| According to different water-bearing media,the groundwater in Kejing Basin of Jiyuan City can be divided into loose rock pore water,clastic rock fissure water and fissure karst water.Among them,clastic rock fissure water has poor water richness and low in mining value;the loose rock pore water is easy to be polluted and mainly used for farmland irrigation;the fissure karst water has good water quality and strong but uneven water.It is the main water supply source for domestic and industrial water for residents in the villages of Jiyuan City and Kejing Basin.This paper only studies the fissure karst water of kejing Basin.The fissure karst water in kejing Basin has only been surveyed in 2000.Due to less work and low research level,the hydrogeological conditions are unclear.In addition,for a long time,the current mining volume,hydrology and meteorology of kejing Basin have changed greatly.In this study,the fissure karst water in kejing Basin of Jiyuan City is investigated in detail,the amount of resources is calculated by water balance method,and the numerical model is established.The water level under different supply or mining conditions is predicted and analyzed,which is of great significance to the social and economic development and the rational development and utilization of groundwater in Jiyuan City.Through hydrogeological survey,water level measurement,long-term observation,pumping test and mining volume survey,the hydrogeological conditions of the fractured karst water in Kejing Basin have been basically ascertained.It mainly receives precipitation infiltration,lateral seepage of Qinhe River,and leakage of Manghekou Reservoir,and is discharged by artificial mining and lateral runoff.Using the water balance method to calculate the amount of water resources for the karst water in the study area,it was concluded that the total recharge amount of fractured karst water in the study area during the equilibrium period was 117,670m~3/d,and the total discharge was 124,497 m~3/d.The equilibrium difference was-6,827m~3/d,the relative error of water volume is 5.8%,and the calculated values of each supplementary item basically conform to the actual situation in the study area.And evaluated the fissure karst water resources under different guarantee rates and different mining conditions.Use FEFLOW numerical simulation software to establish a numerical model of fissure karst water in the study area.After model identification and testing,the calculated and measured end time water level lines are mostly parallel or even coincident;the average root-mean-square error between the calculated water level and the measured water level of the8 long observation holes is 0.38m;the average relative error is less than 1%;the correlation coefficient is at 0.86?0.94;most of the calculated and measured water levels of long observation hole at each time node do not exceed±0.50m.During the verification period,the fitting effect of the calculated water level of the observation hole and the actual water level is also good,which indicates that the accuracy of the model built this time is high,which better reflects the actual situation of the study area,and the model can be used to predict the water level of the fissure karst water in the study area in the future.Use the established numerical model to predict the fissure karst water level in different scenarios.The results show that under the current supply and mining conditions,the fissure karst water level drops slightly;when the mining volume in the Qingduo water source fell to50,000 m~3/d,the fissure karst water level rises significantly;when the Qingduo water source area is not mined,the water level of the nearby pore water is lower than that of the fractured karst water,and the karst water recharges the pore water in the form of overflow. |
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