突出煤层群俯伪斜上保护层开采的保护范围研究

Protection Scope Research of Upper Protective Layer with Bow Pseudo-oblique Mining in Outburst Coal Seams

为研究突出煤层群急倾斜煤层俯伪斜工作面上保护层开采的保护范围划定问题,对某矿4-6区首采工作面上保护层开采的保护范围进行了现场考察研究。结果表明:上保护层开采后沿倾向上、下边界保护范围的卸压角分别为85.7°和79.5°,沿走向保护范围的卸压角在倾向不同高度呈不规则分布,为47.1°~74.1°,急倾斜煤层俯伪斜工作面上保护层考察的保护范围与防突规定划定范围有明显差异;保护层开采后,被保护层的透气性系数增大了53~360倍,卸压瓦斯抽采体积分数达到40%~65%,平均抽采率达到了79.1%,保护层开采瓦斯区域治理措施有效降低了被保护煤层开采的突出危险性。

In order to study the problem of locating the protection scope of steep-inclined upper protective layer with bow pseudooblique mining, a practical test research on the protection scope and protective effect for exploiting upper-protective layer was carried out at the first coalface of 4-6 district in a coal mine. The results show that the pressure-relief angles of upper protective layer are 85.7° and 79.5° along inclined upper and downside boundary respectively, and 47.1° to 74.1° along strike with irregular distribution in different height. As a result, there is significant difference about the protection scope between practical test and reference value of Coal and Gas Outburst Prevention Regulation. And besides, the permeability coefficient of protected layer was increased from 53 to 360 times, the volume fraction of pressure-relief gas drainage reached up to 40% to 65% and the average drainage rate reached up to 79.1%. Therefore, the gas regional control effect is remarkable so that the risk of coal and gas outburst is effectively reduced.