The Collection and Analysis of Discontinuity Orientation Data for Engineering Design, with Examples

Abstract

Publisher Summary Rock masses usually contain such features as fractures, faults, joints, bedding planes, cleavage and other mechanical defects which are here collectively referred to as discontinuities. These discontinuities can have a major influence on the deformability, strength, stability and permeability of the rock mass and thereby play a major part in dictating the design of foundations, slopes, tunnels and other structures associated with discontinuous rock masses. Discontinuity orientation data can be presented and utilized in design by two different methods. If the rock face at the design site is readily accessible, the locations and orientations of actual discontinuities can be measured and used explicitly in the design calculations. If, however, the rock face is not accessible it is necessary to measure discontinuity orientation at other rock faces, or from boreholes, and build up a statistical model that represents the discontinuity orientation characteristics of the rock mass. In most cases the statistical model is based on the fact that geological processes usually generate one or more clusters (or sets) of nearly parallel discontinuities in a given rock mass.