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Rapid Clay Dewatering: Phase II Field-Scale Tests



Two geodrain test sections were installed in a phosphatic clay disposal/reclamation area. The prefabricated geodrain is commercially available and consists of a continuous sheet of dimpled plastic that is covered with a nonwoven polypropylene geofabric. Water seeps through the geofabric into the plenum between the dimples and then flows to a sump. Each test section was 150 feet long by 20 feet wide, nailed to the upstream slope of the embankment near a spillway.

The geodrains were only partially successful in enhancing peripheral drainage of the clay, owing to pipeline failures. Nonetheless, sufficient improvement in the clay shear strength was measured to recommend that another geodrain test section be installed in a new clay area, prior to filling.