Evaluación de la susceptibilidad de caída de rocas en los taludes de la subida Alessandri
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2022
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es
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Universidad Andrés Bello
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Licencia CC
Resumen
Viña del Mar es una ciudad con un importante atractivo turístico y densamente poblada a lo largo de toda su geografía. La extensa distribución urbana en las zonas de alta pendiente influye en los procesos naturales de las laderas interviniendo en la estabilidad de los taludes al perturbar la morfología original debido a la construcción de caminos y viviendas.
El objetivo de este trabajo es determinar el índice de susceptibilidad (IS) de caída de rocas en la Subida Alessandri, segmentando la zona de estudio en tres sectores: Hospital Naval, Intermedio y SE, para luego proponer medidas de mitigación del riesgo que implica una caída de rocas. Las metodologías utilizadas fueron: Caracterización de Muñoz (2013) para los factores que condicionan el proceso de caída de rocas, elaboración de un mapa de susceptibilidad (QGIS), una caracterización geotécnica del macizo rocoso a partir de la clasificación RMR (Bieniawski, 1989) y el modelamiento de alcance de caída de rocas con el software Rocfall en sectores con mayor valor de IS.
Los resultados indican que el macizo rocoso presenta una mala calidad de roca con RMR = 29, una cohesión de 1−2 𝐾𝑔/𝑐𝑚2 , un ángulo de fricción de 15°-25° y una resistencia promedio de 33 Mpa. El mayor IS de caída de rocas obtenido fue de un 66% (susceptible) en el segmento intermedio del macizo rocoso (granodiorita de biotita). Los factores condicionantes que influyen principalmente en la inestabilidad del macizo son de carácter geológico y geomorfológico, junto a un factor secundario que altera la geomorfología original (actividad antrópica).
Las conclusiones indican, que el macizo rocoso en estudio presenta una mala calidad geotécnica, donde la caracterización realizada indica una inestabilidad potencial que podría aumentar. Los valores de resistencia a la compresión simple varían entre 27-37 Mpa y son la respuesta a la perturbación de la matriz rocosa por discontinuidades, meteorización y alteración. Los factores condicionantes que influyen en la estabilidad del talud son factor geológico (aspecto geotécnico y estructural); factor geomorfológico (morfología y ángulo de pendiente) y antrópico (construcción de carreteras y edificaciones). La susceptibilidad de caída de rocas varía de un 46% a un 66% de probabilidad en torno a los valores de IS, siendo la zona más desfavorable el sector intermedio.
Las recomendaciones proponen como medida de mitigación para caída de roca, la construcción de muros de contención inferiores al metro en las cercanías de la autopista, con el fin de aplacar el peligro que esto implica.
Viña del Mar is a important tourist attraction city with an densely populated throughout its entire geography. The extensive urban distribution in the high slope areas influences the natural processes of the slopes, intervening in the stability of the slopes by disturbing the original morphology due to the construction of roads and houses. The objective of this work is to determine the rockfall susceptibility index (IS) in the Alessandri Subway, segmenting the study area into three sectors: Naval Hospital, Intermediate and SE, to propose mitigation measures for the risk involved in a rock fall. The methodologies used were: Muñoz Characterization (2013) for the factors that condition the rock fall process, elaboration of a susceptibility map (QGIS), a geotechnical characterization of the rock mass based on the RMR Bieniawski classification (1989) and rock fall range modeling with Rocfall software in sectors with higher IS value. The results indicate that the rock mass has a poor rock quality with RMR = 29, a cohesion of 1−2 𝐾𝑔/𝑐𝑚2, a friction angle of 15°-25° and an average resistance of 33 Mpa. The highest rockfall IS obtained was 66% (susceptible) in the intermediate segment of the rock mass (biotite granodiorite). The conditioning factors that mainly influence the instability of the massif are of a geological and geomorphological nature, together with a secondary factor that alters the original geomorphology (anthropic activity). The conclusions indicate that the rock mass under study has a poor geotechnical quality, where the characterization carried out indicates a potential instability that could increase. Simple compressive strength values vary between 27-37 Mpa and are the response to disturbance of the rock matrix by discontinuities, weathering and alteration. The conditioning factors that influence the stability of the slope are a geological factor (geotechnical and structural aspect); geomorphological factor (morphology and slope angle) and anthropic (construction of roads and buildings). Rockfall susceptibility varies from 46% to 66% probability around the IS values, with the worst zone being the intermediate sector. The recommendations propose as a mitigation measure for rockfall, the construction of retaining walls less than one meter in the vicinity of the highway, in order to mitigate the danger that this implies.
Viña del Mar is a important tourist attraction city with an densely populated throughout its entire geography. The extensive urban distribution in the high slope areas influences the natural processes of the slopes, intervening in the stability of the slopes by disturbing the original morphology due to the construction of roads and houses. The objective of this work is to determine the rockfall susceptibility index (IS) in the Alessandri Subway, segmenting the study area into three sectors: Naval Hospital, Intermediate and SE, to propose mitigation measures for the risk involved in a rock fall. The methodologies used were: Muñoz Characterization (2013) for the factors that condition the rock fall process, elaboration of a susceptibility map (QGIS), a geotechnical characterization of the rock mass based on the RMR Bieniawski classification (1989) and rock fall range modeling with Rocfall software in sectors with higher IS value. The results indicate that the rock mass has a poor rock quality with RMR = 29, a cohesion of 1−2 𝐾𝑔/𝑐𝑚2, a friction angle of 15°-25° and an average resistance of 33 Mpa. The highest rockfall IS obtained was 66% (susceptible) in the intermediate segment of the rock mass (biotite granodiorite). The conditioning factors that mainly influence the instability of the massif are of a geological and geomorphological nature, together with a secondary factor that alters the original geomorphology (anthropic activity). The conclusions indicate that the rock mass under study has a poor geotechnical quality, where the characterization carried out indicates a potential instability that could increase. Simple compressive strength values vary between 27-37 Mpa and are the response to disturbance of the rock matrix by discontinuities, weathering and alteration. The conditioning factors that influence the stability of the slope are a geological factor (geotechnical and structural aspect); geomorphological factor (morphology and slope angle) and anthropic (construction of roads and buildings). Rockfall susceptibility varies from 46% to 66% probability around the IS values, with the worst zone being the intermediate sector. The recommendations propose as a mitigation measure for rockfall, the construction of retaining walls less than one meter in the vicinity of the highway, in order to mitigate the danger that this implies.
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Tesis (Geólogo)
Palabras clave
Taludes Rocosos, Pruebas, Muros de Contención, Chile, Viña del Mar