An important step on Tuesday alongside SADE, RAZEL-BEC and BESSAC for the latest in a series of initiatives in the Paris area, contributing towards making the River Seine swimmable again.
Lifting out the cutting wheel marked the completion of the first phase of microtunnel construction for a stormwater collector south of the capital, in Vigneux-sur-Seine ; an AVN2500 tunnelled 981 metres under the banks of the river through limestone marl, 17 metres underground, now the longest microtunnel in France.
Accompanying the works contractors directly with a G3 mission, OPTIMUM engineers conducted geotechnical investigations and analysis ahead of time and also provided onsite support throughout the 6-month tunnelling operations. Close monitoring of tunnelling parameters, drilling fluids, cutting face pressure and tunnel frictions ensured that construction of the gravity-flow tunnel ran smoothly.
Phase two of the project will start from the same central entry pit, this time passing under the riverbank and following the course of the Seine, before exiting in urban Athis-Mons.
Project owner : SIAAP, the greater Paris Sanitation Authority
Construction contractors : SADE, RAZEL-BEC, BESSAC
