干燥粉细砂层大断面斜井转入正洞施工技术

大西铁路客运专线干庆隧道3号斜井转入正洞施工中,成功运用了梯形断面弧形巷道垂直挑顶直接转入正洞的施工方案。就干燥粉细砂层地质,针对不同部位综合采取了密排超前小导管注改性水玻璃加固砂层施工技术、多台阶分部开挖法、侧壁超前旋喷咬合桩加固砂层施工方法、强刚度特殊结构门架技术和控制支护脚部下沉施工技术,分别阐述了其施工工艺流程和技术要点。该技术可对类似地质条件下的隧道施工和控制流砂、涌砂甚至砂层滑塌等现象提供指导和借鉴。

Construction Technology of Large Section Inclined Shaft of Dry Fine Sand Layer into the Main Tunnel

＂Rectangular curved roadway vertical top pick＂ was successfully used in construction plan about Gan Qing tunnel 3# inclined shaft into the main tunnel in Datong-Xi＇ an passenger-dedicated High-speed Railway. For dry fine sand layer geology, different construction technologies are used for different parts. Those technologies include Sand reinforced with injecting modified water glass ahead of closely packed small ducts, Multi-step segments excavation method, sand reinforced in tunnel wall churning pile ahead, Special structure mast technology of Strength and stiffness and supporting and foot sink control construction technology. At the same time, Construction process and the operation points of different technology were introduced, which can provide guidance and reference for similar tunnel construction that have similar to the geological conditions and control Quicksand, Sand Bay and Sand collapse in the future.