ABSTRACT: Dam abutment (rock foundation) stability is an important dam safety issue. Modeling discontinuities and foundation block geometry is critical to the stability analysis. This paper focuses on photogrammetric methods for measuring the orientation of geologic features (joints, faults, bedding and shears) and surface topography; however, these methods are equally adept at measuring nearly any features that can be photographed. Three-dimensional (3-D) models were developed from the photogrammetric data. The models are scalable and provide 3-D locations of common points in the photo set. These points can be used to calculate the orientation and location of joint planes and provide the data needed to develop detailed models of discontinuities and foundation blocks. Photogrammetry methods are effective in collecting detailed geologic structure and topographic data. These methods provide enormous amounts of very accurate survey information along with high resolution photographic images. These data are required to develop realistic 3-D geologic models (models that involve multiple 3-D rock blocks). These models are important components of foundation stability analysis. Limit equilibrium, Block Theory [1], rigid block dynamic displacement and Discontinuous Deformation Analysis (DDA) [2] all require realistic geologic models. In this report our photogrammetric measurements of target locations are compared with conventional survey results.
INTRODUCTION Stability of rock foundations and dam abutments is an important dam safety concern. Realistic three dimensional (3-D) geologic models (models that involve multiple 3-D rock blocks) are important components of foundation stability analysis. Limit equilibrium, Block Theory [1], rigid block analysis and Discontinuous Deformation Analysis (DDA) [2] all require them. Photogrammetry can rapidly acquire an enormous amount of very accurate survey information along with high-resolution photographic images that can be used to generate 3- D geologic models.