Aproximación al comportamiento geotécnico de las Ignimbritas ash and pumice a partir de análisis químico-mineralógicos

Abstract

Geological factors controlling the engineering proprieties of the Miocene (ca. 8,3 Ma) ash and pumice phonolitic ignimbrites in Gran Canaria island have been analysed. Emphasis has been paced on the influence of chemical and mineralogical changes on the strength and deformation proprieties. Optical microscopy, X-ray diffraction and X-ray fluorescence techniques have been used for characterization of the geochemistry and mineralogy of these pyroclastic flow deposits. Several physical and mechanical tests (classification tests, uniaxial compression, etc.) have been carried out to determinate the geotechnical behaviour. The alteration degree of vitreous phase is the most important factor of explaining the decrease of quality in the geotechnical properties of these soft rocks.