Coupled crystal plasticity-cohesive zone modeling of rock salt viscoplasticity

Rock salt, owing to its viscoplastic behavior and structural integrity under high pressure, is a promising candidate for safe and large-scale underground energy storage. This study presents a comprehensive numerical framework for modeling the viscoplastic deformation of rock salt, accounting for both intragranular and grain boundary (GB) deformation mechanisms. Intragranular deformation is modeled using a crystal plasticity approach governed by a power-law relation, capturing the activity of crystallographic slip systems. Concurrently, a cohesive zone model (CZM) is introduced to simulate grain boundary sliding (GBS) and opening via a rate-dependent traction–separation law. This modeling strategy enables a detailed analysis of the coupled interplay between crystal plasticity and intergranular decohesion phenomena. • Development of a traction-separation law for grain boundary sliding in rock salt. • Introduction of a method to measure grain boundary sliding/opening at grain junctions. • Implementation of a coupled model combining intra- and inter-granular deformation.