Design methods for drainage of reinforced SOIL structures

Drainage is an essential feature in the design and construction of reinforced soil structures. Both cohesive marginal fills and granular fills with relatively high permeability may be subject to hydraulic conditions which may cause saturation either at the bottom, at the top, or behind the reinforced soil block, hence requiring the design of the drainage system. Various types of draining geocomposites and draining geogrids can be used as drainage medium, in addition to the traditional coarse granular soils. The different drainage conditions that can be encountered should be analysed and the design for each case should be carried out, including the selection of the suitable draining geosynthetics.