Since 2000, Cipa has been executing civil works for the construction of high-speed railway lines, for which our company excavated shafts having different purposes, and executed various tunnel excavation works. Idice Viaduct As to the Idice viaduct located at the entrance to the Raticosa tunnel, on the Bologna side, we excavated six round structural shafts having a diameter of 11 metres, and with depths ranging from 9 to 24 metres. The excavation was carried out using buckets and rock breakers, pre-lining by steel ribs, and quick-hardening shotcrete. Two of the six shafts were excavated near the bed of Idice river at an extrados level of 380 metres a.s.l., i.e. 4.56 metres below the maximum flood level for a return period of 100 years, estimated at 384.56 metres a.s.l. The excavation of drainage trenches guaranteed a dry working environment. At the end of the excavation phase, the shafts were completely backfilled with concrete, apart from abutment SP2, the central core of which was made lighter by using round formwork with a diameter of 4 metres. Diaterna Viaduct Our company took part in the construction of this viaduct, located at the entrance of the Raticosa tunnel, on the Florence side, by excavating eight round structural drainage foundation shafts of a diameter of 7.40 metres and a depth of 22.50 metres for the consolidation of the left shore of Diaterna stream, and a structural shaft for the viaduct abutment, having the same diameter and depth of 11 metres. The excavation works were carried out using not only buckets and rock breakers, but explosives as well. The pre-lining was made of steel ribs, welded wire mesh and quick-hardening shotcrete. At the end of the excavation phase, the shafts were backfilled by reinforced concrete, while preserving, within the drainage shafts, a hollow volume of a diameter of 2 metres and a depth of 11 metres. Raticosa Tunnel For the construction of this tunnel, our company carried out unprecedented work: the excavation, from within the tunnel, of six structural shafts aimed at making the tunnel crown integral with the surrounding rock and connected to the invert in order to prevent tunnel bore deformation due to the considerable load exerted by the Diaterna slope because of its long-lasting instability. Such deformations occurred several times, affecting the works of the various companies involved from time to time. We can proudly state that the successful outcome of our works allowed the excavation of the remaining section of the tunnel – which had been at a standstill since the works on the Diaterna slope side began in 1998 – to be continued, and the last 100 metres of tunnel still to be excavated throughout the entire railway section from Florence to Bologna to be finally completed. The six shafts of a diameter of 6.50 metres, two of which 8.28 metres deep and the other four of 12.18 metres deep, were excavated using buckets, rock breakers and explosives, and pre-lined with steel ribs, welded wire mesh and quick-hardening shotcrete. At the end of the excavation phase, the shafts were reinforced and backfilled with concrete. In addition to the shafts, our company executed the invert and the elements in concrete for 155 metres of the tunnel length, and saw to the final lining in reinforced concrete of the underground structure intended for train shunting, for a length of 12 metres and a cross-section of 34 m2, and the recesses housing the technological systems. Osteto tunnel access (Branch of Firenzuola tunnel) Final lining in reinforced concrete for approximately 700 metres of the tunnel length. Execution of the recesses housing the technological systems. Castelvecchio tunnel access (Branch of Raticosa tunnel) Final lining in reinforced concrete for approximately 1,135 metres of the tunnel length. Execution of the recesses housing the technological systems. Backfilling of the two box-shaped structures intended for train shunting. Rovigo tunnel access (Branch of Firenzuola tunnel) Final lining in reinforced concrete for approximately 510 metres of tunnel length. Execution of the recesses housing the technological systems. Emilia 2 tunnel access (Branch of Pianoro tunnel) Final lining in reinforced concrete for approximately 279 metres of the tunnel length. Widening the tunnel cross-section for connection with the main tunnel. Pianoro Tunnel Final lining of the by-passes providing a link with odd- and even-numbered tracks. Geological investigation and service tunnel (Sesto Fiorentino) Restoration of lining for a length of approximately 540 metres. Construction of crowns and North tunnel portal for a length of approximately 25 metres. San Ruffillo (Bologna) Interconnection As to the San Ruffillo interconnection, we excavated the polycentric tunnel, having an average cross-section area of 130 m2 and length of approximately 115 metres, tunnel-face excavation progressing by truncated-cone-shaped sections of a length of 6 metres, with soil pre-consolidation by jet-grouting along the tunnel contour and the excavation face, forepoling, ribs, welded wire mesh and shotcrete. The waterproofing was executed by TNT+PVC layers and, after reinforcement, the final lining was executed by concrete cast in-situ using formwork. Our company also excavated two ventilation shafts having a diameter of 5.6 metres and a depth of about 26 metres, including the cross-link tunnels to the main line. For the excavation of the shafts we adopted the underpinning method, with pre-consolidation by means of steel ribs, welded wire mesh and shotcrete. The waterproofing was executed by TNT+PVC layers. The cross-link tunnels were excavated by previous erection of steel structures for the purpose of reinforcing the areas of interconnection with the railway line tunnel, using small-size equipment and machinery; the pre-lining was executed by steel ribs, welded wire mesh and shotcrete. TNT+PVC layers were used for waterproofing. The tunnel was lastly lined with reinforced concrete.