This paper presents some improvements of the generalized plasticity model proposed by [PASTOR et al., 1990] that can be used to reproduce “damage” phenomena in geomaterials. First, a simple improvement is introduced to reproduce the mechanical behaviour of bonded soils or weak rocks. In this case, the bond degradation depends only on the plastic strains and affects the plastic modulus. In the limit case, when destructuration is complete, the proposed model coincides with the original one. Then, a hierarchical enhancement of the basic stress-strain relation is also presented for unsaturated soils. It is obtained by introducing a second mechanism of plasticity. Hydraulic hysteresis is reproduced by taking into account the water storage mechanism. In the limit case, when the saturation degree is equal to one, the basic saturated model is recovered, and the transition between saturated and unsaturated conditions takes place without discontinuity. Other degradation phenomena as those caused by thermal or chemical effects can be modelled with the same constitutive assumptions. The main advantage of using generalised plasticity theory is that it gives a simple yet efficient framework within which it is possible to reproduce not only monotonic stress paths but also cyclic behaviour. Finally, some numerical validations of the proposed improvements are described.
This paper presents some impro …
AUTORI: Fernandez-Merodo J.A., Tamagnini R., Pastor M., Mira P. RIG ANNO: 2004 NUMERO: 4 Numero di pagina: 32