Underground bypass of the Monaco railway line: outside structures
Features
The underground bypass of the NICE-VINTIMILLE railway line represented more than 5 years works, separated into 5 packagess including the station (A01), a 3 km tunnel (A02), an open air section with retaining walls (A03), the crossing of the Sainte Devote valley (A04) and the connection to the existing tunnel (A05).
A03 package:
Checking of the umbrella arch in the portal zone.
Stability calculations, for zones with temporary or permanent Monaco walls, including seismic properties.
West tunnel portal: built in screes, with 30 m umbrella arch, divided section excavation, and with jet-grouting under the base of steel arches and for the raft.
Retaining wall (95 m long, 14 m high) then cut-and-cover (30 m long, 20 m maximum height) excavated in a steep natural slope made of screes. This vertical wall is built using the "Monaco" method: permanent panels made of in reinforced concrete with active anchors.
A04 package:
Structure partially outside, located in the Sainte Dévote valley, with excavations over 35m height in Jurassic limestone and implementation of anchors.
Stability calculations using TALREN software developed by TERRASOL and considering plane failure surfaces (along fractures).
TERRASOL, together with SEEE and SDE engineering offices for the structures, performed the whole detailed design relating to geotechnical structures and soil-structure interaction:
