Discontinuities (we call them “joints” ) play a major role in mechanical and hydrological properties of rock mass. We can usually observe them using exploration drifts or boreholes. However, our ability of observation is limited to a certain extent. Hence, it is difficult to estimate joints properties in the whole rock mass.
We studied joint properties in Kurihashi grano-diorite and Ganidake diorite in the Kamaishi mine. These data were used to build a database for the estimation of rock mass properties. In this paper, at first we explain joints database. Next, based on this database, we try to simulate joint distribution in large-scale rock mass. The joints were modeled by a probability model of joints in rock mass, using results that have been obtained by the scanline method. Finally, we also discuss the anisotropy of rock mass permeability.
The following is the summary of this study.
A the oretical estimation suited well with the joint observation by borehole-TV, in Kamaishi site.
Distribution characteristic of filling width was expressed by an exponential function.
Using the discrete probability of the pole of each joint, we calculated the orientation tensor of the permeability tensor. On the orientation, the result agreed with the crosshole permeability test result.