Spatial distribution characteristics of loose bodies in Huaishu River levee and their influence on seepage field

At present, many levees contain a large number of loose bodies as a result of poor-quality construction, biological damage, and other factors. In this context, loose bodies refer to soil with a relative density less than a specified value. Taking the Huaishu River levee in China as an example, this paper studies the distribution characteristics of loose bodies in the levee using statistical methods. First, ground-penetrating radar and other geophysical exploration methods are used to investigate loose bodies in the levee. The frequency distribution and Shapiro–Wilk method are then employed to study the distribution characteristics of the area and depth of loose bodies. The influence of loose bodies on the seepage field of the levee is then examined considering the spatial distribution of the loose bodies. It was found that the areas of loose bodies in the western and eastern upstream slope obey a logarithmic normal distribution. In the shallow layer (depth between 0–1 m), loose bodies appear relatively frequently, and the frequency initially increases with depth before decreasing. The maximum hydraulic gradient of the levee initially increases and then decreases as the depth of the loose body increases.