behaviour of granitic saprolite

Abstract: Large parts of South Africa are covered by granitic rocks of different ages. Due to the present day climatic variation from wet conditions along the eastern coastline to arid conditions along the western coast, varying weathering products and depths to bedrock exist. Furthermore, the mineralogical differences between these granitic rocks also influence the engineering properties of the residual soils. A large volume of engineering geologic data exists on the properties of the weathered zone, especially in the central part of the country where geotechnical investigations for urban development are the main source of the data. The Council for Geoscience has also mapped large areas around growth nodes in the north-eastern parts of the country. The data are comprised mainly of detailed soil profile descriptions, land facet zonation and appropriate laboratory tests. The aim is to combine this existing data (all the available profile descriptions and foundation indicator test results) in order to correlate the geotechnical properties of sites underlain by granites. In particular, a relationship is sought between basic foundation indicator test results and the petrology of the granites. Through conducting these indicator tests in representative soil horizons, and through assessing the mineralogy of the rock, certain correlations can possibly be made with other properties of the saprolite. Finally, as a much cheaper alternative, foundation indicator testing will aid in saving both time and mone