青藏铁路西格二线尕布沟隧道进口塌方处理施工技术

Cave-in Treating Techniques for the Inlet End of the Gabugou Tunnel of the Xi-Ge Second Line of the Qing-Tibet Railway

详细介绍了青藏铁路西格二线尕布沟隧道进口塌方处理方案和施工技术。对塌方体后方围岩和初期支护采取回填碴石、径向锚管注浆或加密拱架、增设锁脚锚管等方法进行加固;对塌方先封闭掌子面及堆碴顶面,尔后采用大管棚与小导管相结合的超前预支护,最后用分部开挖法掘进,尽早进行二衬并对塌腔充填密实。经过上述措施处理,顺利地通过了塌方地段,其经验可供类似工程参考。

The cave in treating techniques and construction techniques adopted for the inlet end of the Gabugou Tunnel of the Xi-Ge Second Line of the Qing-Tibet Railway are introduced in detail iJt the paper. As far as the surrounding rock behind the cave-in body is concerned, back-filling crushed stote is adopted as the initial support, radial slip-casting grout is performed in combination with anchoring tubes, or arch racks are more closely provided, and additional foot-locking anchoring tubes are provided. With cave-in sections, the work face and the top surface of the piled rock are sealed first, and then the large-tube shed is used in combination with the small-tube sheds as the advanced pre-support, with the st ctioned excavation method adopted for the digging, and the secondary lining, and cave-in being filled compactly closely following. After being treated in the above-mentioned ways, construction successfully proceeds through the cave-in sections. The project may serve as a useful reference for other similar projects.