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Estudo geológico e geotécnico de taludes rochosos em S. Pedro da Afurada (Vila Nova de Gaia): contributos para a avaliação da estabilidade estrutural
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Abstract(s)
Este trabalho pretende enfatizar a importância dos estudos geológicos e geotécnicos para
uma melhor compreensão da estabilidade de taludes rochosos graníticos na região de São
Pedro da Afurada (Vila Nova de Gaia, NW de Portugal). Este estudo envolveu, numa primeira
fase, a caracterização da área em questão, nas vertentes topográfica, geológica e
morfoestrutural e, numa etapa posterior, a sua avaliação geotécnica e geomecânica. Foram
compiladas e integradas as principais características cartográficas, geológicas, geotécnicas e
geomecânicas dos três taludes graníticos estudados, tendo-se recorrido à técnica da
amostragem linear aplicada a superfícies expostas do maciço. Além disso, foi avaliada a
resistência à compressão uniaxial do material-rocha com base nos ensaios esclerométrico e de
resistência à carga pontual (Point Load Test, PLT). Procedeu-se, ainda, a um tratamento
estatístico das descontinuidades, bem como dos parâmetros geológico-geotécnicos e
geomecânicos a estas associados sugeridos pela ISRM. Com o intuito de classificar a qualidade
do maciço rochoso, foram aplicadas as classificações geomecânicas RMR, GSI e SMR. A
classificação SMR (Slope Mass Rating) foi particularmente importante para avaliar a
estabilidade dos três taludes e permitiu extrapolar os potenciais mecanismos de rotura. A
projecção estereográfica, em conjunto com o método do cone de atrito, foi também uma
ferramenta muito útil para avaliar os potenciais processos de rotura nestes taludes. Pretendese
que esta metodologia contribua para um melhor conhecimento da estabilidade dos taludes
rochosos na área ribeirinha do rio Douro, em Vila Nova de Gaia e que esta possa ser aplicada
na prevenção e predição da instabilidade de taludes rochosos.
This work emphasizes the importance of a geological and geotechnical study to a better understanding of granitic rock slopes stability in S. Pedro da Afurada locality (Vila Nova de Gaia, NW Portugal). This study involved, in a first stage, the characterization of the study area through topographic, morphostructural and geotectonical criteria and, in a subsequent stage, the characterization throughout geotechnical and geomechanical assessment. The main geological, geotechnical and geomechanical constraints were compiled and integrated along three granitic rock slopes. For this characterisation, the scanline sampling technique of discontinuities has been applied to the study of free rock-mass faces. In addition, uniaxial compressive strength was estimated by means of both Schmidt hardness and Point Load tests. In addition, the evaluation methods of field data for discontinuities sets and the statistical characterisation of all their ISRM parameters are also presented. In order to classify the quality of the granitic rock mass, RMR, GSI and SMR geomechanics classification systems were applied. Slope Mass Rating (SMR) classification was also fundamental to assess the stability of these slopes and to offer insights into the main potential local slope failure mechanisms. Stereographic projection provided a useful tool to assess the type of failure most likely to occur along with the application of the friction cone method. This methodology proved valuable to a better understanding of rock slope stability of left margin of Douro river, in Vila Nova de Gaia and it can applied to the accurate prediction of future slope instabilities.
This work emphasizes the importance of a geological and geotechnical study to a better understanding of granitic rock slopes stability in S. Pedro da Afurada locality (Vila Nova de Gaia, NW Portugal). This study involved, in a first stage, the characterization of the study area through topographic, morphostructural and geotectonical criteria and, in a subsequent stage, the characterization throughout geotechnical and geomechanical assessment. The main geological, geotechnical and geomechanical constraints were compiled and integrated along three granitic rock slopes. For this characterisation, the scanline sampling technique of discontinuities has been applied to the study of free rock-mass faces. In addition, uniaxial compressive strength was estimated by means of both Schmidt hardness and Point Load tests. In addition, the evaluation methods of field data for discontinuities sets and the statistical characterisation of all their ISRM parameters are also presented. In order to classify the quality of the granitic rock mass, RMR, GSI and SMR geomechanics classification systems were applied. Slope Mass Rating (SMR) classification was also fundamental to assess the stability of these slopes and to offer insights into the main potential local slope failure mechanisms. Stereographic projection provided a useful tool to assess the type of failure most likely to occur along with the application of the friction cone method. This methodology proved valuable to a better understanding of rock slope stability of left margin of Douro river, in Vila Nova de Gaia and it can applied to the accurate prediction of future slope instabilities.
Description
Mestrado em Engenharia Geotécnica e Geoambiente
Keywords
Taludes rochosos Geotecnia Técnica da amostragem linear Classificações geomecânicas Análise de estabilidade
Pedagogical Context
Citation
Publisher
Instituo Politécnico do Porto. Instituto Superior de Engenharia do Porto