Fabric and strain analyses support a unified framework for sediment deposition, relaxation, and glass formation

Richard Kilburn, Vashan Wright , Evie Gedminas, Karen E Daniels, Ted Brzinski, Ming Chang

The kinetic energy of particles at deposition Ek is a distinguishing feature of all near-surface environments, varying due to particle mass and local stress field within the fluid that transports the particles. Once deposited, a granular fabric emerges that exerts control on the subsequent relaxation processes, including on whether, when, and how granular sediments catastrophically fail. Despite advances in characterizing relaxation and the recognition that fabrics emerge from the balance of energy input and energy dissipated during deformation, there is no framework linking this energy balance to the 3D fabrics of sediments after deposition or relaxation events. Here we prepare granular samples with increasing Ek, then quantify the fabrics and relaxation dynamics via X-ray micro-computed tomography and light scattering. Higher Ek leads to less dense, less physically connected, and more structurally heterogeneous packings. These effects resemble those associated with faster quenching in glasses and imply that the energy balance governs the rate at which configurational space is explored. We use phenomenological and theoretical arguments to introduce an energy-based dimensionless deposition number Pi_E that characterizes the energy balance and demonstrate its connection with common dimensionless parameters used to study friction, vibration, and flow patterns during relaxation, unifying granular and glass processes.