RELIEF WELL SYSTEMS FOR DAMS AND LEVEES ON PERVIOUS FOUNDATIONS, MODEL INVESTIGATION

RESULTS ARE PRESENTED OF MODEL TESTS PERFORMED TO STUDY THE PHENOMENA OF UNDERSEEPAGE AND THE USE OF PRESSURE RELIEF WELLS AS A MEANS FOR CONTROLLING UNDERSEEPAGE AND SAND BOILS ALONG THE LOWER MISSISSIPPI RIVER LEVEES. THE MODEL STUDIES OBSERVE THE OPERATION OF RELIEF WELLS AND WELL AND SEEPAGE FLOWS AND LANDWARD SUBSTRATUM PRESSURES WITH AND WITHOUT RELIEF WELLS IN OPERATION FOR VARIOUS FOUNDATIONS, SEEPAGE ENTRANCES, AND TOP STRATA. RELIEF WELLS WITH PROPER SPACING AND PENETRATION EFFECTIVELY REDUCED EXCESS HYDROSTATIC PRESSURE LANDWARD OF LEVEES OR DAMS UNDERLAIN BY A PERVIOUS FOUNDATION FOR A WIDE RANGE OF SEEPAGE ENTRANCES, FOUNDATION CONDITIONS, AND LANDWARD TOP STRATA. WITH ADEQUATE WELL SPACING AND PENETRATION, SEEPAGE NORMALLY EMERGING LANDWARD OF A LEVEE (WITHOUT WELLS) MAY ALSO BE MATERIALLY REDUCED, ALTHOUGH THE TOTAL UNDERSEEPAGE FLOW WILL BE INCREASED A CERTAIN AMOUNT. THE IMPORTANCE WAS INDICATED OF INSURING THAT THE WELLS PENETRATE INTO THE PRINCIPAL WATER-CARRYING STRATA IN ORDER TO OBTAIN EFFICIENT PRESSURE RELIEF. BORROW PITS EXCAVATED TO SAND RIVERWARD OF A LEVEE WERE FOUND TO INCREASE UNDERSEEPAGE AND TO HAVE A PRONOUNCED EFFECT ON THE DESIGN OF A RELIEF WELL SYSTEM. FACTORS INFLUENCING THE OPERATION OF THE WELL SYSTEMS IN THE MODELS WERE: WELL SPACING, WELL PENETRATION, SEEPAGE ENTRANCE CONDITIONS, STRATIFICATION OF THE FOUNDATION, DEPTH AND PERMEABILITY OF THE PERVIOUS STRATUM, AND CHARACTERISTICS OF THE LANDSIDE TOP STRATUM. THE DIAMETER OF THE WELLS WAS NOT INVESTIGATED, BUT IS KNOWN TO BE ANOTHER FACTOR WHICH INFLUENCES THE PERFORMANCE OF A WELL SYSTEM. OTHER FACTORS WHICH MUST BE CONSIDERED ARE DESIGN OF THE WELL, MAINTENANCE OF THE SYSTEM, CORROSION, DISPOSAL OF SEEPAGE, AND DEGREE OF PRESSURE RELIEF OR SEEPAGE INTERCEPTION DESIRED. A SUMMARY IS PRESENTED IN THE APPENDIX OF AVAILABLE FORMULAS PERTAINING TO THE DESIGN OF RELIEF WELL SYSTEMS, TOGETHER WITH TYPICAL EXAMPLES OF THEIR USE.

  • Supplemental Notes:
    • No 3-304, 96 PP, 48 FIG, 5 TAB, 7 REF, 1 APP
  • Publication Date: 1949-11

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  • Accession Number: 00204140
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 12 1994 12:00AM