The Dynamic Variation Of The Water And Numerical Simulations Of The L₈ Limestone Of The Mine Floor Affected By The Adjacent Mine Closure

Influenced by adjacent closed mines,the groundwater flow field of mine changes,so the corresponding measures to control water should also be adjusted respectively,such as,draining and blowdowning and blocking water with grouting treatment.This paper,taking the Jiulishan Mine and the Yanma Mine as examples,aims to study the impact of the closed Yanma mine on water gushing of the adjacent Jiulishan Mine.Jiulishan Mine has complex geological structure,boasts the characteristic of fault,and also controls the the occurrence and transportation of groundwater.As Yanma Mine closed and stopped drainage,the water level gradually rises,producing an effect on Jiulishan Mine that exists in the same hydrogeological unit.As a result,the Jiulishan Mine faced real difficulties that water volume increase,water level rises and water pressure increases,which made the risk of the water bursting of limestone water of floor more severe when II-1 coal seam begin to mine.This paper studies the hydrogeological condition of the Jiulishan Mine,the spatial and temporal variation in hydrological information and the variation of water quality and water inflow by collecting and collating hydrogeology information of the Mine,and conducts numerical simulations for the L₈ limestone water of the Taiyuan Formation that is affected deeply by the closed mine,ending up proposing water prevention and control recommendations.Here are conclusions:（1）The water level of each aquifer in Jiulishan mine is on the rise due to the influence of the closed Yanma Mine,among which the water level of the L₈ limestone water aquifer is affected deeply by the closed mine.（2）It was found that rainfall and water inflow were significantly correlated at 0.01level through the correlation analysis to rainfall and water inflow.The water inflow in the mine increased significantly after the mine closure.With the implement of draining and blowdowning and blocking water with grouting treatment,the water inflow began to drop significantly in January 2020.According to the results of water quality analysis,the water quality of groundwater is mainly HCO₃-Na·Ca type,and the concentration of Ca²⁺,Mg²⁺and SO₄^2-in the groundwater of Jiulishan Mine has increased after the mine closure of the Yanma Mine.（3）Based on the analysis of water level of aquifer and mine water inflow,this paper carried out numerical simulation to the evolution of flow field in the L₈ limestone water aquifer of Taiyuan Formation,and obtained the trend of groundwater level change,which fitted well with the actual water level.（4）Theoretical calculation of limestone water release in the bottom slab of the II-1mining area combined with the"water inrush coefficient"is carried out in the II-1mining area as an example,and mining suggestions are given.Based on the results of the numerical simulation and the sparsity calculation,the flow field simulation was carried out for the II-1 mining area that was reduced to the safe water pressure value.