砂卵石地层浅埋地铁车站暗挖施工关键技术  

Key Technologies for Underground Excavation of Metro Station with Shallow Buried Depth in Sand and Gravel Stratum

作　　者：戴志仁[1] 胡瑞青 杨自刚 李小强[1] DAI Zhiren;HU Ruiqing;YANG Zigang;LI Xiaoqiang(China Railway First Survey and Design Institute Group Co.Ltd,Xi’an,Shaanxi 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《铁道工程学报》2024年第10期83-89,共7页Journal of Railway Engineering Society

基　　金：2024年度陕西省重点研发计划(2024SF-YBXM-659);2016年度陕西省重点科技创新团队计划项目(2016KCT-07);国家自然科学基金项目(52478421);中铁一院科研项目(院科19-52)。

摘　　要：研究目的:针对富水砂卵石地层地铁车站明挖法施工面临的道路交通问题,本文依托成都富水砂卵石地层首次采用暗挖法施工地铁车站的成功案例,对暗挖法施工关键工艺开展研究,指明了暗挖导洞设置及其开挖时序、地层超前预加固方式、初期支护类型、永临结合钢管柱以及拱形盖板扣拱等关键工艺,明确了富水砂卵石地层浅埋大跨地铁车站首次采用暗挖法施工的可行性。研究结论:(1)基于“化整为零”的思路,借助大刚度管幕超前支护,明确了导洞设置原则,采用多导洞法实施钢立柱与盖板(顶板)后,可按盖挖法理念完成超浅覆土下的地铁车站暗挖施工;(2)浅覆土管幕打设精度与地层扰动控制是富水砂卵石地层沉降控制的关键,应遵循“精准定位、及时纠偏,欠土顶进、严控超挖,先低速后匀速”的基本原则;(3)基于初期支护主要以被动承载为主,格栅钢架经济性好、施工方便,喷混后抗弯刚度增幅将近8倍,且大于工字钢喷混后等效抗弯刚度,宜采用格栅钢架;(4)顶部预埋倒L形钢板的“蛇形”中立柱,可实现两侧衬砌结构的有效连接与水平向有效传力,液压反循环钻机可满足小净空条件下高精度永临结合钢管柱施作需要;(5)本研究结论可为类似地层暗挖法车站施工提供借鉴与参考。Research purposes:Aiming at the road traffic problems confronted by the open-cut method of subway station construction in the water-rich sandy pebble layer,this paper relies on the successful project of Chengdu subway station construction in water-rich sandy pebble layer for the first time using the concealed excavation method to carry out a study on the key technology of concealed excavation method,indicating the key technology of the concealed excavation guide hole setting and its excavation sequence,the way of over-advanced pre-strengthening of the strata,the type of initial support,the steel pipe columns with permanent-temporary combination,and the arched cover buckling arch and so on,and clarifying the feasibility of the shallow buried large span metro station with water-rich sandy pebble layer for the first time.The feasibility of using the concealed excavation method for the first time in the construction of the shallow buried large-span subway station in water-rich sand and pebble layer was clarified.Research conclusions:(1)Based on the concept of modular tunneling approach,with the pre-support of tube curtain with large rigidity,the basic principle of the pilot tunnel is clarified,and then multiple pilot tunnels are adopted in the construction of steel pile pillars,tunnel roofs.The underground excavation of metro stations with large spans and shallow buried depth can be realized.(2)The precise control of construction accuracy and stratum disturbance of tube curtains with large rigidity plays a key role in the control of stratum settlement.The corresponding basic construction principle is accurate positioning,timely correction,not enough slagging,strict control of over-digging,low-speed drilling at the beginning,and then even speed drilling.(3)Based on the passive bearing properties of initial support,grid steel has a relatively better economic effect and construction convenience,the overall flexural stiffness after shotcrete increases to nearly 8 times.The corresponding stiffness of grid steel is larger

关 键 词：地铁车站 浅埋 大跨 暗挖法 导洞 管幕法 

分 类 号：U2[交通运输工程—道路与铁道工程]