Nice tramway | France

Delicate geology

The Metropolis of Nice Côte d’Azur, as project owner, awarded the Thaumasia consortium (Bouygues, Soletanche Bachy, CSM Bessac, Systra, Colas Midi-Méditerranée, SNAF Routes and Garelli) the contract for the 3.2km urban tunnel with four underground stations to be built as part of line T2 of the Nice tramway.

Sixense were responsible for monitoring at the site, carried out in delicate subsoil and requiring monitoring of buildings’ stability in the areas through which the line passes.

Varied instrumentation

The instrumentation solution included a wide variety of devices, including ten Cyclops located around the stations or along the route for monitoring the tunnel boring machine, inclinometers, strut strain gauges, vibration sensors, piezometers and segment stress gauges controlled by Micron acquisition units, as well as manual levelling.

A Sixense team was on site permanently, to install and manage the monitoring system during construction of the stations and operation of the tunnel boring machine. Geoscope software was made available to the main contractors, project owner and project manager.

The project’s end date of late 2017-early 2018 allowed the line to be opened between 2018 and 2019.