矿井深部防水煤柱超低摩擦滑动型冲击地压机理研究

Anomalous low friction sliding rock burst of waterproof coal pillar in deep mine is a kind of coal mine dynamic disaster with large-scale integral sliding failure of coal pillar in recent years. Its essence is that under the action of periodic dynamic load caused by coal rock fracture and water accumulation in mined-out area, anomalous low friction is formed between coal pillar and roof and floor, and coal pillar has large sliding displacement under lateral disturbance. The project adopts field research and theoretical analysis methods to establish the structural mechanics model of roof-coal pillar-floor structure under the combined action of overburden pressure, periodic dynamic load caused by coal and rock mass fracture and water accumulation in mined-out area. The anomalous low friction experiment of coal pillar was used to test the overlying strata pressure, dynamic load frequency, soaking time of coal-rock, pore water pressure of coal-rock interface and sliding friction displacement of coal pillar under the action of coal seam inclination angle. The relations among overburden pressure, dynamic load frequency, coal and rock soaking time, pore water pressure at coal and rock interface, coal seam inclination, coal pillar stress field and displacement field were studied by numerical simulation method. The purpose of this paper is to put forward the displacement criterion for the occurrence of anomalous low friction of coal pillars, determine the critical threshold of ultra-low friction of coal pillars, reveal the mechanism of rock burst induced by anomalous low friction of deep waterproof coal pillars, and provide a new solution for the realization of efficient prevention and control of water-proof coal pillar rock-burst in deep water-rich mines.

矿井深部防水煤柱超低摩擦滑动型冲击地压是近年来出现的一种大范围煤柱整体滑动破坏的煤矿动力灾害，其实质是深部防水煤柱在煤岩破裂产生的周期性动载及采空区积水作用下，煤柱与顶板、底板间形成超低摩擦，在侧向扰动下煤柱发生较大滑动位移。项目采用现场研究与理论分析方法，建立上覆岩层压力、煤岩体破裂产生的周期性动载和采空区积水的水力共同作用下的顶板-煤柱-底板结构力学模型；采用煤柱超低摩擦实验，测试上覆岩层压力、动载频率、煤岩浸泡时间、煤岩界面孔隙水压力、煤层倾角作用下煤柱滑动摩擦位移；采用数值模拟方法，研究上覆岩层压力、动载频率、煤岩浸泡时间、煤岩界面孔隙水压力、煤层倾角与煤柱应力场、位移场之间的关系。旨在提出煤柱发生超低摩擦的位移判据，确定煤柱发生超低摩擦的临界阈值，揭示深部防水煤柱超低摩擦诱发冲击地压机理，为深部富水矿井实现防水煤柱冲击地压高效防控与治理提供新的解决思路。

矿井深部防水煤柱超低摩擦滑动型冲击地压是近年来出现的一种大范围煤柱整体滑动破坏的煤矿动力灾害，其实质是深部防水煤柱在煤岩破裂产生的周期性动载及采空区积水作用下，煤柱与顶板、底板间形成超低摩擦，在侧向扰动下煤柱发生较大滑动位移。项目采用现场研究与理论分析方法，建立上覆岩层压力、煤岩体破裂产生的周期性动载和采空区积水侧向作用下的顶板-煤柱-底板结构力学模型；采用煤柱超低摩擦实验，测试上覆岩层压力、动载频率、煤岩浸泡时间等不同条件下煤柱滑动摩擦位移；采用数值模拟方法，研究上覆岩层压力、动载频率、摩擦系数与煤柱应力场、位移场之间的关系。提出煤柱发生超低摩擦的位移判据，确定煤柱发生超低摩擦的临界阈值，揭示深部防水煤柱超低摩擦诱发冲击地压机理，为深部富水矿井实现防水煤柱冲击地压高效防控与治理提供新的解决思路。同时揭示水化作用下煤体物理力学性质变化机制，进而研发了新型螯合型湿润剂，利用螯合作用将煤中矿物质溶解，同时使煤中微孔隙得以打开和连通，改变了煤体的骨架结构，改变煤样物理力学性质，降低冲击倾向性指数，并基于冲击地压扰动失稳理论，揭示煤层注水防灾机理，为提高注水效果防治冲击地压等灾害提供技术支持。