隧道管幕暗挖法原理及应用探讨

Discussion on Principle and Application of the Pipe-curtain Tunneling Method

隧道管幕暗挖法是一种在刚性支护体系保护下,实现安全、快速掘进的隧道暗挖施工技术,其设计理念及支护受力体系与“浅埋暗挖法”和管幕工法既有应用存在较大差异,主要特点包括:(1)超强环、纵向刚性支护体系;(2)无锚杆支护体系;(3)管幕钢管局部、间隔布置;(4)提倡大断面、短工序开挖,支护快速封闭成环;(5)根据工程实际可设置无工作井管幕。隧道管幕暗挖法已成功应用于重庆铁路枢纽东环线猫垭口、乔子堡二号隧道下穿渝宜高速公路交叠段工程中,可供类似工程施工参考借鉴。

The pipe-curtain tunneling method is a kind of undercutting tunnel construction technology which can realize safe and quick tunneling with the protection of rigid supporting system.The design concept and supporting stress system of the method are quite different from the existing applications of the“shallow-buried tunneling method”and the pipe curtain construction method.Main characteristics of the method are as follows:(1)Super-strong annular and longitudinal rigid supporting system is used.(2)the supporting system without anchor bolts is used.(3)steel pipes of the pipe curtain are arranged partially,with certain spacing.(4)large-section and short-process excavation is advocated,and the supporting system can be closed as soon as possible to form a ring structure.(5)pipe curtain without working shaft can be set according to the actual construction conditions.The pipe curtain tunneling method has been successfully applied to the construction of overlapping sections of the Maoyakou and Qiaozibao No.2 tunnels(of the East Ring Road of Chongqing Railway Hub)underneath the Chongqing-Yichang Expressway,which can be used as a reference for the construction of similar projects.