对于特厚煤层分层开采，掌握煤层开采后下伏煤层应力分布及破坏特征能够为精准判定采空区瓦斯富集区提供一定理论依据。因此，为厘清倾斜特厚煤层下伏煤层应力及塑性破坏区的分布特征，开展了不同煤层倾角工作面回采的数值模拟计算。首先基于采空区压实理论，获得了采空区垮落岩体的应力-应变关系，进而通过迭代反演确定了充填体的岩体力学参数。在此基础上，通过数值模拟计算及分析，得到了煤层倾角变化对下伏煤层应力分布及破坏特征的影响规律。结果表明：在采空区底板范围内，随着煤层倾角增大，采空区应力恢复“O”形圈不再以采空区中部走向线对称分布，而向倾向下部偏移。沿倾向，在采空区的上下两端，侧向应力集中系数均随煤层倾角增大而减小，但倾向上端侧向应力集中系数始终小于倾向下端侧向应力集中系数。沿走向，在工作面底板，超前支承应力集中系数随着煤层倾角增大而增大。最后，通过分析下伏煤层塑性破坏区的分布可知，工作面以及倾向上下端底板煤体内的塑性破坏深度均随着煤层倾角增大而增大，但倾向上端底板破坏深度始终小于倾向下端底板破坏深度；采空区底板最大塑性破坏深度所在位置逐渐远离采空区中部，向倾向下端偏移。

For the extra-thick coal seam layering mining,grasping the stress distribution law and deformation characteristics of the underlying coal seam after coal mining can provide some theoretical basis for studying the evolution law of permeability distribution of the underlying coal seam and accurately determining the gas enrichment area in gob. Therefore,in order to clarify the stress distribution law and deformation characteristics of coal seam under inclined extra-thick coal seam,the numerical simulation calculation of coal seam mining with different coal seam inclination was carried out. First,based on the theory of gob compaction,the stress-strain relationship of caving rock mass in gob was obtained,and then the mechanical parameters of caving rock mass in caving zone were determined by trial and error. On this basis,through numerical simulation calculation and analysis,the influence law of coal seam inclination change on the stress distribution and failure characteristics of the underlying coal seam was obtained. The results showed that:in the scope of gob floor，with the increase of coal seam inclination，theO ring of gob stress recovery is no longer distributed symmetrically in the central strike line of gob,but migrated to the lower part. Along the dip,the lateral stress concentration coefficient at both the upper and lower ends of the gob decreases with the increase of the coal seam dip angle,but the lateral stress concentration coefficient at the upper dip end is always smaller than that at the lower dip end. Along the strike,in the working face floor,the stress concentration coefficient of advance support increases with the increase of coal seam dip Angle. Finally，through the analysis of the distribution of the plastic failure zone of the underlying coal seam，it can be seen that the plastic failure depth of both the working face and the upper inclined floor increases with the increase of the coal seam inclination,but the failure depth of the upper inclined floor is always smaller than that of the lower inclined floor. The location of the maximum plastic failure depth of the gob floor is gradually away from the middle of the gob，and tends to the lower end.

0 引言

1 数值模拟方案

   1.1 模拟原型及岩体力学参数确定

   1.2 不同煤层倾角物理模型构建

   1.3 模型边界条件及本构模型的选取

2 破碎岩体的力学参数

   2.1 采空区压实理论

   2.2 采空区垮落岩体岩体力学参数

3 数值模拟结果分析

   3.1 煤层倾角变化对下伏煤层应力分布的影响

   3.2 煤层倾角对底板不同深度煤层应力分布的影响

4 结论