Application of in-hole camera and photogrammetry to create calibrated discrete fracture networks and obtain the in-situ block size distribution of a rock mass to blast

This study consists in the analysis of a conspicuous data set collected during two investigation campaign carried out in a pit of an aggregate quarry; the main aim being the geological characterization of the rock mass. The data set is collected at two different scale (televiewer probe monitoring) and highwall scale (terrestrial photogrammetry). The data derived from the televiewer were analysed to obtain the dip angle and dip direction values of the fractures visible on the inner surface of the boreholes. Photogrammetry data, which are the output of a previous study, are obtained through a manual mapping of the traces detectable on the pre-blast highwall surfaces of each blast. The statistical results of the discontinuity sets are the input for the generation of calibrated Discrete Fracture Networks. The models were created through the FracMan software, which uses a distribution algorithm based on the orientation, radius and number of fractures detected during the analysis. The calibration of the number of fractures to generate is based on the linear (P10) and areal (P21) fracture intensity values. The results of the In-situ Block Size Distribution of the models were discussed considering the different sampling scales that correspond to the two methods.