NEWSROOM

Après 835 m de creusement à travers des marnes et caillasses, les travaux du microtunnel AVN 1800 « Magali » sont désormais achevés. Ce tir courbe est le plus long de la série sur le projet CanaMarne, pour la construction d’un collecteur gravitaire des eaux sur 9 km (dont 3km en microtunnelage) et qui permettra de transférer les eaux pluviales de la plateforme aéroportuaire de Paris-Charles de Gaulle vers une station d’épuration avant leur rejet dans la Marne.

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.

Great to have supported SADE and SCAM TP during works at Montpellier university hospital recently for both a 174m long AVN 2000 microtunnel, as well as 5 open trench sections ranging from 35m to 135m in length. OPTIMUM accompanied the engineering teams for all the underground works (trenchless as well as the conventional trench sections), enabling SADE to access a OPTIMUM’s specialist geotechnical tools and expertise for the entire project.

Great to have accompanied SUBTERRA during the successful completion of a complex double DN1400 microtunnel in Portet-sur-Garonne, southwestern France, linking local water treatment facilities. Site conditions, in a dense urban environment, required both tunnels to begin from one central entry pit, tunnelling first west (for 101 metres) then east (for 172 metres) under the busy RD120.

Immensely proud to have accompanied BESSAC and SADE during the now completed 610-metre-long, up to 30-metre-deep, AVN2500 microtunnel crossing under the River Seine in the centre of Paris.

Proud to accompany EIFFAGE yesterday during the successful completion of a 130m-long DN 800 PRV microtunnel in Massy, near Paris, as part of the sanitation network diversions being put in place by the Paris Saclay local authority. The entry / exit shafts were constructed using secant pile walls in a narrow road with limited access in a densely built-up urban area. The ground conditions and inherently congested underground environment made a specialist support mission all the more important.

Boring a 530 metre-long, 2.15 metre-wide microtunnel in one of the hardest and most abrasive rocks calls for the highest levels of vigilance. Add to that a 26-metre height difference between the entry and exit points as well as a crossing both a river and the busy Paris – Brest railway line.