抄録
Permeability of Inada granite was measured under confining pressure up to 20MPa, and pore water pressure up to 16 MPa. The Inada granite has three preferred orientations of splitting planes which are perpendicular each others. A transient pulse method was used to measure the permeability up to nano darcy (10-9) order in the three preferred orientations. The permeability is estimated from the decay curve of pulse of small pressure change combined with the compressibility and viscosity of water, and dimensions of sample. Linear decay characteristics indicate DARCY's law apparently hold even for this rather low pulse pressure.
The measured permeability ranges from about 3×10-8 to 5×10-7 darcies. Permeability was not a simple function of the conventional effective confining pressure, that is, the difference between external confining pressure (Pc) and internal fluid pore pressure (Pp). Changes in permeability were found to be proportional to (bdPp-adPc), where the values of b/a are different for each three preexisting preferred orientations.
