Engineering Geological Properties of the Volcanic Rocks and Soils of the Canary Islands

Abstract

This paper analyses the engineering geological properties of the rocks and soils of the Canary Islands based on data from field studies, laboratory tests and extensive databases for volcanic materials. Geological properties and processes most relevant to geo-engineering are described. Geomechanical characterization of rock masses and soil deposits including rock mass classification, index and strength properties are presented. Some of the most relevant results show materials of low to very low density and low to very low values of strength and expansiveness. These materials, with an exceptional high anisotropy and irregular spatial distribution, are intensely affected by jointing of thermal origin and large discontinuities due to dykes; cavities and tubes can be also present. Landsliding and slope instability, collapse phenomena and other processes causing geotechnical problems are described. Discussion on the geomechanical properties and conditions that may help to identify and differentiate the geotechnical behaviour of the volcanic materials is included.