The Influence of Rainfall Infiltration on Particle Migration of Coarse‐Grained Soil Filler

Abstract The intellectualization and informatization of railway subgrade monitoring is the current development trend. The change of physical and mechanical properties of the subgrade is the basis of intelligent identification. Therefore, it is necessary to reveal the influence of rainfall infiltration on particle migration of coarse‐grained soil filler. A systematic rainfall infiltration test was carried out to investigate the effect of soil layer thickness and particle size on particle migration in coarse‐grained soil filler using a home‐built model test apparatus. The results show that the particle migration depth increases with increasing rainfall and decreases with increasing particle size. The maximum migration depth of clay with particle size ≤0.075 mm was about 500‐600 mm, while the maximum migration depth of quartz sand with particle size 0.315‐0.63 mm was about 300‐400 mm. The migrating particles are deposited between 0‐100 mm to form a zone of aggregation. With increasing rainfall, a second zone of aggregation is formed in the lower part of the soil layer. The results can provide a reference for intelligent identification of coarse‐grained soil subgrade structure deterioration.