复合侵蚀作用下砒砂岩坡面产流产沙过程试验

通过模拟室内风力、水力、冻融条件,进行单一水蚀、冻融+水蚀、冻融+风蚀+水蚀3种营力组合试验,揭示了复合侵蚀条件下的砒砂岩产流产沙变化规律。结果表明:(1)相同降雨条件下,冻融+水蚀、冻融+风蚀+水蚀试验的径流量均为水蚀试验的1.2倍,产沙量分别为水蚀试验的2.4,2.8倍。冻融能够增大砒砂岩产流产沙量,风蚀对增加侵蚀产沙量的作用较小。(2)砒砂岩产流产沙过程的峰值及变幅随营力种类的增多而增大,单一水蚀的产流产沙过程相较于复合营力作用下的水沙过程具有显著的坦化特征。(3)复合侵蚀作用使初始入渗率增加,随着降雨的进行对入渗的影响逐渐减小。营力作用的增加使初始含水率更大,后期更小。(4)砒砂岩的累计产流量与累计产沙量呈幂函数关系。冻融作用对水沙关系的影响较大,风力作用的影响较小。此试验表明,复合侵蚀营力作用的增多会加剧砒砂岩坡面的侵蚀过程,从而使侵蚀产沙量增大。

Experiment on Runoff and Sediment Production Process of Pisha Sandstone Slope Under Composite Erosion

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.