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在开采坚硬顶板煤层时,改善回采工作面的矿压管理,对井工开采极为重要。根据国内几个主要矿区中对有这种煤层的矿井的地质条件分析表明(表1),顶板的构造及其强度性能是各种各样的。直接顶厚度变化为煤层厚度的0～6倍,其抗压极限强度变化为3～60兆帕。并且几乎有一半顶板(占47％)是不稳定和极不稳定的。老顶厚度为1～100米,其抗压强度为45～268兆帕,其中坚硬岩石占73％,极坚硬岩石占27％。开采煤层厚度绝大部分为2米以下,埋藏深度在50～970米。上述开采条件决定了矿压显现的多样性。试验证实,坚硬顶板在下沉期间的矿压
When mining hard roof coal seam, it is very important to improve the underground pressure management in mining face. According to the analysis of the geological conditions in the coal mines in several major mining areas in China (Table 1), the roof structure and its strength properties are various. The direct top thickness changes from 0 to 6 times the thickness of the coal seam, and the ultimate compressive strength varies from 3 to 60 MPa. And almost half of the roof (47%) is unstable and extremely unstable. The thickness of the old roof is 1 to 100 meters and its compressive strength is 45 to 268 MPa, of which hard rock accounts for 73% and very hard rock accounts for 27%. The thickness of most coal mining is 2 meters below the buried depth of 50 ~ 970 meters. The mining conditions determine the diversity of mine pressure. Test confirmed that the rock roof during sinking pressure