松散岩堆体地层下隧道洞口段施工方法及合理进尺  

Construction Methods and Reasonable Advance Distance for Tunnel Portal Sections in Loose Rock Accumulation Stratum

作　　者：舒志勇 谭昌荣 李向宏 SHU Zhiyong;TAN Changrong;LI Xianghong(China Railway Tunnel Group Construction Co.Ltd.,Nanning 530001,China)

机构地区：[1]中铁隧道局集团建设有限公司,南宁530001

出　　处：《铁道建筑》2025年第3期87-92,共6页Railway Engineering

摘　　要：以洞口段穿越松散岩堆体地层的雅康高速公路日地1号隧道为依托工程,通过数值模拟了开挖过程,分析两台阶法、三台阶法、三台阶预留核心土法、三台阶七步开挖法4种工法下隧道洞口段围岩应力和变形特征,综合比选出最适宜隧道洞口段施工的工法,并给出了合理开挖进尺。结果表明:隧道洞口段开挖时掌子面前方拱顶和拱肩的变形最明显;4种工法中,三台阶预留核心土法对拱顶沉降和洞周收敛的效果较好,建议开挖进尺取1.2 m。基于数值模拟结果,依托工程采用了三台阶预留核心土法施工,开挖进尺为1.2 m。经现场监测,隧道变形控制良好。相关研究成果可为类似工程提供借鉴。The Ridi No.1 Tunnel,which traverses a loose rock accumulation stratum at the portal section,serves as the supporting project.By numerically simulating the excavation process,the stress and deformation characteristics of the surrounding rock at the portal section under four construction methods were analyzed,including that the two-bench method,the three-bench method,the three-bench method with reserved core soil,and the three-bench seven-step excavation method.The most suitable construction method for the tunnel portal section was comprehensively selected,and a reasonable excavation advance was proposed.The results show that,the deformation of the surrounding rock and arch shoulder in front of the tunnel face is most obvious during the excavation of the loose rock accumulation stratum at the portal section.Among the four methods,the three-bench method with reserved core soil method has a better control effect on the settlement of the vault and the convergence around the tunnel,with a recommended excavation advance of 1.2 m.Based on the numerical simulation results,the supporting project adopted the three-bench method with reserved core soil and an advance of 1.2 m.Field monitoring showed that the tunnel deformation was well controlled.The relevant research findings can provide valuable references for similar projects.

关 键 词：公路隧道 松散岩堆体地层 施工方法 数值模拟 围岩变形 三台阶预留核心土法 开挖进尺 初期支护应力 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]