Geotextiles in Embankment Dams - Association of State Dam Safety ...

GlossaryCore (FEMA, 2004): A zone of low permeability material in an embankment dam.The core is sometimes referred to as central core, inclined core, puddle clay core,rolled clay core, or impervious zone.Crack:A narrow discontinuity.Creep (ASTM D-4439, 2004): n – the time-dependent increase in accumulativestrain in a material resulting from an applied constant force.Cross-machine direction (ASTM D-4439, 2004): n – the direction in the plane ofthe fabric perpendicular to the direction of manufacture.Cross section (FEMA, 2004): An elevation view of an embankment damformed by passing a plane through the dam perpendicular to the axis.Cutoff trench (FEMA, 2004): A foundation excavation later to be filled withimpervious material to limit seepage beneath an embankment dam.Dam (FEMA, 2004): An artificial barrier that has the ability to impound water,wastewater, or any liquid-borne material, for the purpose of storage or control ofwater.Earthfill (FEMA, 2004): An embankment dam in which more than 50 percent ofthe total volume is formed of compacted earth layers comprised of materialgenerally smaller than 3 inches.Embankment (FEMA, 2004): Any dam constructed of excavated naturalmaterials, such as both earthfill and rockfill dams, or of industrial waste materials,such as a tailings dams.Rockfill (FEMA, 2004): An embankment dam in which more than 50 percent ofthe total volume is comprised of compacted or dumped cobbles, boulders, rockfragments, or quarried rock generally larger than 3 inches.Tailings (FEMA, 2004): An industrial waste dam in which the waste materialscome from mining operations or mineral processing.Dam failure (FEMA, 2004): A catastrophic type of failure characterized by thesudden, rapid, and uncontrolled release of impounded water or the likelihood ofsuch an uncontrolled release. There are lesser degrees of failure, and anymalfunction or abnormality outside the design assumptions and parameters thatadversely affect an embankment dam’s primary function of impounding water isproperly considered a failure. These lesser degrees of failure can progressively lead157