The highway Skhour Rhamna-Marrakech (84km), located in an arid area, witha hot and dry climate, is mostly embanked and required about 4 Mm3 of local materials of loan. The materials issued from excavation or borrow pits are in a very dry state (1 to 2% water content) and their percentage of thins (gravel with diameter < 2 mm) becomes very high after extraction, which does not allow their use in embankments, according to current technical norms and guides. The humidification or the search for "skeletal" materials was technically necessary. The rare ground waters had to be saved for the local population, and the impact on the landscape was to be minimized (limitation of depots and borrow pits). The remote transportation of 1,5 Mm3of water was economically unjustified. The protection of the environment,as well as the absence of any adaptable reference, led to the construction of 10 Mm3 of embankments in unseen technical conditions : thins placed in the core, and protected with lateral layers composed of skeletal elements (providing stability and protection against erosion) ; and minimization of water infiltrations in the embankment with a water-tight central reservation. The minimization of the environmental impacts seems to be achieved,and the construction costs and deadlines respected. For the covering abstract see ITRD E139491.
Samenvatting