Comparison of block size distribution in rockfalls

• Published in: Landslides and Engineered Slopes. Experience, Theory and Practice Vol. 1; pp. 1767 - 1774
• Main Authors: Ruiz-Carulla, R., Corominas, J., Mavrouli, O.
• Format: Book Chapter
• Language: English
• Published: CRC Press 2016
• Edition: 1
• Subjects: Landslide Susceptibility; Matric Suction; Fitted Power Laws; Free Fall Height; Eastern Pyrenees; Detached Mass; Safety Factor; Overburden; Low Energy Scenario; Impact Energies; Homogeneous Zones; Rock Mass Volume; Rock Mass; Individual Rock Blocks; Sampling Plots; Paleocene Age; Fragmentation Process; Rock Avalanches; Pont De; Low Fall; Fragmentation Phenomenon; Slope Stability Analysis; Block Size Distribution; Rockfall Hazard; Bedding Planes
• ISBN: 1138029882; 9781138029880
• DOI: 10.1201/9781315375007-209

Rock masses detached as rockfalls usually disintegrate upon impact on the ground surface. The Rockfall Block Size Distribution (RBSD) generated by the propagation of the rockfall mass is required for the analysis of the trajectories of the blocks, the run-out distances, the impact energies, the quantitative assessment of the rockfall hazard and for the understanding of the fragmentation process. We have measured the volume of the blocks detached in 5 rockfall cases, obtaining the corresponding RBSD. The total volume involved in these rockfall events ranges from 2.6 m3 to 10000 m3. The obtained RBSD can be well fitted by power laws with exponents ranging from 0.51 to 1.27. The results suggest that these exponents may be related to the height of fall (potential energy) and to the proportion of new fractures generated in the rock mass, among other factors. Rock masses detached as rockfalls usually disintegrate upon impact on the ground surface. The Rockfall Block Size Distribution (RBSD) generated by the propagation of the rockfall mass is required for the analysis of the trajectories of the blocks, the run-out distances, the impact energies, and the quantitative assessment of the rockfall hazard and for the understanding of the fragmentation process. Pont de Gullerí rockfall took place near Sant Roma de Tavernoles village. The Omells de na Gaia rockfall is a small-size rockfall that propagated on a stepped soft ground. Vilanova de Banat rockfall is located in Cadi Sierra, in the Eastern Pyrenees. The disaggregation of the blocks in the case of Pont de Gulleri rockfall suggests that the RBSD is controlled by the preexisting joints in the detached rock mass. The cases of Lluca and Omells show a very similar behavior, with the difference that in the Omells case, the stepped ground allows more impacts.