绝对隐蔽度和相对隐蔽度是泥沙颗粒隐蔽度研究中的2大派别。针对韩其为定义的二维泥沙颗粒相对隐蔽度，给出了统计意义上的宽级配非均匀沙颗粒相对隐蔽度的计算式，对该式的物理意义进行了讨论，并提出了基于泥沙相对隐蔽度的宽级配非均匀沙中“大颗粒”、“小颗粒”、“中等颗粒”的概念。

There are two different schools to study the hidden degree of sediment particles: absolute hidden degree and relative hidden degree. The 2-D relative hidden degree of sediment particles defined by Han Qi-wei was elaborated in this paper. The hidden degree formula of wide grain size distribution of non-uniform sediment was deduced statistically. Relevant discussions on the physical significance of the formula were presented, and the concepts of “large grain”, “small grain” and “medium grain”associated with broadly graded nonuniform sediment were proposed as well.