On erosion characteristics of compacted loess during wetting procedure under laboratory conditions

Abstract

The erosion of engineered slope surfaces has become an urgent problem in loess regions in China, which has a serious impact on the safety and stability of the slope projects. In this paper, to study the effect of the confining pressure, dry density of the slope surface, and water flow velocity during wetting procedure on the erosion characteristics of compacted loess, we developed a laterally confined uniaxial compression-erosion apparatus, which was characterized by the fact that it can change the confining pressure of the being eroded soil sample to analyze the loess erosion rates and particle size distributions of the eroded sediments. The fractal dimensions of the eroded sediments were calculated by fractal theory and their variations were analyzed. Results show that the erosion rate is approximately linearly related to the confining pressure. The higher pressure has a tendency to move towards the free top of soil sample, the erosion rate increases. Compared with the water flow velocity, the higher confining pressure plays a greater role in the erosion rate, the influence of water flow velocity on the erosion rate decreases. With the increase of dry density, the erosion rate decreases, the higher dry density enhances the ability of soil sample to resist water erosion. The confining pressure changes the particle size distribution of the eroded sediments of loess samples, the median diameter D50 increases. However, the fractal dimension decreases with the increase in confining pressure. The confining pressure of slope surface has a negative effect on the loess anti-erosion characteristics. The results in this paper would provide detailed information on the mechanisms of loess erosion, which could contribute toward prevention of surface erosion of high fill slopes in loess regions.