朱孟艳 陈国 窦晗 谈闯

摘要：在砂質围岩地层和软弱破碎围岩中开挖隧道会引起围岩扰动卸荷并改变围岩应力状态，若变形控制不当，极易导致掌子面发生破坏。库尔勒隧道为典型的戈壁全风化砂岩浅埋隧道，下穿既有营业线，掘进施工难度大，技术复杂。采用离散元颗粒流软件PFC2D研究全断面法、双台阶法及三台阶法在库尔勒隧道开挖中的适用性，从而确定合理的开挖工法。研究结果表明：采用全断面法和双台阶法施工时，围岩变形控制能力差，塑性区分布面积较大，围岩易产生滑塌。三台阶法更适合开挖库尔勒隧道，仰拱施作后隧道衬砌结构的安全系数较大，结构内力较小。相关研究成果可为今后类似工程提供借鉴。

关键词：  隧道工程  掌子面  全断面法  两台阶法  三台阶法  变形控制

Research on Stability of Excavating Face of the Korla Tunnel

ZHU Mengyan1，2 CHEN Guo1，2 DOU Han1TAN Chuang2

（1. China Railway First Group Third Engineering Co.， Ltd.， Baoji， Shanxi Province，721006 China;2. College of Civil Engineering， Nanjing Forestry

University， Nanjing， Jiangsu Province，210037 China）

Abstract：Tunnel excavation in sandy surrounding rock strata and soft fractured surrounding rock will cause disturbance and unloading of surrounding rock and changes the state of stress distribution of surrounding rock. If the deformation is not controlled properly， it is very easy to cause damage to the tunnel face. Korla tunnel is a typical shallow buried tunnel in Gobi completely weathered sandstone. It crosses the existing business line， which is difficult to excavate and complex in technology. The discrete particles flow software PFC2D is used to study the applicability of the full face method， double-step method， three-step method in the Korla tunnel excavation， so as to determine the reasonable excavation method. It was found that when using the full face and double-step methods in the excavation， the deformation control of the surrounding rock is bad， the distribution area of the plastic area is large， and the surrounding rock is easily collapsed. The three-step method is more suitable to excavate the Korla tunnel， the safety factor of the tunnel lining structure after inverted arch construction is bigger， and the internal force of the structure is smaller. The relevant research results can provide reference for similar projects in the future.

Key Words： Tunnel engineering;Tunnel face;Full face method;Double-step method;Three-step method;Deformation control

随着我国经济的飞速发展，人们出行的需求越来越，公路、地铁和铁路的建设如火如荼。隧道对于节约土地资源、减少线路里程以及改善行车舒适度等均具有非常重要的意义。隧道工程施工难度大、工期长、造价高，而且往往需要穿越复杂地质条件的地层，如软弱围岩、断层破碎带和富水砂层等[1-5]。对于穿越砂岩地层的浅埋暗挖隧道而言，砂层易受扰动，拱顶其施工方法的选择需要充分考虑围岩的工程地质、地下水、隧道断面大小及形状、施工机械配备能力以及工期等要求[6-8]。在隧道的开挖过程中，由于施工不当而导致的围岩松动、拱顶坍塌、地表下沉的破坏现象屡见不鲜。……