应用大管棚偏心钻跟管钻进法处理隧洞塌方实践

Application of large pipe-shed support followed by eccentric drilling in tunnel collapse treatment

牛栏江-滇池补水工程大五山隧洞8号施工支洞岩石完整性极差,施工时突然发生塌方事故。业主、监理、设计和施工单位在分析隧洞地质和塌方情况后,决定采取首先加固未受破坏的初期支护结构,再采取大管棚偏心钻头跟管钻进法进行处理。在总体处理方案确定后,制定了施工工艺流程,确定了施工参数,对施工中可能出现的二次塌方、钻头烧钻、成孔困难等问题进行了分析。按照施工方案处理塌方事故后,隧道后续施工得以安全进行。

Due to very poor rock integrity, No. 8 construction adit of Dawushan tunnel in Niulan River - Dianchi Lake Water Supplement Project collapsed suddenly during construction process. After analysis on tunnel geological and collapse conditions, the owner, supervisor, designer and construction unit jointly decided to reinforce the undamaged initial support firstly and then build large pipe - shed followed by eccentric drilling to treat the collapse. Based on general treatment scheme, the technical process of construction was designed and the construction parameters were determined, and for the possible problems of second collapse, bit burning, difficult hole forming etc. , the solutions were analyzed. After implementation of the construction scheme, the collapse was treated smoothly and the safe construction was guaranteed.