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以某煤矿近距离坚硬顶板煤层上行开采为工程背景,通过理论计算、相似模拟与数值模拟相结合的方法,综合分析了下部煤层中的A603工作面和上部煤层的A6-103上行回采工作面的回采过程中的覆岩破断形态和应力演化规律,并结合现场微震监测结果,将A6-103工作面的整个回采过程分为正常回采阶段、过渡阶段及上行开采等三个阶段。在此基础上,通过对三个回采阶段的对比分析,认为过渡阶段由于受A603采空区边界支承压力和A6-103工作面超前支承压力的叠加影响,使得A603采空区切眼附近、存的易失稳的“悬空结构”成为上行工作面的最大危险源,所以过渡阶段的危险性最大。据此,现场针对该危险源结构采取了预裂爆破、注浆充填及调整推进度等安全保障措施,保证了A6-103工作面的安全回采。
Taking the mining of hard roof coal seam near a certain coal mine as the engineering background, by combining the theoretical calculation, similar simulation and numerical simulation, the A6-103 working face in the lower coal seam and the upper coal seam A6-103 are analyzed synthetically In the process of recovery, the overlying rock breaking patterns and stress evolution rules are combined. Based on the results of on-site microseismic monitoring, the whole recovery process of A6-103 face is divided into three stages: normal mining stage, transitional stage and upward mining. On this basis, through the comparative analysis of the three recovery phases, it is considered that the transitional phase is affected by the superposition of the boundary support pressure of A603 goaf and the advance support pressure of A6-103 working face, Unstable “dangling structure ” becomes the biggest danger source of the upper face, so the transitional phase is the most dangerous. Accordingly, on the spot, the safety protection measures such as presplit blasting, grouting filling and adjusting propulsion are adopted for the structure of the dangerous source, so as to ensure the safe recovery of A6-103 face.