Many problems in subsurface systems are triggered by coupled multiphysical processes—that is, tight interactions among solid deformation, fluid flow/transport, chemical reactions, and other phenomena in geological materials. Examples include rainfall-induced landslides, long-term consolidation settlement, and hydraulic fracturing. Accurate prediction and management of these problems are beyond the capabilities of traditional approaches because they rely on empirical methods oversimplifying these intricately coupled physics.
This talk will introduce some recent approaches to subsurface engineering problems that rely on high-fidelity modeling and simulation of the relevant multiphysics processes. The talk will consist of two parts. The first part will focus on coupled fluid flow and solid deformation in naturally structured soils. Theoretical, constitutive, and computational modeling frameworks that honor the multiscale internal structure of these soils will be presented. The developed framework will then be used to gain insights into the physical origin of secondary compression (creep) and the impact of preferential flow on landslide triggering. In the second part, the focus will be shifted to the failure behavior of geomaterials under a variety of loading conditions. A coupled phase-field fracture–plasticity framework will be described as a way to capture a wide array of failure modes of geological materials from brittle fracture to ductile compaction. This framework will then be combined with multiphysics modeling to simulate cracking and damage from environmental loads.