A LABORATORY STUDY OF DYNAMIC LOAD-DEFORMATION AND DAMPING PROPERTIES OF SANDS CONCERNED WITH A PILE-SOIL SYSTEM

DYNAMIC LOAD-DEFORMATION PROPERTIES AND DAMPING CHARACTERISTICS OF COHESIONLESS SOILS ARE DETERMINED UNDER IMPACT LOADING SIMILAR TO THAT FOUND DURING PILE DRIVING. THE EVALUATION OF DYNAMIC SOIL PROPERTIES IS NECESSARY FOR PILE DRIVING ANALYSIS BY THE WAVE EQUATION. THE APPARATUS DEVELOPED FOR THE DYNAMIC TEST PROGRAM WAS A MODIFIED TRIAXIAL TESTING MACHINE, INSTRUMENTED TO RECORD LOAD, DISPLACEMENT AND PORE PRESSURE. LOAD WAS APPLIED BY A FALLING WEIGHT CONTACTING THE TRIAXIAL LOADING PISTON. THREE LOADING RATES REPRESENTATIVE OF PILE VELOCITIES DURING DRIVING WERE USED. RESULTS WERE CORRELATED WITH CONVENTIONAL TRIAXIAL COMPRESSION TESTS. SPECIMENS OF STANDARD OTTAWA SAND FROM VICTORIA, TEXAS WERE TESTED IN SATURATED AND DRY STATES. TEST RESULTS INDICATED IMPORTANT DYNAMIC EFFECTS. COMPRESSIVE STRENGTH INCREASED WITH INCREASE IN LOADING RATES. THE INITIAL VOID RATIO OF THE SPECIMEN WAS MOST SIGNIFICANT. FOR SATURATED OTTAWA SAND, DYNAMIC STRENGTHS INCREASED 80 PERCENT AND 20 PERCENT OVER THE STATIC TEST FOR DENSE AND MEDIUM SPECIMENS RESPECTIVELY. NO INCREASE IN STRENGTH DUE TO RATE EFFECT WAS OBSERVED IN LOOSE SAMPLES. THE EFFECT OF THE CONFINING PRESSURE APPEARED SLIGHT. THE REPORT DISCUSSES CHANGES IN PORE WATER PRESSURE UNDER IMPACT TESTING. THE DYNAMIC LOAD-DEFORMATION CURVES FOR SANDS OBTAINED IN THE TESTS SHOWED SIGNIFICANT NON-LINEARITIES. RHEOLOGICAL MODELS FOR PREDICTING SOIL BEHAVIOR WERE COMPARED WITH TEST DATA IN AN ATTEMPT TO OBTAIN A MATHEMATICAL MODEL THAT WOULD SIMULATE THE DYNAMIC BEHAVIOR OF THE SOIL. A KELVIN-BODY MODEL WAS CHOSEN AS A ROUGH APPROXIMATION. THE SPRING CONSTANT AND RHEOLOGICAL DAMPING COEFFICIENT OF SANDS ARE TABLED FOR THE PARTICULAR RATES OF LOADING AND INITIAL VOID RATIOS USED IN THE TESTS. /BPR/

  • Supplemental Notes:
    • Hpr-1/6/, NO 2-5-62-33
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 1600 E Lamar Boulevard
    Arlington, TX  USA  76011

    Texas State Department of Highways & Public Transp

    11th and Brazos Streets
    Austin, TX  USA  78701
  • Authors:
    • CHAN, P C
    • Hirsch, T J
    • Coyle, H M
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00230614
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Files: TRIS, STATEDOT
  • Created Date: Aug 15 2004 2:19AM