Time for Development of Internal Erosion and Piping in Embankment Dams

A method is presented for the approximate estimation of the time for progression of internal erosion and piping, and development of a breach leading to failure in embankment dams and their foundations. The method accounts for the nature of the soils in the dam core, the foundation, and the materials in the downstream zone of the dam. Guidance is also provided on the detectability of internal erosion and piping, taking account of the mechanism of initiation, continuation, and progression to form a breach, for internal erosion and piping in the embankment, the foundation and from the embankment to foundation. It is shown that in many dams which have poor internal erosion and seepage control and are constructed mainly of earthfill, the time for potential development of piping is short, and for these dams continuous monitoring of seepage or surveillance would be needed to detect the piping in time to give warning of possible failure, and to give time to attempt intervention to prevent the failure.