Daliuta Coal Mine, CHN Energy Shendong Coal Group Co., Ltd.

基于西北某矿8209工作面的围岩地质条件,对特厚煤层综放开采顶煤冒放性的影响因素进行分析,显示顶煤的冒放性与煤体强度、煤层埋深、煤体裂隙发育、夹矸及顶板条件相关。根据综放工作面顶煤冒落充分松散的必要条件,计算得到采煤高度不低于3.2m,并利用数值模拟软件FLAC3D研究不同采高下超前支承压力的分布规律及顶煤破坏特征。结果显示,采高3.9m时,工作面超前支承压力峰值最大,影响范围最大,顶煤能够完整的破坏;但当采高大于3.9m时,随着采高的继续增大,煤壁加剧破坏,不利于工作面前方的稳定性,因此采高为3.9m时的采放比(1∶3.514)最合理。

This paper analyzes the influential factors on top coal caving with extra thick coal seam in fully mechanized topcoal caving based on the surrounding rock geological conditions of 8209 working face in Tongxin mine. The results show thatthe top coal caving is related to coal body strength, coal seam buried depth, coal body fracture development, gangue inclusionand roof conditions. According to the necessary conditions of fully loose top coal in fully mechanized top coal caving face, themining height is calculated to be no less than 3. 2 m, and the distribution law of advance bearing pressure and top coal failure characteristics under different mining heights are studied using numerical simulation software FLAC3D. The results showthat when the mining height is 3. 9 m, the peak value of advance bearing pressure in the working face is the largest, the influential range is the largest, and the top coal can be completely destroyed; However, when the mining height is greater than3. 9 m, with the continuous increase of mining height, the damage of coal wall intensifies, which is not conducive to the stability in front of the working face, that is, when the mining height is 3. 9 m, the mining-caving ratio ( 1∶ 3. 514) is the mostreasonable.