| This research adopts multivariate clustering algorithms to better characterize discontinuity data from oriented boreholes. Conventional analyses are done by grouping the discontinuities into groups or sets based on orientation only, and then trying to generalize the other attributes to these sets. The new approach uses multivariate cluster analysis to group discontinuities (joints) into sets based on multiple attributes, such as orientation, spatial position (spacing) along the borehole and roughness of the discontinuity surface. Rather than considering one variable at a time, a number of variables are treated simultaneously so that not only the variances but also the covariances are considered. In this way interactions between variables are taken into account. Although drift or surface exposure mapping data allows better characterization of discontinuities, borehole data is often more readily available, because of lower costs. In addition, borehole data may be more useful because boreholes can be drilled to the exact location where the ground needs to be characterized and borehole data is usually available earlier in the life cycle of an engineering project. However, most borehole data are underutilized because of lack of analytical tools.; This research develops a new and cost effective tool of analyzing hard rock discontinuities from oriented core borehole data, various analytical and visualization tools, such as three-dimensional stereonet and stereoscopic net, in the format of software package (named as CYL, short for cylinder), for the characterization of rock mass structure from oriented borehole discontinuity data. It provides fast and objective characterization of oriented core discontinuity data using automated multivariate cluster analysis and the “three dimensional stereonet”. The features of the CYL software includes four methods of cluster analysis, incorporation of multiple variables (orientation, spacing and roughness), various visualization modes, and an automated method to split the data set into different Geotechnical Mapping Units (GMU). In addition the software facilitates the selection of optimum drilling angle for boreholes. |
