N. Khalili, M. D. Liu
Dept. of Civil Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
Keywords: bounding surface, constitutive equations, critical state, dilatancy, plasticity, soils.
ABSTRACT: A new, continuous stress direction dependent plastic potential is proposed for the stress strain behaviour of soils. The resulting flow rule is incorporated into a bounding surface plasticity model within a critical state framework. The hypoplastic bounding surface model thus formulated is employed to predict both the compression and shearing behaviour of soil for various stress paths in the p¢ - q plane. It has been demonstrated that the proposed model describes successfully many important features of the behaviour of soils for loading along complicated stress paths and has improved significantly the performance of bounding surface models with a single set of yield surfaces.
- Introduction
Many constitutive models have appeared in the literature for the stress-strain behaviour of soils. They range
from simple elasto-plastic models, involving a single yield surface and a single plastic potential, to sophisticated constitutive models based on the sub-yielding of the material within the virgin yield surface, multiple yield surfaces, kinematic hardening and bounding surface plasticity among others (e.g., Proc. of 16th International Conference of Soil Mechanics and Goetechnical Engineering, 2005). The conventional elastoplastic models form the basis for a majority of the contemporary models proposed in the literature. The more advanced models are primarily used where the non-linearity and/or the cyclic response of the soil are concerned. Common to a majority of these constitutive models is the use of a stress direction independent plastic potential. This has rendered their numerical prediction for stress-strain behaviour of soils less than reliable particularly along complex non-proportional loading paths.
from simple elasto-plastic models, involving a single yield surface and a single plastic potential, to sophisticated constitutive models based on the sub-yielding of the material within the virgin yield surface, multiple yield surfaces, kinematic hardening and bounding surface plasticity among others (e.g., Proc. of 16th International Conference of Soil Mechanics and Goetechnical Engineering, 2005). The conventional elastoplastic models form the basis for a majority of the contemporary models proposed in the literature. The more advanced models are primarily used where the non-linearity and/or the cyclic response of the soil are concerned. Common to a majority of these constitutive models is the use of a stress direction independent plastic potential. This has rendered their numerical prediction for stress-strain behaviour of soils less than reliable particularly along complex non-proportional loading paths.
In this work a new, continuous stress direction dependent plastic potential is proposed for the stress strain behaviour of soils. The resulting flow rule is incorporated into a bounding surface plasticity model within a critical state framework. The validity and the accuracy of the hypoplastic bonding surface model are demonstrated using experimental data from the literature. It has been shown that the model describes successfully many important features of the behaviour of soils and improves significantly the performance of conventional bounding surface plasticity models for proportional and non-proportional loading paths.
Clic Image To Download Full Journal
0 comments:
Post a Comment