Trabajo presentado en el VII Simposio Peruano de Geoingeniería

Por: R. Pozo, SRK Consulting Perú.

Abstract

In this research, the dispersion of Geological Strength Index (GSI) values obtained with quantitative and qualitative approaches has been evaluated, for which four rock outcrops of different geomechanical quality have been analyzed. The subjective component associated with qualitative or visual methods has been studied by conducting a virtual survey in a group of forty participants made up of civil engineers, geological engineers and mining engineers from Peru, Spain and Chile, who were provided with a sheet with a photograph of the rock mass along with its basic description, it was observed that the GSI values obtained conform to a normal distribution characterized by a mean value and a standard deviation, which in some cases may have moderate to high coefficients of variation (COV). 

Subsequently, the dispersion of the GSI values obtained with the quantitative formulations has been evaluated, and the results have been incorporated into regional databases in order to evaluate trends, mainly of the GSI-RMR' relationships. The results of the study indicate that the average GSI values obtained with both approaches are similar, however, with the quantitative methodologies, COV values classified as low to moderate were obtained, which is in better agreement with the suggested COV values for GSI. Nevertheless, quantitative methodologies should be used with caution, taking into account the characteristics of the rock masses on which the relationships have been defined.