摘要:
现有对于端面顶板冒漏的研究多针对单一煤层，而近距离煤层群开采下的端面顶板稳定性不同于单一煤层，在近距离煤层群开采过程中，由于相邻煤层间距较小，上位煤层开采后会使下位煤层开采区域的顶板结构和应力环境发生变化，容易出现端面冒顶、煤壁片帮和顶板压架等灾变问题。以发生过3次大范围冒顶事故的某矿井17101工作面为工程背景，根据煤壁、液压支架与端面顶板稳定性关系，建立了近距离煤层群重复采动下的“端面顶板-煤壁-支架”模型，确定了近距离煤层群重复采动下端面冒顶的影响因素主要为顶板-围岩强度、支架工作阻力、推进速度和端面距。利用UDEC模拟软件模拟不同影响因素对重复采动下端面冒顶的影响，得出以下结论：① 重复采动过程中顶板与煤体都受到了损伤破坏，顶板与煤壁强度降低，容易出现支架前端顶板冒落，引发顶板冒落与煤壁片帮等灾害，顶板-围岩强度越大，顶板的稳定性越好。② 液压支架工作阻力偏低是造成工作面端面冒顶的重要原因之一，液压支架工作阻力越大，端面顶板越稳定。③ 工作面推进速度对端面顶板稳定性具有明显的影响，工作面推进速度越慢，采场顶板下沉现象越严重。④ 端面距为端面冒顶的重要影响因素，端面冒顶与端面距呈线性相关，冒落高度随着端面距的增大而增加，端面距越小，端面顶板越稳定，但是端面距太小也会影响到工作面的正常开采，应根据实际情况来确定。针对4个主要影响因素，提出了重复采动下端面冒顶的防治措施，即增加顶板与围岩的强度、提高液压支架工作阻力、合理控制推进速度和减小端面距。上述防治措施可为近距离煤层群重复采动下端面冒顶提供有效的解决方法。
Abstract:
The existing researches on face end roof falling are mostly focused on single coal seam, while the stability of the face end roof under short-distance coal seam group mining is different from that of a single coal seam. In the process of short-distance coal seam group mining, due to the small spacing between adjacent coal seams, the roof structure and stress environment of the lower coal seam mining area will change after the upper coal seam is mined. This easily lead to catastrophic problems such as face end roof falling, coal wall spalling and roof pressure frame. Taking the 17101 working face of a mine that has experienced 3 large-scale face end roof falling as the engineering background, based on the stability relationship between the coal wall, hydraulic support and the face end roof, the ‘face end roof-coal wall-support’ model is established under repeated mining of short-distance seam group. This paper introduces the main influencing factors of face end roof falling under repeated mining of short-distance seam group are the strength of the roof and surrounding rock, support working resistance, advancing speed and face end distance. The UDEC simulation software is used to simulate the influence of different influencing factors on the face end roof falling under repeated mining, and conclusions are summarized as follows. ① The face end roof and coal body are damaged during repeated mining, the strength of the face end roof and coal wall is reduced, and the face end roof at the front end of the support is prone to fall, causing disasters such as roof falling and coal wall spalling. As the strength of the roof and surrounding rock increases, the stability of the roof is better. ② The low working resistance of the hydraulic support is one of the important reasons for the face end roof falling of the working face. As the working resistance of hydraulic support increases, the stability of the face end roof is better. ③ The advancing speed of the working face has a significant effect on the stability of the face end roof. The slower the advancing speed of the working face is, the more serious is the roof subsidence phenomenon of the at the stope. ④ The tip-to-face distance is an important influencing factor of the face end roof falling. The face end roof falling is linearly related to the tip-to-face distance. The falling height increases with the increase of the tip-to-face distance. The smaller the tip-to-face distance is, the more stable is the face end roof. However, too short tip-to-face distance will also affect the normal mining of the working face. The tip-to-face distance should be determined according to the actual situation. In the context of the four main influencing factors, the prevention and control measures for face end roof falling under repeated mining are proposed. The measures include increasing the strength of the roof and surrounding rock, improving the working resistance of hydraulic support, controlling the advancing speed reasonably and reducing the tip-to-face distance. The above prevention and control measures can provide an effective solution for the face end roof falling under repeated mining of short-distance seam group.
百度学术
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