聚丙烯酰胺对扰动红壤可蚀性及临界剪切力的影响

为了利用化学措施防治工程水土流失，研究了聚丙烯酰胺（PAM）对扰动红壤土壤可蚀性及临界剪切力的影响。采用室内人工模拟降雨试验，探讨了5o、10o、15o、20o、25o 5种坡度，0.8、1.1、1.4 mm/min 3种雨强下不同土壤处理后坡面水动力学参数、径流输沙率与流量、土壤可蚀性及临界剪切力的变化关系。试验结果表明，在相同的径流流量下，对照的输沙率是施加PAM后的300倍；施加PAM后，红壤扰动土的可蚀性由13.223 g/(min·N)降低到0.2693 g/(min·N)，径流的临界剪切力大小由0.77 N/(m2·min)增加到1.47 N/(m2·min)。施加PAM可显著降低土壤可蚀性，增加径流临界剪切力。研究成果为PAM应用于工程水土流失防治提供了一定的理论依据。

Effects of polyacrylamide (PAM) on soil erodibility and critical shear stresses for disturbed red soil

For applying chemical measures to prevent projects soil and water loss, studying the effects of polyacrylamide (PAM) on soil erodibility and critical shear stresses of the red disturbed soil, stimulated rainfall experiments were conducted in the laboratory with 5 slope degrees as 5o, 10o, 15o, 20o, 25o and 3 rainfall intensities as 0.8 mm/min, 1.1 mm/min, 1.4 mm/min. The characteristics of the slope hydrodynamics parameters, relationships between runoff sediment transport rate and flow volume, variation of soil erodibility and critical shear stresses were analyzed with different soil treatments. The results showed that the sediment transport rate without PAM was 300 times larger than that with PAM when the runoff flow volumes were the same. The soil erodibility decreased from 13.223 g/(min·N) to 0.2693 g/(min·N), the runoff critical stresses increased from 0.77 N/(m2·min) to 1.47 N/(m2·min) with the application of PAM to the red soil. This means that the application of PAM can decrease the soil erodibility remarkably and increase the critical stresses. The results will provide theory basis for application of PAM to engineering soil and water loss prevention.