Simulation of infiltration into typical triangular layered purple soils

Infiltration processes in typical triangular layered purple soils are first investigated using indoor soil infiltration devices. The devices are designed to have two distinct triangular layered soil profiles, which are coarse-to-fine and fine-to-coarse in soil textures from surface to bottom.Experimental results show that the wetting front advance appears to be faster in the first half of the layered soil column compared to that of the second half in the coarse-to-fine soil infiltration device. The opposite result is obtained with the fine-to-coarse soil infiltration device. Observation from the fine-to-coarse soil infiltration device shows that the rate of advance of the wetting front increases more quickly with time in the second half of the layered soil column compared to that of the first half in the coarse-to-fine soil infiltration device. However, there is no significant rate difference in the finer portions of layered soil columns on both devices. The inclined wetting front rate is found to be similar on both devices, which indicates that the soil texture has almost no influence on the rate. A mathematic model for simulating infiltration into triangular layered soils is developed using the power relationship and validated by the experimental data. The modeling result is in a good agreement with the experiment. The model has some physical meaning and can be transformed into the existing empirical models each other.