急倾斜煤层分段开采下部煤岩体应力及位移演化规律

为了掌握急倾斜特厚煤层分段开采时工作面下部煤岩体应力及位移演化规律，采用数值模拟方法研究了工作面下部煤岩体和工作面底板的应力及位移分布，并分析了分段高度和开采深度对下部煤岩体应力及位移的影响。研究表明：上分段开采后，下部不同深度煤岩体卸压范围均呈长轴沿煤层走向的椭圆状，但卸压范围并不对称，底板侧和顶板侧的煤岩体卸压程度不同，靠近底板侧卸压程度更大。下部煤体卸压深度大小为底板侧>工作面中部>顶板侧。煤层底板不同深度出现不对称卸压区，靠近回采分段上端部的煤层底板处垂直应力明显集中。急倾斜煤层分段开采，段高对下部煤体的卸压深度范围影响较小。开采深度不同时，随着埋深增加，工作面下部煤岩体应力集中区域增大，下部同一深度煤体的垂直应力、垂直位移均出现明显增加，开采深度对工作面下部煤岩体的卸压范围影响明显，埋深越大卸压范围也越大。

Evolution Law of Stress and Displacement of Lower Coal Rock in Subsection Mining of Steep Coal Seam

In order to master the evolution law of the stress and displacement of the lower coal rock of the subsection mining of steep and extra thick coal seam working face, the stress and displacement distribution of the lower coal rock of the working face and the the working face floor are studied by using the numerical simulation method, and the influence of the section height and mining depth on the stress and displacement of the lower coal rock is analyzed. The research shows that after the upper section mining, the pressure relief range of the coal rock at different depths in the lower part is elliptical with the long axis along the coal seam trend, but the pressure relief range is not symmetrical. The pressure relief degree at the floor side and the roof side is different, and the pressure relief degree near the floor side is greater. The relief depth of the lower coal body is the bottom plate side > the middle of the working face > the top plate side. Asymmetric pressure relief zones appear at different depths of the coal seam floor, and the vertical stress at the floor near the upper end of the mining section is obviously concentrated. For the subsection mining of steep coal seam, the section height has little influence on the pressure relief depth range. When the mining depth is different, with the increase of the burial depth, the stress concentration area of the lower coal rock of the working face increases, and the vertical stress and vertical displacement of the coal mass at the same depth at the lower part increase significantly. The mining depth has an obvious impact on the pressure relief range of the lower coal rock. The larger the burial depth, the larger the pressure relief range.