摘要
新建顶管上穿施工会引起下方既有盾构隧道纵向隆起位移,影响地铁的正常运行。大直径顶管在注浆充足或在地下水位以下顶进时上浮效应不可忽略,而目前的简化分析方法尚未考虑此效应。采用两阶段法,将既有隧道视为Pasternak地基上的Euler-Bernoulli梁,提出考虑上浮影响的土体非均匀收敛模式下,新建顶管上穿施工引起下方既有隧道响应的简化计算方法。研究表明,均匀土体收敛模式、下沉的非均匀土体收敛模式会低估顶管下方的土体自由位移、既有隧道的纵向位移响应,与工程实测数据的对比验证了所提方法的合理性。进一步参数分析表明,降低土体损失率能有效减少既有隧道竖向位移与弯矩,且土体损失率与既有隧道最大竖向位移和最大弯矩呈线性关系;既有隧道与土体的管土刚度比的增大可减小既有隧道竖向位移,但也会增大隧道管片弯矩;增大顶管与既有隧道竖向净距有利于既有隧道竖向位移与弯矩的控制,实际工程应根据既有隧道的保护要求和顶管的上覆土厚度要求选择合理的净距。
The construction of the new pipe jacking will cause the longitudinal uplift displacement of the existing shield tunnel below,affecting the normal operation of the subway.However,the current simplified analysis methods have not yet considered the significant floating effect that occurs during large-diameter pipe jacking with sufficient grouting or jacking under groundwater level.This study proposed a simplified calculation method,utilizing the two-stage method and treating the existing tunnel as an Euler-Bernoulli beam on the Pasternak foundation,to assess the impact of new pipe jacking on the response of the underlying existing tunnel.The calculation method considered the floating effect and accounted for the non-uniform convergence mode of soil.It is shown that both the uniform soil convergence mode and the non-uniform soil convergence mode of pipe tunnel sinking will underestimate the free displacement of the soil under the new pipe jacking and the longitudinal displacement response of the existing tunnel below.The rationality of the proposed method was verified by the measured data.Additional parametric analysis reveals that decreasing the ground loss rate can effectively reduce the vertical displacement and bending moment of the existing tunnel.Moreover,increasing the pipe-soil stiffness ratio between the existing tunnel and the soil reduces the vertical displacement of the existing tunnel but increases the bending moment of the tunnel segment.Furthermore,increasing the vertical clear distance between the pipe jacking and the existing tunnel is conducive to the control of the vertical displacement and bending moment of the existing tunnel.
作者
姚言
王奎华
应宏伟
朱成伟
张昌桔
李冰河
YAO Yan;WANG Kui-hua;YING Hong-wei;ZHU Cheng-wei;ZHANG Chang-ju;LI Bing-he(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,Zhejiang,China;Key Laboratory of Ministry of Educational for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210024,Jiangsu,China;Hangzhou Municipal Engineering Group Co.,Ltd.,Hangzhou 310014,Zhejiang,China;Zhejiang Province Institute of Architectural Design and Research,Hangzhou 310005,Zhejiang,China)
出处
《地基处理》
2024年第2期116-124,共9页
Journal of Ground Improvement
基金
国家自然科学基金项目(51678523)
浙江省建设科研项目(2018K_(0)25)
杭州市建设科研项目(2018027)。
关键词
新建顶管
上浮效应
土体收敛
上穿施工
既有隧道隆起
两阶段法
new pipe jacking excavation
floating effect
soil convergence
above-crossing tunnelling
existing tunnels uplift
two-stage method
