CLOSURE ON FOUNDATION CUTOFF WALL FOR ALLEGHENY RESERVOIR DAM

THE NEED TO ASSURE ADEQUATE CLEAN-UP STRESSED BY LANE IS DISCUSSED. THE SPECIFICATIONS REQUIRED A MINIMUM TRENCH DEPTH OF 2 FEET INTO ROCK, TO BE CHECKED BY CORE DRILLING EITHER PRIOR TO EXCAVATION, OR SUBSEQUENT TO EXCAVATION OF OVERBURDEN IN A GIVEN PANEL. THE LATTER METHOD, WHICH WAS USED, PROBABLY RESULTED IN SOME OVER-EXCAVATION BECAUSE IT WOULD HAVE CAUSED CONSIDERABLE DELAY TO SET UP THE DRILL RIG MORE THAN ONCE OVER A GIVEN PANEL. ONCE IT WAS DETERMINED THAT THE OVERBURDEN HAD BEEN REMOVED, THE ELEVATION OF THE REQUIRED BOTTOM OF TRENCH WAS KNOWN. FINAL CLEANING OF THE BOTTOM OCCURRED FROM ONE HOUR TO FOUR HOURS PRIOR TO THE BEGINNING OF CONCRETING. THIS CLEANING OPERATION WAS INDIFFERENTLY SUCCESSFUL. TO ASSURE THE MOST THOROUGH TRENCH BOTTOM CLEANING PRACTICABLE, A REVERSE CIRCULATION OF SLURRY SHOULD BE PERFORMED THROUGH A 4-INCH PIPE TERMINATING IN A FUNNEL-SHAPED INLET. ADDITIONAL PIEZOMETER DATA WERE REQUESTED BY LANE. FIGURES ARE PRESENTED WHICH GIVE THESE DATA. BUSH AND BARES DESCRIBED DIFFERENCES IN THE ALLEGHENY OPERATION AND THAT OF THE INSTALLATION AT ARROW DAM ON THE COLUMBIA RIVER, AND PRESENTED SOME INTERESTING RESULTS OF PERSONAL INVESTIGATIONS INTO THE USE OF A LEAN CONCRETE MIX IN LIEU OF THE BENTONITE SLURRY. THIS INFORMATION RELATIVE TO TYPES OF BENTONITE WHICH ARE SATISFACTORY SHOULD BE HELPFUL TO THOSE IN OTHER WORK OF THIS NATURE. CONCERNING THE USE OF CLAMSHELLS WITHOUT PRELIMINARY HOLES, TIME REQUIRED FOR EXCAVATION AT DEPTHS OF IN BOULDERY SOIL, ASSURING ECONOMY AND CONTINUITY OF THE WALL, IS A PROBLEM. IF A UNIFORM MIX OF THE WEAK CEMENT SLURRY CAN BE ASSURED SUBSEQUENT TO EXCAVATION, THE PROPOSAL FOR ITS USE FOR BOTH THE WORKING SLURRY AND LATER, THE WALL, APPEARS TO HAVE MERIT. REFERENCES: FOUNDATION CUTOFF WALL FOR ALLEGHENY RESERVOIR DAM, G. A. FUQUAY, JOURNAL OF THE SOIL MECHANICS AND FOUNDATION DIVISION, PROCEEDINGS OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS, PROCEEDINGS PAPER 5231, MAY 1967.

  • Supplemental Notes:
    • Vol 94, NosM6, PP 1363-1366, 2 FIG
  • Corporate Authors:

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    ,   USA 
  • Authors:
    • Fuquay, G A
  • Publication Date: 0

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  • Accession Number: 00232595
  • Record Type: Publication
  • Report/Paper Numbers: No SM5, Proc Paper 490
  • Files: TRIS
  • Created Date: Aug 15 2004 2:44AM