1. | Boukpeti N.♦, Mróz Z., Drescher A.♦, Modeling rate effects in undrained loading of sands, Canadian Geotechnical Journal, ISSN: 0008-3674, DOI: 10.1139/t03-077, Vol.41, No.2, pp.342-350, 2004Abstract:The present technical note extends the previous work by the authors concerned with formulation of a constitutive model of elastoplastic response of sands (Superior sand model) and its application to the analyses of static liquefaction and instability states in triaxial compression and extension occurring in the undrained deformation of saturated granular materials. To account for time-dependent behavior and strain rate effects, an elastic, viscoplastic extension of the model to triaxial compression is proposed. The constitutive equations derived are used to predict the model response in different loading histories. In particular, strain rate and stress rate effects and undrained creep deformation for specified stress components are discussed in detail. Comparison of model predictions with available experimental data also is provided.Key words: saturated sand, constitutive model, elasticviscoplastic behavior. Affiliations:Boukpeti N. | - | University of Western Australia (AU) | Mróz Z. | - | IPPT PAN | Drescher A. | - | other affiliation |
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2. | Mróz Z., Boukpeti N.♦, Drescher A.♦, Constitutive model for static liquefaction, International Journal of Geomechanics, ISSN: 1532-3641, DOI: 10.1061/(ASCE)1532-3641(2003)3:2(133)#sthash.LLxWvMhd.dpuf, Vol.3, No.2, pp.133-144, 2003Abstract:A general, three-dimensional formulation of the elastoplastic refined Superior sand constitutive model is presented. The model is aimed at realistic simulation of liquefaction phenomena occurring in loose saturated granular materials under monotonic static loading. The isotropic hardening/softening is related to plastic deformation and distance to a reference yield surface. The nonassociated flow rule is used with the closed yield surface introduced previously in the Superior sand model. The refined model accounts for the different response of materials with different deposition densities. The model prediction of drained and undrained plane-strain compression is presented and compared with the response in triaxial compression/extension loading. Static and kinematic instability states also are discussed. Affiliations:Mróz Z. | - | IPPT PAN | Boukpeti N. | - | University of Western Australia (AU) | Drescher A. | - | other affiliation |
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3. | Boukpeti N.♦, Mróz Z., Drescher A.♦, A model for static liquefaction in triaxial compression and extension, Canadian Geotechnical Journal, ISSN: 0008-3674, DOI: 10.1139/t02-066, Vol.39, No.6, pp.1243-1253, 2002Abstract:The response of the elastoplastic refined Superior sand constitutive model in undrained triaxial compression and extension tests is presented. The model is aimed at realistic simulation of liquefaction occurring in loose, saturated, granular materials under monotonic static loading. The yield surface introduced previously in the original Superior sand model is modified, and a non-associated flow rule is used. The isotropic hardeningsoftening is related to plastic deformation and distance to a reference yield curve. The refined model accounts for the different response of materials with different deposition densities. The model prediction of undrained triaxial compression and extension tests is compared with experimental results. The higher tendency for liquefaction response in extension is well described. Instability and phase-transformation states also are discussed, and the energy of liquefaction is quantified.Key words: static liquefaction, constitutive model, triaxial tests, liquefaction energy. Affiliations:Boukpeti N. | - | University of Western Australia (AU) | Mróz Z. | - | IPPT PAN | Drescher A. | - | other affiliation |
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