The paper reviews different types of capping systems, incorporating geosynthetics, commonly used in Europe both for landfills and for contaminated sites. In particular, the relatively recent approach of using drainage geocomposites GCD (instead of granular soils) and geosynthetic clay liners GCL (instead of cohesive soils) will be presented, also with reference to a specific case history referred to a dismissed industrial site in Milano area.Moreover some results of experimental investigations on the geosynthetic clay liners GCL taken from capping systems after several years in service will be outlined, with specific attention to the hydraulic behaviour in terms of permeability tests and also to the mechanical behaviour in terms of tensile tests. Lastly, a section is presented with regards to the recent laboratory studies in order to validate the main engineering properties of some drainage geocomposite GCD to be used in such applications, with specific reference to the interface shear properties using the direct shear tests and the inclined plane tests and also to the variation of the drainage capacity properties, in function of the type of polymer and of the type of structure of the internal geonet used as core of the drainage geocomposite.
展开▼
