降雨条件下坡地水分转化特征实验研究

Experimental study on characteristics of water transformation on slope land

坡地水分转化规律研究对于探讨坡地水土流失以及坡地养分迁移规律具有重要意义。本文以黄绵土为试验材料,通过模拟降雨试验,研究了不同雨强条件下坡面入渗过程与产流特征。结果表明:(1)在地表坡度15°、土壤容重1 28～1 30g cm3的条件下,坡面平均入渗率(ia)与降雨强度(iR)具有极显著的抛物线函数关系,当iR=1 35mm min时,ia具有最大值(1 01mm min);初始产流时间(tp)随iR的增大而减小,二者呈幂函数关系。(2)坡面产流以后,入渗率(i)随降雨历时(t)呈幂函数形式降低,坡面产流强度(VR)随t的延长呈对数函数形式增加。(3)随着雨强的增大降雨的入渗量略有增加,但降雨向土壤水分的转化率则显著降低。

The infiltration process and characteristics of runoff yielding on slope land under the condition of raining with different intensities are studied experimentally in laboratory for rainfall simulation.It is found that:1.the average infiltration rate varies with rainfall intensity following a parabolic function law;2.after the incipient of runoff,the infiltration rate decreases exponentially with the duration of raining but the runoff yielding intensity is logarithmically related to the raining duration;3.the infiltration rate increases if the rainfall intensity increases,but the ratio of rainfall transformed into soil will significantly decrease.