Propagation des surfaces de discontinuite dans un milieu elastoplastique.- The Concept of Bifurcation in Geomechanics.- Experimental Aspects.- Third Invariant Dependent Single Yield Surface Model and Localization Conditions for High Porosity Sandstone.- Interpretation of the Scale Effect in Perforation Failure.- Experimental Investigation of Instabilities of Granular Materials in Relation to Dilatancy and Fabric Issues.- Compactive Cataclastic Flow in Tuffeau de Maastricht Calcarenite: Mechanical Deformation & Permeability Reduction.- Local Second Gradient Models and Damage Mechanics: 1D Post-Localization Studies in Concrete Specimens.- Micromechanical Aspects.- Entropy and Material Instability in the Quasi-Static Mechanics of Granular Media.- A DEM Study of Compaction Band Formation.- Shear Zone Formation in 2D Random Granular Specimens within Enhanced Hypoplasticity.- A Rational Approach to Stress-Dilatancy Modelling Using an Explicit Micromechanical Formulation.- Micro-Fracture Instabilities in Granular Solids.- Constitutive Aspects.- Entropy and Material Instability in the Quasi-Static Mechanics of Granular Media.- Modeling the Influence of Pressure and Moisture Content on the Disintegration of Weathered Rockfill Materials.- Shear Zone Formation in 2D Random Granular Specimens within Enhanced Hypoplasticity.- A Rational Approach to Stress-Dilatancy Modelling Using an Explicit Micromechanical Formulation.- Kinematics of Shear Zone Deformation in Soft Sensitive Clays.- Numerical Aspects.- Numerical Analysis of Deformation of Methane Hydrated Contained Soil due to the Dissociation of Gas Hydrate.- Numerical Prediction of Impact Force of Geomaterial Flow against Retaining Structure using CIP Method.- Numerical Simulation of the Cracked Brazilian Disc under Diametral Compression.- Stress Analysis of Multiply Fractured Porous Rocks.