THE SIGNIFICANCE OF CAP AND BASE RESTRAINTS ON STRENGTH TESTS ON SOILS

THE OBJECTIVE OF THIS INVESTIGATION WAS TO DETERMINE THE SIGNIFICANCE OF THE VARIOUS EFFECTS OF CAP AND BASE RESTRAINT IN STRENGTH TESTS ON SOILS. THE NORMAL CAPS AND BASES USED IN STRENGTH TESTS PREVENT LATERAL EXPANSION OF THE TOP AND BOTTOM OF TEST SPECIMENS. PREVIOUS STUDIES HAVE SHOWN THAT THIS RESTRAINT CAUSES NONUNIFORM VOLUME CHANGES IN DRAINED TESTS, MOISTURE MIGRATION IN UNDRAINED TESTS, AND , IN RAPIDLY CONDUCTED TESTS, NONUNIFORMITIES IN PORE-WATER PRESSURE IN UNDRAINED CLAY SPECIMENS. LUBRICATED CAPS AND BASES WERE USED TO ELIMINATE END RESTRAINT IN UNDRAINED TRIAXIAL AND PLANE STRAIN TESTS ON UNDISTURBED SATURATED CLAY. THE RESULTS OF THESE TESTS WERE COMPARED WITH THE RESULTS OF TESTS PERFORMED USING NORMAL CAPS AND BASES TO ASSESS THE SIGNIFICANCE OF CAP AND BASE RESTRAINT. THESE TESTS SHOWED THAT THE MAGNITUDE OF THE EFFECTS OF CAP AND BASE RESTRAINT ARE NOT SIGNIFICANT. IN CONJUNCTION WITH THIS INVESTIGATION A PROCEDURE WAS DEVELOPED FOR INSURING THE EFFECTIVENESS OF LUBRICATION IN ELIMINATING CAP AND BASE RESTRAINT. THE SAME TECHNIQUES MAY ALSO BE USED TO CALCULATE THE FRICTIONAL FORCES BETWEEN PLANE STRAIN SPECIMENS AND THEIR END PLATES. /AUTHOR/

• Corporate Authors:

  University of California, Berkeley

  College of Engineering, Office of Research Services
  Berkeley, CA  United States  94720
• Authors:
  • Duncan, J M
  • Seed, H B
  • Dunlop, P
• Publication Date: 1966-8

Language

• English

Media Info

• Pagination: 76 p.

Subject/Index Terms

• TRT Terms: Base course (Pavements); Bearing capacity; Calculation; Capillarity; Friction; Lubrication; Pore water pressures; Saturated soils; Soils; Strain (Mechanics); Stresses; Structural plates; Triaxial shear tests; Undisturbed samples; Volume changes
• Uncontrolled Terms: Base; Computation; Plates; Triaxial stress
• Old TRIS Terms: Capillary phenomena; Caps /structural/; End movements; Lateral movement; Strains
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00228899
• Record Type: Publication
• Report/Paper Numbers: Report Te-66-5
• Files: TRIS
• Created Date: Aug 15 2004 1:32AM