A floor aquifuge usually bends and fails when mining above a confined aquifer, which may lead to water inrush disaster. The floor aquifuge was simplified as a thin disc model in this paper, and a series of coupled bending-seepage tests of sandstone were carried out by a patent test system. The variation characteristics of load-displacement, load-time, and permeability-time were analyzed. The deflection and stress in the thin disc rock samples were deduced; the initiation and propagation of cracks were analyzed. The failure behavior of the thin disc rock samples was described. It shows the following: (1) The bending failure behavior relates to the stress distribution and crack evolution inside the thin disc. (2) The main cause of crack initiation is a tension-shear failure. (3) The 5 mm thickness thin discs form petal-shaped cracks, due to tensile stress, while petal-shaped cracks only appear at the cap block of the 10 mm discs, which are sheared into two pieces along the conical surface with an inclination about 45°. (4) Water inrush occurs after bending failure in the floor aquifuge, and it is an opportune moment to grout along the crack propagation trend lines to prevent the water inrush disasters.

中文翻译：

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弯渗耦合条件下薄盘砂岩的破坏行为

在承压含水层上方开采时，地板隔水器通常会弯曲并失效，这可能导致突水灾害。本文将底板隔水器简化为薄圆盘模型，利用专利试验系统对砂岩进行了一系列的弯渗耦合试验。分析了荷载-位移、荷载-时间、渗透率-时间的变化特征。推导了薄圆盘岩样的挠度和应力；分析了裂纹的萌生和扩展。描述了薄盘岩石样品的破坏行为。它表明： (1) 弯曲破坏行为与薄盘内部的应力分布和裂纹演化有关。(2) 裂纹萌生的主要原因是拉剪破坏。(3) 5mm厚的薄盘形成花瓣状裂纹，由于拉应力，花瓣状裂纹仅出现在10mm圆盘的盖块处，沿着锥面剪切成两块，倾斜度约为45°。(4)底板隔水器发生弯曲破坏后出现突水，沿裂缝扩展趋势线灌浆是防止突水灾害的好时机。