Wirth TBM goes to Spain this summer

After the success of its machine on the Guadarrama project (T&TI, June, p10), TBM manufacturer Wirth hopes to have a repeat Spanish success with its 6.19m diameter machine on the Canal de Navarra water project.

T&TI was told that the telescopic shield machine has just been assembled and was being run for commissioning purposes. Construction of the 4km Tunnel de Campanas was due to be started by the TBM, christened "Fast Florentina", at the beginning of August as T&TI went to press said a source from Wirth.

The Spanish government agency Canal de Navarra S.A. is responsible for progressing the scheme, a 177km long canal network. The canals will carry water from the Itoiz dam and artificial lake to irrigate 57,000 hectares of land in central and southern Navarra that traditionally suffers from water shortage problems. In an impressive utilisation of this water resource, the provincial capital, Pamplona will also have its potable water requirements fulfilled, plus a hydroelectric power station is planned for the future, rated at 53MWh. The mountainous topology dictated the choice of a tunnel to connect Pamplona with the artificial lake.

Contractor for the scheme is UTE Canal de Navarra, which is made up of SACYR, COPISA Constructora Pirenáica and ARIAN construction groups. It will drive the 6.19m diameter tunnel for a length of 4,021m installing a 395mm thick lining through geology that is characterised as clay and sandstone with a strength of 40-60MPa. The middle section of the alignment passes through the "conglomerado del Perdón" that T&TI's source said had a substantially higher strength of up to 120MPa. Notwithstanding this, the construction is due to be completed by spring next year.

With the scheme financed mainly by the European Union and the Spanish government, the TBM supply contract is worth Eur7.64M (US$9.33M) with a scheduled delivery date that was "very challenging". In order to meet the time constraints, Wirth opted not to disassemble the entire shield for transport and designed a compact transportation device for the backup gantry.