关键词: 保水开采, 导水裂隙, 数值模拟, 隔水层稳定性, 层次分析

Abstract: Focusing on the stability of N2 laterite and the protection of water resources in the key aquiclude of water-preserved mining in shallow coal seams in Northwest China, the development characteristics of water-conducting fractures and their influence on the stability of N2 laterite aquiclude in typical working face of thin bedrock and thick soil layer in Yushen mining area of northern Shaanxi were explored by means of theoretical analysis, numerical simulation and field measurement. The results show that the height of the water flowing fractured zone is 57.9~113.9 m by theoretical calculation, and 121.10~139.79 m by field measurement. The numerical simulation analysis shows that the development law of water-conducting fracture zone of overburden rock under different working face lengths is similar. When the working face length reaches 170 m, the height of water-conducting fracture increases slowly, and the maximum value is 96.5 m. The water-conducting fracture zone of coal seam mining basically develops to the bottom of N2 red soil layer after penetrating bedrock. Based on the analytic hierarchy process, the evaluation model of mining damage of N2 red soil layer is constructed, and the main factors affecting the stability of key aquiclude of N2 red soil are clarified. Based on the evaluation results of the development height of water-conducting fracture zone, the thickness of red soil layer and the distance between red soil layer and main coal seam, and considering the residual thickness of red soil layer, the results of water-preserved mining are evaluated, and the stability criterion of aquiclude is determined. The research results have important reference significance for safe green coal mining and water resources protection under similar geological conditions in northern Shaanxi coalfield.