Customer Stories

Part of the Grand Paris initiative, the Grand Paris Express will enlarge the capacity of the regional and metropolitan rail of Paris by 200 kilometers (124 miles). With a projected cost in the tens of billions, 90 percent of these new and upgraded lines are being constructed underground. The ambitious timeline and cost-containment goals for the project has put pressure on contractors to implement new technologies and automate as many functions as possible. overview Location PARIS, FRANCE TRANSFORMING THE WAY THE WORLD WORKS TRANSFORMING THE WAY THE WORLD WORKS Partnering on multiple tunnel sections of this ambitious project, prominent European construction firms Eiffage GÉNIE CIVIL and Razel Bec paired robotic total stations with advanced software to automate their tunnel surveys. The firms are constructing several tunnel sections, like the L14 South line, using tunnel-boring machines (TBM). This work requires as-built surveys by total station and scanner on the access trench and associated facilities used by the TBM. In addition, the surveyors must measure each tunnel ring – the segmented concrete assemblies that line and support the tunnel walls. As-built surveys serve multiple purposes. They check fidelity of the bored and lined tunnel rings to the design plan, providing construction crews with timely and precise measurements for the finishing phase. The surveys also provide feedback to the TBM operators on how well they are controlling the machine to conform to the design. With precise measurements, adjustments can be made to improve quality as the TBM progresses along the route. Eiffage GÉNIE CIVIL and Razel-Bec needed to automate surveying processes as much as possible if they hoped to keep up with the tight schedule. RAPID ADOPTION OF A NEW SOLUTION Eiffage GÉNIE CIVIL's Olivier Gauche is a survey engineer with 30 years of experience. He is using the Tunnels Module for Trimble Access software, which includes a solution specifically designed for automatically measuring and analyzing arrays of points on the inside of the tunnel rings. The Trimble Access software controls the total station to profile the tunnel rings at specified intervals. For example, it can shoot 20 to 30 profiles at one-meter stations along the tunnel alignment, and every 20cm around the ring — all this at a rate of 10 to 15 points per second. Gauche confirms the integrity and proper placement of the arched tunnel lining by using underbreak and overbreak analysis routines in Trimble Access. The software compares

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