【摘要】 分 4 个阶段模拟了无人工作面开采坚硬顶板采场顶板的运动规律。第 1 阶段,坚硬顶板的悬而不落是下一区段无煤柱开采的隐患。开采范围达到 8 000 m2时的第 2 阶段,采场坚硬顶板的冲击性垮落,使工作面前方煤体及巷道既已形成的高应力区骤然释放。开采范围继续扩大的第 3 阶段和第 4 阶段,坚硬顶板从整体大范围冲击性运动向周期性分段运动转化。北京矿务局木城涧煤矿无人工作面坚硬顶板在采场面积约为 8 000 m2的初次冲击性垮落,验证了 3DEC理论研究结论,其强制放顶等防冲措施实施的最佳时机为第 2 阶段的开采活动结束之前。更多还原

【Abstract】 The movement of hard roof in manless working face extraction has been simulated with three dimensional distinct element code for dividing into four stages. At the first stage the hanging hard roof is a danger to extract the next district. At the end of the second stage when extracted area has been up to 8000m2, impacted fall of hard roof relieves high stresses comprised before on coal seam and roadways. However, if extracted area is expanded to the third or the forth stage, the whole impacted movement of the hard roof will change to the periodic movement. The theoretical results from 3DEC have been verified in Muchengjian colliery, Beijing Mining Bureau which hard roof of manless working face falls violently at the first time with area of about 8000m2. And the best chance of prevent rock burst with overhead caving is before the end of the second extracted stage.更多还原