Design of draining cores to control seepage through embankment dams

Watertightness of embankment dams can be ensured by an impervious facing covering the upstream slope, or by a silty or clayey core. In the first case, especially in seismic zones, the remote circumstance must be conveniently considered that the facing and the embankment upstream shell severely crack and become wholly ineffective. To face this undesired situation, a draining core, made of cohesionless self-protected material, allowing a full control of the seepage process, can be provided. The core characteristics (geometry, properties and granulometric stability of materials,..), must be carefully designed through advanced numerical analyses, including seepage flow and “granulometric stability”, under critical hydraulic conditions, as proposed in the paper. According to this procedure, the characteristics (geometry, properties) of materials composing a zoned embankment dam in South Italy, endowed with an upstream impervious bituminous facing and a central draining zone, are back-analyzed