软弱围岩隧道锁脚锚管力学特性现场模拟试验  

Field Simulation Test on Mechanical Characteristics of Feet-lock Anchor Pipes for Soft Surrounding Rock Tunnel

作　　者：石州 罗彦斌[1] 陈建勋[1] 刘伟伟[1] 于海涛 SHI Zhou;LUO Yan-bin;CHEN Jian-xun;LIU Wei-wei;YU Hai-tao(School of Highway,Chang'an University,Xi'an Shaanxi 710064,China;Guangdong Provincial Traffic Groupco.,Ltd.,Guangzhou Guangdong 510000,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]广东省交通集团有限公司,广东广州510000

出　　处：《公路交通科技》2021年第7期96-106,123,共12页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51678063,41831286,52078045)。

摘　　要：锁脚锚管在软弱围岩隧道安全施工方面应用广泛,其力学作用机理及合理支护参数的研究对维持结构安全稳定意义重大。以黄延高速公路扩能工程剪子岔隧道为依托,通过现场模拟试验,对软弱破碎围岩条件下隧道锁脚锚管的受力特性和变形分布规律进行了系统研究。本试验根据自主研发设计的隧道钢架-锁脚锚管相互作用模拟试验装置,分析了不同打设角度下锁脚锚管的实测应变及对应的弯曲应变,研究了锁脚锚管的内力分布及荷载响应情况,并结合不同打设角度下锁脚锚管端部位移和试验前后锚杆的变形情况,揭示了锁脚锚管的力学作用机理并提出了锁脚锚杆的合理打设长度和角度。现场试验结果表明:(1)大角度打设的锁脚锚管受力更均匀,且可以将端部荷载传递到围岩更深部位置;(2)锁脚锚管主要靠管口附近部位抵抗弯矩,且锁脚锚管在端部竖向荷载作用下主要依靠其竖向抗弯刚度提供承载力;(3)当荷载相同时,锚管端部水平位移随着打设角度的不同而不同,当打设角度为45°时其水平位移为最大,打设角度为0°时其水平位移为最小;(4)孔口围岩的塑性变形和剥离破坏集中在锚管下方部位,主要由锚管的竖向挤压变形引起。Feet-lock anchor pipes are widely used in safe construction of soft rock tunnels.The study of its mechanical mechanism and reasonable support parameters is of great significance to maintain structural safety and stability.Based on the Jianzicha tunnel in Huangyan expressway traffic expansion project,through field simulation test,the mechanical characteristics and deformation distribution rule of the feet-lock anchor pipes under the condition of weak and broken surrounding rock are systematically studied.Based on the self-developed simulation test device for the interaction between tunnel steel ribs and feet-lock anchor pipes,the measured strains and corresponding bending strains of the feet-lock anchor pipes under different angles are analyzed,and the internal force distribution and load response of the feet-lock anchor pipes are studied.Combining with the end displacement of the feet-lock anchor pipes under different angles and the deformation of the anchor pipes before and after the test,the mechanical mechanism of the feet-lock anchor pipes is revealed,and the reasonable installation length and angle of feet-lock anchor pipes is proposed.The field experiment result shows that(1)the internal force distribution of feet-lock anchor pipes with large angle is more uniform,and the end load can be transferred to the deeper position of surrounding rock;(2)the feet-lock anchor pipes mainly rely on the part near the pipe orifice to resist the bending moment,and the feet-lock anchor pipes mainly rely on the vertical bending stiffness to provide the bearing capacity under the vertical load at the end;(3)for the same size of vertical end load,the horizontal displacement of the end of the anchor pipe varies with the angle,the horizontal displacement is the maximum when the angle is 45°,and the horizontal displacement is the minimum when the setting angle is 0°;(4)the plastic deformation and peeling failure of the surrounding rock at orifice are concentrated in the lower part of the anchor pipe,which is mainly caused by th

关 键 词：隧道工程 软弱围岩 锁脚锚管 现场试验 力学特性 

分 类 号：U452[建筑科学—桥梁与隧道工程]