Project Description
The future hangars in which Airbus will put the finishing touches to its A380 will be built opposite the Hamburg port, by filling a part of the Elbe bay. This work is an extension of the current Airbus plant in this German town. The initial works, a 305 M€ contract won by the association between Moebius and DGI-Menard, consist in the draining of a marshy land of 170 hectares. The soil is very heterogeneous and consists in multiple layers of peat and clay, deposits of the Elbe. Altogether, between 8 and 14 m of poor soils have to be consolidated and the final settlement predicted is between 2 and 4 m.
DGI-Menard is the contractor of one third of the contract in terms of turnover and carries out the technical management of the works. To obtain a ground suitable for development, DGI-Menard will use its patented technology, the Menard Vacuum, which consists in imposing the atmospheric pressure on the soil. The Vacuum can treat 2 to 3 hectare areas. The procedure consists of installing vertical and horizontal vacuum transmission pipes under an airtight impervious membrane and evacuating the air below the membrane.
The resulting vacuum of approximately 0,8 bar is the equivalent of a 4 meter high fill surcharge. The effect of the vacuum is constant on the entire height of the drains and so eliminates the soil failure risk without soil creep.
As the settlement of the ground of the edge of the Elbe progresses, a sandy fill will be built. The final ground level has to be 6 m higher than the initial ground level. Thus, barges will dump 12.000.000 m3 of sand onto the area. The soil consolidation with the Vacuum technique will last between 4 and 6 months. The fulfilment of the works for the 170 hectares of the area is expected after 30 months of work.