The Acoustic Wave Field Features and Thickness Analysis of the Footstone of the Yellow River Levee

Abstract:

The dangerous control engineering often stacks stones, named the footstone, outside the sediment matrix to resist the scour erosion in lower Yellow River. In order to ensure the stability of the bank, the footstones are stacked in the certain proportion. Due to the effect of the seasonal changes and the adjustment of the upstream reservoir, the water depth of the Yellow River near the lobes of banks changes constantly. The scouring erosion in flood season and depositing in dry season make the stacked footstones to be washed away. The thickness and the location of the maximum burial depth of the footstones are the important supporting data for calculating the river scour. Thus, it is significant to investigate the location, thickness and slope of the footstones. This study proposed a new method to distinguish the silt and footing stones according to their frequency differences by applying time-frequency analysis to the sub-bottom profiler data, and to estimate the thickness of the footstones by using the messy reflection waves formed by the riprap, and then to has solved the estimation of the maximum scour depth.