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An investigation on the uniqueness of the incremental response of elastoplastic models for virgin sand

✍ Scribed by Silvia Imposimato; Roberto Nova


Publisher
John Wiley and Sons
Year
1998
Tongue
English
Weight
327 KB
Volume
3
Category
Article
ISSN
1082-5010

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✦ Synopsis


The paper investigates the possibility of the occurrence of a multiplicity of homogeneous responses of soil specimens under the same incremental loading, and the associated non-controllability of the imposed loading path.

It is shown that for non-associated elastoplastic strain-hardening constitutive laws, such a possibility exists even in the hardening regime. Only when the stiffness matrix is positive-de®nite is the incremental solution unique for any loading programme.

A particular constitutive model is chosen and the shape of the loci of non-uniqueness is calculated for various loading programmes. It is shown that the conditions for the occurrence of a shear band and of a peak of the deviator stress in a triaxial undrained test can be seen as special cases of the theory presented. Accordingly, the so-called `instability line' concept in undrained conditions is generalized.