Study On Dynamic Evolution Characteristics Of Groundwater In Closed Mine Of Liuqiao No.1 Coal Mine

With the gradual depletion of shallow resources in many small mines in China,the implementation of the national policy of shutting down wells and eliminating backward production capacity,the mining enterprises that do not meet the national safety and ecological environment standards and have no benefits will be closed,and China is in the period of a large number of mines being closed.Once the mine is closed,the underground water will be recharged to the underground goaf area and roadway system,resulting in the rise of underground water level.If the scientific planning and management can not be carried out in time,a series of geological disasters will be triggered.Therefore,the study on the dynamic evolution of groundwater flow field in closed coal mine is of theoretical and practical significance for ensuring the safety of mine production.Based on the water level rising mechanism of closed pit mine,this paper studied the dynamic evolution characteristics of groundwater flow field in Liuqiao No.l Coal Mine.Through the systematic arrangement of relevant data,the geological and hydrogeological conditions of the study area are elaborated,and the temporal and spatial dynamic characteristics of groundwater level and water inflow in the production stage of the study area was analyzed;Based on the mining space method,the process of water rising in the goaf was reproduced;Using Visual MODFLOW software,the groundwater level rise of closed mine was simulated,and the change trend of groundwater level was predicted.The main achievements are as follows.(1)The temporal and spatial dynamic characteristics of groundwater in exploitation stage was analyzed.The results show that:Under the influence of mining,the water level of the main aquifer in the mine presents a downward trend,and the descending funnel gradually moved from the south wing to the north wing;With the development of mining level,the water inflow of limestone water in Taiyuan Formation increases gradually,and the water inflow tends to be stable after the increase of the water inflow.(2)Based on the hydraulic theory,the change trend of underground water inflow was predicted after the mine was closed;Combined with the monitoring results of water seepage of coal and rock pillar at the boundary of Hengyuan Coal Mine,the value of water inflow was determined at different stages after the mine was closed.(3)According to the three-dimensional shape map of coal seam floor and the actual production of the mine,the path of water level rising is determined,the volume of water accumulated in the goaf is calculated by using the mining space method,and the model of water level rising in the old goaf was established to predict and analyze the process of underground water accumulated after the closure of Liuqiao No.1 Coal Mine.(4)The numerical model of groundwater level rising after the closure of Liuqiao No.1 Coal Mine was established.The process of groundwater level rising was simulated and analyzed.The dynamic change trend of groundwater level after the closure of the mine was predicted.The prediction results are consistent with the calculation value of mining space method,which verified the accuracy of the numerical model.The research results provide a scientific basis for the prevention and control of water disasters in the closed mine.Figure[31]table[17]reference[108]...