habitat rupestre.pdf - Società Friulana di Archeologia

S. Del Prete, M. Parisebution after the excavation, to tectonic vicissitude that involvedthe formation and to tensional releases in correspondence ofsub-vertical cliffs. (Fig. 19).The discontinuities in a rock mass work as sites of stress concentrationand activate a progressive long term reduction of thematerial resistance (Hall et al., 2004).The knowledge of the effective stability conditions of a cavity(for instance, the study of the fissured vaults) and of possiblecauses of collapse is necessary for a correct evaluation of therisks in subterranean failures (Hall et al., 2004). The study onstability conditions is indispensable to set the priorities to planconsolidating works, while the study of the possible causes ofcollapse help to choose the most suitable techniques for themonitoring of the failures.ConclusionsThe influences of geological and geomorphological featureson the realization of subterranean works are a complex andwide topic. Generally, the roles of the various factors can beexamined singularly, but they overlap and act together in combinationsthat depend also on environmental factors (geographyand climate) and on time.For instance, mechanical erosion of running waters and thermalfractures contribute to the remodelling of the section in adraining gallery. Techniques of subterranean excavation areconditioned by geomechanical and/or hydrogeological aspects,which affect times and future usability of the works.Underground water influences the realization and the use ofa subterranean structure. A settlement or a warehouse can beused only if they were realized in well draining rocks, whichgrant for suitable humidity levels. An economical interestcan suggest the drainage of a great quantity of water in mineworks or in the construction of an important road.The overlapping endogenous (resurfacing of fluids at hightemperatures) and structural (such as draining or filled tectonicstructures) factors can complicate the realization of undergroundworks, with repercussions on times of realizationand costs.It is generally evident that the study of geological aspects suppliesfor important indications about the socio-economic aspectsthat brought populations and cultures to realize and usesubterranean structures.AcknowledgmentThe authors wish to thank Roberto Bixio for his critical review,the ideas and the constructive confrontation during thewriting up of this text, and for the wide variety of providedimages. They also wish to thank Prof. Maifredi from the Universityof Genova and all of the authors of the pictures, forsharing their repertoire.Fig. 16 Madonna della Scala (Massafra, Taranto): the rock failures on theright cliff of the ravine has damaged the caves (photo: M. Parise).Fig. 17 Internal view of a trachyte mine (Del Prete, 2004) at the foot ofCamaldoli hill (Napoli): huge rocks detached from the vault and from thepillars (photo: S. Del Prete). The pillars are evidently compressed by thestatic solicitations of the loads.Fig. 18 Examples of underground cavities which have generated sinkholephenomena (Cutrofi ano, top, and Lusciano, bottom) causing, sometimes, seriousdamage to the overlying rural and urban settings (Cutrofi ano photos:M. Parise; Lusciano photos: B. Bocchino, S. Del Prete).* Excerpt from Opera Ipogea, n° 2/2007, journal of the CommissioneNazionale Cavità Artificiali della Società SpeleologicaItaliana - Bologna25volumeRicerca_OK_2012-11-15.indd 25 16/11/2012 15:00:48