A Combined Experimental and Theoretical investigation of reactive flow in brittle media with applications to solid Earth geodynamics
DESCRIPTION: Many important processes in the natural and engineered world involve the infiltration of fluids into materials that then react to form new materials with significantly larger volume. These large volume changes, in turn are thought to induce fracturing which opens up new avenues for fluid infiltration, potentially leading to a cascade of pervasively cracked materials in a process dubbed ?reaction induced cracking?. While many natural systems give indirect evidence of these processes, very little is understood about the physics and efficiency of these mechanisms (or if they even work). The purpose of this proposal is to develop a fundamental understanding of the reactive cracking process by combining laboratory experiments, theory and advanced computational models of reactive brittle materials. A better understanding of these processes could lead to new engineering methods for efficient carbon sequestration or hydrocarbon extraction, could give insight into induced seismicity as well important Earth science processes in the natural world. During this award, we will combine laboratory rock mechanics experiments on simplified systems with computational models that can be used to test and validate a range of hydro-mechanical failure theories directly against the experiments. Lab experiments will be conducted in Lamont?s tri-axial deformation apparatus, with control of fluid flow and monitoring of stresses, pore pressures, acoustic emissions and permeability changes. Experiments will investigate both hydration and dehydration reactions on analog materials chosen to provide large volume changes in a simplified geometry. We will explore the behavior of nested cylinders of materials with an interior reactive cylinder that can either produce or ingest hydrous fluids, surrounded by an outer cylinder of brittle rock under various level of confining pressure. The modeling will be a collaborative effort across multiple departments and schools at Columbia and use an open-source computational framework developed by the PIs. Direct modeling of the experiments will provide the needed control for testing hypotheses, validating theories, and calibrating constitutive relations and failure models. Improved theoretical models of fluid-brittle solid interaction can then be extended to explore their consequences for large-scale geodynamics such as volatile cycling through subduction zones.