双层超前小导管在中短隧道单向出洞施工中的应用

Application of Double-layer Advanced Small Conduit in Construction of Short and Middle Tunnels One-way out of Portal

对于中短隧道的经济开挖方式为单向掘进,在洞口贯通。以广佛肇高速公路罗日免隧道工程为例,介绍了"零开挖单向出洞"的施工工艺,特别是采用双层小导管超前支护替代长管棚洞口工程,打破传统贯通方式,实现安全出洞,取得较好经济价值,可为今后类似工程提供参考依据。

The economic excavation mode of short and middle tunnels is the one-way tunneling and the tunneling through at the portal. Taking Guanghzou-Foshan-Zhaoqing Expressway Luorimian Tunnel Project as an example, the article introduces the 'zero-excavation one-way out-of-portal' construction technology, and especially the application of the double-layer small conduit advanced support to replace the long pipe shed portal project, which breaks the traditional tunneling through mode, realizes the safe tunneling out of portal, and achieves the better economic value. The experience can be referred for the similar projects.