On the computational applicability of the modified Cam-clay model on the 'dry' side

This paper presents a theoretical investigation into the behaviour of the modified Cam-clay model on the 'dry' side and shows that: (a) for arbitrary strain-controlled loadings, local uniqueness is violated when the stress ratio η exceeds a certain critical value ηd; (b) for triaxial loadings, local uniqueness is violated when η exceeds another critical value, lower or equal to ηd, and the predicted response to a strain-controlled process becomes plastically inadmissible, while the response to a stress-controlled process presents a 'snap-back'; (c) stress-point algorithms and displacement-based numerical analysis codes can provide nonsensical results in such cases, which violate plasticity theory.