Experience in Construction in Hard Rock with Roadheader in the Ariz -Basauri section of the Bilbao Metro

The object of the works to be performed is the extension of the Bilbao Metro network (Vizcaya, Basque Region, Spain). The Ariz-Basauri section of line 2 of the Bilbao Metro is being performed by the UTE Ariz-Basauri, a joint venture formed by the companies Exc. Cantábricas S.A., Vda. de Sainz S.A. and Obras Subterráneas S.A. The total length of the section is 2,372 m. of which 2,108 m. are performed in mine tunnel. The section will provide a service to the centre of Basauri with two stations, Ariz station commencing approximately at KP 1+050 and Basauri station at KP 2+105. Introduction of a new transport infrastructure such as a Metro system in an urban environment has an inevitable impact which must be quantified and, as far as possible, minimized. This impact on the urban environment includes a number of aspects, affecting networks and services, buildings, road traffic and rail traffic, not only influencing the line layout, but also and in particular the construction processes to be applied to ensure a minimum impact on both the existing infrastructure and the population. From the constructor’s viewpoint the shallow nature of the work at around 25 m should be highlighted as well as a work plan requiring 3 shifts and involving night work. The decision taken by ETS (Euskal Trenbide Sarea) not to use explosives due to the urban environment in which the Metro is developed is therefore comprehensible