Numerical simulation of mechanical behavior of rock samples under uniaxial and triaxial compression testsy

Abstract

Purpose. The research aims to investigate how the load influences the ultimate compressive strength of rocks at failure. It uses both a uniaxial compression test, which involves incremental displacements, and a triaxial compression test, which applies varying confining stresses while maintaining a constant axial compression stress and incrementally increasing the displacement. Methods. To conduct the investigation, the researchers used RS2D, a rock-soil software, to examine the impact of different incremental displacements and confining stresses on the strength properties of various rock samples. The numerical analysis includes Fayum argillaceous sand, Sinai coal, Aswan granite, Assiut limestone, and Red-Sea phosphate. Findings. The research findings indicate that the ultimate compressive strength of rocks at failure is achieved with minor incremental displacements. Conversely, an increase in the confining stress leads to higher ultimate tensile strength, deviatoric stresses, and volumetric strain. However, the stress factor decreases in relation to the axial strain percentage. Originality. The simulator adopts Mohr-Coulomb failure criterion, presents and discusses the results in terms of stress-strain (σ-ε) curves, stress ratio (σ1/σ3), deviatoric stresses (σ1-σ3) and volumetric strain with respect to the percentage of axial strain. Practical implications. Using numerical modeling analysis, it becomes possible to reproduce the rock failure mechanisms observed in uniaxial and triaxial compression tests. This methodology has the potential to reduce the need for extensive experimental testing when assessing the tensile strength of rocks under different loads. As a result, both time and costs can be minimized.