Consolidation Works - Marche-Umbria road axis and Quadrilatero

As part of the completion works of the Perugia Ancona - Maxilotto 2: Marche-Umbria road axis and Quadrilatero of internal penetration - the detailed and executive design was carried out for the SS.318 section «Pianello-Valfabbrica» ​(sub-lot 1.2) and for the SS.76 «Val d'Esino» in the sections «Fossato di Vico-Cancelli» (sub-lot 1.1A) and «Albacina-Serra San Quirico» (sub-lot 1.1B). Among the works carried out, numerous sustain structures were carried out, consolidation of the excavation fronts and escarpments, as well as works of arrangement and hydraulic protection.

The main design problems were encountered in carrying out the re-profiling and consolidation work on the slope upstream of the Cancelli interchange. The conditions of the excavation walls showed very fractured and broken material often subject to local cortical detachments. In this regard, a gabion wall of 78m in length was built at the foot of the escarpment. The work is to be considered as a gravity wall made up of box-shaped elements made of double-twist metal mesh with hexagonal mesh type 8x10. In order to strengthen the structure, all the edges are reinforced with a wire having a diameter greater than that used for the mesh. The excavation slope on the back of the gabions have an inclination of 45°, and at their foot there is a drainage consisting of a Φ400mm concrete pipe covered with draining material protected by a geotextile. The slope upstream of the support work has been re-profiled with a 30° slope. In order to avoid cortical detachments and the possible consequent fall of material on the roadway, the slope has been protected by means of a hexagonal mesh geo-composite and wire rope. At the top of the gabion there is a prefabricated channel for the interception and removal of surface water.