The authors comment on the discussers observation that the field testing for control of the powerblock fill for Rush Island Plant did not show acceptably uniform testing results for apparent constant characteristics of fill. The authors observe that the powerblock fill relative densities were based on individual maximum-minimum tests for each field density test and not on any Standard Penetration N value. Forty relative desity tests on sand fill dredged from the Mississippi River without any supplemental compaction, but with vertical downward drainage and no pounding, for the Rush Island power-block fill showed relative densities ranging from 22 to about 60 percent with an average of 41 percent. Hydraulic fills with densities as high as 80 percent (and over) have not been tested by the authors without supplemental mechanical compaction. The maximum and minimum laboratory density has not been standardized and at best is erratic between laboratories. It would be unwise to count on obtaining a relative density more than about 50 percent plus or minus 10 percent for hydraulic fills without supplemental mechanical compaction until proved otherwise for the particular sand being pumped and dredging procedure being used. Experience is described where 1,000,000-cu yd extension hydraulic fill was controlled, and another instance where the same dredge was used to place a 1,500,000-cu yd sandfill.

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Filing Info

  • Accession Number: 00097376
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 11269 Proceeding
  • Files: TRIS
  • Created Date: Aug 13 1975 12:00AM