Author(s): Pongpan Kanjanakaroon; Chaiwat Ekkawatpanit; Sanit Wongsa; Udomsak Israngkura; Duangrudee Kositgittiwong
Linked Author(s):
Keywords: Embankment breach; Initial breach position; Solid wall; Breached channel; Eroded soil
Abstract: Many studies of embankment failure from overtopping flow have been conducted in various aspects. Most of them focused on the mechanism of breach, depth and width of erosion, and breach hydrograph. The studied results as obtained either from physical modelling, mathematical modelling or couples modeling techniques were applicable only to the breach position which could be eroded freely on both sides but could not be applied properly to simulate the embankment failure where the breach position occurred near solid wall of structures which was unerodible. The aim of this research was to study the effect of breach position on breach parameter at such location from a physical hydraulic model under various conditions of overtopping flow and embankment properties. Three embankment slopes, 1: 1, 1: 1. 5, and 1: 2, were employed in the study and, for each embankment slope, the breach was initiated at three different positions from the solid wall. The X1 position is the nearest to the wall, the X3 position is approximately at the middle of the embankment length and the X2 position is about the middle between X1 and X3. The results showed that, under the same embankment slope and overtopping discharge, mechanism of embankment breach of every initial breach position started with surface erosion and then developed to headcut erosion by jet scour at the toe of embankment. Eroded soil volume of the three cases, X1, X2 and X3, were almost of the same quantity. Embankment breach width of X3 case was the widest while that of X1 case was the narrowest. On the contrary, breach depth of X1case was the deepest while that of X3 is the shallowest. In conclusion, It was found that breach position did not have any evident effect on the volume of eroded soil but it did have strong effects on the breach depth and width. It was also found that as the initial breach position is closer to the solid wall or non-erodible materials, the depth of breach is deeper and might be a major threat leading to foundation failure of the structure.
Year: 2015