Protecting Levees Against Pipings and Overtopping

Abstract

It is among the requirements of the stability of levees that these should not be overtopped, and that the passage of seepage should not cause piping in the body of levee and the underground. Overtopping and piping are reckoned among the most dangerous events of extreme impacts on levees, which may lead to a failure of the levee with serious consequences. In both cases, the duration of a high river level is also decisive. The loss of local stability is often caused by the formation of passages by water in the form of conduits if particles of the soil become unstable. This results in slow or rapid soil boiling and ends in the general loss of stability. If the river stage rises over the crest of a levee, and begins the process of overtopping the overflowing water acts simultaneously on the crest and the landward slope; the levee could be washed away. Successful protection against pipings and overtopping during floods is difficult. Consequently, prevention outside flood periods is of great importance.