Geosynthetics play an important role in the design of landfill sites. They contribute to environmental protection, structural stability and cost reduction. Raising the height of landfill cells places additional stresses on existing structures. This leads to additional deformation, promoting differential settlement and damage to waterproofing systems. The use of geosynthetic reinforcements can absorb these deformations and ensure the durability of the structure. In this article, we present two examples of ISD landfill riser projects using polyethylene terephthalate (PET) reinforcement geosynthetics. The first project concerns the raising of a landfill cell on its side in the Paris region, using a reinforcement geosynthetic. The height of the new waste is 23 m, with potential subsidence zones 1 m in diameter. The second project concerns the raising of a landfill in the north-west of France,
with a new waste height of around ten meters and potential subsidence zones of 1 to 1.5 m in diameter.