Cross passages between TBM tunnels: The experience in Spanish high-speed railway tunnels

This paper describes, by means of two practical examples, the different approaches employed to design and build cross passages between segmental lined tunnels for high speed railway lines in Spain. The increment of principal stresses at the cross passages leads to the need of an additional support system for the tunnel lining. The chosen solution for this support system depends mainly on the ground conditions, the tunnel overburden and contractor's local experience. The first example is related to the Pajares Tunnels bored in the San Emiliano formation and the second one collects the experiences of the Guadarrama tunnels bored in very hard gneiss and granite rocks. The aim of this paper is to establish some key aspects to be considered when choosing the cross passage design and the corresponding excavation process.