坚硬顶板切顶成巷结构演化与稳定控制机理

Structure evolution and stability control mechanism of hard-roof cutting for roadway retaining

为深入了解坚硬顶板切顶成巷结构演化过程及稳定控制机理,采用物理试验、连续-非连续介质模拟试验、力学分析开展研究。结果表明:切割顶板在采空区侧形成长悬臂梁结构,切割端首先旋转下沉,未切割端首先破断,当切割端顶板触底后,切割顶板沿中部断裂;切顶扰动对采空区顶板结构的影响主要集中在切割顶板岩层,对上覆岩层结构影响较小;切割顶板在巷道上方形成短悬臂梁结构,进一步变形后在煤体深部产生垂直张拉裂缝,然后向采空区旋转变形,并与采空区垮落切割顶板接触,形成平衡结构;切顶高度及切顶角参数对平衡结构的力学作用有较大影响,当切顶角增加到一定值时,平衡结构关键点之间的作用力比较接近,可满足不同部位的顶板岩体协调变形。

To deeply understand structural evolution process and stability control mechanism of hard-roof cutting for roadway retaining,the research was carried out through physical test,continuous-discontinuous medium simulation test,and mechanical analysis.The results have shown that the cutting roof forms a long cantilever beam structure on the side of the goaf.The cutting end first rotates and sinks,and the uncut end first breaks.When the cutting end roof touches the bottom,the cutting roof breaks along the middle.The influence of roof-cutting disturbance on the roof structure of goaf is mainly concentrated on the cutting roof strata,having little effect on the overlying strata structure.The cutting roof forms a short cantilever beam structure above the roadway.After further deformation,vertical tensile cracks appear in the deep coal body,rotate,and then deform toward the goaf in contact with caving cutting roof of the goaf to form a balanced structure.The cutting height and cutting angle have great influence on mechanical action of balance structure.When the cutting angle increases to a certain value,the force between key points of balance structure was relatively close,which can meet the coordinated deformation of roof-rock-mass in different parts.