BEHAVIOR OF AXIALLY LOADED DRILLED SHAFTS IN BEAUMONT CLAY-REPORT 89-8

THE RESULTS OF FIELD TEST OF FULL-SIZED, INSTRUMENTED DRILLED SHAFTS IN BEAUMONT CLAY FORMATION ARE DESCRIBED. DRILLED SHAFTS WITH VARYING BASE GEOMETRY, LENGTH, AND METHOD OF INSTALLATION WERE LOAD TESTED TO OBTAIN MEASUREMENTS OF THE DISTRIBUTION OF AXIAL LOAD WITH DEPTH AND OF BASE LOAD-SETTLEMENT CHARACTERISTICS IN ORDER TO DEVELOP DESIGN CRITERIA. PERTINENT SOIL PARAMETERS WERE OBTAINED BY VARIOUS STANDARD PROCEDURES, INCLUDING THE UNCONSOLIDATED, UNDRAINED TRIAXIAL TEST AND THE T. H. D. CONE PENETROMETER TEST TO PROVIDE A BASIS FOR THE CORRELATION OF TEST RESULTS. THE TEST SHAFTS WERE OBSERVED TO DEVELOP CONSIDERABLE RESISTANCE IN SIDE FRICTION. FURTHERMORE, SIDE RESISTANCE WAS OBSERVED TO DEVELOP MUCH SOONER THAN BASE RESISTANCE, WITH THE RESULT THAT SIDE RESISTANCE WAS OBSERVED TO DEVELOP MUCH SOONER THAN BASE RESISTANCE, WITH THE RESULT THAT SIDE RESISTANCE PREDOMINATED OVER BASE RESISTANCE AT DESIGN LOAD. THE SHAFTS INSTALLED IN DRY BOREHOLES MOBILIZED AN AVERAGE OF ONE-HALF OF THE SHEAR STRENGTH OF THE SOIL IN SIDE FRICTION, WHILE THE SIDE FRICTIONAL STRESSES IN THE SHAFT INSTALLED IN A PROCESSED BOREHOLE WERE SIGNIFICANTLY SMALLER. AN INVESTIGATION SHOWED THAT THE SHAFTS INSTALLED IN THE DRY WERE WELL-FORMED AND BONED SECURELY TO THE SOIL COMPOSING THE BOREHOLE WALLS, WHILE THE SHAFT INSTALLED IN A PROCESSED HOLE CONTAINED POCKETS OF DRILLING MUD BETWEEN THE CONCRETE AND NATUREAL SOIL. BASED UPON THESE OBSERVATIONS, THE NUMERICAL TEST RESULTS, AND FIELD TESTS OF OTHER INVESTIGATORS IN SIMILAR SOIL FORMATIONS, A TENTATIVE DESIGN PROCEDURE INCORPORATING SIDE RESISTANCE IS FORMULATED. /AUTHOR/

  • Corporate Authors:

    University of Texas, Austin

    Center for Highway Research, 200 West 21st Street
    Austin, TX  USA  78712

    Texas State Department of Highways & Public Transp

    11th and Brazos Streets
    Austin, TX  USA  78701

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590
  • Authors:
    • Oneill, M W
    • Reese, L C
  • Publication Date: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00228666
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Apr 1 1971 12:00AM