承压条件下工作面底板破坏规律研究

Research on failure law of working face floor under pressure conditions

根据内蒙古某矿4301工作面概况,以底板破坏情况为研究对象,分析4301工作面推进过程中底板破坏规律,利用材料力学理论分别分析工作面顶板初次来压之前、顶板初次垮落期间以及顶板周期来压期间底板的破坏情况,3种状态底板最大弯曲变形位置;以弹塑性力学的相关理论,计算出了龙泉煤矿4301工作面沿走向的底板最大破坏深度和最大深度的位置,通过UDEC数值模拟软件模拟了4301工作面开采底板破坏情况,模拟结果显示随着煤层开挖底板破坏深度的延伸速度较大,当第二次周期来压后底板破坏深度的延伸速度逐渐减小,煤层底板最大塑性破坏深度为34 m,与理论计算中底板的最大破坏深度32.5 m相近。研究为底板岩层注浆改性层位确定提供重要理论依据。

According to the general situation of a mine in Inner Mongolia,taking the floor failure as the research object,the law of floor failure in the process of No.4301 working face advancing was analyzed,and the floor damage situation before the first weighting of the working face roof,during the first caving of the roof,and during the periodic weighting of the roof were analyzed respectively using the theory of material mechanics,as well as the maximum bending deformation position of the floor in three states.Based on the relevant theory of elastic-plastic mechanics,the maximum failure depth and the location of the maximum depth of the floor along the strike of No.4301 working face in Longquan Coal Mine were calculated.The failure of the 4301 working face was simulated by UDEC numerical simulation software.The simulation results showed that the extension speed of the floor failure depth was larger with the coal seam excavation,and the extension speed of the floor failure depth gradually decreased after the second cycle of pressure.The maximum plastic failure depth of the coal seam floor was 34 m,which was close to the maximum failure depth of 32.5 m in the theoretical calculation.The study provides an important theoretical basis for the determination of the floor rock layer modified by grouting.