Dynamic Characteristics And Simulation Of Groundwater In Qianyingzi Coal Mine

Under the background of increasing scale,intensity,depth and goaf of coal mining,a series of groundwater problems such as groundwater environment and groundwater pollution have become increasingly prominent.Under the influence of mining,the hydrodynamic equilibrium conditions,water cycle relations and hydrogeological conditions of the mine groundwater system have undergone continuous changes,and the groundwater system has become increasingly complex.Therefore,the study of mine groundwater dynamics and its influencing factors is an important basis for mine water prevention and rational utilization of water resources.Taking Qianyingzi Coal Mine as the research object,this paper analyzes and discusses the dynamic evolution characteristics of groundwater under the influence of mining from the aspects of groundwater level and hydrochemistry.At the same time,the influencing factors that cause the dynamic changes of flow field and hydrochemical field of the main aquifer in the study area are discussed,and the influence degree of various factors on groundwater level and the influencing mechanism of hydrochemical dynamic changes are analyzed.Finally,the groundwater numerical simulation method is used to study the evolution law of water flow field and water level change trend of main aquifer under the influence of mining.The results show that:（1）Under the influence of mining in the study area,the water level of the fourth aquifer has the largest decline,from the high in the southeast and low in the northwest direction of the early mining to the low water level in the first and second mining areas of the west,and the high water level in the unexploited area.The water level change is obviously affected by mining.The water level of Taiyuan Formation limestone generally shows a single steady decline law,but has little effect on its spatial hydraulic gradient.The Ordovician limestone water level is generally stable,and its spatial distribution changes from high in the south to low in the north to high in the south.The common point of each aquifer is that the water level gradually tends to be stable in the later mining period.（2）In terms of hydrochemistry,the contents of cation Ca²⁺and Mg²⁺in the fourth aquifer water showed an increasing trend,and the content of K⁺+Na⁺showed a decreasing trend,while the change trend of cation content in sandstone water was opposite.The contents of anion SO₄^2-and HCO₃^-showed similar changes,and the overall change of Cl^-content was slight,indicating the mixing effect of the fourth aquifer and sandstone water.In terms of hydrochemical types,the water in the fourth aquifer is enriched to Na⁺,and HCO₃^-is evolved to SO₄^2-;sandstone water is generally between HCO₃ and SO₄ types.（3）Combined with mathematical statistics and water-rock interaction,it is concluded that the water in the fourth aquifer tends to desulfurate,and the sandstone water tends to’hardening’.At the same time,taking the formation mechanism of water chemistry as the starting point,the influence of different physical and chemical effects on the water chemistry of aquifer is analyzed.The analytic hierarchy process is used to analyze the influencing factors of groundwater level.The main influencing factors are geological structure,mine drainage and grouting treatment,and their weights are 0.3543,0.2867 and 0.1433,respectively.（4）The simulation analysis and prediction of the water level and flow field dynamics of the fourth aquifer in the study area show that the water level of the fourth aquifer continues to decline as a whole under the influence of mining,but the decline rate has a slow decreasing trend.At the same time,the decline rate of groundwater level and water level in the mining area is significantly lower than that in the area without mining or with small mining intensity.The dynamic changes of groundwater level and water flow field in the fourth aquifer are most affected by mining.Figure:48 Table:10 Reference:80...