Introduction

The stability of slopes is a concern for both natural slopes and artificial embankments. Failures can result in major hazards.

Definition

The failure mechanisms of natural slopes can be categorized as follows:

  • Collapse

  • Planar, rotational, or complex sliding

  • Mudflows or clay flows

  • Creep

Artificial embankments are primarily affected by sliding and sometimes by creep. They can be classified based on the type of structure:

  • Cut or fill slopes

  • Retaining structures against deep-seated sliding

  • Earth dams and levees

Reminder

Any stability study must be preceded by a detailed geological and geotechnical investigation to identify factors favoring instability, such as:

  • Local heterogeneities

  • Favorable dip for sliding

  • Cracks

  • Water circulation

Since these factors are not always quantifiable, estimating the actual safety factor[1] against the risk of failure is challenging, regardless of the approach used.

However, extensive experience has been gained in both calculation methods and stabilization techniques, allowing slope stability problems to be resolved with reasonable reliability today.

This chapter highlights the mechanisms leading to the failure of certain slopes or embankments. The most common calculation methods for assessing slope and embankment stability are described using the concept of a global safety factor.

How Landslides Work