Experiment Research on the Effect of Surface PAM Coverage on Erosion Soil Critical Shear Stresses of Slope Cultivated Land by Rainfall

A direct calculation method of the critical shear stresses was established according to experiment datum on simulated rainfall. Based on the principle of hydraulics, through observing the initial place of slope erosion, rainfall intensity, soil infiltration rate, and the average velocity of slope flow, the critical shear stresses were calculated. At the same time, effects of slope degree and PAM coverage on the critical shear stresses were analyzed. The experiment was designed to have 1 level of rain intensity: 100 mm/h, 3 slope degrees: 10°, 20° and 25°(17.63%, 36.4% and 46.63%), and 4 treatments: control, 3 PAM coverage 40%, 60% and 80%. The results show that the critical shear stresses decline with slope degree increase; and the critical shear stresses increase with PAM coverage increase.