초록
Permeability was not represented as a simple function of the difference between confining pressure($P_c$) and pore pressure($P_p$). The effective pressure($P_e$) for measurements of the permeability is shown to be $P_c-{\alpha}P_p$, where $\alpha$ is a coefficient of effective pressure. Local values of $\alpha$ were determined at intervals along the pressure path which range 25MPa to 55MPa. The values of $\alpha$ ranged 0.65 to 1.09 for Pocheon granite and 1.20 to 1.43 for Wonju granite. Also, the value of $\alpha$ calculated by the cross-plotting method was 0.90 for Pocheon granite, 1.59 for Wonju granite and 4.35 for jointed Pocheon granite. $\alpha$ was found to be stress-history dependent.