Prediction Of Water Richness And Risk Assessment Of Water Inrush In Sandstone Aquifer Of No.2 Coal Roof In QingShuiying Coal Mine

The coal-bearing strata in Qingshuiying Minefield are the Jurassic Middle-Lower Yan'an Formation,and the Jurassic Middle-Zhizhi Formation and Anding Formation are overlying.The main coal seam is No.2 coal seam.After the coal seam is mined,the water-conducting fracture zone develops a high-level sandstone aquifer in the Zhiluo Formation.The sandstone aquifer of the Zhiluo Formation has a large thickness and medium water richness,and is the main aquifer in the well field.This paper takes Qingshuiying Minefield as the research object,analyzes and discusses the hydrogeological conditions of the Minefield based on the geological and hydrogeological data of the study area,and on the basis of the detailed division of the coal seam roof and water barrier,the Zhiluo Group sandstone is filled with water The water-rich aquifer is classified and predicted in different zones.After the coal seam is mined,the mine field is zoned according to the degree of roof cracking,and combined with the influence of the fracture structure,the risk of water inrush(burst)from the roof of the mine field is evaluated.Using PFC2D numerical simulation software to establish the model,the destruction of overburden rock during the mining process and the development law of water conducting fracture zone were studied.With the coal seam mining,the development height of the water guide fracture zone gradually increased.After reaching a certain value,the height of the water guide fracture zone no longer continued to increase.According to the results obtained by the numerical simulation method,and comparative analysis with the empirical formula provided in the code,the development height of the water conducting fracture zone in this area is comprehensively determined.The main influencing factors of water-rich water content in four aquifers,including sandstone equivalent thickness,lithology combination index,brittle plastic lithology ratio,core adoption rate,are selected,and fuzzy analytic hierarchy process and Cantiere weighting method are combined to improve the game theory.The combined weights were determined,and a water-rich aquifer prediction model for the roof-filled aquifer was constructed,and a hierarchical zoning prediction was made for the water-rich aquifer of the direct water-filled aquifer.Combining the water richness index,roof cracking degree and the influence of fracture structure,and using the improved game theory method to comprehensively analyze the weights obtained by fuzzy comprehensive evaluation and the Cantiere weighting method,a roof gushing(burst)water evaluation model was constructed and 2 coal Evaluation of the risk of roof gushing(bursting).