Simulation Study Of Aquifer Flow Pattern In The Process Of Water Intake From Seepage Well

The reversed water intake project for seepage wells is an economical and efficient way to use water resources.With the operation of water intake projects,the determination of a reasonable amount of projected water and the blockage of seepage wells have received extensive attention.however,The characteristics of changes in groundwater flow conditions and changes in aquifer pressure during the process of water intake are the important factors that directly affect the determination of reasonable water intake and silting problems,and ultimately determine the design site for water intake projects.Therefore,it is very important to fully understand the characteristics of groundwater flow patterns and aquifer pressure changes in reversed water intake projects for seepage wells.In this paper,combining with the actual engineering problems,with the help of indoor simulation experiment,Feflow numerical simulation,matlab and other research methods,the change law of groundwater flow state and the change of internal pressure in aquifer are studied.To lay the foundation for solving the practical problems of reversed water intake in seepage wells.The main research results of this paper are as follows:?1?In the process of water intake in the seepage well,the water intake Q?cm³/s?increases as the depth s?cm?increases.Because the surface water supply capacity is limited,when the depth drop reaches an effective maximum value,the water withdrawal amount is not Then,it increases with the increase of the depth,and eventually becomes stable.Under the conditions of constant-draw and deep-draw water,the law of the amount of water taken over time can be divided into four stages:Darcy seepage,non-linear seepage,rapid water release,and stable seepage.?2?Observed pore water pressure curve with time is similar to“V”type in the process of reversed water intake in seepage wells.With the increase of radial distance,the effect of water intake on the pore water pressure inside the aquifer gradually decreases;the greater the vertical depth,the greater the pore water pressure,indicating that the closer the water intake from the seepage well,the greater the decrease in pore water pressure.The function of pore water pressure in the first half minus interval can be P?x,y,t?=P_i+^?,The function of the fitting function P?t?=at³+bt²+ct+d?a,b,c,d are constant?can be used in the second half of the increment interval function.?3?The pore water pressure drastically decreases during the initial period of water intake,resulting in the formation of a negative pressure zone in the middle of the aquifer directly above the water intake of the seepage well.?4?A percolation well pipe model C+kU²=P is proposed to calculate the water withdrawal volume from the pore water pressure and use the pore water pressure time lag effect to predict the actual engineering seepage well water intake to determine the reasonable water withdrawal for the seepage well.the amount.?5?Through the Feflow numerical simulation of groundwater flow pattern simulation in the aquifer of reversed water intake in seepage wells,the groundwater state in the surface aquifer is always saturated.The pore water pressure in the process of water intake is not affected by the infiltration strength and the infiltration degree of the aquifer.Impact,there is always a full of water.Due to water intake,a negative pressure zone is formed inside the aquifer.The aquifer system will consist of surface water layer,negative pressure zone,unsaturated zone,and saturated groundwater zone.This also reveals the characteristics of multi-flow coexistence in practical projects.