Wei Weijie, Pan Weidong, Zhang Jinwang, Zhao Zhining, Yang Liu, Zhang Xiangyang
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Abstract
Dynamic sublevel caving technology (DSCT) proposed by the researchers is one of effective methods to solve the problems of low top coal recovery, poor drawing balance and support stability in longwall top coal caving (LTCC) with large dip angle. To investigate the reasonable number of supports in a sublevel (N) and the top coal drawing mechanisms under DSCT, this research takes Panel 7401 in Zouzhuang Coal Mine as the geological background. Firstly, the optimal threshold value of N is theoretically analyzed, and the numerical simulations of drawing experiments under different Ns are calculated. The results show that when N = 3, the top coal recovery is the highest, the number of excessive drawing top coal at the upper end is relatively small, and the drawing balance is great, which is conducive to improving the resource recovery and safety management. With increasing N, the over-development of right top coal boundary towards the upper end increases, the range of coal ridge in the lower sublevel also gradually increases, while the strong force chain area at the upper end gradually decreases, resulting in the support stability becoming worse. In addition, the displacement of top coal at the upper end gradually increases with increasing N, and the permanent loss feature of residual top coal exists in the upper sublevel. The field top coal recovery under DSCT was measured finally, obtaining that DSCT can improve the top coal recovery by about 5% and promote the stability and working efficiency of the support. The research results have great theoretical and guiding significance for the high yield and high efficiency LTCC technology for thick coal seam with large dip angle.
期刊介绍：
Although many phenomena observed in granular materials are still not yet fully understood, important contributions have been made to further our understanding using modern tools from statistical mechanics, micro-mechanics, and computational science.
These modern tools apply to disordered systems, phase transitions, instabilities or intermittent behavior and the performance of discrete particle simulations.
>> Until now, however, many of these results were only to be found scattered throughout the literature. Physicists are often unaware of the theories and results published by engineers or other fields - and vice versa.
The journal Granular Matter thus serves as an interdisciplinary platform of communication among researchers of various disciplines who are involved in the basic research on granular media. It helps to establish a common language and gather articles under one single roof that up to now have been spread over many journals in a variety of fields. Notwithstanding, highly applied or technical work is beyond the scope of this journal.
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