| With the increasing range and depth of coal mining and the closure of some abandoned mines,the regional hydrogeological conditions have changed,affecting the response conditions of groundwater spatial distribution and evolution.Underground mining activities break the original dynamic equilibrium state of groundwater,which is directly reflected in the changes of groundwater occurrence state and flow field characteristics.Meanwhile,for the sake of mastering the detailed hydrogeological basic data of coal mines,coal mines usually carry out the hydrogeological supplementary exploration within and around the mine.Besides,in order to ensure that mining is not threatened by water hazard,coal mines have implemented systematic water prevention and control projects,such as fourth water exploration and drainage,karst water damage regional treatment,depressuration and drainage,curtain grouting,etc.These measures have changed the hydrogeological conditions of the mining area to some extent.Therefore,in order to obtain the spatio-temporal evolution characteristics of hydrological dynamics under mining conditions in mining areas,it is urgent to comprehensively analyze the mines in mining areas.In this paper,taking the Linhuan mining area of Huaibei coalfield as the analysis object,the hydrogeological and engineering geological conditions of the study area are systematically combed,and the box diagram method and principal component analysis method are used to study the groundwater characteristic ions.Meanwhile,the water quality distribution and variation characteristics of the mining area are analyzed by PHREEQC hydrochemical reverse simulation software.The dynamic change law of groundwater level in time and space was analyzed by relevant auxiliary software,and the dynamic characteristics of water temperature and water inflow of each aquifer were obtained.Subsequently,many factors affecting groundwater quality,water level and water temperature are discussed.Based on the comprehensive analysis of hydrogeological conditions and tempo-spatial dynamic changes of groundwater in the study area,The mathematical model of groundwater flow in the study area has been established by FEFLOW numerical simulation analysis software based on the finite element theory,and the dynamic simulation analysis has been carried out on the main aquifers of groundwater under mining disturbance in the study area.After the study of groundwater in Linhuan mining area,the following conclusions are drawn:（1）The study area is located in the II2 area of the hydrogeological unit in the south of Huaibei coalfield,which is controlled by deep faults such as Subei Fault,Fengwo Fault,Banqiao Fault and Nanping Fault.The whole area is a closed geological unit.The four water cuts at the bottom of the loose layer in the mining area are weak to medium water-rich.Permian coal measures sandstone fissure water supply condition is poor,mainly for static reserves,water-rich degree is weak.The development of karst fractures in Carboniferous and Ordovician is uneven,and some areas are rich in water,but they are mainly weak to moderate.（2）The influencing factors of groundwater quality mainly include the lithologic characteristics of aquifer and water-rock physicochemical effect;the main factors affecting the dynamic change of groundwater level are rainfall and underground drainage,among which the influence of drainage project on groundwater level is obvious.The main factors of groundwater temperature are geothermal gradient,aquifer burial depth and regional magmatic activity.（3）The established three-dimensional groundwater flow geological model has been used to analyze the tempo-spatial dynamic changes of water levels in the fourth aquifer,Taihui and Ordovician limestone aquifers.Typical hydrological observation boreholes in aquifers are selected to fit the actual water level with the simulated water level,and the actual groundwater flow field and the simulated water flow field at the end of the simulation period have been compared and verified.Through the quantitative evaluation of the model effect,it is further determined that the simulation effect is better,indicating that the simulated water level and groundwater flow field of ground observation holes can be fitted to the actual situation to the greatest extent.Figure[63]table[14]reference[80]... |
