ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 11 February 2011
Page Count: 9

Performance of a Cubical Triaxial Apparatus for Testing Saturated and Unsaturated Soils

Reis, Rodrigo Martins
Associate Professor, State Univ. of Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ

de Azevedo, Roberto F.
Professor, Federal Univ. of Viçosa, Viçosa, MG

Botelho, Betânia Severino
Federal Univ. of Brasilia, Brasilia, DF

Vilar, Orencio Monje
Professor, Univ. of São Paulo, São Carlos, SP

(Received 14 July 2010; accepted 9 December 2010)

Abstract

This paper deals with the performance of a stress and suction-controlled cubical triaxial device developed to test 6-cm cubical soil specimens in saturated and unsaturated conditions. In saturated tests, saturation is achieved by back-pressure while matric suction during unsaturated tests is imposed to the specimen assuming valid the axis-translation technique. The paper describes details of the new device, the testing methodology, as well as presents a series of drained conventional triaxial compression tests on a young residual soil from gneiss performed with the new equipment. The developed apparatus works properly and is adequate to perform tests at different stress-paths that can be helpful to obtain soil parameters needed in the development or improvement of constitutive models for soils. Test results compare well with results from conventional triaxial tests and have showed that suction increased the initial stiffness and the shear strength of the soil, which is commanded by an increase of the cohesion intercept, since the friction angle remained approximately constant.

Keywords:
residual soil, unsaturated soil, matric suction, axis-translation technique, cubical triaxial cell, stress/suction-controlled system

Paper ID: GTJ103256
DOI: 10.1520/GTJ103256
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