为划定急倾斜俯伪斜上保护层开采的保护范围,对东林煤矿急倾斜俯伪斜上保护层开采的被保护层瓦斯压力进行了现场考察试验.根据急倾斜俯伪斜采煤法的特点,对被保护层瓦斯压力考察方案进行了设计;研究了被保护层的原始瓦斯压力赋存规律,瓦斯压力随保护层工作面推进的变化规律和“四带”范围;在此基础上,划定了考察区域保护层沿倾斜下山方向和走向的保护范围.结果表明:该矿考察区域急倾斜俯伪斜保护层沿倾斜下山方向的卸压角为78.7^o;保护层伪斜工作面倾向各处的走向卸压角呈非均匀分布,其大小为43.5^o~53.6^o.考虑到煤层采掘过程中的不可预测因素的影响,东林煤矿急倾斜俯伪斜上保护层的保护范围沿走向和倾斜下山方向分别按40^o和78^o的卸压角划定是安全可靠的.
An investigation of the gas pressure of steep-inclined upper protective layer during pitching oblique mining (POM) was carried out to locate the protection region in the Donglin coal mine. The investigation was designed according to the characteristics of POM. The original gas pressure in the protected seam, the variation in pressure, the "Four-zone" range of pressures and the mining protective layer were studied. This investigation located the protected regions along the inclines and strikes of the protective layer. The results show the underside of the steep, inclined protective layer has a pressure relief angle of 78.7 degrees and that the strike pressure relief angle along the oblique working face of the protective layer is 43.5 to 53.6 degrees. It is safe to demarcate the protected regions of the steep, inclined protective layer during POM in the Donglin coal mine as a 40 degree strike and a 78 degree incline of the pressure relief angle. These values allow for the uncertainties present in the mining process.