Numerical Simulation Of One-dimensional Two-way Coupling Water And Salt Transportation

Soil salinization is one of the major types of soil desertification and land degradation in the whole world nowadays and is a global environmental problem many nations have to face. Especially, the soil salinization is serious in China. The law of water and salt migration in the soil is the important theoretical basis of management and prevention of soil salinization, which can play as a guideline in the actual production.Based on the water movement equation and solute migration equation and taking into account changes in the soil parameters, the paper considers the influence on the soil parameters of the salt concentration and attains the modified model. Then the one-dimensional water and salt migration was simulated by the modified model. The results are as follows:1.Under the condition of infiltration, the numerical results of the modified model are exact, and are in good agreements with the experimental results and meet the actual requirements.2.Based on the rationality of numerical simulation in the washing salt infiltration, the results that the infiltration capacity of the soil increases as seepage salinity largens, which can not be simulated by the previous model, is achieved by the modified model. In the process of washing salt infiltration, when the salinity of infiltrated water is within the specfic range, the higher salinity of infiltrated water, the better the effect on washing salt by infiltration.3.For water and salt migration in boundary-condition of evaporation, the numerical simulations show that the higher the groundwater level, the greater the groundwater salinity, the more likely surface salt accumulation.