| Popis: |
Joint intersection points are of interest because of their relations to the blocks that comprise the rock mass. Removable tetrahedral blocks, for example, have exactly one joint intersection point at the interior block apex; thus joint intersection probabilities are related to occurrence probabilities of rock blocks, and hence to stability of rock slopes and excavations. A solution is obtained giving relative probabilities of intersection of sets of parallel, impersistent joints in a discontinuous rock mass. A solution is also found for intersection probabilities of line segments in the plane. These probabilities are shown to depend on the joint intensities and on the relative orientations of joint sets or line sets. They prove to be remarkably simple functions of parameters that may be readily measured or estimated in the field. The ambiguities of the traditional definitions of persistence and spacing are avoided by use of joint intensity as a measure of density. Methods for the estimation of joint intensity by area sampling and line sampling techniques are discussed. |
