含结构体工程堆积体土壤侵蚀研究

Study on Soil Erosion of Engineering Accumulation with Structure

为探究野外实际调查中常见的含结构体工程堆积体土壤侵蚀过程,设计含结构体工程堆积体和对照组2种试验材料(对照组为不含结构体工程堆积体,后文中对2种试验材料简称为结构体和堆积体),通过室内模拟降雨试验,研究了结构体和堆积体坡面径流侵蚀特征与雨强和场次的关系。结果表明:(1)初产历时随雨强和场次的增加而减小,结构体对初产历时有延缓作用,这与结构体的土壤特性和下垫面特征有关;(2)平均径流率和平均流速均随雨强和场次的增加而增大,堆积体平均流速和平均径流率分别是结构体的1.11~1.22,1.11~1.37倍,而结构体流速和径流率快速增加和趋于稳定的时间均较堆积体提前,且用时更短;(3)雨强对侵蚀速率、流速和径流率的贡献率较大,场次与侵蚀速率负相关,各条件下结构体的侵蚀速率均大于堆积体,且侵蚀速率和总侵蚀量分别是堆积体的1.03~2.15,1.36~2.63倍;(4)径流功率能够更好地描述结构体和堆积体侵蚀动力过程,结构体发生侵蚀的临界径流剪切力和径流功率均小于堆积体。

In this paper,taking the common engineering accumulation with structure in field investigation as the research background,two test materials including structural engineering accumulation and control group were designed(the control group is engineering accumulation without structures,which will be referred to as structure and accumulation for short in the later paper).Using the method of indoor rainfall simulation,the effects of rainfall intensity and rainfall field on slope runoff erosion of structure and accumulation were studied.The results show that:(1)the initial production duration decreases with the increase of rainfall intensity and rainfall field times,and the structure can delay the initial production duration,which is related to the soil characteristics and underlying surface characteristics of the structure;(2)The average runoff rate and average velocity increase with the increase of rainfall intensity and rainfall times.The average velocity and average runoff rate of the accumulation are 1.11~1.22 and 1.11~1.37 times that of the structure,respectively.The time for the rapid increase and stabilization of the velocity and runoff rate of the structure is earlier and shorter than that of the accumulation;(3)The contribution rate of rainfall intensity to erosion rate,velocity and runoff rate is large,and the rainfall times is negatively correlated with erosion rate.Under all conditions,the erosion rate of structure is greater than that of accumulation,and the erosion rate and total erosion amount are 1.03~2.15 and 1.36~2.63 times of accumulation;(4)Runoff power can better describe the erosion dynamic process of structure and accumulation.The critical runoff shear force and runoff power of structure erosion are less than those of accumulation.