乌兰木伦煤矿大断面硐室围岩变形破坏规律及控制

Deformation and failure law and control of surrounding rock in the large section chamber of Ulan Mulun Coal Mine

  • 摘要: 针对煤矿井下巷道大断面硐室的围岩变形破坏问题,以乌兰木伦煤矿井下分选及充填大断面硐室为研究对象,采用相似模拟实验方法,进行单调递增加载和恒定荷载加载单轴压缩实验,对大断面硐室围岩变形破坏规律进行了研究。结果表明:① 2种加载方式在压密阶段、弹性变形阶段及微破裂稳定发展阶段破坏演化和变形位移趋势相似。② 采用单调递增加载方式的试样裂纹较少但裂纹缝隙较大,试样沿着主裂纹突然发生破断,期间有大量碎屑飞出,试样变形位置主要集中在围岩边界,破坏时释放能量较多,但峰后释放能量持续时间较短。③ 采用恒定荷载加载方式的试样应力保持不变,应变缓慢增加,期间产生大量微小裂纹,试样变形位置主要围绕在硐室周围,破坏时释放能量较少,但峰后释放能量持续时间较长。依据大断面硐室围岩变形破坏规律,提出了锚杆索支护方案:硐室顶部打长锚索,将顶板和上方坚硬岩石连成整体;在硐室煤岩交界处打倾斜锚杆,将煤岩交界面与周围岩体紧密连接。数值模拟结果表明,支护后围岩应力、位移、塑性区均明显减小,围岩稳定性大幅提高,支护效果良好。

     

    Abstract: In response to the deformation and failure of surrounding rock in large section chamber underground roadways of coal mines, this study focuses on the sorting and filling of large section chamber underground roadways in Ulan Mulun coal mine. Similar simulation experiments are conducted using monotonically increasing and constant load uniaxial compression methods to investigate the deformation and failure laws of surrounding rock in large section chamber underground roadways. The results show the following points. ① The failure evolution and deformation displacement trends of the two loading methods are similar in the compaction stage, elastic deformation stage, and micro fracture stable development stage. ② The sample using monotonically increasing loading method has fewer cracks but larger crack gaps. The sample suddenly breaks along the main crack, during which a large amount of debris flies out. The deformation of the sample is mainly concentrated at the boundary of the surrounding rock. More energy is released during the failure, but the duration of energy release after the peak is relatively short. ③ The stress of the specimen loaded with a constant load remains constant, and the strain slowly increases, during which a large number of small cracks are generated. The deformation position of the specimen mainly surrounds the chamber, and the energy released during failure is relatively small, but the duration of energy release after the peak is longer. Based on the deformation and failure law of the surrounding rock of the large section chamber, a bolt and cable support scheme is proposed. A long anchor cable is installed at the top of the chamber to connect the roof and the hard rock above it as a whole. The inclined anchor rods are installed at the coal rock interface of the roadway to tightly connect the coal rock interface with the surrounding rock mass. The numerical simulation results show that after support, the stress, displacement, and plastic zone of the surrounding rock are significantly reduced, the stability of the surrounding rock is greatly improved, and the support effect is good.

     

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