急倾斜煤层端面顶板稳定性分析
Stability Analysis of End Face Roof of Steep Inclined Coal Seam
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摘要: 急倾斜顶板矿压显现规律复杂,并且急倾斜煤层在形成过程中由于受到构造运动的强烈挤压,煤层及其顶底板中节理、裂隙等软弱面比较发育,易失稳垮落,支护不当时易发生片帮与冒顶事故。针对急倾斜煤层开采端面顶板破碎情况严重影响安全生产,以陈蛮庄煤矿3402工作面为工程背景,进行顶板孔观测、构建顶板力学模型、理论分析、数值模拟等,进一步分析了急倾斜煤层端面顶板稳定性。研究结果表明:急倾斜煤层工作面顶板比较破碎,易造成顶板垮落事故,影响液压支架的支护能力,进而引起频繁的煤壁片帮,造成安全事故;工作面上部由于充填不充分,应力集中程度仍然随着工作面推进距离的增加而增大。造成急倾斜煤层端面顶板破坏程度较严重;针对急倾斜煤层端面顶板破断特征规律,通过建立急倾斜煤层采场的物理模型,经过理论公式计算出顶板初次来压步距L,最大拉应力与顶板岩层抗拉强度比较得出急倾斜煤层顶板破碎的根本原因。Abstract: The pressure of the steep roof is complicated, and the steep coal seam is strongly extruded by the tectonic movement in the process of formation. The soft surface of the joints and cracks in the coal seam and its top and floor is more developed, and it is easy to lose stability and collapse. Take 3402 working face of Chenmanzhuang Coal Mine as the object, the roof hole observation, the theoretical analysis of the roof mechanics model and the numerical simulation are carried out to further analyze the stability of the face roof of the steep coal seam, and the results show that the steep inclined coal is a steep coal seam. The roof of the working face is relatively broken, which easily causes the roof falling accident and affects the supporting capacity of the hydraulic support, and then causes the frequent coal wall caving and the safety accidents. The stress concentration degree still increases with the increase of the advancing distance of the working face because of the insufficient filling. The failure degree of the top plate of the steep coal seam is serious, and the physical model of the face roof of the steep inclined coal seam is established. Through the establishment of the physical model of the stope of the steep seam, the initial pressure step L of the top plate is calculated by the theoretical formula, and the maximum tensile stress is compared with the tensile strength of the roof rock, and the roof breakage of the steep seam is obtained.