Three-Dimensional Stability Analysis of Rock Slope Using Aerial Photogrammetry Data

The performance and maintenance of infrastructure assets passing through rock cuts depend on the stability of the rock slopes. Most of the previous slope stability works used simplistic two-dimensional slope analysis due to the limitations in analysis software and data collection methods. Three-dimensional understanding of the slope behavior is necessary to estimate the factor of safety of slopes with complex geometry. Three-dimensional analysis conducted in this research is based on method of columns which is an extension of method of slices considered for most two-dimensional analyses. This analysis requires comprehensive data collection of slope geometry, but the present traditional methods are limited by their inaccessibility to hard-to-reach areas on the steep rock slopes. The advancement in lightweight compact sensors complimenting the robust unmanned aerial platforms have found their applications in remotely conducting quantitative assessments of infrastructure assets. The research presented in this study discusses the usage of aerial photogrammetry in collecting rock slope data and three-dimensional stability analysis using commercially available software in which the generalized Hoek-Brown (HK) failure criterion is used to represent the true failure envelope of rock mass. Morgenstern-Price stability analysis method was used to evaluate the global minimum factor of safety. This approach has resulted in significant savings in data collection time and cost, but also provided comprehensive idea about the stability of rock slopes for a given set of material properties.