PAM对寒区粉壤土堤防护坡产流产沙特征的影响

Effect of PAM on the Characteristics of Runoff and Sediment Yield in Protection Slope of Embankment of Silty Loam in Cold Area

为研究解决寒区粉壤土堤防背水坡面的水土流失问题,基于室外模拟降雨试验,研究第二松花江流域粉壤土堤防坡面施加聚丙烯酰胺(PAM)后在不同坡度和下垫面条件下对坡面侵蚀特征的影响。试验包括4个坡度(10°,15°,20°,25°)和5种PAM浓度(0,2,3,4,5 g/m 2)。结果表明:降雨强度和下垫面条件相同时,坡度从10°增大至25°,坡面平均产流率先增大后减小,产沙率随坡度增大而增大。降雨强度和坡度相同时,聚丙烯酰胺浓度2 g/m 2增大至5 g/m 2,平均产流率相较于0 g/m 2降低了10.6%~20%;平均产沙率随浓度的增大而减小。将坡度和浓度的平均产沙率进行拟合,得出产沙率与坡度呈现正相关性,与浓度呈现负相关性。0 g/m 2坡面的侵蚀形态主要表现为溅蚀和面蚀特征,施加PAM使得坡面侵蚀严重区域面积相较于0 g/m 2减小54.57%,起到了一定控制侵蚀的效果。可见,在坡面上施加一定量的聚丙烯酰胺可以使土壤水分入渗能力增强,减少侵蚀产沙,在实际工程中具有运用的价值。

In order to solve the problem of soil and water loss on the backwater slope of the silty loam dyke in the cold region,based on the outdoor simulated rainfall experiment,the influence of PAM on the slope erosion characteristics of the second silty loam dyke in the Songhuajiang River basin under different slope gradients and underlying surface conditions were studied.The treatments included 4 slope gradients(10°,15°,20°,25°)and 5 PAM concentrations(0,2,3,4,5 g/m 2).The results showed that the slope gradients increased from 10°to 25°,the average runoff of the slope first increased and then decreased,and the sediment yield increased with the increase of the slope under the same rainfall intensity and underlying surface conditions;the concentration of polyacrylamide increased from 2 g/m 2 to 5 g/m 2,and the average flow yield decreased by 10.6%~20%compared with bare land under the condition of the same rainfall intensity and slope;the average sediment yield decreased with the increase of concentration;there were the positive correlation between sediment yield and slope and the negative correlation between sediment yield and concentration based on fitting average sediment yield of slope and concentration;the erosion pattern of open slope was mainly characterized by splash erosion and surface erosion;the application of PAM reduced the area of serious slope erosion by 54.57%compared with that of open slope,which had a certain effect of erosion control.It is concluded from this experiment that the application of polyacrylamide on the slope can enhance the soil water infiltration capacity and reduce the erosion and sediment production.