Spontaneous liquefaction as an energy-releasing state transition in saturated granular systems

This work presents a state-based energetic framework for spontaneous liquefaction in saturated granular systems. Liquefaction is interpreted as an energy-releasing transition between two admissible system states—a structured granular configuration and a fluidized configuration—evaluated using static enthalpy under prescribed boundary conditions. The formulation is deliberately independent of triggering mechanisms, temporal evolution, and constitutive stress–strain descriptions. Liquefaction occurs when the fluidized state represents a lower-enthalpy configuration, rendering mobilization energetically favorable once accessibility is achieved. Within this framework, spontaneous liquefaction is understood as a state transition, not as the exceedance of a critical stress or strain threshold. The geometric consequences of such a mobilization are addressed separately in a complementary end-state.