Effect of sediment cover thickness on loess slope infiltration and simulation

The sand-loess binary structure landform, formed under multi-dynamic interactions in wind-water erosion crisscross regions of the Loess Plateau, exhibits unique erosion patterns. Studying the influence of sand-cover thickness on loess slope infiltration characteristics can deepen the understanding of erosion mechanisms in such structures. Through indoor simulated rainfall experiments, this research investigated the effects of varying sand-cover thickness on infiltration features and evaluated the applicability of three common soil infiltration models in this context. The results indicated that: (1) Sand-cover treatment significantly delayed the initial runoff occurrence time, and the wetting front migration rate increased with sand-cover thickness. (2) Sand-cover enhanced soil infiltration rates and shortened the time required to reach stable infiltration. (3) The Kostiakov model demonstrated the best performance in simulating infiltration processes under sand-loess binary structures, followed by the Jiang Dingsheng model and Philip model. In conclusion, sand-cover layers profoundly affect soil infiltration capacity, with distinct patterns emerging as thickness increases. These findings provide scientific insights for effective management and benefit evaluation in wind-water erosion crisscross regions.