煤矿长壁开采引起的覆岩破坏高度对于水体下采煤、保水开采以及瓦斯治理的解放层开采等均具有重要意义。采用理论分析和数值模拟方法对煤矿高强度长壁开采引起的覆岩破坏高度及其达到覆岩破坏充分采动的判据进行了研究。基于覆岩破坏充分采动的定义，分析了覆岩破坏充分采动的特征及其影响因素，包括工作面开采厚度、开采尺寸(走向、倾向长度)、开采深度与覆岩岩性;提出了以“梯形-面积”、“四棱台-体积”为依据的覆岩破坏充分采动理论判别方法，并将煤矿长壁开采三维覆岩破坏及地表下沉简化为4类采动影响体积(采空区长方体体积、上覆岩层预破坏四棱台体积、覆岩破坏后的体积与地表下沉体积)之间的关系，得到了工作面达到覆岩破坏充分采动时的覆岩破坏高度理论表达式与覆岩“两带”破坏模式的判别式;基于某高强度开采工作面，建立并校核了考虑现场最大、最小水平主应力方向与工作面推进方向夹角的三维数值模型，采用离散元数值模拟方法分析了高强度开采工作面不同开采厚度、开采尺寸与开采深度对覆岩破坏充分采动的影响。结果表明:高强度长壁开采工作面达到覆岩破坏充分采动时的推进距离与工作面倾向长度、深厚比成反比，研究给出了高强度长壁开采覆岩破坏充分采动的判据及其适用条件。

The overburden failure height caused by longwall mining is of great significance to under water body mining,water conservation mining and gas control in the mining of liberated strata.The overburden failure height,overburden critical failure and its criteria induced by high intensity longwall mining were investigated by means of theoretical analysis and numerical simulation.Based on the definition of overburden critical failure,its characteristics and influencing factors were analyzed,including the mining height,mining size (the strike length and dip length of a panel),mining depth and strata lithology.A theoretical assessment method of overburden critical failure was proposed based on trapezoidal area and quadrilateral prism volume.Overburden failure and surface subsidence due to longwall mining were simplified as four kinds of mining volumes,i.e.,the cuboid volume of gob,the quadrangle volume of pre damaged overburden,the volume of damaged overburden and the volume of surface subsidence.The theoretical equation of overburden failure height when overburden critical failure is achieved and the judgement equation of “two zones” overburden failure mode were obtained.Based on a high intensity mining panel,the 3D numerical models that consider the maximum horizontal principal stress and minimum horizontal stress and their orientations with the panel advance direction were established.The influence of different factors (mining height,mining size and mining depth) on overburden critical failure was analyzed by the numerical simulation.The results show that the advanced distance when the overburden critical failure is reached is inversely proportional to the dip length and depth to thickness ratio of the panel.The criteria of overburden critical failure in high intensity mining and its applicable conditions is given and applied to some panels.It can provide an important theoretical basis for the measurement of the maximum overburden failure height and the safe mining under the water body.

1 覆岩破坏充分采动特征及影响因素

2 覆岩破坏充分采动理论

    2.1 二维覆岩破坏充分采动理论

    2.2 三维覆岩破坏充分采动理论

3 覆岩破坏充分采动数值模拟

    3.1 数值模拟方案

    3.2 数值模拟结果

4 高强度开采覆岩破坏充分采动判据

    4.1 覆岩破坏充分采动模拟结果

    4.2 高强度开采覆岩破坏充分采动判据

    4.3 工程实例验证

5 结论