EFFECTS OF INITIAL FABRIC AND SHEARING DIRECTION ON CYCLIC DEFORMATION CHARACTERISTICS OF SAND

Sushil K. Chaudhary , Jiro Kuwano , Satoshi Hashimoto , Yutaka Hayanoi, and Yuhei Nakamura

ABSTRACT: The paper presents a study of the effects of initial fabric and shearing direction on the cyclic deformation characteristics such as stress-strain response, shear modulus and damping ratio from drained static cyclic tests on medium dense Toyoura sand using hollow cylinder apparatus. The apparatus allows independent control of stress components, sz, sq, sr and tzq, and accurate measurement of strain components, ez, eq, er and gzq, over a wide range of strains from 10-3% to 10%. Three methods of sample preparation: air pluviation, water pluviation and dry rodding were employed to produce different initial fabrics. Samples were sheared cyclically in p�‘-constant plane along the direction of major principal stress 0�‹ (90�‹), 22.5�‹ (-67.5�‹) and 45�‹ (-45�‹) relative to the direction of deposition. Anisotropic behaviour was observed in stress-strain response and the secant shear moduli defined separately for each direction of major principal stress. However, the equivalent shear modulus was found little affected by the direction of the major principal stress. Also the effect of the initial fabrics was not significant. The same was found for hysteretic damping ratio.

Key words: damping ratio, deformation, repeated load, sand, shear modulus, special shear test, torsion (IGC: D6/D7)