The microtunnels are part of the three different underground crossings were performed. The first microtunnel was designed in order to cross the railway Puyoo-Dax, operated by the French company SNCF. SNCF required to carry out drilling operations working 24hours a day, 7 days a week, due to the need of minimizing possible settlements that may have occur at the railway track bed. A continuous monitoring system was deployed to identify and signal possible settlements.
The second microtunnel was designed to cross under the “Le Luy de France” river. The third microtunnel involved the underground crossing of the Les Gaves Réunis river.
For both works, casing pipes in reinforced concrete ID1200 have been employed, with a length of 180 m, 193 m, and 453 m, respectively.