软弱地层浅埋大跨隧道跳仓法拆撑空间效应研究  

Spatial Effect of Support Dismantling through Alternate Bay Construction Method in Shallow-buried Large-span Tunnels in Soft and Weak Strata

作　　者：高鑫 王文娟 李清菲 冯世杰 吴琦 GAO Xin;WANG Wenjuan;LI Qingfei;FENG Shijie;WU Qi(China Railway Liuyuan Group Co.,Ltd.,Tianjin 300308)

机构地区：[1]中铁第六勘察设计院集团有限公司,天津300308

出　　处：《现代隧道技术》2022年第2期111-121,共11页Modern Tunnelling Technology

摘　　要：对于在软弱、破碎、富水地层中采用双侧壁导坑法修筑的暗挖大跨隧道,跳仓法施工依赖于初期支护的“棚护效应”维持拆撑后大跨结构的稳定性,常常面临拆撑步距小、风险高、效率低、代价大的困境,一旦拆撑方案采取不当,极易造成塌方安全事故。针对这一问题,以青岛地铁4号线错埠岭站为依托工程,通过理论分析与数值计算相结合的手段,论证了拆撑后初期支护“空间棚护效应”主要由“横向成拱效应”和“纵向成梁效应”组成,二者共同维持大跨结构的安全性与稳定性;同时确定了合理、安全、高效、快速的拆撑分区长度与隔仓分区长度,分别为L=9 m、S=18 m,并顺利通过了现场施工的检验。结果表明:软弱地层大跨隧道采用“隔二拆一、先内部后洞口”的拆撑方案是切实可行的,可为后续工程提供借鉴与指导。For a mined large-span tunnel constructed through the double side drift method in soft,weak,broken and water-rich strata,the alternate bay construction is completely dependent on the"shed support effect"of the initial support to maintain the stability of the large-span structure after support dismantling,which is often in the dilemma of small support-dismantling step,high risk,low efficiency and high cost,and if an improper support-dismantling scheme is taken,safety accidents such as the collapse will be easily induced.To address this problem,this paper takes the Cuobuling Station of Qingdao Metro Line 4 as the engineering background and applies the combination of theoreti⁃cal analysis and numerical calculation to demonstrate that the"spatial shed support effect"of the initial support after support dismantling is mainly composed of the"transverse arching effect"and the"longitudinal beam effect",both of which help maintain the safety and stability of the large-span structure.Also,this paper determines reasonable,safe,efficient and fast support-dismantling zone partition length and compart zone partition length,which are L=9 m and S=18 m respectively and have successfully passed the verification of on-site construction.The results show that the support-dismantling scheme of"comparting two partitions and dismantling one partition,constructing inside first and then portal"is practical and feasible for subsequent projects.

关 键 词：大跨结构 双侧壁导坑法 跳仓法 空间效应 拆撑分区 隔仓分区 拱部沉降 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]