Contractor joint venture (JV) ACE broke through on 7 September, a month ahead of schedule, on the $49M, 2.5km long northern extension to the Lisbon Metro Yellow Line in Portugal.
The JV, comprising Somague Engenharia/Bento Pedroso Construções/Engil Sociedade de Construção Civil/Spie Batignolles TP, used a 9.8m diameter Lovat EPBM to drive the single tube tunnel from Ameixoeira to Campo Grande, providing a link between the existing metro and the northern suburbs (T&TI, March 2000, p10).
The Lovat bored through a geology that varied from clay to limestone, requiring the machine to work in EPB mode through the soft and hard ground up to 20m below the water table.
The tunnel was lined to an i.d. of 8.8m using precast segments of 0.36m thick and 1.2m long. Each universal ring comprised six segments and a key with the segments manufactured by Spie Batignolles.
The completed tunnel will be fitted out as a two-carriageway system, in keeping with the Lisbon tunnel configuration.
The machine is owned by the client, Metropolitano De Lisboa, who had contracted Lovat to refurbish the TBM that was previously used to bore the metro’s connecting tunnel to the Lisbon 1998 Expo site. The contract was awarded to the JV in February 2000 with a 21-month completion schedule, and also included the construction of two ventilation shafts, the shaft for TBM extraction and installation of steel ring beams in the station areas.
