Study On Physical Simulation Experiment Of Water Intake Of Radial Collector Well

Exploitation of water resource near the river with radial collector well is advantageous inlarge water yield and the relatively clean water,etc.It has been one of the highly efficient waysof water exploitation.But up to now,each factor on the effect of water intaking has noquantitative research,the design and construction of radial collector well is mostly accordingto experience so that the most optimal scheme mostly can not be used and the best effect ofwater intaking can not be achieved.This is against the use and promotion of radial collectorwell.This thesis relies on the National Natural Science Foundation of China “Study on thecalculation model and physical modeling of non-casting-well groundwater-collectingstructure working mechanism”. Conducting simulation test on the effect of water intaking ofradial collector well by using seepage sand tank,miniature model of radial collector well,measurement system, water circulation system and other devices.The simulation test is onthree different buried depth of radial collector well,three differenent elevation angles ofcollector pipes,three different drawdown of vertical shaft,two different rivers of leakagecapacity,and the data of each corresponding scheme that get from the test are shaft drawdowndata,water yield data and drawdown distribution data of each observation point in the sandtank.By comparing the test results of each scheme,basically have the following conclusion:(1)When radial collector well intakes water under the condition of saturated seepage and otherconditions are identical,the stronger of river leakage capacity,the larger of the water yield;when the angle of collector pipes is small,water yield of radial collector well increases withthe increase of elevation angle of collector pipes;the larger of the buried depth of radialcollector well,the smaller of the water yield; the larger of the drawdown of vertical shaft,thelarger of the water yield.(2) When radial collector well intakes water causes unsaturatedseepage,intaking water is affected by the unsaturated zone,with the buried depth of radialcollector well increase,the water yield start with decrease,but with the further increase ofburied depth the water yield increase;when the radial collector well is close to the supplysource,the larger of the elevation angle of collector pipes,the greater impact on intaking water;when the radial collector well is far from the supply source,unsaturated zone has smallimpact on intaking water,the larger of the elevation angle of collector pipes,the larger of thewater yield;when the drawdown of vertical shaft within limits,the water yield increases withthe increase of the drawdown of vertical shaft,while the water yield of unit drawdown ofvertical shaft decrease.By comparing the drawdown distribution of observation point in the sand tank, basicallyhave the following conclusion:when radial collector well intakes water,it impacts thesurrounding aquifer as the center of collector pipes,the closer to collector pipes,the larger ofthe drawdown;when other conditions are identical,the larger of the buried depth of radialcollector well,the greater of the affected area in the aquifer,but the smaller of the drawdownof water table;the weaker of river leakage capacity,the greater of the affected area in theaquifer and the greater of the large drawdown area; the larger of the elevation angle ofcollector pipes,the greater impact on vertical and the less impact on lateral direction.The entire sand tank as the study region,according to the full size of the devices of thesand tank simulation test,on the basis of the finite difference grid,using the exchange flowrate between the aquifer and the well pipe as the coupling points to establish the coupledseepage–pipe flow model of each scheme to calculate the water yield. The model calculationresults indicate that, when intaking water by radial collector well does not cause unsaturatedflow, the calculation results is satisfied fitting the measured flowrate,calculation model isvalid;when intaking water causes unsaturated seepage,the calculation results is differ withmeasured flowrate,indicates that the selected model does not apply to simulate theunsaturated seepage.Quantitative calculation on water yield of radial collector well under the influence ofvarious factors is made by the selected model. By drawing influencing factors and water yieldcurve,basically have the following conclusion：when radial collector well intakes water doesnot cause unsaturated seepage and other conditions are identical, the water yield is basicallyincrease linearly with the increase in shaft drawdown,the water yield is decrease with theincrease of buried depth of radial collector well,at the beginning,water yield of radialcollector well increases with the increase of the leakage ability of river,when the river leakagecapacity reaches a certain level,little change in the water yield until no further increase, indicating that the river can be regarded as the first boundary condition;when the coditionsare different,the critical leakage leakage ability and water yield are different when rivers canbe used as the first kind of boundary condition.