An Elasto-Viscoplastic Model for Clay Considering Destructuralization and Consolidation Analysis of Unstable Behavior

Self Cite

A multiphase deformation analysis of a river embankment was carried out using an air-soil-water coupledˆnite element method capable of considering unsaturated seepage ‰ow. A numerical model for unsaturated soil was constructed based on the mixture theory and an elasto-viscoplastic constitutive model. The theory used in the analysis is a generalization of Biot's two-phase mixture theory for saturated soil. An air-soil-water coupledˆnite element method was developed using the governing equations for three-phase soil based on the nonlinearˆnite deformation theory, i.e., the updated Lagrangian method. Two-dimensional numerical analyses of the river embankment under seepage conditions were conducted, and the deformation associated with the seepage ‰ow was studied. We have found that the occurrence of large deformations corresponds to the large values of the hydraulic gradients at the toe of the embankment, and that the over‰ow of river water makes the embankment more unstable. It has been conˆrmed that seepage-deformation coupled three-phase behavior can be simulated well with the proposed method.

Section: Constitutive Equationsmentioning

confidence: 99%

“…( 3 7 ) where Ã M * is supposed to be constant in the NC region and varies with the current stress in the OC region (Kimoto and Oka, 2005).…”

Section: ＝0mentioning

confidence: 99%

A Seepage-Deformation Coupled Analysis of an Unsaturated River Embankment using a Multiphase Elasto-Viscoplastic Theory

Oka

Kimoto

Takada

et al. 2010

Self Cite

“…An elasto-viscoplastic constitutive model was extended to describe the instability of the failure state which is connected to structural degradation. The model can reproduce the apparent compressive strain localization regarded as compaction bands, when structural degradation is considered (Kimoto and Oka, 2005).…”

Section: Shear Band Formation and Localizationmentioning

confidence: 99%

“…Asaoka et al (1997) explained in detail the formulation of an elastoplastic model to solve the incremental form of the equilibrium equation. Kimoto and Oka (2005) presented an elasto-viscoplastic constitutive model and explained theˆnite element formulation for the computation of visco-plasticity. The return mapping method is an iteration algorithm used to calculate plastic strain; it is becoming increasingly popular.…”

Section: Finite Deformation and Constitutive Equationsmentioning

confidence: 99%

Numerical Methods

Murakami¹,

Wakai²,

Fujisawa³

2010

This paper provides a comprehensive survey of the numerical methods related to geotechnical problems, most of which were reported in papers appearing in Soils and Foundations. The reason why most of the reviewed papers are concentrated in Soils and Foundations is that if we were to include papers appearing in other journals in theˆeld of geotechnical engineering, closely related to numerical methods, e.g., Computers and Geotechnics, Int. J. Numer. Anal. Meth. Geomech., etc., we would have to deal with almost all the papers in those journals. Firstly, we present a description of the current status of the numerical methods, and then give a brief review of the literature covering several topics in geotechnical applications. The scope of the review is limited, and thus, the authors do not profess to cover the entire range of literature.

“…A change in the stress history tensor gave a softening behavior associated with soil structure degradation. Kimoto and Oka (2005) developed an elasto-viscoplastic model with structural degradation by shrinking the bounding surface and the static yield surface, which allowed them to model unstable behavior during consolidation. Asaoka et al (2000a) introduced a three surface model, in which the outmost yield surface called the``super-subloading surface'' was a function of soil structure.…”

Section: Time Dependent Deformationmentioning

confidence: 99%

Modeling of Geomaterials Behavior

Soga

O’Sullivan

2010

The review of 50 years of papers published in Soils and Foundations demonstrates that signiˆcant eŠort has been made by many researchers to develop soil models. The contributions of Soils and Foundations in the area of soil modeling are subdivided into two topics: (a)``macro''-mechanics and (b)``micro''-mechanics. The attention to macro-mechanics is focused on continuum-based models, whereas that to micro-mechanics is focused on discrete based models. Soils are examples of complex systems, made up of basic units that interact to generate an emergent response that is more complex than the response of the units themselves. Despite the challenges posed by the complexity of the systems, our understanding of the link between the particles, their interactions and the overall``macro-scale'' soil response has signiˆcantly been improved over the life of Soils and Foundations. In this review of contributions to soil modeling, many examples of macro-scale soil models developed with a real consideration of the mechanical response of the individual particles were found.