Hydraulic Fracturing in Embankment Dams

There is now sufficient evidence to conclude that concentrated leaks occur commonly through the impervious sections of embankment dams by hydraulic fracturing without being observed, even in dams which are not subjected to unusually large differential settlement. Usually these concentrated leaks do not cause erosion, either because the velocity is too low or because the leak discharges into an effective filter. Subsequently the leakage channel is squeezed shut by swelling or softening of the embankment material forming the walls of the crack. In the typical case no measurable leakage emerges downstream and there is no other indication that a concentrated leak developed and was subsequently sealed. This action probably occurs to some degree in most embankment dams.