莲花山1号隧道富水全强风化花岗岩地段施工技术探讨

Probe into Construction Techniques for Water-rich Fully and Strongly Weathered Granite Section of No.1 Tunnel of Lianhua Mountain

莲花山1号隧道进口段485 m为富水全强风化花岗岩地层,采用双侧壁导坑法开挖。施工过程中,通过采用合理的分部开挖、加强超前支护、洞内引排水及洞外井点降水,有效降低了全强风化花岗岩遇水崩塌的危险性,保证了施工安全与进度。介绍莲花山1号隧道在富水全强风化花岗岩地层中的施工技术,总结大断面隧道在此类地质条件下的施工方法,为同类工程施工提供参考。

Inlet section at a length of 485m of No. 1 Tunnel of Lianhua Mountain is water- rich fully and strongly weathered granite stratum and is excavated in two side- wall pilot tunnel method. During construction, adoption of reasonable partial excavation, reinforcement of leading support, water diversion and drainage in tunnel and well - point dewatering outside the tunnel effectively reduces the risk of collapse of fully and strongly weathered granite when encountering water and guarantees construction safety and progress. This paper introduces construction techniques for No. 1 Tunnel of Lianhua Mountain in water - rich fully and strongly weathered granite stratum, and summarizes construction methods for large - erosssection tunnels under such geological condition to provide a reference for construction of similar projects.