RESIDUAL STRENGTH DETERMINATION IN DIRECT SHEAR

PROCEDURES FOR RESIDUAL STRENGTH TESTING HAVE NOT PREVIOUSLY BEEN SATISFACTORILY DEFINED. SEVERAL VARIABLES HAVE THEREFORE BEEN INVESTIGATED TO DETERMINE THEIR EFFECTS ON THE LABORATORY STRENGTH ESTIMATE. SELECTED RESULTS ARE USED FOR ILLUSTRATION. AN AUTOMATIC REVERSING 6CM SQUARE SHEAR BOX WAS MODIFIED TO ALLOW HALF AN INCH DISPLACEMENT OF THE UPPER BOX BEFORE AND AFTER THE CENTRAL POSITION. THE MAIN CONCLUSIONS WERE: (1) AREA CORRECTIONS ARE NOT APPLICABLE EVEN WHEN BOX DISPLACEMENTS ARE VERY LARGE (0.5 IN. DISPALCEMENT OF 2. 36 IN. BOX): (2) SOME SOILS REQUIRE SUBSTANTIALLY MORE THAN QUARTER OF AN INCH TRAVEL BETWEEN REVERSALS TO MOBILIZE THE FULL RESIDUAL STRENGTH-A SHEAR BOX WHICH CAN BE DISPLACED IN BOTH DIRECTIONS IS THEN DESIRABLE; (3) SPEEDS WHICH ARE TOO GREAT FOR DRAINED CONDITIONS TO BE ADEQUATELY ESTABLISHED FREQUENTLY GIVE RISE TO LOAD-DISPLACEMENT CURVES WHICH DO NOT LEVEL OUT BETWEEN REVERSALS; (4) COMMERCIAL KAOLIN GAVE A TAN PHI RESIDUAL VALUE OF 0.18 FOR NORMAL STRESSES OF BOTH 30 AND 60 P.S.I.; (5) BRITTLENESS INDICES AS HIGH AS 0.75 AT 30 P.S.I. NORMAL STRESSES HAVE BEEN MEASURED ON SOME AUSTRALIAN SOILS. /AUTHOR/

  • Authors:
    • Cullen, R M
    • DONALD, I B
  • Publication Date: 0

Language

  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00237047
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Conf Paper
  • Files: TRIS
  • Created Date: Nov 18 1973 12:00AM