The slope stability model

Software Manual Data Data landslidemodels.org

r.slope.stability 2.0 User manual

by Martin Mergili


r.slope.stability is designed for physically-based slope stability analyses over large areas (up to hundreds of square kilometres). It offers five modes of physically-based slope stability simulations. Four of them build on large numbers of randomly located, randomly sized slip surfaces, ellipsoidal in shape, whereas one employs the infinite slope stability model. In principle, r.slope.stability uses an elevation raster map and a system of soil classes and layers. Each soil class or layer is associated with geometric and geotechnical characteristics. For the ellipsoid-based simulations, it can be chosen whether to consider only the ellipsoid bottom or also the bottom of layers intersecting the ellipsoid. It is further possible to test only one ellipsoid with fixed parameters.

Limit equilibrium approaches with a Mohr-Coulomb failure criterion is applied. Thereby, for the ellipsoid-based simulations, two versions of the Hovland (1977) model can be used to compute the factor of safety for each slip surface. This model works for dry or fully saturated soil and can deal with slope-parallel and layer-parallel seepage. The geotechnical details of the model are outlined in Mergili et al. (2014b). In addition, seismic slope stability can be computed using the pseudostatic or the Newmark approach.

Alternatively to the factor of safety, r.slope.stability can be used to compute the slope failure probability: for each ellipsoid, user-defined numbers of values of cohesion, angle of internal friction and - optionally - truncated depth are tested within prescribed ranges. Using probability density functions, a probability of slope failure in the range 0-1 is derived for each raster cell (Mergili et al. (2014a).

r.slope.stability further offers the possibility for exploiting the advantages of multi-core computers in order to reduce computational time (Mergili et al., 2014a) and allows choosing inhowfar to use the GRASS Segment Library. It contains comprehensive functionalities for the empirical confirmation of the model results against a landslide inventory and for the visualization of the results.


r.slope.stability 2.0 runs on LINUX operating systems. It relies on GRASS 7, Python 3, and R.


r.slope.stability 2.0 can be easily installed through a script provided along with the software.


r.slope.stability 2.0 is most efficiently operated through shell scripts.


r.slope.stability 2.0 is very flexible with regard to input.


r.slope.stability 2.0 automatically creates raster maps, graphics, and other files.

Please cite this site and its content as: Mergili, M., 2014-2021. r.slope.stability - The slope stability model. r.slope.stability 2.0 User manual. https://www.slopestability.org/manual.php