Civil Engineer, US Army Corps of Engineers, Tulsa, OK
Chief, US Army Corps of Engineers, Tulsa, OK
Pages: 17 Published: Jan 1992
After near failure in 1949 by piping through the embankment, Wister Dam operated with no serious leakage problems to actively threaten the safety of the embankment. However, investigations revealed horizontal and vertical cracking that, combined with the dispersive clay embankment material and lack of sand filter, made the potential for a piping failure too great to ignore. Significant underseepage occurred at modest pool differences through preferred seepage paths that appeared to be cracks resulting from differential settlement. Emergency repairs performed in 1949 and 1950 apparently hydrofractured the embankment. To minimize the potential for a piping failure of the dam a sand filter was constructed in the downstream embankment and a plastic concrete slurry wall cutoff was constructed along an upstream berm. A method for determination of maximum safe panel length for the slurry wall was devised and a plastic concrete mix design was developed to increase the ability of the wall to yield or deform.
piping, hydrofracturing, dispersive clay, slurry wall, plastic concrete
Paper ID: STP19738S