黄土区毗邻风道初期支护结构PBA洞群暗挖施工安全控制研究  

Research on Safety Control of the Concealed Excavation Construction for PBA Tunnel Group Adjacent to the Air-duct’s Primary Support Structure in Loess Area

作　　者：张华 商学旋 雷奇 席宇 刘义 杨焜 李伟 ZHANG Hua;SHANG Xuexuan;LEI Qi;XI Yu;LIU Yi;YANG Kun;LI Wei(Shaanxi Construction Engineering Group Co.,Ltd.,Xi’an,Shaanxi 710003,China;Shaanxi Architecture Science Research Institute Co.,Ltd.,Xi’an,Shaanxi 710082,China)

机构地区：[1]陕西建工集团股份有限公司,陕西西安710003 [2]陕西省建筑科学研究院有限公司,陕西西安710082

出　　处：《施工技术（中英文）》2022年第21期44-49,共6页Construction Technology

基　　金：陕西省科学技术厅重点研发计划项目(2021SF-459);陕西建工集团股份有限公司科研项目(SJKT-2020-11);陕西省建筑科学研究院有限公司科研项目(2021h-13-379)。

摘　　要：西安地铁2号线何家营车站采用PBA洞桩法暗挖施工,存在工序转换频繁、工期紧、洞群与风道等多种空间交叉结构施工作业等特点,潜在风险较大。基于前期变形监测验证的三维有限元力学计算模型,考虑竖井、风道施工路径效应,开展黄土区毗邻风道初期支护结构PBA洞群暗挖施工安全控制研究。研究结果表明,洞群施工诱发风道初期支护结构弯矩增量较小、轴力增量较大;自下1-C导洞施工至风道阶段开始,风道格栅拱架-喷射混凝土支护结构安全系数已不满足规范限值要求;风道格栅拱架-喷射混凝土支护结构及地表最大变形值均满足监测控制要求。为确保洞群安全施工,建议下1-C、下2-C、上2、上3导洞施工安全距离控制在距风道初期支护结构10.0m,并进行掌子面封堵,待风道二次衬砌施作后可贯通施工,其余导洞可先行施工至风道。The Hejiaying station of Xi’an Subway Line 2 adopted the PBA method for the concealed excavation construction, which has the characteristics of frequent process conversion, tight construction period, and construction of multiple spatial-crossing structures such as the tunnel group and the air-duct, with high potential risks. Based on the three-dimensional finite element mechanics calculation model verified by deformation monitoring, the safety control study of the concealed excavation construction of the PBA tunnel group adjacent to the air-duct’s primary support structure in the loess area was carried out by considering the path effect of the shaft and the air-duct. The results show that the bending moment increment of the air-duct’s primary support structure is small and the axial force increment is large influenced by the tunnel group’s construction. With the beginning of the construction stage of the lower 1-C pilot tunnel to the air-duct, the structural safety factor of lattice girder reinforced shotcrete support is less than the specification limit. The maximum deformation value of the lattice girder reinforced shotcrete support and the ground surface meets the requirements of monitoring and control standards. In order to ensure the PBA tunnel group construct safely, it is recommended that the construction safety distance of the lower 1-C, lower 2-C, upper 2 and upper 3 pilot tunnels should be controlled at a position 10.0 m away from the air-duct’s primary support structure, and the tunnels’ face should be blocked, the tunnels can be penetrated for construction after the air-duct’s second lining is constructed, the remaining pilot tunnels can be constructed to the air-duct first.

关 键 词：地铁 隧道 空间交叉结构 路径效应 PBA洞群 初期支护 安全控制 

分 类 号：U231[交通运输工程—道路与铁道工程]