软弱围岩小净距偏压隧道进洞施工技术

Driven Tunneling Technology of Weak Surrounding Rock and Small Clear Distance Unsymmetrical Loading Tunnel

文章以湖北省麻竹高速公路宜城至保康段第4合同段二分部的黄堡隧道和香山隧道为例,通过对软弱围岩小净距严重偏压隧道围岩压力分析,得出洞口施工顺序,并通过提高思想认识,设置偏压挡墙、套拱和超前支护、明洞的反压回填和加强监控量测等进洞技术措施,提出了小净距隧道、洞口浅埋、偏压开挖进洞施工技术,以期为类似工程提供经验和技术支持。

This article took Huangbao tunnel and Xiangshan Tunnel of second subsection of No.4con-tract section of the section from Yichen to Baokao of Mazhu expressway in Hubei Province as example,worked out portal construction sequence by analyzing surrounding rock pressure of weak surrounding rock small clear distance severe unsymmetrical loading tunnel,and proposed tunnel-entering construc-tion technology of small-distance tunnel,tunnel portal shallow-depth,bias voltage excavation by enhan-cing ideological understanding,establishing bias voltage retaining wall,cover arch,forepoling,back pressure backfilling of open cut tunnel and strengthening monitoring measurement and other entrance technology measures so as to provide experience and technical support for similar engineering.