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倾斜地层巷道锚杆-拱架联合支护破坏特征及控制对策

Failure characteristics & control measures of bolt-arch combined supportin roadways buried in inclined strata

  • 摘要: 为明确倾斜地层巷道锚杆-拱架支护失效机理,寻求围岩变形控制对策,以典型案例为工程背景,利用FLAC3D锚杆-拱架精细化模拟平台,开展了不同地层倾角下的直墙半圆形巷道锚杆-拱架联合支护数值试验。结果表明:①地层倾斜对巷道变形影响显著,围岩以及锚杆、拱架的破坏情况具有明显的非对称性,且岩层倾向巷帮变形较严重;②巷道顶板沉降和巷帮内移受地层倾角影响较小,但巷道底鼓随倾角增大而显著增大。针对失效关键部位与变形破坏特征,以20°倾角为例,进一步开展了3种优化方案数值模拟对比分析。结果显示,通过增大锚杆直径取得的支护效果并不显著,拱腿仍率先屈曲变形进而造成整体失效,而关键部位锁拱锚杆的施加提高了拱架结构整体性。基于此提出倾斜地层巷道单侧锁拱等非对称支护对策,并得到现场验证。

     

    Abstract: In order to clarify the failure mechanism of bolt-arch support in inclined formation roadways and seek the countermeasures for surrounding rock deformation, taking the typical case as the engineering background, the bolt-arch numerical simulation platform in FLAC3D was used to carry out the numerical simulation test under different dip angles.The results show that:①The stratum inclination had a significant impact on roadway deformation, the failure of surrounding rock, rock bolts and supporting arch were obvious asymmetry, and roadway sidewall on the down-tilt direction tended to be more severely deformed.②The deformation of roadway roof and ribs were less affected by the increasing dip of strata, but the floor heave volume increases significantly with the increase of the inclination angle.Aiming at the asymmetric deformation and failure characteristics of roadway, taking the model of 20° dip strata as an example, the numerical simulation comparative analysis of three optimization schemes were further carried out.The results show that the control effect obtained by increasing the diameter of the bolt was insignificant, and the arch was still subject to buckling deformation and thus caused overall failure, but the application of the locking arch bolt in the key part improved the structural integrity of the arch structure.Based on this, the asymmetrical support measures such as single-sided locking archway of inclined strata roadway were proposed and verified on site.

     

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