CONSTRUCTION OF THE OA7 BRIDGE cut-and-cover tunnel

No.7 bridge will allow light vehicles (LVs) and coaches to leave the Port before entering the central lane of the Ring Road. On the other hand, heavy goods vehicles (HGVs) will take a more traditional insertion way.

The specificity of OA7  which some would call a tunnel, is that it is a “cut-and-cover tunnel”. Its foundation piles were built over several months after the diversion was implemented in September 2018. Once the crowning civil engineering was completed, the slabs made, the struts installed, the inner space of the cut-and-cover tunnel was cleared, thus freeing up the access to the ring road. This structure excavation was carried out “as an underground mole work” using a tracked front loader to evacuate the volume and a crawler excavator that lifted off the agglomerated sand on the piles. Waterproofing and surface network works are still to be carried out to finalize a structure that will be of great importance for the fluidity and safety of road flows of the future port.

 

Passengers crossing the Channel travelling by car will use a dedicated lane from the boat disembarkation to the ring road. Once the tunnel is crossed, the progressive access to the insertion route will be done in the open air and the separate flow circuit will then be safe and fast.