Present since 2003 in Turin, a city dear to Cipa for many reasons, we took part in building Italy’s first automatic underground, seeing to the construction of many shafts and adits. Even though the works we did do not enjoy the privilege of visibility and of being taken into consideration by ordinary riders, they were and remain to this day important to the success of the proposition of providing Turin with an underground. Some “service” adits and shafts had the sole purpose of permitting access by the machinery used for injections and consolidations to safeguard the stability of the constructions above, making the TBM’s subsequent transit safer. Once they served their purpose, the service shafts and adits were sealed. Of these, with the aid of small-sized equipment, we built the adits of shafts “B” and “C,” excavating and pre-lining an average cross-section of 13.5 m2, extending for about 45 metres into the adit of saft B, and for about 55 metres into the adit of shaft C. We also built the tunnel using the traditional excavation method, between the service shaft and the Principi D’Acaja station, affected at the time by working operations that prevented the TBM’s transit. The tunnel’s purpose was also to house the TBM’s backup, reassembled at the bottom of the service shaft to continue its work beyond the station. The average tunnel cross-section is 72.5 m2 for a length of about 40 metres, with advance by heading rounds and pre-support using forepoling, ribs, and shotcrete. The shafts also comprise those for ventilation and for access to the line, including the five ones numbered from “5” through “9,” with an excavation diameter of 6 metres and a depth of 11.5 metres each, built in underpinning. Another shaft, number “12,” has an excavation diameter of 6.5 metres and a depth of about 12 metres, made in underpinning and from which an adit 27 metres in length begins, while two shafts, 11 and 28 metres in length, leave shaft “D.” Special mention should be made of the branching of shafts and adits, called shaft “10.” From shaft “10,” about 40 metres deep, an adit at a depth of approximately 22 metres was built, with considerable complexity and variability of execution, with current excavation cross-sections, widening cross-sections, and cross-sections with forepoling in the final stretch in the curve, from which were constructed a shaft with a small portal facing the TBM’s tunnel, and two small opposite adits from which two more shafts were excavated; these are connected to the TBM tunnel. It need hardly be mentioned that in order to do this, we had to grapple with particular difficulties, given the work’s complexity and the highly reduced available areas for working and manoeuvring. We recently excavated four ventilation and access shafts named PL3, PL4, PL5 and PL6, with a diameter of 5.60 metres and depths varying between 14 and 19 metres, each with an access adit to the TBM tunnel, with a cross-section of 27 m2 and from 3.5 to 10 metres in length. In parallel with the building of the shafts, we also constructed three niches in the line tunnel, 2.5 metres deep, and with a cross-section of 23 m2.
Place: Italy - Turin
Period: August 2010 - December 2010
Status advancement work: 100%