The Petra monumental site is located on the left rim of the Rift Valley in central-southern Jordan. The entire valley, which is tectonic in origin, rests on Late Cambrian quartzarenite rock formations of continental origin. Past research conducted by our team has allowed us to identify the following main causes of the weathering processes: thermal expansion and shrinkage of rocks caused by the great differences in day and night temperatures contribute to the loosening of quartz grains and lead to rock disruption. Heavy rainfall and above all surface runoff contribute signi?cantly to the removal of weathered materials from the surface. Other forms of decay are caused by the presence of salts along the fractures. Both ?eldwork and laboratory analyses performed in the past in a climate chamber have demonstrated that the products usually used in conventional restoration work are not very effective, due to the "extreme" climate and the chemical and physical characteristics of the rocks. This risk had been hypothesized by the Nabataean builders of these monuments, who succeeded in mitigating its effects by setting up an ef?cient network of drains and rainwater collection cisterns upslope from the monumental structures. Moreover, these complex hydraulic engineering projects also ensured an adequate water supply for the local population. Today, this drainage system is no longer operational, as it has been blocked by both the accumulation of debris and collapses caused by landslides and earthquakes. The project proposes the realization of a GIS aimed at acquiring complete knowledge of the man-made structures and hydraulic system underlyng the routes of the canalizations and identifying the cisterns. This work is meant to contribute a valid support aimed at the restoration, which will involve several different disciplines, including the geological and chemical analysis of the rocks, the topography and the 3D photogrammetry.
Antica rete idrologica di Petra. Studio e restauro nell'ottica della conservazione dei beni architettonici
Gabrielli R;Angelini A;
2008
Abstract
The Petra monumental site is located on the left rim of the Rift Valley in central-southern Jordan. The entire valley, which is tectonic in origin, rests on Late Cambrian quartzarenite rock formations of continental origin. Past research conducted by our team has allowed us to identify the following main causes of the weathering processes: thermal expansion and shrinkage of rocks caused by the great differences in day and night temperatures contribute to the loosening of quartz grains and lead to rock disruption. Heavy rainfall and above all surface runoff contribute signi?cantly to the removal of weathered materials from the surface. Other forms of decay are caused by the presence of salts along the fractures. Both ?eldwork and laboratory analyses performed in the past in a climate chamber have demonstrated that the products usually used in conventional restoration work are not very effective, due to the "extreme" climate and the chemical and physical characteristics of the rocks. This risk had been hypothesized by the Nabataean builders of these monuments, who succeeded in mitigating its effects by setting up an ef?cient network of drains and rainwater collection cisterns upslope from the monumental structures. Moreover, these complex hydraulic engineering projects also ensured an adequate water supply for the local population. Today, this drainage system is no longer operational, as it has been blocked by both the accumulation of debris and collapses caused by landslides and earthquakes. The project proposes the realization of a GIS aimed at acquiring complete knowledge of the man-made structures and hydraulic system underlyng the routes of the canalizations and identifying the cisterns. This work is meant to contribute a valid support aimed at the restoration, which will involve several different disciplines, including the geological and chemical analysis of the rocks, the topography and the 3D photogrammetry.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
