Probabilistic model of soil and cohesive ground erosion.

Abstract

An equation based on a hydrophysical approach was developed to describe the detachment of soil aggregates and cohesive grounds. According to this equation, the detachment of aggregates and particles is proportional to the kinetic energy of flow at the velocities that are above the threshold. At velocities that are close to the threshold, particle detachment depends on the ratio of the probability of exceeding threshold (depending on soil detachability) to the probability of not exceeding the detaching force of the flow by soil particles. The suggested model was adequately verified by the experimental data obtained by Nearing et al. [16]: the coefficient of determination was equal to 0.98-0.99. The soil detachment at lower velocities seems to be induced by the degradation of interaggregate bonds, owing to exchange and other nonhydraulic processes occurring between the soil and the flow. According to the model, the velocity should be considered as threshold when the instantaneous values of forces affecting the soil surface exceed its resistance to detachment 50% of the time.