Léon-Asturias High Speed Rail, Pajares LOT 2

Administrador de Infraestructuras Ferroviarias ADIF
Dragados S.A.
$250 million USD
May 2006 — June 2016
Services performed
Construction inspection and scheduling for initial and final liner and waterproofing; analysing monitoring data and project's progress; daily site inspection and ground conditions reports.
The Pajares Rail Tunnel is part of the new Leon-Asturias High Speed Rail Line, and with a length of 25.7km one of the longest tunnels in the world. The project encompasses twin 10m dia. TBM hard rock tunnels, bifurcation chambers, cross passages, and emergency stops. The tunnel is lined with a pre-cast segmental lining made from high-strength with a thickness from 50 to 60cm. The connection between the access tunnel and the main tunnel requires the construction of a large-span Bifurcation Chamber and a short mined tunnel.
The predominant rock formation is the Lancara Formation consisting of dolomite, red limestone and gray limestone. The design groundwater head is 434 m.
León - Asturias, Spain


  • Final design of large bifurcation cavern
  • Use of canopy pipe umbrellas
  • Engineering support services during construction
Numerical Analysis of Bifurcation Chamber

Numerical Analysis of Bifurcation Chamber

Completed Bifurcation Cavern

Completed Bifurcation Cavern