无工作室超前管棚施工技术在某输水隧洞中的应用

隧洞施工在遇到不良地质时,通常采用管棚超前支护.常规管棚施工存在扩挖、工程成本增加、后期处理难度大、安全保障差等缺点,故可采用无工作室超前管棚施工技术.其施作要点是取消管棚工作室,在隧洞设计开挖轮廓线内侧40 cm处,按设计外插角开孔并进行管棚孔钻设,将管棚与钻杆连接逐节推进至孔内;对于管棚侵限位置,采用自制的管棚推进器将管棚推进至隧洞设计开挖轮廓线外.无工作室管棚在某输水隧洞中成功应用,并取得了良好效果.该方法施工方便,灵活性强,经济性好,安全性高,可供类似工程参考采用.

Application of Non-cavern Advanced Pipe Shed Construction Technique in the Water-conveyance Tunnel

In the face of bad geological tunnel construction, usually pipe shed pre-support is applied. Because conventional pipe shed construction has the disadvantages of enlarging excavation, the increase of engineering cost, the difficultly of post-processing, poor se- curity, non-cavern advanced pipe shed construction technique is created. Its construction elements includes： cancelling pipe shed cavern, at 40 cm inside the tunnel excavation contour, according to the design angle of extrapolation with pipe shed hole drill, the pipe roof section is linked one by one to hole with drill pipe. For the pipe shed contamination limit position, using self-made pipe shed propeller, tube shed is advanced to the designed excavation contour of the tunnel. It is applied successfully in the water conveyance tun- nel, and achieves good results. Non-cavern pro-supporting pipe shed construction technique has a characteristic of convenience, flexi- bility, good economic performance and high safety, and can provide a reference for similar engineering.