couche drainante de consolidation

OBS: couche drainante : Couche constituée de matériau perméable mise en place derrière un ouvrage (mur enterré, soutènement) ou sous un ouvrage (radier, dallage, route, barrage) pour faciliter l'écoulement de l'eau du sol et éviter en particulier sa mise en pression. Synonyme : tapis drainant, matelas drainant.
OBS: consolidation : Réduction progressive de volume d'un sol résultant d'une augmentation de la contrainte de compression.

CONT: The need for a consolidation drainage blanket decreases rapidly with time because the rate of consolidation settlement decreases rapidly ... In a saturated soil with one-way drainage towards the ground surface, the volume of water expelled is equal to the volume of soil consolidation. [If, for example, it took 848 days to reach 90% consolidation, equal to 900 mm, on a particular site.] The design of consolidation drainage blankets is based on calculating the average consolidation drainage during 1/848 of the time for 90% consolidation, i.e. during the period when the first 3.8% of consolidation occurs.
OBS: consolidation: The process whereby the application of pressure on a soil layer over a period of time causes a reduction in its volume by expelling fluid from the pores and by packing the soil grains closer together. The amount and rate of consolidation are important factors in the computation of settlement of structures and thus their foundation design.
OBS: See record ""drainage blanket"".