Terminology and Definitions

This subsection provides a list of terms that are used in the subsequent sections and their meaning, with the purpose of reducing ambiguity and making it easier to correctly understand the requirements.

  • Factor of safety: The global stability metric of a slip surface of a slope, defined as the ratio of resistive shear force to mobilized shear force.
  • Slip surface: A surface within a slope that has the potential to fail or displace due to load or other forces.
  • Critical slip surface: Slip surface of the slope that has the lowest factor of safety, and is therefore most likely to experience failure.
  • Water table: The upper boundary of a saturated zone in the ground.
  • Stress: The ratio of an applied force to a cross-sectional area.
  • Strain: A measure of deformation representing the displacement between particles in the body relative to a reference length.
  • Normal force: A force applied perpendicular to the plane of the material.
  • Shear force: A force applied parallel to the plane of the material.
  • Mobilized shear force: The shear force in the direction of potential motion, thus encouraging motion along the plane.
  • Resistive shear force: The shear force in the direction opposite to the direction of potential motion, thus hindering motion along the plane.
  • Effective forces and stresses: The normal force or normal stress carried by the soil skeleton, composed of the effective force or stress and the force or stress exerted by water.
  • Cohesion: An attractive force between adjacent particles that holds the matter together.
  • Isotropy: A condition where the value of a property is independent of the direction in which it is measured.
  • Plane strain: A condition where the resultant stresses in one of the directions of a three-dimensional material can be approximated as zero. This condition results when a body is constrained to not deform in one direction, or when the length of one dimension of the body dominates the others, to the point where it can be assumed as infinite. Stresses in the direction of the dominant dimension can be approximated as zero.