Effective pressure law for permeability of westerly granite under cyclic loading
- 10 March 1986
- journal article
- Published by American Geophysical Union (AGU) in Journal of Geophysical Research
- Vol. 91 (B3) , 3870-3876
- https://doi.org/10.1029/jb091ib03p03870
Abstract
The permeability of Westerly granite was measured under cyclic loading conditions for confining pressures Pc to 96 MPa and pore pressures Pp to 86 MPa in order to determine the coefficient α of the effective pressure equation Pe = Pc ‐ αPp, where Pe, Pc, and Pp are effective, confining, and pore pressures, respectively. Two methods of determining α are described, based on the cubic root law, k1/3 = A + B In (Pe), which relates permeability k to effective pressure in fractures. A and B of this equation are functions of the geometric parameters of the cracks; α was close to 1 under all conditions of pressure and loading history. Pressure cycling had significant effects on the permeability of the granite, as demonstrated by the large variations in the coefficients A and B of the cubic root law.Keywords
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