Analysis of Rockfalls by Means of a Fractal Fragmentation Model

Abstract

We present the performance of the rockfall fractal fragmentation model (RFFM) developed by Ruiz-Carulla et al. (Landslides 14(3):875–889. doi.org/10.1007/s10346-016-0773-8, 2017) and based on Perfect (Eng Geol 48:185–198, 1997). The RFFM combines disaggregation of the initial rock mass and breakage of the blocks. The model has been upgraded as to meet the mass balance, and to generate both a continuous decreasing and scale variant distribution of fragments volumes. The input of the model may be either a single block or a rock mass characterized by its In situ Block Size Distribution (IBSD). The measured fragment size distributions of seven inventoried rockfall events are used to calibrate the model. The results of the simulations fit well to the measured volume distributions. Our findings indicate that fragmentation is better characterized by the whole volume distribution of fragments generated and the increase of new surface area of the rock fragments. A relation has been observed between the potential energy of the first impact, the new surface area of fragments generated, and the model parameters. Although a greater number of parametric analyses and calibration exercises are required, this relation is proposed as a first approach to model rockfall scenarios.