人工模拟降雨条件下不同雨强、坡度对紫色土坡面产流的影响

目的]研究不同降雨强度和坡度对紫色土坡面产流过程的影响,为紫色土区域的水土流失防治提供科学依据。方法]基于室内人工模拟降雨试验开展研究。结果]不同雨强和坡度下的产流过程可大致分为"下凹"型和"上凸"型,且分别可以用指数函数和对数函数描述。随着雨强和坡度的增大,产流时间逐渐减小,产流过程逐渐趋于一致,坡面径流量逐渐增加。坡度和雨强对径流总量的贡献率有着对比消长的关系,小雨强下(雨强为33和54mm/h),坡度是坡面径流总量的主要贡献因子,随着雨强增大(雨强为94和125mm/h),雨强为坡面径流总量的主要贡献因子。结论]坡度和雨强均为坡面侵蚀的主要影响因子,随着坡度和雨强的增加,坡面侵蚀更加剧烈,主要侵蚀因子也由坡度转变为雨强。

Impacts of Rainfall Intensity, Slope Gradient on Overland Flow of Purple Soil Under Simulated Rainfall

Objective] The effects of rainfall intensity and slope gradient on runoff process were studied to provide scientific basis for soil and water conservation control on purple soil areas. Methods] Researches were studied based on indoor artificial rainfall simulation experiments. Results] Runoff courses could be generally divided into concave and convex type, and can be described by exponential function and log function, respectively. With the increases of rainfall intensity and slope, the runoff initiation time decreased, the runoff amount increased, and the runoff course became similar. At low rainfall intensity, the effect of slope gradient was obvious in runoff generation, while at high intensity, the effect decreased. In this case, slope gradient was the main factor at low rainfall intensities(33,54 mm/h), while rainfall intensity became the main factor at high rainfall intensity(94,125 mm/h). Conclusion] Both rainfall intensity and slope gradients were the main factors of hillslope erosion. With the increase in rainfall intensity, the hillslope erosion became more sharply. And the main erosion factor transferred from slope to rainfall intensity.