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Slope stability

Stability concerns occur during and after landfill operation. Landfills can fail in several ways during cell excavation, during liner system construction, during waste filling, and after landfill closure

Several huge failures along liner slopes, trough landfill foundations and within the waste mass itself have occurred.

Two main types of failure can be distinguished: the rotational and the translational failure.

  • An example of translational failure is the failure of the capping through the liner system    Showcase
  • An example of rotational failure is the massive displacement of waste from a slope   Showcase


The criterion to differentiate the 2 failure modes is based on the ratio of the failed mass thickness to the failed length:

  • Rotational: ratio of the thickness of the failed mass to the failure length is in between 0.15-0.33
  • Translational: ratio of the thickness of the failed mass to the failure length is much less than 0.1


Along lined slopes, two main recurring stability concerns can be identified:

  • The leachate collection layer deposited on the base liner before waste is hauled in,
  • The final covering or capping system on top of the waste.

While instability of these relatively thin layers can be classified as failures, their impact is usually localized and repairs can sometimes be made at a reasonable cost. They are referred to as veneer failures. In contrast, foundation failures beneath the waste and failures of the waste mass itself are generally severe.

Read more on types of landfill failures