| With the continuous improvement of composite geomembrane production and construction technology,as well as the excellent anti-seepage performance of geomembrane itself,more and more plain reservoirs are using composite geomembrane for reservoir anti-seepage.Among the composite geomembranes,the main anti-seepage function is geomembrane,and geotextile mainly plays a protective role.Therefore,this article mainly studies the impact of geomembrane in anti-seepage.Due to the fragility of the material of the geomembrane itself,it is easy to cause damage and damage during transportation,construction,and use in the storage area,leading to the appearance of defective holes,which can reduce the anti-seepage performance of the geomembrane.Different defect areas,defect shapes,defect sizes,defect locations,number of defects,and overlying water head heights can have different impacts on defect leakage.This article summarizes and analyzes the changes in defect leakage of geomembranes under different defect areas,defect shapes,defect sizes,defect locations,defect numbers,and overlying water heads through indoor experiments and numerical simulations.The following conclusions are drawn:(1)Based on the instrument and principle for measuring the vertical permeability coefficient of geomembrane,indoor experiments were conducted,and numerical simulation calculations were conducted based on the indoor experiments.It was found that the leakage amount of geomembrane defects is linearly related to the defect area of geomembrane defect holes;The relationship between the defect shape and the defect hole of the geomembrane is relatively small;There is a linear relationship with the defect size of the defect hole in the geomembrane;Related to the location of defects in the geomembrane,the leakage amount of defects with concentrated distribution of defect holes is smaller than that with dispersed distribution of defect holes,and the relationship with the range of dispersed distribution of defect holes is relatively small;It has little to do with the number of defects in the geomembrane.When the defect area is the same,the leakage amount of defects in the concentrated distribution of porous holes is roughly the same as that in the single hole defect holes;There is a linear relationship with the height of the overlying water head.(2)Combined with the numerical simulation calculation of the indoor test part,the defect area,defect shape,defect size,defect location,number of defects and overlying head were simulated and calculated,which was consistent with the indoor test results,which verified the credibility of the software and laid the foundation for the simulation calculation of the actual engineering reservoir.(3)A numerical calculation model for the leakage of geotextile membrane defects in a plain reservoir in Xinjiang was established,and the leakage amount was simulated using calculation software under ideal conditions without defects in the geotextile membrane and under different water head conditions with an average of 26 holes per 10000m~2.In practical engineering,the more defects there are,the larger the defect area,and the greater the leakage of defects;The same defect hole,the closer it is to the dam foot,the greater the leakage amount of its defect;The higher the water level,the greater the leakage of defects,and there is a significant difference in leakage between when defect holes appear and when there are no defects.The properties of the underlying soil of the geomembrane also have a significant impact on the leakage of defects in the geomembrane.The larger the permeability coefficient of the underlying soil,the greater the leakage of defects in the geomembrane pores.This article studies the variation law of defect leakage under different defect holes,and based on this,simulates and calculates the variation law of leakage amount of geotextile membrane defect holes in plain reservoirs,which is of great significance for building high-quality reservoirs. |
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