厚煤层放顶煤长壁工作面矿压研究

本文在分别采用长顶梁及短顶梁两种掩护支架的两个工作面开采试验的基础上对厚约6m的长壁放顶煤回采时上覆岩层及顶煤活动规律,支架受载及合理架型作出分析,认为放顶煤工作面支架截荷并不高于类似条件下小采高的分层工作面。长顶梁支架适用于顶煤较硬的条件,若采用超前工作面平行煤壁深孔注水可降低煤体强度,增加顶煤放出率。试验中观测到上覆竖硬岩层超前工作面断裂迫使顶煤于工作面前8m处就开始产生斜向断裂裂缝,并逐渐扩展,加密而降低其刚度。因此,放顶煤工作面支架实际处于工作面前方煤体及后方岩石支承的上覆台阶错动的平衡岩石块梁结构的掩护下,其截荷主要为顶煤及下覆破碎直接顶的重量。图7,表5,参3.

A RESEARCH INTO UNDERGROUND PRESSURE IN LONGWALL.FACE INDUCED BY USE OF SUBLEVL CAVING IN THICK SEAM

This report is written basically in according with the test results of two fully mechanized longwall sublevel caving faces. One was equipde with a set of power caving supports with long canopy and twin armored face conveyors, and the other was equiped with a set of power caving supports with the short canopy and installed with one armored face conveyor. This paper mainly deals with the movement laws of roof coal and upper strata, and support loadings and types when coal face is under operation which has thickness of coal seam about 6 meters. It is believed that support loading in sublevel caving working faces do not surpass that in slicing coal faces which have similar roof and coal seam conditions. It is aiso proved that the caving supports with long canopy are best suitable for use in hard thick coal seams. If decp holes are drilled in the panel in parallel with facline and are injccted with high pressure water, the strength of coal body will be reduced, and the caved roof coal recovery will be incerased. It has been observed in-mine during the period of underground test that the hard upper roof strata brode in the front of coal face, and the broken strata enforced coal seam to crack at 8 meters before facclinc. Then the ercvics in coal seam extended and gradually, became denser in according with the advance of working face, meantime the rigidity of coal seams was decreased. Through practical observation and analysis, it is also proved that caving supports in thick coal seams are protected by the coal body before the faceline and the broken overburden ballance structure which is formed as beam block with descending steps Thus the loading in caving support are mainly from the weight of lower broken immediate roof strata. 7figs, 5tabs, 3refs.