Mining accidents due to inrushing water are caused by sudden changes in seepage owing to structural damage to key strata of the aquiclude. The backfill mining method can be used to control the movement of the strata, weaken the evolution of fractures owing to damage by key aquiclude strata (KAS), and control the channel for inrushing water. This study develops a mechanical model of a composite beam on a non-uniform elastic foundation of the KAS by analyzing the coupling relationship between the filling body and the key water-resisting layer of the aquiclude. Equations of the deflection-induced deformation, bending moment, and maximum tensile stress of the KAS are analyzed, formulae to calculate the allowable tensile stress and backfill materials’ compaction ratio (BMCR) to ensure structural stability are derived, and are used to provide the critical BMCR for their structural instability. The results of field measurements show that the subsidence of the roof was 600–700 mm with an average BMCR of 80.63%. Damage to the overlying strata was controlled to ensure safe mining and the disposal of solid waste from the aquifer. The research here is useful for ensuring safety during mining while protecting water resources.

突水采矿事故是由于隔水层关键地层的结构破坏导致渗流突然变化引起的。回填开采法可用于控制地层运动，弱化关键隔水层（KAS）破坏裂缝演化，控制突水通道。本研究通过分析充填体与隔水层关键阻水层的耦合关系，建立了KAS非均匀弹性地基上的组合梁力学模型。分析了KAS的挠曲变形、弯矩和最大拉应力方程，推导了计算许用拉应力和回填材料压实比（BMCR）以确保结构稳定性的公式，并用于为其结构不稳定性提供关键的 BMCR。现场测量结果表明，顶板沉降600～700 mm，平均BMCR为80.63%。控制对上覆地层的破坏，以确保安全采矿和处理来自含水层的固体废物。这里的研究有助于确保采矿过程中的安全，同时保护水资源。