THE USE OF LOCAL STRAIN MEASUREMENTS IN TRIAXIAL TESTING TO INVESTIGATE BRITTLENESS OF RESIDUAL SOIL

Stress path testing, with local strain measurement, is one of the most important tests for identifying the brittle behaviour of weakly bonded soils. During the last ten years, this type of test has been used increasingly to measure soil properties at low strain levels, less than 0.5%, in situations where conventional triaxial tests, with external strain measurement, are of little use for identifying yield at small strains. During the last four years, the authors have been investigating residual soils in southern Brazil, which originated from the weathering of a local sandstone. Formation was found to behave according to a framework, whose central concept is that most bonded soils have a weakly bonded structure and a characteristic yield surface. The authors' experiments showed that this residual soil has a yield surface, and either a ductile or a brittle behaviour according to the stress path followed. It was found that weakly bonded soils show brittle behaviour during stress path tests, where the effective stress is reduced but the shear stress is not reduced. Such behaviour is important for slope stability problems where pore pressure increase induces failure. Site investigation for such problems should include stress path triaxial testing, with local strain measuring to identify brittleness. For the covering abstract see IRRD 883023.

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 867-74

Subject/Index Terms

Filing Info

  • Accession Number: 00729304
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-7277-2513-0
  • Files: ITRD
  • Created Date: Dec 12 1996 12:00AM