摘要
我国西南地区铁路沿线地形高差大、地质构造复杂,其隧道工程具有埋深大、构造应力强、围岩条件复杂等特点,给设计及施工带来巨大挑战。依托某板岩隧道的地质工程背景,针对高地应力陡倾层状围岩,首先分析锚杆的支护作用,后通过离散元数值模拟的手段研究锚杆在隧道中的支护效果,并对其进行优化设计。结果表明:陡倾顺层板岩隧道在垂直结构面处将发生结构弯曲变形和岩石变形,在平行结构面处以岩石变形为主;高地应力下陡倾层状板岩隧道随着锚杆长度的边墙收敛有所减少,竖向变形影响不大,可当隧道锚杆长度达到一定长度时对隧道结构稳定性增加效果不佳;针对陡倾层状围岩变形机理,边墙处采用长锚杆、仰拱拱顶处采用短锚杆(锚杆的非等参)设置即可控制隧道收敛变形,在其他方向的变形及围岩塑性区大小也可达到全环锚杆相同的效果。
The terrain height difference and complex geological structure along the railway line in southwest China have large burial depth,strong structural stress and complex surrounding rock conditions,which greatly challenge the design and construction.Relying on the geological engineering background of a slate tunnel,first analyzes the supporting effect of the bolt for the steep-dipping layered surrounding rock with high geostress,and then studies the supporting effect of the bolt in the tunnel by means of discrete element numerical simulation,and optimizes the design.The results show that the steep-dipping slate tunnel will undergo structural bending deformation+rock deformation at the vertical structural surface,and the rock deformation will be the main at the parallel structural surface.Under high geostress,the steep-dipping layered slate tunnel decreases with the convergence of the side wall of the bolt length,and the vertical deformation has little effect,but when the length of the tunnel bolt reaches a certain length,the effect on increasing the stability of the tunnel structure is not good.According to the analysis of the deformation mechanism of steep-dipping layered surrounding rock,the convergence deformation of the tunnel can be controlled by using long anchors at the side wall and short anchors(nonisoparametric of the bolts)at the top of the innovated arch,and the deformation in other directions and the size of the plastic zone of the surrounding rock can also achieve the same effect as the full-ring anchor.
作者
焦康杰
方钱宝
Jiao Kangjie;Fang Qianbao(China Railway Eryuan Engineering Group Co.,Ltd.,Guiyang 550002,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2023年第S02期813-818,835,共7页
Chinese Journal of Underground Space and Engineering
关键词
隧道
锚杆
高地应力
陡倾顺层
优化设计
tunnel
anchor
high geostress
steep bedding
optimal design
