KARKIZANO RAILWAY TUNNEL REHABILITATION
DETAILED DESIGN PROJECT DEVELOPMENT FOR THE REHABILITATION AND REINFORCEMENT OF THE KARKIZANO TUNNEL IN ELGOIBAR, ON THE BILBAO-DONOSTIA LINE OF ETS.
Tunnel reinforcement and repair of all existing pathologies
Area of activity
Railways, subway and LRT
ETS – Euskal Trenbide Sarea
- Detailed design project development
The Euskal Trenbide Sarea (ETS) railway network has a total length of about 200 km along the territories of Bizkaia and Gipuzkoa, of which about a quarter run in tunnels. In the updating works of the “Inventory of ETS tunnels”, it was detected that the Karkizano tunnel presented a series of pathologies that show an important deterioration of the lining and/or a thrust of the ground of its backside, as well as deficiencies in its drainage.
The Karkizano tunnel is located in the municipality of Elgoibar, between KP 56+064 and 56+457 (393 m) of the Bilbao-Donostia line. It has a single track on ballast, concrete coating and drainage in concrete ditch. It runs in a curve under the A-8 freeway with a maximum cover of about 30 meters.
At various points along the entire length of the tunnel, alterations can be observed in the concrete lining, such as cracks, spalling, fissures and deformations. This clearly shows a loss of functionality of the lining. On the other hand, there are abundant points of water entry into the tunnel with seepage, drips, dampness between concreting points and cold joints. In some cases, there is precipitation of efflorescence and oxidation.
The most critical area is in the false tunnel at the entrance mouth, which, with a length of about 50 m and without being completely covered with earth, is very deteriorated. It presents numerous longitudinal and transversal cracks of great continuity and variable opening (some reaching 15 mm), belly cracks and deformations, having even lost the verticality of the gables in some sections.
The purpose of this contract is to draw up a construction project defining the actions to be carried out for the rehabilitation or reinforcement of the Karkizano tunnel, correcting all the existing pathologies. Thus, work has been carried out along its entire length, reviewing in detail and updating the mapping of existing pathologies, identifying all the areas with problems in the lining and drainage, with special attention to the false tunnel at the entrance, where the action is a priori of greater scope.