【摘要】 为了探究兖州矿区山西组3号煤层浅部上覆巨厚松散层底部砂层抗渗透破坏及突水溃砂特征，以杨村煤矿和兴隆庄煤矿两相邻矿井薄基岩区为背景，通过现场地面钻孔底含取样，室内采用宏-微观测试分析、模型实验和解析等方法对4组底含砂样宏-微观及抗渗透破坏特征进行了系统研究。对16组模型实验结果进行分析，发现在其他条件不变情况下裂缝宽度决定突水溃砂发生与否和其类型，可分为快速突出型和波动突出型两种。在裂缝宽度较小条件下突水溃砂特征主要受颗粒级配、成分和结构等本身特征所控制，但当裂缝超过一定宽度后，裂缝宽度起主要控制作用，而砂样本身特征起次要作用。这与基于承压水完整井定流量非稳定流理论建立的采动突水溃砂临界水力坡度计算模型结果基本一致。一定宽度裂缝是控制突水溃砂发生与否的关键，在此基础上提出在薄基岩区开采尽量采取相关措施，减轻采动对覆岩的扰动破坏程度。更多还原

【Abstract】 The anti-seepage failure behavior and water inrush and sand burst of the bottom sand soil layer within the ultra-thick unconsolidated overburden above the shallow No. 3 coal seam of the Shanxi Formation in the Yanzhou mining area were systematically studied. Sand soil samples were collected from the thin-bedrock zones of the adjacent Yangcun and Xinglongzhuang coal mines, and a series of surface borehole sampling and laboratory tests were conducted to characterize the macro-and micro-scale features and anti-seepage failure behavior of four groups of sand soil samples. The results show that crack width governs both the occurrence and failure mode of water inrush and sand burst, with all other conditions remaining unchanged. Two distinct failure modes were identified, namely rapid-burst and fluctuating-burst modes. At relatively small crack widths,the burst behavior is primarily controlled by the intrinsic properties of the sand soil samples, including particle-size distribution, composition, and internal structure. Once the crack width exceeds a critical threshold, crack width becomes the dominant controlling factor, whereas the influence of the intrinsic characteristics of the sand soil samples becomes secondary. This finding is generally consistent with predictions from a critical hydraulic gradient model for mining-induced water inrush and sand burst established based on the constant-discharge unsteady seepage theory of a fully penetrating artesian well. The results further show that a critical crack width is the key factor controlling the occurrence of water inrush and sand burst. Therefore, appropriate measures should be adopted during mining in thin-bedrock areas to mitigate mining-induced disturbance and damage to the overburden.更多还原