Dynamic Change Characteristics Of Groundwater Level In Water Supply Well With Large Flow And Mining Optimization Mechanism

How to exploit mineral water resources scientifically and effectively is not only a scientific but also a technical problem.In terms of discipline,the optimal exploitation of mineral water supply wells belongs to the hydrogeological problem in the discipline of water conservancy engineering.For a mineral water source area,the optimal exploitation under the condition of large flow rate of water supply wells has been restricting the production capacity of large-scale mineral water production enterprises,which is also one of the hot issues in hydrogeological research.This paper takes Wawutang high quality mineral water source area in Suining County,Hunan Province as the research object.On the basis of the analysis of hydrogeological conditions,the field pumping test is carried out to obtain the dynamic change characteristics of groundwater level when the water supply well is supplied with large flow.Based on this,the mining optimization mechanism is studied.The research results can directly provide scientific basis for the large-scale development of mineral water in Yili Group.The main results of this paper are as follows:1.The hydrogeological parameters of the study area are obtained by collecting data,sorting out,field exploration and investigation,monitoring of outcrop spring discharge in the study area,pre-drilling,simple pumping test,production large flow unsteady flow pumping test,and data analysis and calculation of pumping test.2.Based on the analysis of a large number of pumping test data,a series of hydrogeological parameters such as permeability K 0.454~1.2m/d,hydraulic conductivity T 15.3~41.8m2/d,aquifer thickness M 27~78.8m,water storage coefficient(also known as water storage coefficient,water release coefficient)0.094~0.535m/d,influence radius R(also known as falling funnel)12~510m and pumping time curves such as S-t,Q-t were obtained.The dynamic change characteristics of groundwater level with time during pumping test are obtained.3.Further revealing the characteristics of dynamic Q-S curve of underground mineral water in the study area,and using the least square method to fit and analyze the Q-S curve,the Q-S relationship equation is obtained: Q=342.18237+77.21498s-2.35102s2(well W2),Q=3475.63902-138.65221s+1.79326s2(well.S1).The equation can be used to predict the groundwater level and water yield.4.The project has carried out large-flow unsteady-flow pumping tests on production wells(the method is often used to calculate hydrogeological parameters,which is easy to operate and suitable for the determination of hydrogeological parameters under various conditions),catastrophic pumping tests and attenuation pumping tests under three different working conditions to explore the optimal mining optimization mechanism.Through the analysis of the data of three test conditions,various historical curves and Q-S curves are drawn.Through the analysis of the characteristics of the curves,it is known that the stable output of water is about 824.7 m3/d when the depth is 24 m and 900 m3/d when the depth is 40 m.Compared with the stable flow pumping condition achieved by the test,the catastrophicand attenuating pumping conditions can obtain more mineral water in the same pumping time.Attenuation pumping test condition is the best mining optimization scheme.This scheme can not only avoid disturbance affecting the stability of formation wellbore,but also help the recovery of underground mineral water without destroying the ecological balance of groundwater,avoid the occurrence of landing funnel to avoid geological hazards such as land subsidence and subsidence,and can also obtain more water output and social and economic benefits than the ordinary stable flow pumping.5.Combining the hydrogeological conditions and hydrogeological parameters of the study area,the hydrogeological model of the study area is established by using the finite element simulation software Feflow.The calculated mineral water recoverable quantity is more precise,which is highly consistent with the pumping test,and the model has high reliability.6.The results show that the optimum exploitation amount varies seasonally,750~850m3/d in dry season and 1500~2000m3/d in high season.Flow in different seasons has reached the fourth-grade spring standard,which can meet the demand of mineral water in high-temperature season and small demand of mineral water in low-temperature season.