超前支护对软弱围岩隧道掌子面稳定性的影响研究  

Study on the Influence of Advanced Support on the Stability of Tunnel Face in Soft Surrounding Rocks

作　　者：张艺腾 王明年[1,2] 于丽[1,2] 王志龙[1,2] 张霄 ZHANG Yiteng;WANG Mingnian;YU Li;WANG Zhilong;ZHANG Xiao(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotoug University,Chengdu 610031;School of Civil Engineering,Southwest Jiaotoug University,Chengdu 610031)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031 [2]西南交通大学土木工程学院,成都610031

出　　处：《现代隧道技术》2020年第S01期119-128,共10页Modern Tunnelling Technology

基　　金：国家自然科学基金(51878567).

摘　　要：Ⅳ级、Ⅴ级围岩要实现机械化全断面施工,合理的掌子面超前支护措施是保障。文章以郑万高铁湖北段软弱围岩隧道采用机械化全断面施工为工程背景,通过FLAC 3D数值模拟软件分别从围岩位移、塑性区方面研究了超前管棚、掌子面锚杆及其组合措施对掌子面的加固效果,在此基础上对管棚直径、注浆加固范围、超前加固长度及锚杆超前长度进行了探讨。研究结果表明:超前管棚对预收敛、最终位移及拱顶上方塑性区控制效果明显,掌子面锚杆对掌子面挤出变形及掌子面前方围岩塑性区控制效果明显,两者可以形成互补以达到最佳效果;随着管棚直径及其四周注浆半径的增加,预收敛、最终位移略微减小,效果甚微;管棚合理超前加固长度为15~20 m,掌子面锚杆合理长度也为15~20 m。经开挖后监测数据验证,措施有效,确保了软弱破碎围岩隧道的顺利施工,对类似工程具有一定的借鉴意义。In order to realize mechanized full-face construction of tunnels in surrounding rocks of classⅣandⅤ,reasonable advanced support measures for working face are necessary.Taking Zhengzhou-Wanzhou high-speed railway tunnels(railway section in Hubei province)constructed by full-face mechanized construction methods in soft and weak surrounding rocks as the engineering background,the numerical simulation software FLAC 3D is used to study the reinforcement effect of advanced pipe roof,tunnel face bolt and its combinations on tunnel face from the aspects of surrounding rock displacement and plastic zone.On this basis,some issues in terms of the diameter of pipe roof,the length of advance reinforcement,the grouting reinforcement range and the length of bolt are discussed in this paper.The results show that the pre-convergence,final displacement and plastic zone above the vault are controlled effectively by the advanced pipe roof,extrusion deformation of tunnel face and plastic zone in front of tunnel face are controlled effectively by the face bolts,the two methods can complement each other for best control results;with the increase of the diameter of the pipe roof and the grouting radius,the pre-convergence and the final displacement decrease slightly with little effect;reasonable advanced reinforcement length of pipe roof is 15-20 m,and reasonable length of face bolt is 15-20 m.It is verified by the monitoring data after excavation,ensuring the smooth construction of the tunnel in soft and broken surrounding rocks,which has certain reference value for similar projects.

关 键 词：隧道 全断面工法 软弱围岩 掌子面稳定性 超前管棚 掌子面锚杆 

分 类 号：U451[建筑科学—桥梁与隧道工程]