Yuhua Coal Mine, Shaanxi Shanmei Tongchuan Mining Co., Ltd.

为了解决玉华煤矿特厚煤层综放开采条件下采空区瓦斯涌出量大的问题,开展特厚煤层综放工作面覆岩裂隙演化物理相似模拟实验。掌握特厚煤层采动覆岩裂隙分布特征、“三带”高度及底板应力变化规律,以此为基础设计试验工作面采空区瓦斯抽采钻孔的合理层位,最终以卸压瓦斯抽采效果为考察指标,利用定向长钻孔代替常规高位钻孔对抽采钻孔层位布置的合理性进行验证。结果表明,工作面冒落带高度22m,冒采比2.2,裂隙带高度140m,裂采比14。参考矿井实际顶板垮落情况,确定顶板定向长钻孔的3个合理终孔层位分别为7m、15m、40m。通过瓦斯抽采效果对比得到定向长钻孔的瓦斯抽采浓度和有效抽采距离均比普通钻孔提高了1倍以上,抽采效果良好。

To solve gas outburst under the condition of extra-thick coal seam fully-mechanized mining in Yuhua coal mine,the physical analog simulation experiment on overburden rock fracture evolution process of extra-thick coal seam fully-mechanized mining face is conducted. The distribution characteristics of extra-thick coal seam mining-caused fracture and thechange law of “ three zones” height and floor stress are obtained. The reasonable drilling horizon of gas extraction in the goafof the experimental working face is designed, and the effect of pressure release gas extraction is finally regarded as an examination index. The effectiveness of determining the borehole horizon by directional long borehole instead of conventional highposition borehole is proved. The results show that the height of the caving zone of the working face is 22 m with caving-mining ratio of 2. 2, and the height of the fracture zone is 140 m with fracture-mining ratio of 14. Referring to the actual roof collapse of mine, three reasonable final hole horizon of directional long borehole in roof are determined as 7 m, 15 m an 40 m,respectively. In terms of gas extraction effect, the gas extraction concentration and effective extraction distance of directionallong borehole are double, compared with conventional borehole.