Influence of Microstructure on Fracture Propagation in Rock
Final rept. 18 Dec 1970-18 Dec 1971
BATTELLE COLUMBUS DIV OH
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The report describes the results of research to correlate the fracture resistance with microstructural features of Salem limestone and Berea sandstone. Tests were conducted on wedge-loaded double-cantilever-beam specimens containing machined slots as crack starters. The fracture resistance of Salem limestone measured in terms of R, the energy dissipated per unit area of projected surface, was found to increase in the initial stage of crack extension but finally reached a constant value which was strongly dependent on crack orientation with respect to the bedding plane. For this limestone R ranges from about 50 joules sq m to 230 joules sq m. The sandstone which is a softer and more compliant rock exhibited similar fracture behavior while the R values ranged from 465 joules sq m to 1580 joules sq m.
- Geology, Geochemistry and Mineralogy