3D assessment of rockfall hazard and risk mitigation

Quick to learn, intuitive to use

Implementation of the model is simple and guided step by step via the Study Manager. The pre-processing steps (DTM import and meshing, creation and assignment of soils, definition of sources and protections) are streamlined and integrated, allowing to focus on interpreting your results. Visualisation and analysis of results are facilitated by an intuitive user interface with multiple interactive and scalable views.

Physical model

The physical model is based on a hybrid lumped-mass formulation that integrates the effects related to block rotation and accounts for most phases of block kinematics i.e. free-fall, impact, translation and transitions. Impacts are modelled using standard (constant) or velocity-dependent restitution coefficients, translation using a dynamic Coulomb rolling friction numerically integrated with geometric accuracy control.

Additional geometrical transition conditions allow the model to switch automatically between free-fall and translation kinematics and vice versa.

Stochastic approach

In the probabilistic mode, the stochastic approach (Monte-Carlo type) offers the choice between Gaussian or equiprobable variables for the properties of soils (i.e. restitution and friction coefficients, lateral deviation, rebound flattening) and blocks (initial starting conditions, initial position, mass, rebound perturbations).

The number of blocks thrown is also decisive, as explained here.


Model topography and soils

The model topography can be created from 2D profiles, from imported digital terrain models (e.g. digital elevation models, regular or irregular triangular meshes…) or from user digitised topographic maps.

Display realism can be enhanced by mapping orthoimages and also adding level curves onto the DTM.

Soils can be easily assigned to the DTM by selection of faces, zones or by filters (XY coordinates, altitude, dip, orientation).

Non-conforming meshes

After creating or importing a DTM, its mesh can be further edited to detect non-conforming meshes, decimate, resample, extract zones, apply noise or smoothing, or apply geometric transformations.


Sources and protections

Geometry of sources and protections can be created either interactively by projecting (horizontally or vertically) their baseline onto the DTM, or can be imported from shapefiles or points files.

Protections can be defined as vertical or inclined (normal to the DTM or at a given inclination angle).

Trajectories: from global to local scale

Visualisation of block trajectories and impacts allows analysis of the distribution of reached distances and travel times for all blocks.

Detailed analysis of individual trajectories with evolution of energies, velocities, heights and time on the elevation profile is useful when a refined analysis is required at local scale (e.g. impacts).

Protection structures: element dimensioning

In addition to the visual analysis of all block trajectories intersecting  protections, their statistical analysis is easily accessible and can be refined.

All statistical results are available in tables to provide a comprehensive summary of the analysis.

A convergence indicator is also available for each statistical result, making it possible to assess the relevance of the results in terms of protection dimensioning.

Maps and envelopes: hazard assessment

For large scale analysis, maps and envelopes represent the studied area spatially as discrete scalar fields. Envelopes allow to select the preferred statistical indicator for a particular field.

To sum up, three types of maps and envelopes are available: generic maps (number of trajectories, impacts, stop points), envelopes for protection dimensioning (energies, velocities, height, minimum travel time) and maps for hazard assessment (energy classes, trajectory density, probability of propagation, classes of probability of propagation), either according to CADANAV (2013) or MEZAP (2022) methodologies.