Abstract:Through the simulation of indoor wind, hydraulic and freeze-thaw conditions, the combined experiments of single hydraulic erosion, freeze-thaw hydraulic erosion, and freeze-thaw wind hydraulic erosion were carried out. The law of runoff and sediment production of Pisha sandstone under the condition of composite erosion was revealed. The results showed that:(1) Under the same rainfall conditions, the runoff of freeze-thaw hydraulic erosion and freeze-thaw wind hydraulic erosion test is 1.2 times of that of hydraulic erosion test, and the sediment yield is 2.4 and 2.8 times of that of hydraulic erosion test respectively. Freezing and thawing could increase the runoff and sediment yield of Pisha sandstone, while wind erosion had little effect on the increase of erosion and sediment yield. (2) The peak value and variation amplitude of runoff and sediment yield process of Pisha sandstone increased with the increase of the types of operating forces, and the runoff and sediment yield process of single hydraulic erosion had a significant flat feature compared with the water and sediment yield process under the effect of compound operating forces. (3) The composite erosion increased the initial infiltration rate and decreased with the rainfall. The initial water content was larger and the later was smaller with the increase of the operation force. (4) The relationship between the cumulative yield and the cumulative yield was power function. The effect of freeze-thaw erosion on the relationship between water and sediment was greater than that of wind. This experiment shows that the increase of the combined erosion force will aggravate the erosion process of the Pisha sandstone slope and increase the sediment yield.