强降雨条件下砖红壤坡面产流产沙过程研究

Study on Process of Runoff and Sediment on Laterite Slope in Condition of Strong Rainstorm

利用人工模拟降雨试验,对强降雨条件下砖红壤坡面入渗、产流产沙过程进行定量分析。结果表明,强降雨条件下降雨强度对初始产流时间的影响大于坡度;砖红壤坡面入渗强度随时间的变化规律符合Horton模型,平均决定系数为0.958;砖红壤坡面产流过程分为4个阶段:初始入渗阶段、初始产流阶段和稳定产流阶段、结束产流阶段,推导出产流过程方程;砖红壤坡面产沙过程分为5个阶段:无产沙阶段、产沙能力上升阶段和产沙能力下降阶段、稳定产沙阶段(75,100,125mm/h降雨强度)或波动阶段(150,175mm/h降雨强度)和停止产沙阶段,累计产沙量随时间的变化规律符合二次多项式模型,不同坡度不同降雨强度情况下各拟合方程决定系数在0.970以上。研究结果为建立砖红壤坡面产流产沙物理模型及水土资源管理提供了理论基础。

The process of runoff and sediment on laterite slope in condition of strong rainstorm was quantificationally analyzed using simulated rainfall experiment.The results showed that rainfall intensity on the effects of initial runoff time was greater than the slope.Horton model could be used to express the law of the variation of infiltration intensity along with initial time on laterite slope.The process of sediment on laterite slope was divided into four stages：initial infiltration stage,initial runoff stage,stable runoff stage and stop runoff stage.The process of sediment on laterite slope was divided into five stages：no sediment stage,sediment ability rising stage,sediment ability dropping stage,stable stage（75,100,125 mm/h rainfall intensity）or fluctuating stage（150,175mm/h rainfall intensity）and stop sediment stage.The variation of accumulative sediment yield of laterite slope along with time obeyed the law of second degree polynomial function.The results would be helpful for building and perfecting the soil erosion physical prediction model in laterite area.