Short rock corrections are used to reduce standard penetration test blow counts recorded using rod lengths shorter than 10 m to values that would have been recorded if longer rods had been used. They are based on the assumption that energy transferred during secondary impacts does not contribute to sampler penetration. This paper described modifications made to a safety hammer to provide hammer-anvil contact histories. Data collected demonstrate the occurrence of secondary impacts prior to the time at which the hammer and anvil were originally assumed to separate. These impacts can be predicted given only the dimensions of the hammer and rods. Secondary impacts are also observed after this time and the energy transferred is quantified. The data suggest that the total transferred energy is independent of rod length and that the secondary impacts occur early enough to contribute to a sampler penetration. Modified short rod corrections may still be justified if transferring energy over a series of impacts leads to a different blow count than transferring the same amount of energy during a single impact.

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    American Society of Civil Engineers

    1801 Alexander Bell Drive
    Reston, VA  United States  20191-4400

    West Virginia University, Morgantown

    Morgantown, WV  United States  26506
  • Authors:
    • Walker, B
    • Jackson, R S
    • Howie, J A
    • Daniel, C R
  • Publication Date: 2005-4


  • English

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  • Accession Number: 00989570
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Apr 18 2005 12:00AM