深部特厚煤层巷道围岩渐进弱化诱发冲击地压机理研究

Rock burst is one of the most serious dynamic hazards in underground coal mines in China. The rock burst in extra-thick coal seams has complex mechanism and many types. Among many types of rock burst, the one induced by the gradual weakening of surrounding rock of roadways is one of the typical rock bursts occurring in deep extra-thick coal seams, and the mechanism of the rock burst needs to get to know. On the basis of understanding the characteristics of support structure evolving and rock burst induced by the gradual weakening surrounding rock of roadway in deep extra-thick coal seam, with rock mechanics and underground pressure theories combining in-site investigation, numerical simulation, large-scale physical experiments, laboratory testing and in-site monitoring, the project analyses the mechanism of the support structure evolving induced by the gradual weakening surrounding rock of roadway in deep extra-thick coal seam and its characteristics, firstly. Secondly, the valuation method for surrounding rock weakening and support structure failure of support structures of surrounding rock of roadways in deep extra-thick coal seams and its failure mechanism will be discussed. Then, the transfer mechanism of failure effect of support structures of surrounding rock of roadways in deep extra-thick coal seams and burst response will be studied. Based on the above research, the relation among of surrounding rock weakening of roadways in deep extra-thick coal seams, support structure evolving and its failure, failure effect transfer and rock burst appearance will be revealed, and which will be used to reveal the mechanism of support structure failure, failure effect transfer and rock burst response induced by the gradual weakening surrounding rock of roadway in deep extra-thick coal seam. The research results will provide theoretical basis for the prevention of this type of rock burst.

冲击地压是我国井工开采煤矿面临的最为严重的动力灾害之一。深部特厚煤层冲击地压机理复杂，围岩渐进弱化诱发冲击地压是深部特厚煤层冲击地压的典型类型之一，机理有待揭示。项目结合深部特厚煤层巷道围岩渐进弱化诱发承载结构演化及冲击地压特点，运用岩石力学、矿山压力等理论，并结合现场调研、数值模拟、大型物理模拟试验、实验室试验、现场监测等，首先分析深部特厚煤层巷道围岩渐进弱化诱发承载结构演化机制及其特征，其次探讨深部特厚煤层巷道围岩弱化与承载结构失稳评判方法及失稳机制，然后研究深部特厚煤层巷道围岩承载结构失稳效应传递机制及冲击响应，从而揭示深部特厚煤层巷道围岩弱化、承载结构演化与失稳、失稳效应传递、冲击地压显现之间的联系，用以揭示深部特厚煤层巷道围岩渐进弱化诱发冲击地压机理。期望通过研究，深入揭示深部特厚煤层巷道围岩渐进弱化诱发承载结构失稳及失稳效应传递机制和冲击响应，为此类冲击地压防治提供理论依据。

深部特厚煤层巷道围岩弱化诱发冲击地压机理与传统的冲击地压不同，围岩弱化诱发承载结构演化和失稳，失稳效应（主要是位移）传递至冲击体上，冲击体发生失稳。围岩承载结构失稳效应是冲击地压的力源，冲击体发生冲击是被动的。本项目采用理论分析、数值模拟、相似材料模拟、现场监测数据分析等方法，研究了深部特厚煤层巷道围岩弱化、围岩承载结构演化与失稳、围岩承载结构失稳效应传递、冲击地压显现之间的相互关系。结果表明：冲击地压具有显著的煤层厚度效应，煤层厚度越大，发生冲击地压危险性越大；弱化系数、均布载荷、支护强度、弱化半径都对巷道围岩承载结构演化特征具有显著的影响，但影响程度由大到小依次为弱化系数、均布载荷、支护强度、弱化半径；轴对称圆形巷道围岩承载结构的稳定性取决于自身的几何参数、力学参数和原岩应力，巷道半径越大、围岩的粘聚力及内摩擦角越小，围岩承载结构临界平衡状态时的径向位移越大，越易失稳；巷道围岩弱化伴随着应力演化和承载结构演化，围岩位移、应力、震动等物理量具有明显的变化特征，巷道围岩渐进弱化造成围岩承载结构向外扩大，薄壁圆环在高应力作用下的结构性失稳；深部特厚煤层巷道围岩弱化诱发冲击地压的典型响应物理量是位移，可监测的直接物理量为巷道围岩位移、锚索受力、围岩离层，可监测的间接物理量为围岩应力（承载结构体内）、微震；深部特厚煤层巷道围岩弱化诱发冲击地压的过程是“围岩弱化→承载结构演化→承载结构失稳→失稳效应传递→冲击显现”。在获得上述认识的基础上，提出了三种冲击地压模型。. 课题组将获得的上述成果应用于特厚煤层采区下山保护煤柱合理宽度的确定及煤巷支护体系抗冲击能力评估等。. 本项目对深部特厚煤层开采冲击地压防治具有重要的现实意义。