ABSTRACT
The field test developed in the summer of 1993 at the Michelshöhe landfill site was intended to give information on the working and practicability of the sealing method chosen, which included GCLs. The field test site dimensions were 12 m wide × 20 m long. In order to record the actual site conditions, the slope inclination was 1 : 10 for the first 10 m, and then increased to a steeper 1 : 3 in the remaining section of 10 m. The construction of the capping sytem envisages a regulating course, with grain size 0/32, on the existing body of waste. An overlying geocomposite has been stipulated for gas drainage. Above this is the GCL, which itself is covered by a geocomposite to carry away precipitation. In order that the precipitation may have practically unimpaired access to the liner, a water-permeable gravel layer with a thickness of 30 cm was installed above the stitch-bonded GCL, instead of a cover soil layer of cohesive soil.
Cap seal systems for landfills have to meet the following requirements:
shear stability on slopes
low permeability at all times
tensile strength of overlaps
These requirements were evaluated both in the laboratory and at the field test site. The result of the investigation is the subject of this paper.
