不同工况下深部围岩分区破坏非连续变形试验研究

Experimental study on zonal failure discontinuous deformation of deep surrounding rock under different working conditions

以淮南矿区-1000 m为典型代表的深部地下开挖工程引发的支护难题越发突出。针对丁集煤矿-910 m西二11-2采区南轨道大巷实测发现的巷道分区破裂化现象,基于深部巷道围岩破裂机理与支护技术模拟试验系统,开展了4种工况下硐室的模拟试验研究,旨在获取最大荷载方向与硐室轴线垂直、斜交、平行条件下巷道围岩的受力与破坏特征,揭示深部巷道围岩发生分区破坏的条件。试验结果显示,模型拱顶、侧墙和底板周边径向应变均呈现拉应变,形成环状裂缝;在较大轴压作用下,巷道周边产生剪切破坏和拉伸破坏,但拉伸、剪切破坏区的形成不同步,拉伸破坏的速度远大于剪切破裂的速度,使周边岩体产生这种不连续且交替出现的环状裂隙区。直墙圆拱巷道发生分区破裂的特点为帮部呈现分层断裂,拱顶和底部呈现滑移型断裂。研究结果可为深部高地应力下巷道围岩的支护对策及优化提供参考。

The groud support problem caused by the deep underground excavations with Huainan mine-1000 m as a typical representative has become more and more prominent.This study aims to obtain the stresses and damage characteristics of the surrounding rock of the roadway under vertical,oblique and parallel conditions of the maximum load direction and the axis of the roadway,and to reveal the conditions under which the surrounding rock of the deep tunnel fails.The test results show that the radial strains around the model arch,sidewalls and bottom slab all exhibit tensile strains,forming annular fractures;under greater axial pressure,shear and tensile damage occurs around the perimeter of the roadway,but the formation of tensile and shear damage zones is not synchronized,and the rate of tensile damage is much greater than the rate of shear rupture,resulting in such discontinuous and alternating annular fracture zones in the surrounding rock mass.The zonal rupture occurring in the straight-walled round-arch roadway is characterized by the presentation of stratified fracture at the side walls,and slip-type fracture at the top and bottom of the arch.The results of the study can provide reference for the support countermeasures and optimization of the roadway surrounding rock under high ground stress in the deep mining.