工程堆积体标准小区界定与可蚀性因子改进

将USLE模型应用于工程堆积体侵蚀预报时结果偏差较大,这是因为其标准小区与土壤可蚀性因子不适合直接应用于工程堆积体侵蚀预报。针对这一问题,结合对我国6大水蚀类型区工程堆积体参数的调查、统计、分析,界定工程堆积体标准小区的坡度、坡长;结合国内外已有研究成果,分析论证堆积体可蚀性因子的改进办法,并引用相关数据验证其可行性。结果表明,6大区域工程堆积体坡度、坡长及坡面物质组成均与USLE中规定的标准小区相差较大;为了尽量消除误差,建议工程堆积体标准小区坡度采取众数35°,坡长采取平均值5m;堆积体可蚀性因子更名为土石质因子Tr,并将单位体积土石混合体中石砾总表面积Cs,作为石砾因素指标纳入堆积体土石质因子Tr中,与堆积体物质中土壤可蚀性因子K共同构建工程堆积体土石质因子函数。验证结果表明,堆积体可蚀性因子改进办法是可行的。工程堆积体坡度、坡长的界定及可蚀性因子的改进,对提高基于USLE模型的堆积体侵蚀预报精度有重要意义。

Defining of Engineering Accumulations Unit Plot and Improvement of Engineering Accumulations Erodibility Factor

The large deviation of engineering accumulations erosion prediction by the model of USLE is due to the unit plot and the soil erodibility factor cannot be directly used to erosion prediction of engineering accumulations . This study aims to define the gradient and slope length of engineering accumulations unit plot according to the survey of engineering accumulations from six water erosion area in China, analysis the improvement method of engineering accumulations erodibility factor according to relative research achievements and prove the feasibility of this improvement method by published data. Survey results show that the gradient, slope length and surface composition of engineering accumulations from six water erosion area is large different from the unit plot of the model of USLE. So, we choose the mode 35° of gradient and the mean 5m of slop length of engineering accumulations from six water erosion area as the gradient and the slop length of engineering accumulations unit plot. In order to distinguish soil erodibility factor K from engineering accumulations erodibility factor, we give engineering accumulations erodibility factor a name of soil and rock factor (Tr). Bring the index of unit volume soil-rock mixture"s total surface area of rock (Cs) into soil and rock factor, building a function of Tr with soil erodibility factor K. Verification results show that this improvement method of engineering accumulations erodibility factor is reasonable. In conclusion, the defining of the gradient and slope length of engineering accumulations unit plot and the improvement method of engineering accumulations erodibility factor is significant to enhance the accuracy of engineering accumulations erosion prediction by the model of USLE.