Geotechnical engineering for the preservation of monuments and historical sites: The Itahan case

The outstanding patrimony of monuments, old cities and historical sites in Italy has undergone continuous transformation through millennia of construction, reconstruction, expoliation, restoration, underpinning and filling activity. The Italian physical territory is composed of soils and rocks ranging from clays – soft, heavily preconsolidated or highly tectonized – to marls, sandstones, limestones, tuffs and granites. On account of the peculiar geological history, complex soil-rock formations composed of intricate associations of units of very different mechanical properties, are frequent in many parts of Italy. Seismic activity is intense in large areas of the territory. For historical and defense reasons, particularly in the southern portion of the peninsula and in the islands, many old cities and important villages are sited on top of hills delimited by very steep slopes, where landslides are frequently activated or reactivated by seismic actions. Single monuments and monumental complexes are widely distributed over the territory; frequently these monuments have unsound foundations or are located in subsiding areas or on unstable slopes. The relationship between subsoil, monuments and corresponding actions gives rise to very complex geotechnical situations, requiring painstaking, yet fascinating, multidisciplinary comprehensive research for the proposition of reliable hypotheses and stabilizing measures. The present bibliographical review informs the international scientific community on the advancement of Geotechnical Engineering applied to monuments in Italy, where a well established geotechnical tradition and a broad fundamental cultural interest for the preservation of an immense architectural patrimony coexist.