初支联拱二衬分离矿山法断面在地铁工程中的应用

城市地铁矿山法隧道建设受周边环境、运营需求等多方面影响,线路左右线线间距较小,无法采用两个独立单洞施工,针对此情况提出初支联拱二衬分离矿山法断面。对该断面结构设计及施工步序进行详细介绍,并将其与“双侧壁导坑法”断面及“中洞法”断面进行比较。该断面具有结构受力合理、工序转换少、施工速度快、对周边建筑物的影响小等优点,为一种新型的矿山法隧道断面,成功应用于北京地铁16号线某隧道建设中。采用有限元软件建立模型,对该断面开挖过程及其对周边环境的影响进行模拟,并利用现场实测数据验证,可为同类工程设计与施工提供参考。

Application of Mine-Tunneling Method with Connected Primary Support and Separate Secondary Support in Subway Construction

The distance between two lines is limited during tunnel construction in the mine tunneling method in cities because of the influence of various factors,like the surrounding environment and operational requirements;the line cannot be constructed with two single tunnels.The mine tunneling method with connected primary support and separate secondary support was proposed in this study to solve this problem.The section structure design and construction procedure for the proposed method was introduced in detail.The proposed method was also compared with“the double-side-drift method”and“the center drift method”;the results show that the new method has the advantages of a reasonable force acting on the structure,less process conversion,fast construction speed,and less influence on the surrounding environment.This new design was used in the construction of a section of the Beijing Metro Line 16.Furthermore,the new design was simulated with a finite element model;the response of the section during excavation and the influence on the surrounding environment was monitored during the simulation and was verified with the monitored data from the field.The proposed method provides a reference for the design and construction of similar projects.