Evaluation On The Water Abundance Of Aquifer In Weathered Zone Of Basement Of Jinjitan Coal Mine

The Yu(Yulin)Shen(Shenmu)mining area in the north of Erdos Basin has become a national large-scale coal base with an annual output of more than 100 million tons.However,due to the long-term erosion and weathered of the Jurassic coal measure strata in the mining area,a weathered zone of basement with a certain thickness was formed on its top,and the area is a pores-fissure aquifer,which is one of the main water sources of mine water inrush.Therefore,it is an important work to evaluate the water richness of aquifers in weathered zone,but there are relatively few related researches.In this thesis,the Jinjitan coal mine of Yushen Mining area is taken as the target area,and all kinds of exploration data of weathered zone of basement are taken as the basic data.The main factors affecting the water richness of weathered zone of basement are analyzed and proposed,and the model of multi-factor synthesis evaluation of weathered zone of basement water richness is established,and the evaluation zoning results are given.Combined with the predicted results of the height of water-conducting fracture zone in coal seam mining,the water inflow of coal seam mining in different production way is predicted.The main results are as follows:(1)It is determined that there is a large difference in the water inflow of the east wing and the west wing of the mine,and the reason for the large water inflow of the east wing is that the weathered zone of the east wing is relatively thick and the fracture zone of the water conduction is developed in a large height.It has entered the weathered zone of basement and partially passed through the weathered zone of basement into the overlying loess.The aquifer of the weathered zone of basement is directly filled with water.In addition,the sand layer above the loess layer has some seepage.(2)Six main influencing factors,including the thickness of weathered bedrock in the research area,the thickness of aquifer in the weathered zone,RQD value,wash fluid consumption,core adoption rate and permeability coefficient,were selected to evaluate the water enrichment of weathering bedrock aquifer in the research area of Jinjitan Coal Mine.AHP(subjective weight)and entropy weight method(objective weight)were used to determine the comprehensive weight value.MATLAB and other software were used to standardize and normalize the measured data.Arc GIS,Surfer and other software were used to analyze the single factor and data superposition of each selected main control factor.On this basis,the comprehensive zoning map of relative water richness of bedrock weathered zone aquifer is obtained.The results show that the water richness of the east wing of the mining area is higher than that of the west wing.(3)Test the results of water-rich zoning according to the measured data obtained from the pumping test within the weathered zone of basement in the study area.Combined with the development height of the water-conducting fracture zone and the evaluation results of water richness,the superposition analysis was carried out to carry out the water outburst(gushing)safety zoning of the study area.The results showed that the risk of the east wing was higher than that of the west wing.(4)Combined with the results of water richness evaluation zoning,the water inflow of Jinjitan Coal Mine was predicted by analogy method,and then compared and verified with the water inflow predicted by traditional "large well method" and "water collection corridor method".Finally,the normal water inflow and maximum water inflow of bedrock weathering aquifer in different mining methods were obtained.