人工红壤坡面对超大雨强降雨的响应过程

为了研究人工红壤坡面对超大雨强降雨的响应过程,利用人工模拟降雨系统和变坡土槽,分别采用140,160,190mm/h的雨强和10°,15°,20°,25°的坡度,对经过简单人工处理的红壤坡面在超大雨强降雨条件下的产流产沙响应过程进行了试验。结果表明:经过简单人工处理的红壤坡面在140~190mm/h超大雨强下的土壤侵蚀模数明显低于50~120mm/h雨强下未进行相应处理的坡面,细沟发育较为缓慢,对坡面土壤的处理方式能够有效提高坡面的抗侵蚀能力。在同雨强下,随着坡度的增加,产流时间先延长后缩短,在20°~25°存在产流的临界坡度。侵蚀模数在同雨强下随着坡度的增大呈先增大后减小的趋势,且不同雨强的临界坡度不一致,雨强为140mm/h时侵蚀临界坡度为15°~20°,雨强为160mm/h和190mm/h时侵蚀临界坡度为20°~25°。总体来看,侵蚀过程受雨强的影响大于坡度的影响,雨强为140mm/h时,不同坡度的侵蚀过程均较为平稳,细沟发育微弱;雨强为160mm/h时,侵蚀有所加强,但侵蚀过程无明显规律;雨强为190mm/h时,侵蚀主要发生在降雨的前30min,且细沟发育相对较为剧烈,30min之后趋于稳定。

Experimental Study on the Response of Artificial Red Soil Slope to the Large Rainfall Intensity

By using artificial rainfall simulation system and variable slope soil trough,the runoff and sediment yield responses of red soil slope under heavy rainfall were tested to study the response of artificial red soil slope to heavy rainfall.The rainfall intensities included 140,160,and 190 mm/h,and the slope degrees included 10 °,15 °,20 ° and 25 °.The experimental results showed that the erosion modulus in red soil slope with simple artificial treatment under super rain intensity of 140 ～ 190 mm/h was significantly lower than that in slopes without treatment under rain intensity of 50～120 mm/h,and the rill development process was slow.This indicated that soil treatment on slope could effectively improve the soil erosion resistance.Under the same rainfall intensity,the runoff yield time firstly delayed and then shortened with the increasing of slope degree,and the critical gradient of the runoff yield was between 20°and 25°.Under the same rainfall intensity,the erosion modulus firstly increased and then decreased with the increasing of slope degree,and the critical gradient was different under different rainfall intensity.The erosion critical gradient was 15°～ 20° when the rainfall intensity was 140 mm/h,and it was 20°～25° when the rainfall intensity was 160 mm/h and 190 mm/h.Overall,the erosion process was affected by the rainfall intensity more than the slope degree.The erosion processes of slopes with different slope degrees were relatively stable when the rainfall intensity was 140 mm/h,and the development of rill was weak.The erosion was strengthened when the rainfall was 160 mm/h,but there was not obvious tend in the erosion process.When the rainfall intensity was 190 mm/ h,the erosion mainly occurred in the first 30 min of the rainfall,and the development of rill was relatively severe,and it tends to be stable after 30 min.