O presente estudo desenvolveu uma metodologia para mapeamento de potencial de instabilização de taludes rodoviários. Utilizou-se, para tanto, SIG (Sistema de Informações Geográficas) e seções geológico-geotécnicas de detalhe obtidas em levantamentos de superfície. Esta metodologia foi utilizada em trecho da Rodovia Washington Luís (SP-310), sob duas condições distintas. Inicialmente, foi aplicada à totalidade da área estudada a ponderação dos atributos de percentual de declividade, materiais inconsolidados, curvatura de encostas e direção de vertentes, obtendo-se o mapa de potencial de instabilização. Na faixa da ADA (área diretamente afetada da rodovia - com 50 m de largura), esta metodologia deu especial ênfase às seções geológico-geotécnicas, que permitiram uma melhor compreensão da geometria dos taludes de corte e aterro e disposição dos materiais inconsolidados e foram utilizadas como critérios para a compartimentação destes taludes resultando no mapa de potencial de acidente. Outros produtos cartográficos deste estudo são os mapas hipsométrico, de declividade, de curvatura de encostas, de direção de vertentes e de materiais inconsolidados que serviram de base para a realização dos mapas de potencial de instabilização e de acidente, todos elaborados na escala de 1:10.000. / The present study developed a methodology for mapping of instability potential of road slopes. It was used, for in such a way, GIS (Geographic Information System) and obtained geologic-geotechnical of detail sections in surface surveys. This methodology was used in a section of Road Washington Luís (SP-310), under two different conditions. First, it was applied to the totality of the studied area the weight of the attributes of declivity percentage, unconsolidated materials, hillsides curvature and slopes direction, obtaining itself the map of potential of instability. In the ADA band (area directly affected of the highway - with 50 m of wide), this methodology gave special emphasis to the sections geologic-geotechnical that had allowed one better understanding of the unconsolidated materials disposal and had been used as criteria for the fill and cut slopes compartimentation, resulting in the map of potential of accident. Final products of this study are map of slope, derive slope, curvature, derive aspect and unconsolidated materials maps that had served as base for the accomplishment of the map subject of this work, the potential of instability and accident map. The main scale adopted for these cartographic documents was 1:10.000.

O Estado de São Paulo possui uma extensa malha rodoviária que atravessa diferentes compartimentos geológicos e geomorfológicos. Os taludes presentes nestas rodovias podem apresentar diferentes processos de instabilização a depender destes condicionantes. Na busca do entendimento da deflagração destes processos em taludes de corte, a presente pesquisa é baseada no estudo da influência da forma de escoamento superficial, da geometria dos taludes e dos tipos de perfis de alteração dos solos. Para este estudo foi escolhida uma área de 13,6 km² localizada na Rodovia Luís Augusto de Oliveira (SP-215), entre os quilômetros 170 e 183, nos municípios de São Carlos, Ibaté e Ribeirão Bonito em SP. A pesquisa foi realizada em duas escalas, de semi-detalhe e de detalhe. Na primeira foram definidas quatro classes de potencial de instabilização para os setores no entorno dos taludes utilizando como base os condicionantes críticos cartografados nos mapas temáticos (declividades maiores que 15%, perfil de encosta côncavo, direção de escoamento superficial coincidente com o mergulho do talude e de uso e ocupação de cultura), além da altura dos setores. A definição do potencial de instabilização foi realizada considerando os condicionantes de forma isolada e de forma conjunta (fazendo uso do somatório ponderado). Os potenciais de instabilização definidos pelos dois métodos foram validados em relação a disposição das cicatrizes de escorregamento em campo. Os potenciais de instabilização alto e muito alto, definidas a partir dos condicionantes críticos considerados de forma conjunta, coincidiram com os locais com escorregamento. Na segunda escala de análise foi feita análise da estabilidade de seções geológico-geotécnicas dos taludes de corte, utilizando do método determinístico de Bishop Simplificado. Uma segunda validação do potencial de instabilização foi feito comparando as classes com os valores de fatores de segurança (FS) obtidos das análises de estabilidade (feitas com os parâmetros de resistência dos solos da retroanálise e os mínimos obtidos nas referências). Os FS mostraram-se compatíveis com as classes definidas, principalmente os FS obtidos das análises de estabilidade feitas com os parâmetros de resistência obtidas nas retroanálises. A metodologia de investigação proposta de potencial de instabilização apresentou resultados relevantes no estudo de estabilidade de