Evaluation of permeability of intact rock under confining pressure condition using a constant-head permeability tester

Abstract

This study first developed an original constant-head permeability tester for rocks, which can represent the pressure environment that is deep underground (approximately 1,000 m) and directly measure runoff volume using an electronic balance. Second, this study measured the permeability of three intact rocks (Inada granite, Toyooka basalt, and Shakudani tuff) under confining pressure conditions using the constant-head permeability tester. The test was performed at 22±1°C in a temperature-controlled room. As result, we found that the hydraulic conductivity of Inada granite, which was measured using this device, is quite similar to that reported by Kato et al. [1]. In addition, the observed decline in permeability due to the confining pressure is consistent with the observations of Kato et al. [1]. Therefore, the permeability measurement system used in this study is established and reliable. In this full paper, an evaluation of the permeability of three intact rocks under confining pressure conditions using a constant-head permeability tester is pre-sented along with the experimental data.