Experimental study of opening-mode crack growth in rock. Technical progress report

Technical Report · Tue Feb 01 04:00:00 EST 1983

OSTI ID:6450407

Gordon, R B

Measurements of fracture strength have been made on rocks containing a wide range of minerals and microstructures. Elastic moduli determined from data recorded during the fracture experiments were used in the computation of the strain energy release rate. Measured steady-state fracture energies range from about 40 J/m/sup 2/ (Portland sandstone) to about 280 J/m/sup 2/ (Barre granite). While the energy of crack initiation and crack propagation depends on the strength of the constituent minerals, each is controlled primarily by the microstructure of the rock. The density of pores and microcracks and the degree to which they are interconnected are most important. The weakest rocks are those that have either a weak structural component that forms nearly continuous, non-branching surfaces within the microstructure (as in the Salem limestone) or a very high porosity (as in the Portland sandstone). The strongest rocks are polymineralic and have connected microcrack networks that permit formation of multiple crack paths through the structure (as in the granites). The fracture energy depends on crack speed and chemical environment. Water weakening ranges from a reduction of more than 50% of the strength in the Portland sandstone to nil in diabase, marble, and the Cardium sandstone.

• Research Organization: Yale Univ., New Haven, CT (USA)
• DOE Contract Number: AC02-79ER10445
• OSTI ID: 6450407
• Report Number(s): DOE/ER/10445-3; ON: DE83007192
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
CRACK PROPAGATION
DATA
EXPERIMENTAL DATA
FRACTURE PROPERTIES
INFORMATION
MECHANICAL PROPERTIES
NUMERICAL DATA
ROCKS