Analysis on Time-Related Changes of Mechanical and Hydraulic Characteristics of Artificial Fault Core Specimen

In this study, a permeability test was conducted on remolded and artificial specimens to examine whether artificial fault core specimens can be applied to permeability tests instead of fault core materials, of which it is difficult to collect an undisturbed specimen in a natural state. In addition, since the physical–mechanical-hydraulic characteristics of fault materials containing clay change with time lapse, the permeability test and the direct shear test were conducted with a time difference in seven steps (immediately after specimen preparation, after 1 day, after 3 days, after 7 days, after 14 days, After 21 days and after 28 days). When the water permeability test was conducted on the remolded and artificial specimens under the same conditions, the hydraulic conductivity was shown in similar ranges for fault breccia and fault gouge, 1.03 × 10–4 to 1.16 × 10–5 cm/s and 4.88 × 10–7 to 2.65 × 10–7 cm/s, respectively, indicating that artificial clay can substitute fault gouge. In addition, as a result of analyzing the change in the permeability and friction characteristics of the artificial specimen, the hydraulic conductivity decreased and the friction angle increased with time laps, clearly showing the hardening phenomenon.