Quarry waste and slope instability: preliminary assessment of some controlling factors in the carrara marble basin (italy)

Abstract

The intense quarrying activities in the Carrara marble district (Apuan Alps, Italy) has led to the formation of widespread and thick quarry waste accumulations, which lie on steep slopes and invade many valley bottoms. In this area, rainstorms often cause floods, landslides, debris flows and deaths (e.g. on September 23, 2003).This research is aimed at determining the triggering conditions of the instability involving quarry waste. Firstly, the 23 September 2003 event was analysed in order to characterize its pluviometric features and effects. Then, three quarry dumps were selected upstream of Carrara and their evolution was studied. Subsequently, geomorphologic surveying distinguished areas with different characteristics (quarry activity, landslide areas, debris flow prone areas, land use, etc.). Furthermore, several grain size analyses were performed. Finally, in order to evaluate the hydrological behaviour of the quarry waste, the discharge of a spring at the toe of a quarry dump was examined and compared with the trend of a rainfall event.The research is still in progress, but these results may represent a first important step to identifying the main triggering factors of debris flows in quarry dumps.