ABSTRACT
Several Hydro-Mechanical coupling tests were conducted on artificial granitic joint samples at Kyushu University in Japan. The experiments consist of three major stages: first, joint geometrical properties were determined. Then, hydro-mechanical properties of rock joints were investigated under normal and shear modes. Finally, hydro-mechanical coupling properties of rock joint were modeled and compared with experimental results.
To determine hydro-mechanical coupling properties of rock joint, a new test apparatus with different flow systems was designed and developed to perform test under high hydraulic head and low hydraulic gradient. Test results showed that during normal closure – hydraulic conductivity test, joint conductivity decreased with increasing normal stress. Increasing in inlet water pressure caused slight increasing of hydraulic conductivity. Hydraulic conductivity decreased at the onset of shear and then increased rapidly and almost remained constant in residual shear region.
To model hydro-mechanical coupling properties, joint aperture distribution data in normal and shear modes were used. Based on the values of each element in joint, an original flow model was developed which applied the effective aperture instead of nominal aperture. Results showed that the new flow simulation gave close results to experimental findings, especially in residual shear region.
