针对蹬空状态下煤层底板岩层完整性与承载力影响制约工作面安全高效开采的问题。以草垛沟矿8201综采工作面为研究背景，通过对8-2煤层下伏11煤巷柱式采空区顶板岩层结构与受载进行分析，建立基于弹性地基假定的顶板-煤柱系统力学模型，推导并解析了顶板岩梁弯曲下沉挠度函数；将工作面底板视为半无限平面体，建立工作面走向不同区段静载荷对底板采动附加应力模型，得到底板不同深度处应力分布规律及其岩层损伤破坏深度解析解；运用数值模拟软件对8-2与11煤层回采过程采场围岩应力、覆岩裂隙分布特征及其时空演化规律进行模拟研究，确定8-2与11煤层层间稳定岩层最小厚度；通过制定现场专项钻孔探测方案对下伏11煤巷柱式采空区覆岩裂隙带发育形态展开探测研究。研究结果表明：① 顶板岩梁在相邻介质交界面的弯曲下沉挠度具有连续性且在巷柱式采空区交汇处弯曲下沉最大为2 cm；② 8201综采工作面回采期间受采动应力影响下巷柱式采空区顶板-煤柱系统形成的稳定平衡结构仍具有稳定性，综合理论计算、数值模拟结果可确定8-2与11煤层层间存在稳定岩层且最小厚度D min1为14 m；③ 专项钻孔探测显示了8-2与11煤层层间稳定岩层最小厚度D min2为12.2 m。因此，近距离煤层间重复采动影响下8201综采工作面底板存在稳定岩层且岩层较完整具有一定的承载能力，排除蹬空开采期间下伏11煤层潜在安全隐患。

The integrity and bearing capacity of rock strata in the coal seam floor heavily affect the mining safety and efficiency at the working face under the state of mining above mined out area. Taking No.8201 working face at Caoduogou coal mine as the research background,based on the structure and load analysis of the roadway goaf in the No.11 coal seam under No.8-2 coal seam,the mechanical model of the coal seam roof pillar system is established under the assumption of elastic foundation. Then,the bending descending deflection function of the coal seam roof beam is deduced and analyzed. By regarding the working face floor as a semi infinite plane,this study presents the model of mining additional stress applied to the working face floor caused by the static load in different sections along the direction of the working face. The law of stress distribution at the different depths of the floor and the analytical solution of the damage depth of the floor are obtained. Subsequently,a numerical simulation is applied to simulate the distribution characteristics of surrounding rock stress,overburden rock fracture and its space time evolution in the mining process of No.8-2  and No.11 coal seam. The minimum thickness of stable rock formations between No.8-2 and No.11 coal seam is determined. Finally,the special borehole detection scheme is developed to investigate the formation of overburden rock fracture in the No.11 coal seam roadway goaf. The results show that ① the deflection function of the coal seam roof beam at the adjacent media interface is continuous,and the maximum descending of the coal seam roof beam at the intersection of the roadway goaf is 2 cm;② the balanced structure formed by the coal seam roof pillar system in the roadway goaf under the influence of mining stress at the No.8201 working face is stable. The minimum thickness of existing stable rock strata between No.8-2 and No.11 coal seams (Dmin1) is 14 m;③ special drilling detection indicates the minimum thickness of stable rock strata (Dmin2) is 12.2 m. Therefore,the stable rock strata at No.8201 working face floor is complete,the bearing capacity of rock strata is competent under repeated mining,which indicates some potential safety hazards of No.11 coal seams during mining above mined out area can be-eliminated.

1 近距离煤层蹬空开采条件分析

   1.1 工程概况

   1.2 地质特征及上下层关系

   1.3 近距离煤层蹬空开采地质条件概况

2 巷柱式采空区覆岩裂隙演化规律

   2.1 巷柱式采空区顶板力学模型

   2.2 巷式工作面采动应力、覆岩裂隙演化规律

3 采场底板应力分布及破坏特征

   3.1 采空区煤柱稳定性分析

   3.2 开采扰动下工作面底板破坏深度

   3.3 开采扰动下工作面底板裂隙演化数值模拟

4 覆岩裂隙带发育形态钻探测量

   4.1 现场钻探探测钻场布置概况

   4.2 巷柱式采空区上覆岩层结构观测

   4.3 覆岩裂隙带发育钻探探测分析

5 结论