高瓦斯隧道塌方段综合治理技术

研究目的:瓦斯是隧道及地下工程施工的一个重要地质灾害,因瓦斯异常涌出发生瓦斯爆炸事故而造成隧道塌方事故也是时有发生,因此,对含有高瓦斯的隧道塌方进行综合治理,确保后期施工顺利进行就显得尤为重要。本文结合都汶高速公路紫坪铺隧道塌方段的施工,对高瓦斯隧道塌方段综合治理的关键技术进行探讨分析。研究结论:高瓦斯隧道塌方段综合治理成败的关键在于选择合理的治理方案。本工程实施三阶段治理方案:(1)地质探测预报初步确定坍塌段的长度、高度及围岩情况;(2)进行坍塌范围内的瓦斯治理;(3)进行初期支护拆换及塌方处理。采用超前钻孔探测裂隙瓦斯情况进行瓦斯治理、75+51长短自进式锚杆(注浆)进行超前支护、预注浆稳固塌体、台阶分部法开挖塌体,短进尺掘进、喷射混凝土封闭新开挖面、初期支护和二次衬砌紧跟的处理方法,使塌方段得到了有效控制和处理,保证了隧道安全顺利通过塌方段。

Technology for Treating Collapse Area of High Gas Tunnel

Research purposes: Gas is a major source to cause the geological disaster in tunnel and underground engineering.The collapse accident caused by the explosion accident due to abnormal emission occurs sometimes.The treatment of the collapse of high gas tunnel is crucial to later-stage construction of the tunnel.This paper discusses and analyzes the key technology for the collapse area of Zipingpu Tunnel of Chengdu-Wenchuan Expressway.Research conclusions:Choice of reasonable comprehensive treatment plan is crucial to treating the collapse area of high gas tunnel.The treatment of the collapse of this tunnel included three stages:(1) The geological exploration was conducted to determine the collapse length and height and surrounding rock circumstances.(2) The treatment was conducted to the gas within the scope of the collapse.(3) The primary support was removed and replaced to treat the collapse.The advanced drilling was conducted to detect the fracture gas for gas control,the 75 + 51 long self-feeding anchor(grouting) was used for the advanced support,the pre-grouting was conducted to solid the collapse body,the bench method was used to excavate the collapse body,the short footage drilling was used,and the concrete was shotcreted to close the new excavation face,following by doing the primary support and secondary lining.With these treatments,the collapse area was effectively controlled and treated and the tunnel passed through the collapse area safely.