The mining-induced failure of the coal seam floor is essential for water inrush. The mining disturbance to the floor, especially in the thick coal seam, is severe, and the water inrush risk is also higher than that in regular thick coal seam excavation. The superposition of many stresses, including in situ stress, mining-induced stress, and confined water pressure, must be considered in the prediction of the floor failure depth. This study adopted the elasticity analysis, FLAC3D numerical simulation, and on-site acoustic wave test comprehensively. The thick coal seam working face of the Zhong-Yu coal mine affected by confined water was selected as the engineering background to study the characteristics of the floor failure. Based on elastic foundation theory and the superposition principle, the mechanical model and the failure depth criterion of the floor were established, respectively. The distribution and evolution of mining-induced stress and the plastic zone in surrounding rock during the mining process are obtained by FLAC3D. In addition, the changes in the P-wave wave velocity in the floor before and after mining were compared and studied by the acoustic wave test method. The range of floor damage depth is determined on the basis of the above research.

煤层底板开采引起的破坏是突水的关键。尤其是厚煤层对底板的开采扰动严重，突水风险也高于常规厚煤层开挖。在预测底板破坏深度时，必须考虑许多应力的叠加，包括地应力、采矿引起的应力和承压水压力。本研究综合采用弹性分析、FLAC3D数值模拟和现场声波试验。选取受承压水影响的中榆煤矿厚煤层工作面为工程背景，研究底板破坏特征。基于弹性基础理论和叠加原理，分别建立了楼板的力学模型和破坏深度判据。通过FLAC3D获得了采矿过程中采矿诱发应力和围岩塑性区的分布和演变。此外，采用声波试验方法比较研究了开采前后底板P波波速的变化。在上述研究的基础上确定了楼板损坏深度的范围。