Similarity Model Test on Rainfall Scouring Mechanism of High-Speed Railway Subgrade Slope

Abstract

The subgrade slope, when exposed to the natural environment for a long time, is easily affected by rainfall scouring, which leads to a large loss of filling materials and soil sliding, affecting the stability of the subgrade slope. In this paper, the model test of a high-speed railway subgrade slope under rainfall scouring was conducted to quantitatively study the occurrence and development process of subgrade slope erosion. Compared with the model test results and the theoretical results, the incipient flow velocity formula of coarse-grained soil was verified. Then, the curve of rainfall intensity varied with the incipient particle size under different rainfall intensities, slope gradients and soil particle grading conditions was analyzed. Results show that during rainfall scouring, the smaller the particle size, the earlier the scouring erosion occurs. In addition, the soil particles on the slope bottom were scoured more severely than those on the slope upper. With the increase in rainfall intensity, slope gradient, and the change in soil particle gradation (removing the minimum particle size), the incipient flow velocity of soil particles on the slope will be reduced. The curve of the rainfall intensity varied with the incipient particle size, which plays an early warning role in the analysis of slope erosion stability and reflects the particle size range of the scouring erosion incipient on the slope surface under different rainfall intensities, providing the basis for the analysis of slope erosion stability and the slope protection design of the high-speed railway subgrade slope.