盾构下穿引起的既有隧道沉降变形研究  

Study of Settlement Deformation of Existing Tunnels Due to Tunnel Down⁃Crossing

作　　者：王理想 刘四进 王军 段其广 WANG Lixiang;LIU Sijin;WANG Jun;DUAN Qiguang(China Railway 14th Bureau Group Co.,Ltd.,Jinan 250101,Shandong,China;Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China)

机构地区：[1]中铁十四局集团有限公司,山东济南250101 [2]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《力学季刊》2024年第3期855-866,共12页Chinese Quarterly of Mechanics

基　　金：中铁十四局集团有限公司科技研发计划项目(913700001630559891202106);国家重点研发计划(2023YFC3806703)。

摘　　要：新建盾构隧道下穿会对既有隧道周围土体产生扰动,导致既有隧道产生较大的沉降变形.针对该工况,基于两阶段分析法,提出一种理论解析方法,以预测新建盾构隧道下穿引起的既有隧道的沉降变形.利用简化的随机介质理论,求解新建隧道开挖引起的土体自由沉降,并将该沉降施加于既有隧道之上.将既有隧道简化为Timoshenko梁模型,利用Vlazov地基模型模拟隧道-土的相互作用,构建盾构下穿作用下既有隧道的沉降变形微分方程.利用有限差分法对沉降变形微分方程进行求解,得到既有隧道在盾构下穿作用下产生的沉降变形解答.结合两个工程案例,将理论解析结果与实测数据进行对比,验证了所提出的理论解析方法的合理性.对影响既有隧道沉降变形的三个关键参数进行分析,结果表明:既有隧道最大沉降与地层损失率之间呈线性关系,地层损失率越大沉降也越大;随着隧道夹角的减小,既有隧道的变形范围显著增大;增大新旧隧道轴线距离,能够显著减小隧道沉降.New shield tunnel down-crossing inevitably disturbs the surrounding soil and leads to significant settlement deformation of the existing tunnels.Based on the two-stage method,this paper proposed a new analytical method to predict the settlement deformation of existing tunnels due to down-crossing construction of new shield tunnel.The tunneling-induced soil settlement was predicted by the simplified stochastic medium theory,and was then imposed on the existing tunnel.The existing tunnel is simplified as a Timoshenko beam model,and the Vlazov foundation model was adopted to consider the interaction between the tunnel and the soil.The differential equation of settlement deformation of the existing tunnel was established,and solved by the finite difference method.The solution of settlement deformation of the existing tunnel under the new tunnel downcrossing was obtained.The proposed analytical method was validated through comparison with the field measurement data from two case studies.A parametric analysis was conducted to study the influences of three key parameters on the existing tunnel deformation.The results indicate that the maximum settlement of the existing tunnel increases approximately linearly with the volume loss.As the skew angle between tunnels decreases,the deformation range of existing tunnels significantly increases.Increasing the distance between the axes of the new and old tunnels can significantly reduce the tunnel settlement.

关 键 词：盾构隧道 沉降变形 简化随机介质理论 Timoshenko梁隧道模型 隧道开挖 

分 类 号：U45[建筑科学—桥梁与隧道工程]