As the mining depth of North China-type coal fields increases year by year, the threat of Ordovician limestone karst water damage to coal seam mining is increasing, and the risk of floor water inrush increases gradually. To ensure safe production in coal mines and avoid casualties and economic losses, it is essential to accurately predict the risk of coal floor water inrush. The traditional approach to determine whether there is risk during the mining process is the water inrush coefficient method, which has certain limitations because it does not fully consider the water yield of the aquifer and the actual hydraulic resistance of the aquitard. Therefore, in this paper, a new method was put forward and applied for predicting the floor water inrush risk attributed to the Ordovician karst fissure confined aquifer from the Permian-age coal deposits in the Xiayukou coal field, Hancheng mining area, Shanxi, China. The influence of floor water inrush is comprehensively considered from the three aspects of the aquifer’s water yield, the hydraulic resistance characteristics of the aquitard and the tectonic development of the study area. Based on the new analytic hierarchy process-linear weighted average (AHP-LWA) method, a water abundance structure index (WASI) was created using the burial depth of the Ordovician aquifer (Dp), water abundance layer (Ly) and morphological features of the aquifer (Mf). Similarly, a hydraulic resistance structure index (HRSI) model was established using aquitard thickness (Tk), number of aquifers and aquitards (Num), sand–mud ratio (SMr) and core recovery rate (CRr); additionally, fractal dimension values were used to characterize the degree of structural development. Finally, a water inrush risk evaluation model was constructed, and a contour map was drawn using the risk index method of floor water inrush (RIWI) values and revealed three water inrush risk zones: normal mining area (0.18–0.32), medium-risk area (0.32–0.38) and high-risk area (0.38–0.52). Model verification was accomplished by the actual exposed water inrush points during the No. 3 coal seam mining work, which are all located in the high-risk area zoned by the RIWI method, and the water sources are all from the third section of the Upper Majiagou strong aquifer. The results show that the new evaluation model has high prediction accuracy, small error and wide applicability, and the model meets the basic requirements of mine production safety, provides favourable technical support for floor water inrush prediction during the Carboniferous–Permian lower coal group mining above the confined aquifer and is of great significance to ensure safe and efficient production of the coal mine.

中文翻译：

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山西下峪口煤矿奥陶系裂隙承压含水层底板突水风险评价新方法的应用

随着华北型煤田开采深度逐年增加，奥陶系灰岩岩溶水害对煤层开采的威胁日益增大，底板突水风险逐渐增大。为保证煤矿安全生产，避免人员伤亡和经济损失，准确预测煤底板突水风险至关重要。传统的判断开采过程中是否存在风险的方法是突水系数法，由于没有充分考虑含水层的产水量和透水层的实际水力阻力，具有一定的局限性。因此，在本文中，提出并应用了山西韩城矿区下峪口煤田二叠纪煤田奥陶系喀斯特裂隙承压含水层底板突水风险预测方法。从含水层产水量、透水层水力阻力特征和研究区构造发育三个方面综合考虑底板突水的影响。基于新的层次分析法-线性加权平均（AHP-LWA）方法，利用奥陶系含水层埋深（Dp）、水丰度层（Ly）和地貌特征，建立水丰度结构指数（WASI）。含水层（Mf）。同样，利用透水层厚度（Tk）建立水力阻力结构指数（HRSI）模型，含水层和透水层的数量 (Num)、砂泥比 (SMr) 和岩心采收率 (CRr)；此外，分形维数值被用来表征结构发展的程度。最后，构建突水风险评价模型，并采用井底突水风险指数法（RIWI）值绘制等高线图，揭示三个突水风险区：正常矿区（0.18-0.32）、中等风险区。区 (0.32–0.38) 和高风险区 (0.38–0.52)。模型验证是通过3号煤层开采工作中实际暴露的突水点完成的，均位于RIWI法划分的高危区，水源均来自上三段马家沟强含水层。结果表明，新的评价模型具有较高的预测精度，