INFLUENCE OF END RESTRAINT ON DETERMINING ANISOTROPIC STIFFNESSES OF TUFF

Abstract

 In this study, the variation of stress-strain relationships of anisotropic tuff due to the condition of end restraint were investigated by consolidated drained triaxial compression test. For ordinary method of evaluating triaxial test results, the normal strains and the volumetric strains of specimens with the ratio of height to diameter, h / d = 2.0, was not influenced whether with or without sliding mechanism and Teflon sheets on the end of specimen, and Young's moduli and Poisson's ratio were not influenced by the end conditions. On the other hand, for evaluating strain tensor, shear strains were actually occurred and directions of principal strains were inclined due to end restraints. These phenomena indicated the possibility of inaccurate anisotropic stiffnesses obtained by the proposed method of determining anisotropic elastic properties by a single triaxial test.