Research On The Development And Utilization Of Pore Confined Water In Guoyang County

Guoyang County is located in the central and western Huaibei Plain of Anhui Province,and it is a county with a large population based on agriculture;the county is located on the south bank of the middle reaches of the Guo River.In the past 20 years,with the economic and social development,the population of the county has rapidly increased from 100,000 in 2005 to 360,000 in 2019;the domestic water consumption in urban areas has also rapidly increased to 60,000 m~3/d,which is expected to increase by2025 to 84,000 m~3/d.Restricted by regional water resources,the domestic water in the county is single and depends on the pore-pressure water in the Cenozoic(aquifer buried depth 120-300m);as the county continues to expand to the periphery,the early mining wells built in the periphery of the old city have gradually surrounded by the new city.In the urban area,the groundwater level of the mining layer has been rapidly and continuously declining for a long time and high-strength exploitation of pore-pressure water,and a groundwater funnel with a total area of 112.2km~2 has been formed in the county area,Chengxi Town and Zhabei Town;Due to the high overlap of the three areas of the urban area,mining area and restricted mining area(ie,the scope of Anhui Province No.34163112 groundwater restricted mining area),if the groundwater continues to be extracted with high intensity,it will cause a series of serious environmental hydrogeological problems.In this paper,based on the conditions of regional water resources,on the premise of ensuring the domestic water supply in Guoyang County,with no basic environmental hydrogeological problems and meeting the groundwater extraction regulations as the basic requirements,the technically feasible and economically reasonable pore pressure water extraction scheme is determined.First,based on regional geological and hydrogeological conditions,establish a hydrogeological conceptual model;then use Visual MODFLOW software to establish a corresponding numerical simulation model of groundwater flow to predict the evolution trend of groundwater flow field.Secondly,the Latin Hypercube Sampling method was used to sample the pumping volume of 10pumping well groups to obtain a pumping volume sample data set;the artificial neural network method is used to establish a surrogate model of the corresponding numerical simulation model of groundwater flow,which is trained and tested.Finally,the trained and tested surrogate model is coupled with the optimization model to establish an optimized management model for pore confined water mining with the minimum function of controlling the total pumping cost as the objective function and satisfying the constraints of water demand,control point water level drop less than the limit value;use genetic algorithm to optimize and solve it,get the best optimized mining plan.Research shows that under the specific conditions of the example,the optimized mining plan can meet the urban domestic water consumption of 60,000 m~3/d;compared with the current plan,within the planning period(2020-2025),the pore pressure in the mining area is limited The water level formed in the II confined aquifer was reduced by about 7.95km~2 in the range of less than-20m,and reduced by about 10.20km~2 in the range of less than-16m.The maximum rise of the water level in the mining center was 3m,which meets the requirements for groundwater extraction.