Analysis of the propagation and set-up of the RockGIS model

Programs of simulation of rockfalls usually use raster maps in which the properties of the terrain are assigned to each cell: elevation of the digital elevation model(DEM), roughness, coefficients of restitution, etc. The evaluation of these attributes is subject to great uncertainty since the resolution of the DEM significantly affects the results of the modeling of detachments.

The improvement of the resolution of models obtained by LiDAR or digital photogrammetry allows defining more precise form parameters such as roughness. However, it can not be dissociated from other parameters such as the coefficient of restitution. This problem will be addressed in objective 3a, which seeks to analyze the various factors that intervene and condition the propagation of blocks, their trajectories and fragmentation.

In the Rockrisk project, we developed a propagation model (RockGIS) that has been integrated in a GIS platform, and incorporates, as a novelty, the fragmentation of the blocks (Matas et al., 2017). The results obtained so far reproduce satisfactorily the detachments analyzed.However, the model must refine the modeling of the rolling mechanism, the treatment of the roughness (that affects the blocks differently according to their size), as well as the algorithm for the distribution of velocities and trajectories between the different sizes of block.

Objective 3b is the calibration and validation of the code with real cases of fragmentary rockfalls. Specifically, it requires the calibration of the fractal fragmentation model developed in Rockrisk as well as the fragmentation laws and implementation of the results of objective 3a.

References:

Matas G., Lantada N., Corominas J. , Gili J.A., Ruiz-Carulla R., Prades A. (2017). RockGIS: A GIS-based model for the analysis of fragmentation in rockfalls. Landslides. DOI.doi:10.1007/s10346-017-0818-7. Accepted: 13 March 2017 (in press). The final publication is available at Springer via http://dx.doi.org/10.1007/s10346-017-0818-7. Full Paper