不同降雨强度下滑坡表面冲蚀体积试验

Experiments of soil erosion under different rainfall intensities on slope surface

在山区,降雨导致的土壤冲蚀是产生堆积物、改变地貌地形的主要因素。其过程复杂并且受如降雨强度、地表粗糙度等多种因素影响。为研究不同降雨强度条件下降雨对滑坡表面冲蚀的体积指标特性,采用实验室模拟降雨试验平台进行实验,Golden Surfer软件直接读取堆积体体积、3D模拟模型研究降雨与输出数量关系等方法,再现了以体积量直接输出的堆积物与降雨之间的关系。结果表明:降雨过程中,坡体深部土壤体积含水率变化较小,浅层土壤孔隙水压与含水率变化较大;降雨初期,降雨入渗有效提高表层孔隙水压力,地表径流小,带沙能力弱;随降雨时间增加,地表径流强度增加是提高水流冲刷力的主要因素,累计冲蚀堆积体体积随降雨强度增加而增大,但是增速减小,其主要原因是降雨后期,地表形成冲刷沟壑,累计冲蚀堆积体体积受地表粗糙程度限制;通过对降雨时间、降雨强度以及冲蚀堆积体体积进行三维拟合,发现三者幂函数曲线的拟合较好。

Soil erosion is a complex phenomenon involving the detachment and transport of soil particles,storage and runoff of rainwater,and infiltration.The relative magnitude and importance of these processes depends on a host of factors,including rainfall intensity,surface roughness,subsurface soil water pressure,and so on.Thus,in our study,the soil erosion results of a series of experiments were reported in the form of a volume index.Different rainfall intensity in relation to the erosion rate was investigated for the chronological phenomenon and more insight and detail were got to improve estimation of eroded volume of the slope surface.The results show the surface runoff by rainfall is the key factor in producing the soil sediment.And a sequence of rainstorms of increasing intensity on an initially smooth surface cause high soil loss rate,but which will be slowed down with the aggravation of surface roughness and the formation of rills.The highlight is the use of 3Dfitting model by which the interaction and function among rainfall intensity,duration,and soil yield sediment is investigated.