio increases,and reaches the maximum value when the depth ratio of the shield tunnel is 8.1.The theoretical values obtained by the proposed method and the estimated ones by the numerical simulation are well fitted,and the measured results and the relevant specifications also further verify the engineering applicability of this method.The proposed method provides theoretical guidance for the rational development of the design and construction program of similar tunnel crossing projects.

关 键 词：盾构隧道 既有桥梁 桩基 正交侧穿 桩-隧中间土体 尖点突变理论 临界安全距离 

分 类 号：TU473[建筑科学—结构工程] U455[建筑科学—土工工程]