高韧性煤层综放开采难冒放机理及弱化效果研究

Study on difficult falling mechanism and weakening effect of fully-mechanized top coal caving mining in high ductibility seam

为改善高韧性煤层综放开采顶煤冒放性,以煤样物理力学参数测定试验为基础,从理论方面对高韧性特厚煤层综放开采顶煤难冒放机理和弱化机理进行了分析;运用UDEC模拟软件从初采和正常推进2个阶段对顶煤冒放情况进行了数值模拟。结果表明:高韧性煤层弹性模量小于顶板岩层时,在矿山压力作用下,顶煤的变形挠度大于顶板,导致顶板不能将矿山压力较好的传递给顶煤,综放作业时顶煤难破碎垮落,易形成悬顶,冒放性较差,不利于顶煤的回收;对顶煤采取弱化措施后,回采时顶板垮落情况明显改善,直接顶随采随冒,较好的充填了采空区,顶煤冒放性较好。

In order to improve the top coal cavability of fully-mechanized top coal caving mining face in high ductibility seam, based on the experiment of physical and mechanical parameters of coal sample, from theoretical aspect, an analysis was conducted on the top coal difficult caving mechanism and weakening mechanism of fully-mechanized top coal caving mining face in high ductibility seam. UDEC simulation software was applied to numerical simulation on top coal caving condition at initial mining stage and the normal mining advancing stage of the coal mining face.The results showed that when the elastic modulus was lower than the roof strata, under the role of mine pressure, the deformation bending of the top coal would be higher than the roof and would cause the roof ditont well pass mine pressure to the top coal. Thus during the fully-mechanized top coal caving operation,the top coal would be difficult to be broken and fallen and a suspended roof would be easily formed.The top coal caving would be poor and would not be favorable to top coal recovery.After weakening measures conducted on top coal, during coal mining operation, the top coal falling condition was obviously improved, the immediate roof would be caved with mining operation and would be well backfilled in the goaf.The top coal cavability was good.