分岔隧道过渡段施工结构稳定性分析  

Study on Structure Stability of Transition Segment of Bifurcation Tunnel during Construction

作　　者：刘晓勇[1] 胡强 LIU Xiaoyong;HU Qiang(Guizhou Transportation Planning Survey & Design Academe Co., Ltd., Guiyang 550081, China)

机构地区：[1]贵州省交通规划勘察设计研究院股份有限公司,贵阳550081

出　　处：《交通科技》2021年第3期98-103,共6页Transportation Science & Technology

摘　　要：为研究分岔隧道过渡段施工过程中的受力特性,以西南地区某山岭隧道为依托,通过三维有限元数值分析,研究在环形开挖预留核心土法(先行洞)及CD法(后行洞)组合施工情况下的分岔过渡段围岩形变规律和支护结构的力学特性,提出相应的处治建议。研究结果表明,相比后行洞CD法开挖,先行洞所采用的环形开挖预留核心土法对围岩扰动性较大,隧道左、右洞易出现差异沉降;极小净距段落的中夹岩柱厚度较薄,承载能力偏弱,施工过程中易出现净空收敛扩容现象;后行洞CD法在进行侧导洞临时支护拆除时易产生结构偏压荷载。To study the mechanical characteristics during the construction of the transition segment of the bifurcated tunnel,a three-dimensional model was established based on a mountain tunnel in the southwestern region,the finite element numerical analysis method is adopted to study the deformation law of the rock and the mechanical characteristics of supporting structure under the annular excavation reserved core soil method(the first tunnel)and CD method(the second tunnel),and the corresponding treatment construction suggestions were put forward.The results show that,compared with thesecond tunnel under the CD method,the first tunnel under the annular excavation reserved core soil method has greater disturbance to surrounding rock,and the tunnel are prone to differential settlement.The thickness of the rock between the first tunnel and the second tunnel is weak,and the clearance convergence expansion phenomenon is easy to occur in the construction process.When the temporary support of side pilot tunnel is demolished by the CD method,the unsymmetrical load of structure is easy to occur.

关 键 词：分岔隧道 差异沉降 支护结构 稳定性分析 

分 类 号：U455[建筑科学—桥梁与隧道工程]