A kinematic hardening constitutive model for sands: the multiaxial formulation

✍ Scribed by Gajo, A.; Muir Wood, D.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 341 KB
• Volume: 23
• Category: Article
• ISSN: 0363-9061
• DOI: 10.1002/(sici)1096-9853(19990810)23:9<925::aid-nag19>3.0.co;2-m

✦ Synopsis

This paper explores the possibility of using well-accepted concepts*Mohr-Coulomb-like strength criterion, critical state, existence of a small strain elastic region, hyperbolic relationship for representing global plastic stress}strain behaviour, dependence of strength on state parameter and #ow rules derived from the Cam-Clay Model*to represent the general multiaxial stress}strain behaviour of granular materials over the full range of void ratios and stress level (neglecting grain crushing). The result is a simple model based on bounding surface and kinematic hardening plasticity, which is based on a single set of constitutive parameters, namely two for the elastic behaviour plus eight for the plastic behaviour, which all have a clear and easily understandable physical meaning.

In order to assist the convenience of the numerical implementation, the model is de"ned in a &normalized' stress space in which the stress}strain behaviour does not undergo any strain softening and so certain potential numerical di$culties are avoided.

In the "rst part the multiaxial formulation of the model is described in detail, using appropriate mixed invariants, which rationally combine stress history and stress. The model simulations are compared with some experimental results for tests on granular soils along stress paths lying outside the triaxial plane over a wide range of densities and mean stresses, using constitutive parameters calibrated using triaxial tests. Furthermore, the study is extended to the analysis of the e!ects induced by the di!erent shapes of the yield and bounding surfaces, revealing the di!erent role played by the size and the curvature of the bounding surface on the simulated behaviour of completely stress-and partly strain-driven tests.