Techniques Used in Studying the Fracture Mechanics of Rock

Proceedings from the 41st Annual Meeting, Eastern Section, Seismological Society of America, Blacksburg, Virginia - Oct. 6-7, 1969

“…It should be noted that no time-independent dilatation was observed even at stress levels of the order of 91%. This is at variance with data presented by Bieniawski (1967c), Paulding (1966) and others who report that time-independent dilatancy appears at stresses as low as 35% of the ultimate strength. The apparent variance, however, may be due only to differences in experimental technique.…”

“…Failure mechanisms in geologic materials have been studied directly by a number of workers (e.g., Brace, 1964;Hoek, 1965;Paulding, 1965Paulding, , 1966. In most cases, these have been limited to studies under uniaxial and biaxial stress in thin plates and have, for the most part, involved the investigation of fracture propagation rather than failure initiation.…”

Effect of loading direction on the critical characteristic strength and energy evolution of quartz mica schist and microscale mechanisms

“…For compressed rocks, the microscale heterogeneity, caused by discrepant sizes and mechanical properties of mineral grains as well as preexisting microcracks or pores, generally gives rise to the concentration of tensile stress. Owing to the poor resistance to tension compared to the shear capacity, new tensile cracks initiate at the stress concentration zone and propagate toward the direction of axial stress, which has been confirmed by compressibility tests (Matsushima 1960) and compressional wave velocity tests (Paulding 1965). Numerical simulations by discrete element code PFC revealed that tensile cracks dominate the failure process of the sample (Diederichs et al 2004).…”

Critical review of the state-of-the-art of fracture mechanics with emphasis on layered rocks

“…It is believed that a deliberate introduction of a precrack would alter the natural fracture properties of an oil shale specimen. Paulding [48] has suggested a test method which makes use of a solid cylindrical specimen made of partially broken material.…”