DENSE SAND WEAKENED BY CONTINUOUS PRINCIPAL STRESS DIRECTION ROTATION

The authors discuss the effects of cyclic loading and suggest the such effects cause some of the most pressing uncertainties in geotechnical engineering today, reflecting the general concern about the consequences of earthquakes and the safety of offshore structures. Reference is made to the problems associated with the hollow cylinder apparatus used to resolve such uncertainties, and a new apparatus which completely controls the principal stress directions applied to a uniformly stressed soil sample sheared in plane strain. This technical note reports on the use of this new apparatus, known as a "directional shear cell" in which drained tests were made on dry dense leighton buzzard sand with the effective stress ratio held as nearly constant as possible throughout. The apparatus is described by reference to a cross-sectional drawing of the cell, and information provided on preparation and testing. A summary of the data obtained is presented and discussed, and stress variations obtained during a test cycle illustrated and described. The authors suggest that the data from this test series are unusual in yielding a single result of great potential significance: the large reduction in strength induced in a drained dense sand by cyclic continuous rotation of the major principal stress direction. It is suggested that there is a need for independent confirmation of such a result bearing in mind that it was obtained from tests made in a new apparatus. /TRRL/

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 91-96
  • Serial:
    • GEOTECHNIQUE
    • Volume: 1
    • Issue Number: 29
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00301876
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Dec 19 1979 12:00AM