UNDRAINED INSTABILITY OF VERY LOOSE HOSTUN SAND IN TRIAXIAL COMPRESSION AND EXTENSION .2. THEORETICAL-ANALYSIS USING AN ELASTOPLASTICITY MODEL

The characteristics of the loss of stability associated with the initi ation of the static liquefaction phenomenon is obtained using the CJS model within the elastoplasticity framework. This model is based on th e characteristic line concept. The determining factors involved in the prediction of this phenomenon and in the modelling process are identi fied. The importance of the elastic components is highlighted, in part icular its non-linearity. The possibilities and the limits of the prop osed model to describe the undrained behaviour of very loose sand are examined, taking into consideration the effects of the more or less co mplex stress history. Finally, the conditions leading to the appearanc e of the uniqueness domain are indicated. The findings of this theoret ical study rely entirely on the experimental data presented in a compa nion paper, with emphasis on the triaxial tests on anisotropically con solidated samples. (C) 1997 by John Wiley & Sons, Ltd.