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Vedeggio-Cassarate Tunnel

As part of a new traffic concept for the Lugano region in future a new road tunnel is to be built with directional traffic as part of the northern bypass for the city. A safety tunnel runs parallel to the road tunnel, which serves as an evacuation tunnel and as an access for emergency services. This safety tunnel was driven by means of a tunnel boring machine (TBM) by a JV spearheaded by the Hochtief Construction AG. The bore diameter amounted to 4.53 m. For reasons of space first of all a 60 m long advance tunnel was produced by the NATM on the site installation yard at the Vedeggio portal. In the process the Gotthard railway route, the main north-south link, was undertunnelled with 14 m overburden. The mechanised tunnel drive initially took place on the rise over 1,200 m (1.6 %) and t hen on the dip (1.0 %) in the direction of Cassarate. The shield drive wound up as scheduled in the quaternary soft ground at the Cassarate portal. The TBM was then dismantled underground and pulled back to the Vedeggio portal. The rock formations which have to be penetrated by and large comprise crystalline schist, gneisses and amphibolites as well as a soft ground zone with moraine material. The rock strength varies from 15 to 120 MPa. The maximum overburden amounts to 150 m. The tunnel was secured by shotcrete, anchors and support arches. A temporary road consisting of compacted excavated material was installed. The final support will be provided when the cross-passages to the main tunnel are driven in a subsequent contract section.

 

 

  • Country: Switzerland
  • Region: Tessino
  • Tunnel utilization: Traffic
  • Type of utilization: Safety Tunnel
  • Client: Canton of Tessino, Dipartimento del Territorio
  • Consulting Engineer: Deutsche Eisenbahn-Consulting GmbH
  • Construction monitoring: Deutsche Eisenbahn-Consulting GmbH
  • Contractor: Hochtief Construction AG/Muttoni S.A.
  • Main construction method: Trenchless
  • Type of excavation: Tunnel boring machine (TBM)/Drill-and-blast?
  • Lining: Shotcrete?
  • No. of tubes: 1?
  • Tunnel total length: 2,320 m (total), 60 m (NATM)
  • Cross-section: 4.53 m (excavation,TBM), 45 m² (NATM)
  • Contract Volume: approx. 11 mill. euros
  • Construction start/end: 2005 till 2007