Contribution Ã la Reconnaissance GÃ©ologique et GÃ©ophysique du Pont Naturel dâ€™Iminifri-Maroc - Bouhachim, Said; Benmoussa, Amroumoussa; Wafik, Amina; Najine, Abdessamad; Abdletife, Raji (European Scientific Journal, ESJ, 2023)
Le pont naturel dâ€™Iminifri lâ€™objet de cette Ã©tude est situÃ© dans la commune de Tifni. Administrativement, il relÃ¨ve du cercle de Demnate, la Province dâ€™Azilal-Maroc.Lâ€™Ã©tude gÃ©ologique et gÃ©ophysique des diffÃ©rentes formations pour la vÃ©rification de la stabilitÃ© du pont . la lâ€™analyse des rÃ©sultats et leur interprÃ©tation montre que lâ€™ossature du pont naturel dâ€™Iminifri est formÃ©e principalement de concrÃ©tions travertineuses calcaires. Ce sont des formations quaternaire sconstituÃ©es par desdÃ©pÃ´ts bio-carbonatÃ©s correspondant Ã dâ€™anciennes Ã©mergences liasiques aujourdâ€™hui disparues ou dÃ©placÃ©es. La nature variÃ©e des formations travertineuses tÃ©moignent de leur formation dans des milieux diffÃ©rents : les ruptures de pente, les chenaux Ã Ã©coulement pÃ©renne, les berges concaves des mÃ©andres soumises Ã lâ€™action prolongÃ©e des embruns dÃ©gagÃ©s par lâ€™agitation de lâ€™eau. Plusieurs types dâ€™encroÃ»tement travertineux ont Ã©tÃ© identifiÃ©s. Les plus abondants sont les encroÃ»tements plans, les encroÃ»tements de buissons, les encroÃ»tements sur support vÃ©gÃ©tal et les encroÃ»tements sur galets. Toutes les constatations effectuÃ©es confirment que les matÃ©riaux de la dalle formant lâ€™ossature du pont sont fragilisÃ©s et visiblement dÃ©gradÃ©s. La lente altÃ©ration et le comportement diffÃ©rÃ© des matÃ©riaux soumis Ã des contraintes agressives sont en gÃ©nÃ©ral Ã lâ€™origine de la dÃ©gradation des conditions de stabilitÃ©. Des facteurs exogÃ¨nes jouent Ã©galement un rÃ´le prÃ©pondÃ©rant comme les infiltrations pluviales et les vibrations engendrÃ©es par le trafic routier. Ils peuvent brutalement accÃ©lÃ©rer un processus de dÃ©gradation qui semblait Ãªtre de plus en plus accentuÃ©. Objectif de cette Ã©tude Ã la vÃ©rification de la stabilitÃ© du pont et Ã lâ€™analyse des rÃ©sultats et leur interprÃ©tation. La reconnaissance gÃ©ologique a Ã©tÃ© complÃ©tÃ©s par des investigations gÃ©ophysiques en utilisant des mÃ©thodes adaptÃ©es aux conditions pÃ©trophysiques des formations gÃ©ologiques Dâ€™aprÃ¨s les Ã©tudes effectuÃ©es sur le pont, il est raisonnable de dire que la structure dâ€™Iminifri Ã©volue plus ou moins rapidement vers sa ruine. Ce qui nous pousse Ã trouver des solutions urgentes pour sauver ce patrimoine gÃ©ologique du danger dâ€™effondrement. The natural bridge of Iminifri, the subject of this study, is located in the commune of Tifni. Administratively, it falls under the Demnate circle, Azilal Province, Morocco. The geological and geophysical study of the various formations is aimed at verifying the stability of the bridge. The analysis of the results and their interpretation shows that the framework of the natural bridge of Iminifri is primarily composed of limestone travertine concretions. These are Quaternary formations consisting of biocarbonate deposits corresponding to ancient Liassic emergencies that have since disappeared or shifted. The diverse nature of the travertine formations reflects their formation in different environments: slope breaks, perennial flow channels, concave banks of meanders subjected to the prolonged action of spray generated by water agitation. Several types of travertine encrustations have been identified, including flat encrustations, bushy encrustations, encrustations on vegetation, and encrustations on pebbles. All observations confirm that the materials forming the bridge’s framework are weakened and visibly degraded. Slow deterioration and delayed behavior of materials subjected to aggressive stresses are generally the cause of deteriorating stability conditions. Exogenous factors also play a significant role, such as rainwater infiltration and vibrations generated by road traffic. They can abruptly accelerate a degradation process that appeared to be increasingly pronounced. The objective of this study is to verify the stability of the bridge and analyze the results and their interpretation. Geological reconnaissance was complemented by geophysical investigations using methods adapted to the petrophysical conditions of the geological formations. Based on the studies conducted on the bridge, it is reasonable to conclude that the structure of Iminifri is evolving towards its ruin, more or less rapidly. This pushes us to urgently find solutions to save this geological heritage from the danger of collapse.