A Study of Soil Detachment Capacity of Slope Flow Based on Kinetic Theory

Efficient description of soil detachment capacity is essentially important for predicting soil erosion processes, while most of detachment functions are semi-empirical ones unable to elucidate detachment mechanics. Therefore, a new detachment function was developed based on kinetic theory for sediment transport, aiming to describe soil detachment in a theoretical way. Soil detachment capacity was described as the maximal upward soil flux detached from parent soil per unit time and unit area, resulting from interaction between soil particles and flow turbulence. The new function was an integration of particle velocity over the upward motion, with the velocity distribution function acting as a central part and capable of revealing the key external forces to detach particles. The soil detachment function was verified with different experiments and compared to 3 other representative detachment formulas. Results showed that the calculations were well consistent with the observations from different resources, and 78% of comparison data had relative errors distributed in [-0.5, 0.5]. The new function was also of higher accuracy compared to others. More important, since the new function was derived on basis of kinetic theory, which connected the microscopic particle motion and macroscopic statistical characteristics of soil detachment, it helped provide theoretical foundation to further elucidate the soil detachment mechanism. © 2021, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.