禾洛山隧道富水地段施工技术

Technique for Construction of Heluoshan Tunnel in Water-rich Stratum

研究目的:隧道穿越富水地层时,极易发生涌水、突水事件,造成隧道塌方,支护变形等质量事故,严重影响隧道正常施工,并给人身设备安全造成巨大安全隐患。为保证正常施工,最大程度地减少富水隧道施工中造成的工程投入和人员伤亡,迫切需要解决这方面的施工技术难题。研究结论:隧道穿越富水地层时,必须做好地表宏观地质预报和施工中的预报工作。隧道开挖中,集中股状型涌水采取了掌子面和掌子面后方同时进行超前引水措施,开挖支护采取正台阶法预留核心土施工,超前支护使用3排超前小导管。片状型涌水采用掌子面超前引水措施,掌子面出现凝灰岩的按照三台阶法开挖支护,上台阶预留核心土,超前支护使用2排小导管。没有出现凝灰岩的按照正台阶法施工,上台阶预留核心土,超前支护使用3排小导管。

Research purposes： When a tunnel passes through water-rich stratum,the accidents of water inrushing and water bursting are easy to occur,resulting in tunnel collapse and support deformation to seriously affect the normal tunnel construction and bring about enormous latent danger to the safety of person and equipment.In order to ensure the norm tunnel construction and reduce the construction cost and personal injury as much as possible,it is urgent to do the research on techniques for construction of tunnel in water-rich stratum.Research conclusions：When a tunnel passes through the water-rich stratum,the geological forecast should be conducted well for the tunnel construction.In the course of tunneling,for the centralized strand-shaped water-inrushing,the water should be diverted both at the working face and place behind the working face,the heading-and-bench method should be adopted for tunnel excavation and supporting with core soil reserved and the small-diameter pilot tubes in three rows should be used for supporting in advance.And for platy-shaped water-inrushing,the water should be diverted at the working face in advance,the three-bench method shall be used for excavation and supporting with the core soil reserved at the upper bench when tuff is encountered at working face,and the small-diameter pilot tubes in two rows should be used for supporting in advance.The heading-and bench method should be used with the core soil reserved at the upper bench,and the small-diameter pilot tubes in three rows should be uses for supporting in advance if there is no tuff.