Experimental study on infiltration of unsaturated soil and solution of permeability coefficient

During the unsaturated infiltration, water content, infiltration rate, infiltration amount and other physical quantities are all related to the water supply approaches and intensities. In order to study the change of water migration and the permeability coefficient in vertical infiltration of one-dimensional soil column with different infiltration conditions, this paper designs an experimental device for a one-dimensional soil column infiltration model. Three sets of infiltration tests with different intensities were carried out in two ways: artificial rainfall infiltration and ponding infiltration. The results show that the infiltration under the conditions of rainfall infiltration and ponding infiltration presents a similar trend. The infiltration of ponding in the initial stage of infiltration has greater fluctuations than the infiltration of rainfall, but after the latter stabilizes, the infiltration capacity of ponding infiltration and rainfall infiltration tends to be the same. Finally, on the basis of the theory of soil water energy state and the law of conservation of energy, a new method for solving the permeability coefficient of unsaturated soil under free infiltration is obtained.