Rock Mechanics Project progress and results: rock fracture and pore collapse

Problems in rock fracture and pore collapse were studied with the intent of understanding mechanisms of and developing models for rubble formation, permeability enhancement, and wave propagation. Results are reported for studies on explosive-induced fracture and fluid flow in a gas-bearing sandstone at confining pressures to simulate in situ conditions; explosive-induced fracture in a brittle plastic with multiple charges fired both simultaneously and sequentially; the effect of several intermediate-strain rates on strength and fracture in limestone; and development and testing of a theoretical model for yielding and pore collapse in porous rocks. The specific technical objectives of the project is to understand the physical mechanisms and develop models for the creation of fractured material or rubble and the enhancement of permeability by underground high-explosive detonations. This understanding will benefit in situ energy and resource technologies that use high explosives to achieve or enhance recovery of underground resources.