大断面半煤岩巷道变形破坏机理研究及控制技术

Deformation and failure mechanism of large cross-section semicoal rock roadway and control technology

针对大断面半煤岩巷道围岩变形控制难题,以小保当煤矿一号井大断面半煤岩巷道为研究背景,测试了巷道围岩岩层分布、围岩地应力分布及裂隙发育,分析了巷道围岩的变形破坏演化特征。通过实验室试验以及数值模拟分析了半煤岩组合体力学性能及其变形破坏形态,揭示了强度较低的煤体最先在煤岩交界面发生破裂、滑移,变形不断向深部延伸,随着煤岩体完整性及强度的持续弱化,造成巷帮由下而上的非均匀渐进性失稳破坏,揭示了提高大断面半煤岩巷道围岩稳定性的关键在于控制煤岩交界面非协调变形。基于此提出了采用高预应力锚杆支护与薄弱区域加强支护的变形控制思路,制定了小保当一号井大断面巷道半煤岩巷道围岩变形控制方案,并开展了井下工业试验,取得了较好的应用效果,在监测期内巷道顶板的位移量为28 mm,两帮的位移量为80 mm,底板的位移量为43 mm,随后围岩变形趋于稳定,巷帮煤岩交界处的变形控制效果显著,表明采用该方案可有效控制大断面半煤岩巷围岩变形。

Aiming at the difficulty of surrounding rock deformation control in large section semi coal rock roadway,taking the Xiaobaodang No.1 Mine as the research background,the distribution of rock layers,in-situ stress distribution,and crack development in the surrounding rock of the roadway were tested,and the deformation and failure evolution characteristics of the roadway surrounding rock were analyzed.Through laboratory experiments and numerical simulations,the mechanical properties and deformation failure forms of semi coal rock composite were analyzed.It was revealed that the coal with lower strength first ruptured and slid at the coal rock interface,and the deformation continued to extend deeper.As the integrity and strength of the coal rock mass continued to weaken,non-uniform and progressive instability failure of the roadway was caused from bottom to top.The key to improving the stability of surrounding rock in large cross-section semi coal rock roadway is to control the non coordinated deformation of the coal rock interface.Based on this,a deformation control concept of using high prestressed anchor support and strengthening support in weak areas was proposed.And the deformation control plan for the surrounding rock of the semi coal rock roadway in the large section of Xiaobaodang No.1 mine was developed,and underground industrial experiments were conducted,achieving good application results.During the monitoring period,the displacement of the roadway roof was 28 mm,the displacement of the two sides was 80mm,and the displacement of the bottom plate was 43 mm.Subsequently,the deformation of the surrounding rock stabilized,the deformation control effect at the intersection of coal and rock in the roadway is significant,indicating that this scheme can effectively control the surrounding rock deformation in large cross-section semi coal rock roadway.