不同雨强下PAM分子量对土质堤防产流产沙的影响OA北大核心

[Objective]The objectives of this study are to explore the effect of different molecular weights of PAM on the erosion prevention of the protective slope of an embankment in Northeast China,and to explore the effect of PAM solution on the slope surface of the embankment under spraying mode,so as to provide a theoretical basis for the treatment of soil embankment in northeast China.[Methods]An indoor artificial simulated rainfall experiment was designed to study the backwater slope of the embankment in the upper reaches of a black soil area in northeast China,and three different rainfall intensities(180,200,220 mm/h),bare ground(molecular weight 0)and four different PAM molecular weights(1 200,1 400,1 600,1 800)were set up,and the PAM concentration was 4 g/m2,and the PAM solution was sprayed on the experimental slope with 4 g/m2 PAM ratio of 3.5 L water.The characteristics of runoff and sediment generation on the slopes with different molecular weights of PAM under three rainfall intensities were studied,and their hydraulic parameters were analyzed.[Results](1)Under the same rainfall intensity,the amount of runoff and sediment yield on the slope with PAM is smaller than that on the bare slope.(2)Under the same molecular weight of PAM,runoff and sediment generation on the slope increases with increasing of rainfall intensity.Under the three types of rainfall intensities,the sediment reduction effect of 18 million molecular weight was the best,and the maximum sediment reduction was 57.74％.(3)By calculating the Frode number(Fr)and Reynolds number(Re)of slope flow,it is found that Re＜500 shows that the flow form is laminar flow,and when the rainfall intensity is 220 mm/h,the flow pattern of bare slope is rapid,and the rest are slow flow.Rainfall intensity,PAM molecular weight to water flow power,and unit water flow power can be described by power functions.[Conclusion]It can be seen that the application of PAM solutions with different molecular weights on the slope of an embankment in northeast China can effectively reduce the amount of sediment produced by runoff,and the effect of sediment reduction is particularly obvious,and in the molecular weight interval of PAM selected in the experiment,the application of PAM with a molecular weight of 18 million has the most significant effect on the sediment reduction of the experimental slope,and the PAM can improve the infiltration capacity of soil water and provide a reference for the control of soil erosion in soil embankments.