Energetic Stability and Structural Admissibility in Granular Systems: Hydro-Mechanical Coupling and Saturation-Induced Destabilization

This preprint develops a hydro-mechanical configurational framework for saturated granular systems within the broader theory of energetic stability and structural admissibility in granular materials. The work examines how saturation modifies metastable granular structure through buoyancy, hydro-mechanical coupling, barrier weakening, and amplification of configurational accessibility. Instability is interpreted as progressive collective configurational evolution within a non-convex energetic landscape rather than solely as isolated constitutive failure or pore-pressure accumulation. The formulation focuses specifically on: - metastable admissible states,- hydro-mechanical coupling,- barrier-controlled rearrangements,- collective destabilization,- configurational accessibility,- and hydro-mechanical marginal admissibility. The manuscript represents the hydro-mechanical component of the broader “Energetic Stability and Structural Admissibility in Granular Systems” framework and forms part of a modular theory hierarchy including dry configurational micromechanics, hydro-mechanical weakening, external energetic activation, and dynamically evolving collective transition. Related framework papers: • Energetic Stability and Structural Admissibility in Granular Systems: Dry Configurational Micromechanics and Barrier-Controlled Rearrangements DOI: 10.5281/zenodo.20283705 • Energetic Stability and Structural Admissibility in Granular Systems: General Energetic Theory of Granular Systems DOI: 10.5281/zenodo.20056042 This manuscript is a scientific preprint intended for theoretical discussion and future peer-reviewed development.