| Aiming at the problem that the Yellow River has large water flow and large sediment concentration and low cost filtration in high-efficiency water-saving irrigation in Ningxia Yellow River Irrigation District,the non-full flow filtration device for high-yield sandy water farmland was studied.The method of experimental comparison was used to design "unsaturated soil water+buried vertical filter(V)","unsaturated soil water+buried horizontal filter(L)","unsaturated soil water+radiation well filtration".Four different non-full flow filtration schemes of formula(R)","saturated soil water+seepage well(S)",systematically filter the high-sand and non-full-flow filtration effect of the Yellow River water as the water source.The experimental research provides theoretical basis and technical support for non-full flow filtration of high sandy water farmland in the Yellow River irrigation area.The experimental research results are as follows:(1)Through the indoor soil column experiment,the soil infiltration law in the test area under different water head conditions was obtained,and the optimal head of the high-sand water non-full flow filtration device in the Yellow River irrigation area under suitable farmland conditions was obtained.The infiltration of 20cm(H20),57.5cm(H57.5)and 95cm(H95)water heads was designed for the infiltration of the farmland soil near the foot of Tanglai Canal in the Yellow River Irrigation District..The experiment results show that the migration speeds of the wetting fronts are different under different heads,but they all follow the law of the power function of the index,which is H95>H57.5>H20 from large to small.Cumulative infiltration and cumulative infiltration rate are directly proportional to the water head,but when the water head increases to 57.5 ml and the water head continues to increase,the cumulative infiltration and cumulative infiltration rate increase.The soil moisture content during water infiltration is mainly divided into three stages:rapid rise phase,slow rise phase,and stabilization phase.The amount of effluent from the three schemes was H95>H57.5>H20,which were 146.46 ml,258.83 ml,and 305.83 ml,H57.5 increased by 76.72%compared with H20,and H95 increased by 108.81%compared with H20,but H95 ratio The water output of H57.5 only increased by 18.16%,which indicated that the water output increased correspondingly with the increase of the water head.However,when the water head increased to 57.cm and continued to increase,the water output increased.(2)Through the field experiment,the filtration effect of different non-full flow filtration devices for micro-irrigation and high-sand water was obtained and the optimal scheme was selected.Designed"unsanded concrete pipe+needle-punched non-woven fabric+quartz sand+soil" unsaturated soil water"buried vertical filter(V)","buried horizontal filter(L)","radiation well Filter(R)" and saturated soil water "filtration well(S)" four different piping methods,under the condition of 20cm head of the water head,the non-full flow filtration device for the high-sand water of Tanggu in the Yellow River irrigation area The test results show that the water output per unit length of the four schemes is S>R>L>V,which is 0.1376m3·(h·m)-1,0.0311 m3·(h·m)-1,0.0227 m3(h·m)-1,0.0156 m3·(h·m)-1,seepage well filtration is the optimal solution for water filtration.When the V and L groups were tested for 50h and the R and S groups were carried out for 70h,the sediment concentration in the filtered water was less than 0.4kg/m3,and the sediment concentration gradually decreased as the test progressed.The maximum sediment particle size is 0.112mm,and the particle size is greater than 0.1mm,which only accounts for 0.077%,which can meet the requirements of drip irrigation for water quality.In summary,the seepage well treatment adopts anti-leakage treatment,and the replacement of water-permeable sand is the filter medium,and the water output reaches 0.1376m3·(h·m)-1,which is the most cost-effective and easy to promote.Excellent filtration device solution. |
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