大断面粉砂土隧道出洞施工技术

Exit Tunnel Construction Technology in Large Section Tunnel in Sand Layer

对于单口掘进的中、短隧道,安全出洞是实现整座隧道顺利贯通的关键工序。大西客运专线下白隧道、朱家山隧道洞口端河沟深切、地质条件差,如采用单侧掘进贯通的施工方法,易引发边坡失稳及工程性滑塌、坍塌,同时可能产生冒顶,安全风险大。从出口端开辟工作面,需另外增加空压机、发电机等大型设备,投入较高,耗时长。施工中通过采用上台阶超前导洞出洞,从出口端反掘贯通的施工方案,成功解决了隧道出洞难题,取得了显著的经济效益和社会效益,颇值类似工程借鉴。

Safe tunneling out is the key process in the construction of middle, short tunnel. Due to the entrenched river bed and poor geological condition at the exit of Xiabai Tunnel and Zhujiashan Tunnel on Datong-Xi＇ an Passenger Dedicated Railway of geology, single-sided driving is prone to security risks of engineering sliding, collapse and slope instability, as weU as roof collapse, if construction begins from the outlet port open face, additional equipment such as air compressors- generators are needed, which means more input and longer time. Through the use of higher level advance pilot tunnel in tunneling out by reverse tunneling from exit end, problems were successfully solved out, which achieve great economic and social returns and provides reference for similar project.