Abstract
The aim of the present paper is to construct a constitutive model of soft rocks that can precisely describe not only strain-hardening-softening behavior but also dilatancy characteristics. That is, the Adachi-Oka's elasto-plastic constitutive model is modified by introducing a new volumetric strain dependent plastic potential function and by improving the stain hardening law. The model is evaluated through a comparison of the calculated results and the experimental results of tests on tuffaceous rock (Tomuro-ishi).
