Abstract
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The collection of geomechanical data in the mining industry is often hindered by limited access to rock exposures. Consequently, F
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there is a need for a tool that permits fast and safe acquisition of information that best characterizes a geological structural regime. k\EMO\je
This paper presents a digital face mapping methodology used to construct discontinuity trace maps from photographs of rock faces. j tZ@`io
The method is applicable under a range of ground conditions, while at the same time trying to keep user intervention to a minimum. ?vZ& CB
The developed procedure uses a series of photographs of a rock face taken under symmetrical lighting orientations. All digitized sl)_ HA7G
pictures are then introduced into the developed software, where pre-processing optimizes subsequent analysis. Discontinuity traces )q#b^( v
are then extracted from the enhanced images using edge and line detection algorithms. This results in a binary image where black "xh]>_;&'
pixels correspond to the detected features. The nature of these features is identified using artificial neural networks, specifically ?^yZVmAo]
trained for this application. As a result, it is possible to distinguish between segments in the image that are due to the presence of a I3SLR
discontinuity and those due to other phenomena. This classification process provides a series of binary images that represent r`"
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discontinuity traces in the area of interest. These images are superposed and merged. All processes described above are fully U'@_fg
automatic. In order to complete the process, the system operator ensures that incomplete discontinuity segments are reconstructed. <uA|nYpp
Following this, a discontinuity trace map is constructed and the discontinuity network is characterized using geomechanical criteria. iKDGYM
The methodology to construct discontinuity trace maps is illustrated using an example from a rock exposure in an underground %DiZ&}^Ck
mine. Subsequently the methodology is implemented in two case studies from underground mines and one in a quarry. These case PPohpdd)
studies represent different geological and lighting conditions. This information is then used to successfully characterize the ^*iZN
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investigated rock masses. Present limitations of the method are also identified. 1{DHlyA6g
r 2003 Elsevier Ltd. All rights reserved.
