暗洞明做在欧家山隧道出口左洞的应用

Application of Open Dark Cave in the Left Cave of Oujiashan Tunnel Exit

欧家山隧道左线采用单侧壁法单端掘进出洞施工对现行左线出洞施工不具备指导作用。欧家山隧道为本标段控制性工程,左线导坑ZK36+400~ZK36+403段拱部发生局部垮塌,洞内浅埋段围岩渗水后会造成塌方扩大化,对已开挖完成且为进行二衬施工的段落(ZK36+367~ZK36+395)造成危害,存在极大的安全风险;同时,对出口段左线ZK36+395至出口明暗分界线ZK36+427段进行明挖施工,该部分土方可作为路基填料,有利于资源利用。通过本公司在山岭隧道施工中积累的经验,以及"暗洞明做"施工工艺较为成熟,出口段左线采取由ZK36+395至出口明暗分界线ZK36+427段进行明挖法施工的"暗洞明做"施工工艺。

The left-hand side of the Oujiashan Tunnel adopts single-sided wall excavation and single-ended tunneling to construct the tunnel and does not provide guidance for the current construction of the left-hand tunnel. The Oujiashan tunnel is the control project of this section. The local arch collapsing of ZK36 ＋ 400 ~ ZK36 ＋ 403 on the left-hand line lead to local collapse. After seepage of the surrounding rock in the shallow buried section of the tunnel will cause landslide enlargement. After excavation has been completed in the meantime, there is great safety risk to the paragraph（ZK36 ＋367 ~ ZK36 ＋ 395） for the construction of the second liner. At the same time,the open excavation of the section ZK36 ＋ 427 at the exit of the left line ZK36 ＋ 395 to the exit light-dark boundary line shall be carried out. This part of earth can be used as subgrade filler, which is good for resource utilization. Through the experience accumulated by China Railway 14 th Bureau Group No.2 Engineering Co., Ltd. in the construction of mountain tunnels and the construction technology of ＂open dark cave＂, the left-hand lane of the exit section adopts the method of ＂ open dark cave ＂ construction from ZK36 ＋ 395 to the section ZK36 ＋ 427 of the exit light-dark boundary line of the exit.