An Efficient Strength Criterion Based Constitutive Model for Geomaterials: Development and Application

ABSTRACT Porosity is a fundamental property of geomaterials and significantly influences their overall mechanical behavior, including yield strength and volumetric deformation. In this study, a general elliptic macroscopic yield criterion with an explicit and simple form is proposed for geomaterials, based on their yield behavior under tensile and compressive hydrostatic loadings. This criterion is then applied to a porous material whose matrix follows the Drucker–Prager model, characterized by tension‐compression asymmetry. It explicitly incorporates both porosity and matrix properties. Despite its simplicity, the proposed criterion demonstrates strong robustness and high accuracy, as validated by finite element simulations over a wide range of frictional parameters and porosity values. Building on these promising results, a complete elastoplastic constitutive model is developed, incorporating appropriate plastic hardening and flow rules. The model is applied to characterize the mechanical behavior of porous sandstone and is validated through comparisons with experimental data under various confining pressures. Furthermore, it successfully captures the evolution of microstructure throughout the loading process.