taludes de corte em condições de relevo suave, como ocorre na área de estudo. / São Paulo State has an extensive road network that crosses different geological and geomorphological compartments. The slopes present in these highways can have different instability processes depending on their conditions. In the search for better understanding the deflagration processes in cutting slopes, the present research is based on the study of the influence of the surface runoff, the slope geometry, and the soil alteration profile. For this study, an area of 13.6 km² was selected, which is located on the Luís Augusto de Oliveira Highway (SP-215), between the kilometers 170 and 183, in São Carlos, Ibaté and Ribeirão Bonito cities in SP. The research was carried out in two scales (semi-detail and detail). In the semi-detail scale, four classes of instability potential were defined for the sectors around the slopes. The index was defined using as a reference the critical conditioners outlined in the thematic maps (such as slope bigger than 15%, concave slope profile, runoff direction coincident with slope dip and land use and occupation), as well as the height of the sectors. The definition of the instability potential was performed considering the conditioners by themselves and in a joint manner (using the weighted summation). The instability potentials defined by the two methods were validated in relation to the landslides scars disposition in the field. The high and very high instability potentials classes, which were defined considering the conditioners together, coincided with the landslides scars. The detail scale of analysis corresponded to stability analysis of geological-geotechnical sections of cut slopes using the Simplified Bishop\'s deterministic method. A second validation of the instability potential was made comparing the classes with the safety factor (FS) values obtained in the stability analyzes (made with the soil resistance parameters from retroanalysis and with the minimums parameters obtained in the references). The FS were compatible with the defined classes, mainly the FS from the stability analysis made with the resistance parameters obtained in the retroanalysis. The proposed research methodology of instability potential presented relevant results in the study of stability of cut slopes under conditions of gentle relief, as occurs in the study area.

O presente estudo desenvolveu uma metodologia para mapeamento de potencial de instabilização de taludes rodoviários. Utilizou-se, para tanto, SIG (Sistema de Informações Geográficas) e seções geológico-geotécnicas de detalhe obtidas em levantamentos de superfície. Esta metodologia foi utilizada em trecho da Rodovia Washington Luís (SP-310), sob duas condições distintas. Inicialmente, foi aplicada à totalidade da área estudada a ponderação dos atributos de percentual de declividade, materiais inconsolidados, curvatura de encostas e direção de vertentes, obtendo-se o mapa de potencial de instabilização. Na faixa da ADA (área diretamente afetada da rodovia - com 50 m de largura), esta metodologia deu especial ênfase às seções geológico-geotécnicas, que permitiram uma melhor compreensão da geometria dos taludes de corte e aterro e disposição dos materiais inconsolidados e foram utilizadas como critérios para a compartimentação destes taludes resultando no mapa de potencial de acidente. Outros produtos cartográficos deste estudo são os mapas hipsométrico, de declividade, de curvatura de encostas, de direção de vertentes e de materiais inconsolidados que serviram de base para a realização dos mapas de potencial de instabilização e de acidente, todos elaborados na escala de 1:10.000. / The present study developed a methodology for mapping of instability potential of road slopes. It was used, for in such a way, GIS (Geographic Information System) and obtained geologic-geotechnical of detail sections in surface surveys. This methodology was used in a section of Road Washington Luís (SP-310), under two different conditions. First, it was applied to the totality of the studied area the weight of the attributes of declivity percentage, unconsolidated materials, hillsides curvature and slopes direction, obtaining itself the map of potential of instability. In the ADA band (area directly affected of the highway - with 50 m of wide), this methodology gave special emphasis to the sections geologic-geotechnical that had allowed one better understanding of the unconsolidated materials disposal and had been used as criteria for the fill and cut slopes compartimentation, resulting in the map of potential of accident. Final products of this study are map of slope, derive slope, curvature, derive aspect and unconsolidated materials maps that had served as base for the accomplishment of the map subject of this work, the potential of instability and accident map. The main scale adopted for these cartographic documents was 1:10.000.

