煤矿工作面高强度、大尺度快速推进,导致采场覆岩运动范围增大,空间结构复杂。多工作面情况下,工作面与采空区覆岩结构协同运动,相互影响,造成的矿山动力灾害,称之为覆岩空间结构失稳型动力灾害。根据工作面上覆岩层边界状态的不同,将覆岩空间结构分为OX,F与T型3类。研究OX-F-T演化特征,即顶板O-X破断形成的OX结构为覆岩基本形式,同时又作为相邻工作面的边界条件,一侧为OX结构形成F型覆岩结构,两侧存在OX则形成T型覆岩结构。阐述不同结构的断裂运动规律,并将各结构进行详细分类。利用现场SOS微震监测系统,分别选取代表OX,F与T覆岩结构的单一工作面、双工作面、孤岛工作面,分析各工作面开采过程中的震源分布规律。针对不同覆岩结构特征,提出不同的防治措施,为冲击震动的预防工作提供理论指导。
The rupture and movement scope of overlying strata increase sharply since the high strength and rapid exploitation of the longwall mining faces;and the spatial structure formed by fractured strata becomes much more complex.The overlying strata would move and interact coordinately when more workfaces exist;hence leading to mining dynamic disasters that defined as spatial structure instability in this paper.Based on the boundary conditions,three basic forms that named OX,F and T structure are identified,respectively.The OX-F-T evolution of the overlying strata is presented that the O-X fracture is the elemental structure of overlying strata and also the boundary of adjacent workface,one side is OX constitute F structure,and both side with OX is T structure.The characteristics and detailed classifications for each type are elaborated.The microseismic system is used for on-site monitoring,single,double and isolated workfaces that represent the OX,F and T structure are selected respectively to research the distribution rules of seismic events;the results confirmed the OX-F-T spatial structure feature.At last,specialized methods are proposed targeted to workfaces with different spatial structures.The research results provide theoretical guidance for dynamic disaster prevention and control in coal mines.