Abstract
This paper aims mainly at providing an incremental elastoplastic constitutive model for heterogeneous porous rock-like materials in the frame of micromechanics. The studied material is considered to be made up of randomly distributed spherical pores embedded in a pressure-sensitive solid matrix obeying Drucker–Prager yield function. The effective elastic properties of porous rocks are obtained by the use of Mori and Tanaka homogenization scheme, which are on function of the bulk and shear moduli of the solid matrix and of the value of porosity. For the macroscopic nonlinear phase, a limit analysis-based macroscopic criterion is adopted to derive the basic constitutive rule by considering an associated plastic flow rule. In order to capture the typical hardening effects of rocks, an originally proposed hardening function of the solid matrix is also taken into consideration, which is related on the accumulated equivalent plastic strain. In order to verify its accuracy, the proposed micro-macro constitutive model is implemented by a numerical procedure including elastic predictions and plastic corrections and compared to experimental results of triaxial compression tests of sandstone with different confining pressures. It is observed that the numerical simulation is in accord with the experimental data, indicating that the obtained model is able to predict the main mechanical behaviours of rock-like materials.
Highlights
In recent years, rock-like heterogeneous materials have been widely encountered in engineerings, such as nuclear waste storage, petroleum industry, and mining constructions, which contain microstructures at different scales [1, 2]
Experiments have shown that inners pores or voids exhibit a great influence on the effective strength and mechanical behaviours on such materials [3,4,5], which lead to the complex plastic deformation, brittle-ductile transition, and sensitivity to confining pressure. e safety of rock engineering [6,7,8,9] is the most important subject to the researchers
A limit analysis-based kinematical approach of porous media with a von Mises type solid matrix containing spherical voids was firstly introduced by Gurson [13] in the framework of micromechanics, in which the influence of porosity at microscale on the macroscopic strength was directly taken into account
Summary
Rock-like heterogeneous materials have been widely encountered in engineerings, such as nuclear waste storage, petroleum industry, and mining constructions, which contain microstructures (cracks, pores, and inclusions) at different scales [1, 2]. The effects of the voids on the strength and the failure related to its plastic deformation and voids evolution cannot be explicitly reflected To this end, a limit analysis-based kinematical approach of porous media with a von Mises type solid matrix containing spherical voids was firstly introduced by Gurson [13] in the framework of micromechanics, in which the influence of porosity at microscale on the macroscopic strength was directly taken into account. We will provide a modified micromechanics-based constitutive model for porous rock-like materials by considering a new hardening law, such that only an associated plastic flow rule is concerned. Both the macroscopic axial and lateral strains predicted by the present model are validated.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
