research engineer, OYO Corporation, Tokyo,
Associate Professor, Institute of Industrial Science, University of Tokyo, Tokyo,
Pages: 12 Published: Jan 1988
Drained triaxial compressive and extension strengths of air-pluviated sand were evaluated by means of a conventional triaxial apparatus taking into account both strength anisotropy and the effects of sample slenderness, that is, height/width or diameter ratio (H/D). The initial values of H/D employed were 2.0, 1.0, 0.5, and 0.25. The direction of the major principal stress σ1′ was either normal to or parallel to the bedding plane. It was found that the triaxial extension strength is greatly influenced by H/D. Strengths in the following four stress conditions were compared: (1) triaxial compression where the σ1′ direction is normal to the bedding plane, (2) triaxial extension where one of two σ1′ directions is normal to the bedding plane while the other is parallel to the bedding plane, (3) triaxial compression where the σ1′ direction is parallel to the bedding plane, and (4) triaxial extension where both σ1′ directions are parallel to the bedding plane. It was found that while the relative strength is a complicated function of H/D, generally the strength is the largest for the second case, intermediate for the first and fourth cases, and the smallest for the third case. This result suggests that (φ) is not a simple function of b = (σ2′ − σ3′)/(σ1′ − σ3′), which represents the relative magnitude of σ2′ against σ1′ and σ3′, but the strength anisotropy and failure mode, especially in triaxial extension, should be taken into account in a combined manner.
triaxial compression test, triaxial extension test, sandy soil, angle of internal friction, strength anisotropy, sample slenderness
Paper ID: STP29105S