包家山特长隧道富水千枚岩地段快速施工技术

Rapid Construction Technology in Water-rich Phyllite Stratum in Baojiashan Extra-long Tunnel

结合包家山特长隧道富水段的施工,围绕"上部弧形导坑预留核心土三台阶七步开挖平行流水作业法",从施工方案和支护参数的选择、开挖方法的确定、支护体系的形式等5个方面详细介绍了富水千枚岩隧道施工方法,总结形成了富水千枚岩隧道快速施工技术。三台阶七步流水法结合超前、径向堵水技术,有效地控制了围岩的变形,相对于国内以往千枚岩地质隧道大多采用正台阶法及大截面型钢、锚索等控制变形的施工方法来说,本施工技术具有操作简便、转换灵活、施工快捷等特点,对同类工程具有一定参考价值。

Taking the construction of Baojiashan extra-long Tunnel in water-rich stratum as an example, the author introduces the construction technology for tunnel in water-rich phyltite stratum in detail and develops a rapid construction technology in these geologic conditions, based on ＂ construction technology of three-bench and seven-step parallel production with upward arc heading and core soil＂. The construction technology for tunnel in water-rich phyllite stratum is described in such aspects as selection of construction schemes and support parameters, determination of excavation methods and types of support system. Compared with the top bench tunnelling method and deformation control by large-cross shaped-steel and anchoring cables usually used in tunnel excavation in phyllite stratum in China, the newly developed method combined construction technology of three-bench and seven-step parallel production and advance water controlling technology and radial water controlling technology, has such advantages as easy operation, easy conversion of construction method and rapid construction speed. The construction technology can provide references for similar projects in the future.