Client / Owner
Office federal des routes - OFROU-F1
2013 - 2018
The Ligerz tunnel was commissioned in 1991. Consisting of a single bi-directional tube, it is no longer meeting the current security requirements. The main security default is the absence of fire exits.
The project for securing the Lugerz tunnel include:
- construction of a security gallery, parallel to the main tunnel, with connection every 300 m.
- construction of 4 new technical rooms underground.
- construction of an underground central technical office new the western portal.
- good quality limestones and marls (Cretaceous & Malm)
- important risk of karstic water inflows up to 1500 l/s.
Excavation on the western portal
- earthworks of 20'000 m³, mainly in rock;
- proximity of the tunnel, under operation, with geomonitoring;
- drilling of a water discharge (micro boring machine, under the N5 highway and railways (D 1100 mm / L 45 m).
- lengths: 2170 m;
- excavation with hard rock boring machine, diameter 4.75 m.
Connection / underground technical rooms
- 9 connections from the main tunnel to the security gallery (longueur 18 m à 40 m);
- 4 technical rooms;
- excavation with rock splitter and explosives;
- final connections to the main tunnel only during night closures of the tunnel.
Central technical office on the western portal
- underground centre (6000 m³ on 2 floors).
- Detailed design
- Construction design
- Works supervision