Background Assessing water filling intensity in coal seam floors lays a foundation for the prevention and control of water hazards in mines. However, in the Jurassic coalfield in the northern Ordos Basin, complex hydrogeological structures and sedimentary heterogeneity pose severe challenges to traditional evaluation methods.

Methods This study investigated the water hazard characteristics in the superimposed aquifers of the Jurassic Yan’an and Zhiluo formations in the Dahaize Coal Mine in northern Shaanxi. The purpose is to establish a zoning and assessment system of water filling intensity that is suitable for continental sedimentary settings and to provide a scientific basis for the prevention and control of water hazards in mines. Based on the law of sedimentary water control, this study determined five primary control indices (i.e., aquifer thickness, index of sedimentary environment quantitation, core recovery, permeability coefficient, and index of mining-induced aquifer damage) from the perspective of lithological, hydraulic, and mining characteristics. Subsequently, the weights of the five indices were determined at 0.270, 0.155, 0.059, 0.349, and 0.168, respectively using the analytic hierarchy process (AHP) method. In combination with GIS technology, this study performed normalization and spatial overlay analysis of the multi-source data, establishing a zoning-integrated dual assessment model.

Results and Conclusions  The third member of the Yan’an Formation exhibits high water filling intensity in the south and low in the north, and the reverse is true for the first member of the Zhiluo Formation. Using the Jenks natural breaks classification method, the superimposed water filling intensity was divided into five grades: very weak, weak, moderate, strong, and very strong, with the strong grade and above primarily distributed in the west-central and northeastern parts of the mining area. Verification using the water inflow data of mining faces 20101 and 20201 reveals a high degree of spatial match between the measured water inflow and the predicted zoning results, corroborating the reliability of the proposed model. The proposed zoning and evaluation method for water filling intensity of coal seam roofs in the Dahaize Coal Mine effectively overcomes the limitations of traditional homogenous models in terms of their limited suitability for discontinuous sand bodies and layered seepage mechanisms. This method provides a quantitative basis for decision-making in the prevention and control of water hazards in deep Jurassic coalfields, holding great value in widespread applications.