RINA - Démonstrateur d’utilisation de l’intelligence artificielle pour la gestion opérationnelle des risques naturels gravitaires géologiques | FEREC 2020

Taking into account the geology was done by defining norms to separate the cliff into different zones. The criteria was chosen in order to find zones which have similar geological structures. The cliff is composed of three different geological structures: inferieur, intermediary and superieur, as described in section 2.1. The inferieur and superieur structures are present throughout the cliff. The intermediary is more ponctuel. The chosen criteria is as follows: - Zone 0 : predominance of the inferieur structure - Zone 1 : predominance of the superieur structure - Zone 2 : presence of the intermediary structure The inferior and superior structures are similar, but have different behaviors, as the inferieur is more compact, leading to different resistances. The présence of the intermediary structure leads to irregularities that could cause rock falls. The separation was made by analysing the different images taken of the cliff. The final separation is found in Figure 12. Figure 12: Geological zoning Two topographic indexes, the standard area and the Standard Concavity Index (SCI), are calculated from profiles of the cliff. The standard area is a value that normalises the vertical and horizontal dimensions, as shown in Figure 13, and calculates the area under the cliff []. Smaller values tend to indicate a steeper cliff while larger values tend to indicate a smoother cliff. Figure 13: normalisation of dimensions for the calculation of the (a) standard area index and (b) SCI 20