What is it about?
It is essential to correctly simulate the behavior of the soil in the range of small strains. The EPHYSS model is an advanced elastoplastic model that can reproduce the nonlinear reversible, hysteretic and dependent on recent history soil behavior in the range of small strain, considers strain-induced anisotropy and can also reproduce soil plastic behavior. EPHYSS model corrects some inconsistencies of the HS-SS model of Plaxis, and its performance and a comparison with HS-SS model is presented in some experimental and numerical tests, and in a boundary value problem of a large excavation in Barcelona.
Featured Image
Why is it important?
Multiple engineering problems, especially those related to works in urban areas, require realistic calculations of soil displacements under serviceability conditions in which small strains must be correctly simulated. There are numerous advanced constitutive models capable of simulating the behavior of the soil in the whole strain range, including small strain part, although the use of many of them is reduced to an academic use. However, some of these advanced models have managed to extend to the professional practice. Among them, stands out the well-known HS-SS model. After analyzing in depth 54 constitutive models that consider the soil behavior in the range of small strains, there have been identified some aspects that can be improved in the elastic part of the HS-SS model in relation to: (1) nonlinear behavior; (2) hysteretic behavior; (3) deviatoric strains reversals effect on the elastic bulk modulus; (4) consideration of the strain induced anisotropy; and (5) correction of some inconsistencies that have been detected. All these points have motivated the development of the EPHYSS model with the aim of being used in the geotechnical engineering professional practice.
Perspectives
The aim of EPHYSS model is to be used in professional practice since it improves the approximation to the experimental measures with respect to the HS-SS model, especially in those boundary value problems that present partial reversals in the deviatoric strains or high cumulated strain values prior to reversals; resolves the inconsistencies of the latter with a reasonable computational cost; and requires simple parameters, most of them common to those of the HS-SS model. The entire code of the EPHYSS model, implemented in the User Defined Soil Model (UDSM) modulus of Plaxis may be consulted in the PhD Thesis of the first author.
Javier Castellón
Universitat Politecnica de Catalunya
Read the Original
This page is a summary of: Development of a new advanced elastoplastic constitutive model that considers soil behavior at small strains. The EPHYSS model, International Journal for Numerical and Analytical Methods in Geomechanics, May 2022, Wiley,
DOI: 10.1002/nag.3360.
You can read the full text:
Contributors
The following have contributed to this page
