管棚预支护下隧道掌子面稳定性理论分析  

Theoretical Analysis of the Stability of Tunnel Face under Pipe Roof Presupport

作　　者：安永林[1] 李佳豪 欧阳鹏博 刘文娟[1] 苏光明 周健 AN Yonglin;LI Jiahao;OUYANG Pengbo;LIU Wenjuan;SU Guangming;ZHOU Jian(Hunan University of Science and Technology,Xiangtan 411201;China Construction Tunnel Corp.,Ltd.,Chongqing 401320;China Railway 16th Bureau Group Road and Bridge Engineering Co.,Ltd.,Beijing 101500)

机构地区：[1]湖南科技大学,湘潭411201 [2]中建隧道建设有限公司,重庆401320 [3]中铁十六局集团路桥工程有限公司,北京101500

出　　处：《现代隧道技术》2021年第3期115-122,共8页Modern Tunnelling Technology

基　　金：国家自然科学基金项目(51408216,51308209);湖南省教育厅资助科研项目(20A187,17C0623)。

摘　　要：为了探究管棚预支护下隧道掌子面稳定情况,文章结合管棚受力特点,首先建立管棚Winkler地基模型,然后将地基反力作用于模型掌子面上部;并基于刚体极限平衡理论,推导了掌子面稳定安全系数计算公式,最后以巴东隧道三号横洞某里程段为工程背景,分析有无管棚下掌子面的稳定性,并讨论各参数对管棚挠度以及掌子面稳定性的作用规律。结果表明:随着管棚直径增大、管棚支座位移减小、开挖进尺与开挖台阶高度降低、围岩内摩擦角与粘聚力增大,管棚最大挠度减小,掌子面稳定安全系数提高;较好围岩条件、较小开挖高度和较小管棚支座位移下,短进尺开挖对提高掌子面稳定的作用更明显;随着隧道埋深增大,掌子面稳定安全系数先减小,后增大,然后保持不变。这与选用的规范中围岩压力计算公式有关,隧道在浅埋条件下,围岩压力随着埋深的增大而增大;隧道在深埋与浅埋之间时,由于存在两侧岩体的夹制作用,围岩压力随着埋深增大而减小;而隧道在深埋条件下,存在塌落拱效应,围岩压力趋于稳定。In order to investigate the stability of the tunnel face under pipe roof support,this paper takes into consideration the stress characteristics of the pipe roof,establishes a Winkler foundation model for the pipe roof,and applies the foundation reaction force on the upper part of the tunnel face in the model.Meanwhile,based on the rigid limit equilibrium theory,this paper derives the calculation formula of the safety coefficients for the stability of the tunnel face.Finally,taking the No.3 transverse adit of Badong tunnel as the engineering background,this paper analyzes the stability of the tunnel face with and without the pipe roof,and discusses the effect law of each parameter on the deflection of the pipe roof and the stability of the tunnel face.The results show that the maximum deflection of the pipe roof and the displacement near the tunnel face will decrease and the safety factor for the stability of the tunnel face will increase,as the diameter of the pipe roof increases,the displacement of the support at the end of the pipe roof decreases,the advance per round and the height of excavation bench decrease,and the internal friction angle and cohesion of the surrounding rock increase;shorter advance length has more obvious effect on improving the stability of the tunnel face under better surrounding rock conditions,lower excavation heights and smaller pipe roof support displacements;as the tunnel buried depth increases,the safety factor for the stability of the tunnel face first decreases before it increases,and then remains constant.This is related to the calculation formula for the surrounding rock pressure specified in the code,for a shallow buried tunnel,the larger the buried depth,the larger the load;for a tunnel located between the deep buried depth and shallow buried depth,due to the existence of the confining effect from both sides of the surrounding rocks,the surrounding rock pressure will decrease when the buried depth increases;for a deep buried tunnel,the load will remain constant due to the col

关 键 词：隧道工程 掌子面稳定 管棚 WINKLER地基模型 

分 类 号：U495.1[交通运输工程—交通运输规划与管理]