Landfill capping

The major problem during the design and construction of a permanent landfill covering system (capping) is to maintain an adequate thickness of topsoil on the impermeable slopes in order to permit vegetation growth.

The angle of friction at the interface between the impermeable liner and the soil mass usually has a very low value, inadequate for the prevention of soil sliding, even on shallow slopes.

Studies must be carried out to guarantee the drainage of any water that, by running between the membrane and soil mass, can reduce to zero the soil/membranes’ coefficient of friction. If such a situation developed, the soil mass overlying the impermeable membrane would be subject to slippage.

The soil spread onto the landfill slopes is subject to forces that tend to cause slippage towards the base, and to other forces that favor stability. If these forces are not equalized with an acceptable safety factor, then it is necessary to use a suitable geosynthetic material capable of conferring to the topsoil those properties required for guaranteeing stability.

TENAX MULTIMAT R reinforced geomats or TENAX TENWEB geocells, by means of their high frictional three-dimensional structure, allow for the retention of a thick layer of topsoil even on steep slopes.

Placed directly above the impermeable membrane (or if required, above a filtering-draining TENAX TNT geocomposite), they are secured in place either in an anchor trench at the crest of the slope or secured to a permanent structure using suitable fixing pins. Once installed, topsoil can be placed, compacted and if required seeded.

Products

TENAX TENWEB geocells

TENAX MULTIMAT R geomats