Congratulated by CASQY, one of the project managers.
In the vicinity of Trappes, the RD10 departmental road, also known as the ‘Nationale 10’, is soon to ‘vanish’. It will be placed underground, a task involving considerable preparatory works, including the rerouting of water supply and wastewater networks, entrusted to the Normandy Regional Division by their respective project owners, SMG SEVESC and the Saint-Quentin-en-Yvelines Local Authority (CASQY).
An impressive task…but not for SADE!
Water supply network
Rerouting the water supply networks required the laying of 725m of 150mm-diameter cast-iron tubes using conventional techniques and 1,500m of 600mm-diameter using trenchless works to bypass a certain number of obstructions. Works thus consisted in 2 horizontal boreholes (50m and 36m), 1 horizontal 600mm-diameter pipe jacking (22m) and 2 directional boreholes (50m and 52m). Works also included 11 junctions. The project was completed in just 4 months with 4 teams and considerable material means.
Wastewater/stormwater
As with the water supply networks, the separate gravitational wastewater/stormwater systems were built using conventional techniques for the most part, at a great depth and along a 2mm to 5mm/metre incline. Specifically, 220m of Moduloval 165*100, 1,659m of 400mm to 1,200mm-diameter concrete tubes and 363m of 200mm to 400mm-diameter polypropylene tubes were laid. Two 53m pipe jackings enabled the laying of a 600mm-diameter cast-iron tube and a 1,200mm-diameter concrete pipe.
Important specificities
During works to the drainage networks, the SADE teams maintained flows via pumping, which made operations transparent for users. In compliance with the established protocol, the teams also had to dispose of elements containing asbestos which were located along the works pathway.
A particular risk
On this worksite, in addition to usual urban constraints such as heavy traffic and the presence of numerous utility networks, one risk in particular had to be managed; the potential presence of WW2 explosives buried in the ground. Pyrotechnical inspections were therefore carried out systematically prior to excavation operations.
Congratulations from the customer
After 3 years of works, a letter of congratulations was sent by the councillor for the Saint-Quentin-en-Yvelines water cycle, upon completion of the water network rerouting project.