Elastoplastic Deformation Characteristics of Gravelly Soils

This study explores the elastoplastic deformational behavior of gravelly soils. A series of drained triaxial tests with controlled stress paths [conventional triaxial compression (CTC) and conventional triaxial extension (CTE)] were conducted using large specimens composed of gravelly soils. Experimental results reveal that the elastic and plastic deformation of gravelly soils exhibits the following characteristics: (1) the elastic shear modulus stiffens under increase of hydrostatic loading; (2) during the CTC tests, plastic deformation occurs before the failure state, and the influence of confining pressure on the plastic strain is insignificant; (3) through the CTE path, the shear strain dominates the plastic deformation; (4) based on the distribution of plastic flows, the gravelly soils follow the nonassociated flow rule; and (5) this study proposes a possible geometry of plastic potential surface for gravelly soil, which includes two parts: an approximately horizontal line and an elliptic surface in the p - root J(2) plane. (C) 2013 American Society of Civil Engineers.