VANE SHEAR STRENGTH OF CLAYS /IN JAPANESE/

AN ATTEMPT WAS MADE TO CLARIFY SOME UNCERTAINTIES CONCERNING THE INTERPRETATION OF VANE TESTS DUE TO INSUFFICIENT KNOWLEDGE OF STRESS CONDITIONS AND MODE OF STRAIN WITHIN THE FAILURE ZONE. THE TENTATIVE CONCLUSIONS REACHED ARE: (1) THE SHEAR STRENGTHS MEASURED IN THE VANE TRIAXIAL TESTS ON KO-CONSOLIDATED VERY SENSITIVE CLAYS (SENSITIVITY: 25-85) ARE IN GOOD AGREEMENT WITH THAT OF THE IN-SITU VANE TESTS. THIS MAY MEAN THAT THE RECONSOLIDATION FOLLOWING UPON SAMPLE DISTURBANCE HAS LITTLE INFLUENCE ON THE SHEAR STRENGTH OF SENSITIVE LOW PLASTIC CLAYS. (2) THE C/P-RATIO MEASURED IN THE VANE TEST ON NORMALLY CONSOLIDATED CLAY DECREASES FOR THE DECREASING VALUE OF K, WHERE K = HORIZONTAL CONSOLIDATION PRESSURE/VERTICAL CONSOLIDATION PRESSURE, AND THE C/P-RATIO CORRESPONDING TO K=53 CONDITION IS MUCH SMALLER THAN THAT CORRESPONDING TO K = 1.0, WHERE KO IS THE COEFFICIENT OF EARTH PRESSURE AT REST. (3) THE MEASURED TORQUE ON THE VANE IS A FUNCTION OF THE DIMENSION OF THE VANE, THE MAXIMUM STRESSES DEVELOPED IN THE SOIL AROUND THE PERIPHERY OF THE VANE AND A FACTOR (ALPHA) DEPENDENT ON THE SHEAR STRESS DISTRIBUTION ACROSS THE ENDS OF THE VANE AS INDICATED IN CADLING'S EQUATION (1950). THE VALUE OF FACTOR (ALPHA) MEASURED IN THE TESTS IS FOUND TO BE 1/4, WHICH IS SMALLER THAN THE VALUE USED FOR THE CONVENTIONAL CALCULATION METHOD. (4) THE SHEAR STRENGTHS ACTING ALONG THE VERTICAL AND HORIZONTAL PLANES, ARE NOT DEVELOPED AT THE SAME ANGLE OF ROTATION OF THE VANE. AT THE ANGLE OF ROTATION FOR THE MAXIMUM VALUE OF THE SHEAR STRENGTH ALONG THE VERTICAL PLANE, THE SHEAR STRENGTH ALONG THE VERTICAL FAILURE SURFACE IS NOT FULLY MOBILIZED. (5) THE COMPARISON OF VANE SHEAR WITH RESULTS OF BOTH BOX SHEAR AND TRIAXIAL-SLICE SHEAR TESTS INDICATED THAT THE VANE SHEAR STRENGTH OF UNSATURATED LOW PLASTIC CLAY CAN POSSIBLY BE EQUAL TO THE DRAINED SHEAR STRENGTH. THE MEASUREMENT OF RESIDUAL STRENGTH OF CLAYS IS MADE WITH SUCCESS IN THE VANE-TRIAXIAL APPARATUS. /RRL/A/

  • Supplemental Notes:
    • No 11b, pp 537-547
  • Corporate Authors:

    Kyoto University

    Disaster Prevention Research, Gokasho
    Uji City, Kyoto,   Japan 
  • Authors:
    • Shibata, T
    • Tagawa, S
  • Publication Date: 1968-3

Subject/Index Terms

Filing Info

  • Accession Number: 00234914
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Files: TRIS
  • Created Date: Oct 13 1970 12:00AM