Effect Of ?-PGA Water Retaining Agent On Soil Water And Salt Transport Characteristics In One Dimensional Vertical Infiltration Soil

In order to reveal the influence of the one-dimensional vertical infiltration law and water salt migration characteristics of ?-PGA,Based on a large number of domestic and foreign related literature,using silt sand as the research object and laboratory experiments and research methods combined with theoretical research and numerical simulation.The study on the one-dimensional vertical infiltration characteristics of the soil and the characteristics of water and salt migration were carried out.The effects of different factors such as the amount of y-PGA,the applied layer and soil bulk density on the one-dimensional vertical infiltration characteristics and water and salt transport of the ?-PGA water retaining agent were analyzed.One-dimensional vertical infiltration model was established after the soil was added to the ?-PGA,and the model was verified by the indoor test results.The main research results are as follows:(1)The experimental study on the water movement characteristics of a one-dimensional vertical infiltration soil through the gamma-pga mixtures shows that:With the increase of the amount of y-PGA,the migration distance of wetting front was gradually shortened,and the cumulative infiltration volume decreased gradually,while the infiltration rate increased gradually;In the process of water redistribution,the soil moisture content in the upper section is opposite to that of the soil moisture content in the lower section;meanwhile,the soil moisture content decreased gradually with the increase of the ?-PGA.The changes of the wetting front migration distance,the cumulative infiltration volume and the decrease rate with time are respectively consistent with the Kostiakov infiltration model,the power function model and the logarithmic function model;And set up by ?-PGA intake and infiltration time as the independent variable,the mathematical model of wetting front transport distance as the dependent variable,and compared with laboratory test results,the results show that the higher the fit of the model.(2)The experimental study on the characteristics of soil water movement in a one-dimensional vertical infiltration soil by means of the amount of y-PGA and the input layer and soil bulk density is shown in this paper.The influence of soil bulk density on migration distance,cumulative infiltration rate and infiltration rate was the largest,and the influence of y-PGA applied layer was the second,and the influence of y-PGA was minimal.According to the change law of time,the change of the rate of infiltration is consistent with the model of logarithmic function.(3)According to the experimental study of water and salt migration characteristics,the saturated water content of the soil increases gradually with the increase of the amount of y-PGA,and the saturated water content is in line with the three-binomial equation between the amount of saturated water content and the amount of y-PGA.The water characteristic curve of the soil was fitted with the Van Genuchten model,and the model was verified.By adding the y-PGA soil solute breakthrough curve shows that with the increase of y-PGA intake,the initial penetration volume number decreases,and fully penetrate the volume increase in the number,and the measured data using CXTIFIT2.1 software established CED model,the results show that the fit of the model is higher...