Les mesures de végétalisation ou de restauration écologique nécessitent de comprendre les mécanismes qui sous-tendent les changements de composition et de structure de la végétation au cours de la succession écologique. Des perturbations, d’intensité et fréquence variables, naturelles ou causées par l’Homme, agissent souvent en interaction sur la dynamique temporelle de la végétation. Cependant, l’influence d’une perturbation récurrente combinée aux changements écologiques au cours de la succession est restée peu étudiée jusqu’à présent.Les communautés végétales de talus routiers représentent un modèle pertinent pour étudier cette problématique. L’historique d’aménagement et de gestion des talus est particulièrement bien renseigné ; on a donc une connaissance précise de l’âge des communautés et de leur régime de perturbation par la fauche. Les talus routiers fournissent ainsi un plan quasi-expérimental in situ permettant l’étude des processus qui affectent l’assemblage des communautés au cours de la succession sous l’influence d’une perturbation récurrente.L’objectif principal de cette étude est de caractériser la dynamique successionnelle initiée par la mise en place d’un talus routier en région méditerranéenne et de déterminer les processus écologiques et les facteurs environnementaux influençant cette dynamique. On s’intéresse en particulier à l’influence de la fauche récurrente sur cette dynamique.Pour cela, nous avons étudié la composition floristique et la diversité des traits fonctionnels (traits foliaires et de phénologie de floraison principalement) de la végétation de talus routiers de l’Hérault (France). Chaque talus inclut une partie fauchée et une partie non fauchée, l’ensemble formant une chronoséquence sur près de 70 ans.L’analyse des variations taxonomiques entre les communautés végétales de talus routiers montre un large remplacement des espèces au cours de la succession. Ce turnover floristique est associé à des changements fonctionnels au sein des communautés. Ces derniers sont structurés par des filtres environnementaux qui influent (1) sur la synchronie de floraison entre espèces au sein des communautés au cours du temps et (2) sur la diversité de combinaisons de traits fonctionnels entre communautés d’âge similaire. Ces changements de filtres environnementaux au cours du temps semblent liés à des changements pédologiques et à l’augmentation de l’hétérogénéité spatiale des conditions de lumière et de température (avec la fermeture progressive de canopée). La fauche altère les trajectoires floristiques et fonctionnelles, notamment en provoquant un ralentissement du changement de stratégie d’utilisation des ressources au cours de la succession par rapport à la trajectoire naturelle, sans fauche. De plus, cette perturbation récurrente induit une augmentation de la diversité taxonomique et fonctionnelle au sein des communautés alors qu’elle la réduit entre communautés d’âge similaire. Finalement, la fauche agit comme un filtre environnemental supplémentaire sur l’assemblage des communautés au cours de la succession et induit une homogénéisation de la végétation entre communautés d’âge similaire.Les conclusions de cette étude contribuent à la connaissance écologique fondamentale. En termes d’implications pour la gestion des communautés végétales de talus routiers, nos conclusions suggèrent, entre autres, que l’association de végétation fauchée et non fauchée au sein des mêmes sites pourrait servir d’habitat pour une plus grande diversité de faune associée. Cette association permettrait de plus d’avoir un rendu paysager agréable aux usagers de la route, tout en garantissant une bonne visibilité pour la sécurité routière. / The success of revegetation or ecological restauration highly depends on our knowledge of mechanisms underlying changes in composition and structure of the vegetation along the ecological succession. Natural or human-induced disturbances of varying intensity and frequency often occur simultaneously to influence vegetation temporal dynamics. However, the influence of a recurrent disturbance combined with ecological changes along plant succession remains poorly documented.Plant communities growing on road slopes are particularly appropriate to study this issue. Construction work and management history are well documented, so that the age of the vegetation and its disturbance regime by mowing can be precisely informed. Thus, road slopes plant communities represent an in situ quasi-experimental framework particularly adapted to study processes affecting community assembly along the ecological succession under the influence of a recurrent disturbance.The principal objective of this study is to characterise the successional dynamic initiated after road slope construction in the Mediterranean area, and to identify the ecological processes and environmental factors influencing this dynamic. We particularly focused on the influence of recurrent mowing on this dynamic.We studied the floristic composition and the diversity of functional traits (mainly leaf traits and flowering phenology traits) in a 70-year long chronosequence of French Mediterranean (Hérault, France) road slopes, each including both mown and unmown vegetation.The analysis of taxonomical variations between road slopes plant communities reveals a large species turnover along the ecological succession. This floristic turnover relates with functional changes within communities. These functional changes are structured by environmental filters influencing flowering synchrony within communities on one hand, and the diversity of a combination of functional traits between communities of similar age on the other hand. These environmental filters changing along the succession relate with changing soil parameters and increasing spatial heterogeneity of light and temperature conditions with canopy closure.Mowing alters floristic and functional trajectories along the succession, notably through the decrease of speed in resource-use strategy changes along the succession in mown communities compared to unmown communities. In addition, this recurrent disturbance increases taxonomic and functional diversity within communities, while it decreases taxonomic and functional turnover between communities of the same age. Finally, mowing acts as an additional environmental filter on community assembly along the succession and homogenises vegetation between communities of the same age.The conclusions of this study provide basic knowledge in ecology. It also has implications for the management of road slopes plant communities in the perspective of their revegetation after construction work. Our conclusions suggest, amongst others, that combining mown and unmown vegetation could provide habitats for a higher diversity of associated fauna. In addition, it would allow vegetation to be pleasant to road users, while still ensuring a good visibility for road safety.