Abstract
A new constitutive model for compacted bentonite material is proposed in this paper in order to evaluate mechanical characteristics of buffer material. According to the results for a series of consolidation tests for the compacted bentonite material, it is found that nonlinear stress-strain behavior at the unloading process gets dominant comparing to the ordinary clay material. These peculiar characteristics of bentonite material cannot be described by conventional elasto-plasticonstitutive models such as an original Cam-clay model. Therefore, in this paper, a new function to describe the nonlinear behavior at unloading process is proposed and it is introduced into the original Cam-clay model. The simulationresults of the triaxial compression test show that the modified model proposed in this paper isreasonably applicable to the bentonite material.
