变截面渡线隧道暗挖关键施工技术  

Key Construction Technology of Tunnel Undercutting with Variable Section

作　　者：尉洪利 郑尚朋 李荐 YU Hongli;ZHENG Shangpeng;LI Jian(Haiwei Engineering Construction Co.,Ltd.of CCCC First Highway Engineering Group Co.,Ltd.,Beijing 101119,China)

机构地区：[1]中交一公局海威工程建设有限公司,北京101119

出　　处：《施工技术》2020年第23期96-101,共6页Construction Technology

摘　　要：变截面渡线隧道截面突然转换时常出现初支受力不稳定,造成施工坍塌、冒顶问题。为解决这一问题,在确定整体施工顺序由大桩号向小桩号施工基础上,确定7个开挖阶段6步施工顺序。左线施工在完成标准断面后,台阶法转换为CRD法,采用"反掏"施工方法,增设中隔壁、挑顶、扩挖,逐渐扩大断面实现渐变扩大段施工。过程中临时封堵开挖掌子面,注浆和拉锚加固楔形土体避免了土体失稳,明确了工法转换过程中支撑及拆撑的具体操作方式。本研究表明,采用该方法可解决变截面隧道断面转换问题,应用MIDAS软件对二次衬砌盘扣支架进行设计验算,减少了标准模板台车无法施工二衬问题。The sudden transformation of the cross section of the variable cross-section transit tunnel often leads to the instability of the initial support,which results in construction collapse and roof falling. In order to solve this problem,this paper determines the construction sequence of seven excavation stages and six steps on the basis of the overall construction sequence from large stations to small stations. The benching tunnelling method was transformed into the CRD method after completing the standard section in the left line construction.The reverse cut method was used to gradually expand the cross section to realize the construction by adding median lamella,propping and cave extension. In the process,the specific operation made clear support and dismantling temporary shoring,meanwhile the tunnel face was temporarily blocked,which avoided the instability of soil mass by grouting and anchor pulling to reinforce wedge soil.This study show that the problem of cross-section transformation could be solved by using this method.MIDAS software was used to design and calculate the second lining tray buckle bracket reducing the standard formwork failing to construct.

关 键 词：隧道工程 变截面 渡线 暗挖 施工技术 有限元分析 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]