Weathering of ordovician slates in the Salamanca urban area: geotcchnical implications

This paper deals with the geotechnical properties of the ordovician weathered slates outcropping in the urban area of Salamanca. Due to the mesozoic weathering, the originated profile imported characteristics of residual soils to the slates in some locations. This process has important effects on the geomechanical behaviour of these materials. The slates have been tested in moisture content, granulometric analysis, liquid and plastic limit, apparent density, Proctor, permeability, compression strength and California Bearing Ratio (C.B.R.). The weathered slates are low permeability silty or clay soils with low plasticity (ML-CL); they are composed of kaolinite, illite, quartz and feldspar. According to the requirements of the Pliego de Prescripciones Técnicas Generales para obras de Carreteras y Puentes (PC-3), this kind of slates are appropriate soil