Collecting discontinuity data at Kartchner Caverns using LIDAR for the purpose of numerical modeling

The addition of discontinuity data into geomechanical numerical models can allow for a better understanding of the behavior of the overall rock mass. For this study, LIDAR data has been collected at the Kartchner Caverns site in Cochise County, Arizona. The discontinuity data collected at this site can be divided into two types. The first type is the overall trends of small to medium-sized discontinuities such as short joints and small fracture faces that appear consistently in the LIDAR point clouds. When added to the numerical model, these fractures can be applied throughout the entire model as joint sets. This is done by inputting statistical information representative of all of the discontinuities in the set such as the mean discontinuity plane orientation, a measure of orientation scatter such as the Fisher constant, and statistical information about joint spacing and joint roughness. The second type of discontinuity information is data collected on a single specific discontinuity such as a major fault or a persistent bedding plane. Because the interaction of these large scale features with one another and with the overall geometry of the cave openings may be relevant to the overall stability of the system, it may be advantageous to model these discontinuities individually, and input them into the numerical model in their actual location.