Geotechnical aspects in the preservation of the historical town of Orvieto

In this paper the importance of geotechnics in ithe preservation nf Orvieto is illustrated. The mechanism governing the evolution of the tuffaceous slab and of the underlying clay which form the Orvieto butte are illustrated. The results are based on a quantitative analysis of the stability evolution resulting from laboratory and in situ investigations calibrated on a geotechnical reading og historical sources. In the lighti of this mechanism of evolution. the preservation criteria adopted from the past century up to the undergoing stabilization program are re-examined and appraised.