基于煤体损伤演化的煤柱承载规律与宽度确定研究

Research on Determination of Coal Pillar Bearing Law and Width Based on Coal Damage Evolution

为了解决工作面煤柱承载规律不清晰和合理宽度难确定的现场难题,通过运用数值模拟和现场工业性试验等方法,对工作面巷道围岩变形规律、煤柱承载特性演化规律、煤柱内裂隙扩展规律和支护控制进行研究。分析了煤柱在受两侧采动影响下内部裂隙的演化过程和分布特征,揭示了采动应力下原生裂隙的扩展到宏观破裂面产生的损伤破坏机制,确定了煤柱两侧的损伤范围;在煤柱第1次损伤的基础上,进一步研究了沿空掘巷后煤柱内部裂隙由两侧向中间发育的破坏机理,建立了剪切裂隙和张拉裂隙的分布特征与煤柱承载特性的关系;研究了不同宽度煤柱对应的巷道围岩稳定性,最终确定了7106工作面风巷的护巷煤柱合理宽度为7.0 m;提出了使用高强度螺纹钢锚杆与双筋双梁钢筋梯子梁支护,并利用预应力锚索加强支护的工作面煤柱稳定性支护控制技术。现场应用实践表明支护控制效果良好。

In order to solve the on-site problems of unclear coal pillar bearing law and difficult determination of reasonable width,this paper uses numerical simulation and on-site industrial tests to analyze the wall rock deformation law, coal pillar bearing property evolution law, the law of internal crack propagation and support control of coal pillar. The evolution process and distribution characteristics of internal cracks of coal pillars under the influence of mining on both sides are analyzed, and the damage and failure mechanism of the expansion of the original cracks to the macro-fracture surface under mining stress is revealed, and the damage range on both sides of the coal pillar is determined. Based on the first damage of the coal pillar, the failure mechanism of the internal cracks of the coal pillar from the two sides to the middle after the roadway was excavated, and the distribution characteristics of the shear cracks and the tensile cracks and the pillar load were established. The stability of roadway surrounding rock corresponding to coal pillars different widths are studied, and finally the wind at 7106 face is determined. The reasonable width of the coal pillar of the roadway is 7.0 m;the coal pillar stability support control technology is proposed by using high-strength threaded steel bolts and double-ribbed double-beam reinforced ladder beam support, and using prestressed anchor cable to strengthen the support. Field application practice shows that the support control effect is good.