Elastic shear modulus of Bangkok clay during undrained triaxial compression

INTRODUCTION The elastic stiffness is one of the main parameters in performing elastic-plastic analysis. When compared with the effort given to formulating the complicated plasticity partner, its importance is generally ignored by treating it as a constant throughout the analysis. Elastic stiffness is known to be a function of several factors, including effective stress level, anisotropy stress condition, plasticity index, and overconsolidation ratio. Abundant literature can be found on this topic (e.g. Hardin & Drnevich, 1972; Roesler, 1979; Yu & Richart, 1984; Yan & Byrne, 1991; Tatsuoka & Shibuya, 1992). However, information on the variation of elastic stiffness during shearing has been limited (Yu & Richart, 1984; Tanizawa et al., 1994; Kohata et al., 1997; Rampello et al., 1997). The elastic shear modulus is generally expressed as a function of the effective stresses. The most common stress component adopted is the effective mean stress, p9[1⁄4 ( 9 1 þ 9 2 þ 9 3=3)]: G 1⁄4 C( p9) (1)