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

The SCI is similar to the standard area index as both involve normalising the dimensions and calculating an area, but in this case the normalisation is different and the area calculated is between the cliff and the straight diagonal line that joins both extremities of the cliff []. This is illustrated in Figure 14. Comparing both formulas it is observed that profiles with a small standardized area will have a large SCI value and vice versa. Profiles perpendicular to the road were extracted from the DTM map every 10 m along the road. A total of 1122 profiles were extracted and analysed. This was done by transferring the DTM map to Cloud Compare and extracting sections of the cliff over the trace of the road seen in Figure14. Figure 14: RN1 trace used for the extraction of the topographical profiles In order to calculate both indexes it is necessary to estimate the highest point the block may depart from the cliff and arrive at the road. This was done with a specific developed code. The program looked for the extremity of the road closest to the cliff as the arrival point of the blocks and for the point from which blocks fell. The second one is complex as different people have different interpretations as one segment can have more than one cliff. The last point with a strong slope, but without any large segment in front of it with a weak slope, would be considered the departure point. Some examples of the profiles are shown in Figure 15. 21