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Authors
Abstract(s)
Das grandes barragens a nĆvel mundial, as barragens de aterro sĆ£o as mais comuns.
No que respeita os fenĆ³menos que desencadeiam a rotura, no caso particular das barragens de aterro, o āgalgamentoā Ć© a segunda causa mais comum. Os eventos de rotura de barragens representam um elevado risco para as populaƧƵes e bens
nas zonas de inundaĆ§Ć£o. Em particular, a rotura de barragens de aterro pode originar escoamentos geomĆ³rficos de elevada magnitude, podendo causar impactos significativos nos vales a jusante.
TĆŖm-se realizado diversos estudos laboratoriais acerca da rotura por galgamento de barragens de aterro que tĆŖm produzido informaƧƵes Ćŗteis para a validaĆ§Ć£o de modelos numĆ©ricos, mas que falharam na produĆ§Ć£o de informaĆ§Ć£o fenomenolĆ³gica detalhada da morfologia da brecha. Desta forma, estas falhas sĆ³ conseguirĆ£o ser reduzidasaprofundando o conhecimento dos mecanismos envolvidos na evoluĆ§Ć£o temporal da brecha, particularmente no que respeita a compreensĆ£o dos fenĆ³menos geotĆ©cnicos envolvidos e da sua interaĆ§Ć£o com os fenĆ³menos de erosĆ£o hidrodinĆ¢mica.
Foi neste contexto que surgiu este trabalho final de mestrado tendo como objetivo principal a realizaĆ§Ć£o e anĆ”lise de trĆŖs ensaios experimentais, em condiƧƵes hidrĆ”ulicas e geotĆ©cnicas controladas.
Os ensaios experimentais permitiram extrair as seguintes variĆ”veis: i) hidrogramas efluentes da brecha; ii) variaĆ§Ć£o do campo de velocidades do escoamento superficial;iii) avaliaĆ§Ć£o da variaĆ§Ć£o da largura da brecha durante a ocorrĆŖncia de episĆ³dios de erosĆ£o geotĆ©cnica (queda de grandes massas de solo do corpo da barragem); e iv) morfologia da brecha durante a rotura (com auxĆlio de um sensor de movimento - Kinect Sensor).
As variĆ”veis recolhidas permitiram, para alĆ©m da caracterizaĆ§Ć£o dos hidrogramas efluentes da barragem, compreender a relaĆ§Ć£o entre a hidrodinĆ¢mica do escoamento e a morfologia da brecha durante a ocorrĆŖncia de episĆ³dios de erosĆ£o geotĆ©cnica.
Permitiram igualmente, perceber a resposta do hidrograma efluente da brecha Ć ocorrĆŖncia destes episĆ³dios.
Desta forma esta tese foi uma contribuiĆ§Ć£o para o aumento da capacidade de prever a evoluĆ§Ć£o de uma brecha em barragens de aterro, ou seja, para estimar com mais rigor o hidrograma efluente da brecha.
Abstract: Embankment dams are the most common type of dam worldwide and the overtopping is their second cause of failure. In a general way the events of rupture of dams represent one high risk for the populations located in the flooding zones. In particular, the rupture of embankment dams can originate geomorphic drainings of high magnitude, being able to cause significant impacts in the downstream valleys. Until now, many laboratory studies have been developed about the overtopping, the same have brought useful information for the validation of numerical models, which failed on the production of detailed phenomenological information about the breach morphology, therefore, this uncertainty can only be reduced deepening the knowledge of the mechanisms involved in the temporal evolution of the breach, particularlyconcerning the understanding of the geotechnical phenomena and the interaction with the hydrodynamic erosion. It was in this context that this master thesis emerged having as main purpose the realization and analysis of three experimental tests under controlled hydraulic and geotechnical conditions. With the realization of these experimental tests it was possible to extract data on the following variables: i) breach effluent hydrograph; ii) variation of the velocities field of the surface run; iii) evaluation of the variation of the width of the breach in the occurrence of geotechnical and iv) morphology of the breach during the rupture (with the aid of a motion sensor ā Kinect Sensor). The variables collect allowed to beyond the characterization of the effluent hygrograms of the dam, to understand the relationship between flow hydrodynamics and the morphology of the breach during the occurrence of geotechnical erosion episodes. They also allowed to understand the effluent hydrograph response of the breach to the occurrence of these episodes. In this way, this thesis was a contribution to the increased capacity to predict the evolution of a breach in an embankment dam, that is, to estimate more accurately the effluent hydrograph of the breach. Consequently, the work developed in this thesis is a contribution to reduce the uncertainty associated to the models of flood simulation due to this type of breaks.
Abstract: Embankment dams are the most common type of dam worldwide and the overtopping is their second cause of failure. In a general way the events of rupture of dams represent one high risk for the populations located in the flooding zones. In particular, the rupture of embankment dams can originate geomorphic drainings of high magnitude, being able to cause significant impacts in the downstream valleys. Until now, many laboratory studies have been developed about the overtopping, the same have brought useful information for the validation of numerical models, which failed on the production of detailed phenomenological information about the breach morphology, therefore, this uncertainty can only be reduced deepening the knowledge of the mechanisms involved in the temporal evolution of the breach, particularlyconcerning the understanding of the geotechnical phenomena and the interaction with the hydrodynamic erosion. It was in this context that this master thesis emerged having as main purpose the realization and analysis of three experimental tests under controlled hydraulic and geotechnical conditions. With the realization of these experimental tests it was possible to extract data on the following variables: i) breach effluent hydrograph; ii) variation of the velocities field of the surface run; iii) evaluation of the variation of the width of the breach in the occurrence of geotechnical and iv) morphology of the breach during the rupture (with the aid of a motion sensor ā Kinect Sensor). The variables collect allowed to beyond the characterization of the effluent hygrograms of the dam, to understand the relationship between flow hydrodynamics and the morphology of the breach during the occurrence of geotechnical erosion episodes. They also allowed to understand the effluent hydrograph response of the breach to the occurrence of these episodes. In this way, this thesis was a contribution to the increased capacity to predict the evolution of a breach in an embankment dam, that is, to estimate more accurately the effluent hydrograph of the breach. Consequently, the work developed in this thesis is a contribution to reduce the uncertainty associated to the models of flood simulation due to this type of breaks.
Description
DissertaĆ§Ć£o para obtenĆ§Ć£o do grau de Mestre em Engenharia Civil na Ćrea de EspecializaĆ§Ć£o em HidrĆ”ulica
Keywords
Rotura por galgamento Break from overtopping Barragem de aterro Embankment dams Morfologia da brecha Morphology of the breach Campo de velocidades superficial (PIV e PTV) Variation in the velocities field of the surface run (PIV and PTV) ReconstruĆ§Ć£o de superfĆcies 3D (kinect sensor) Reconstruction of 3D surfaces (kinect sensor)
Citation
MENDES, Solange Valente - Rotura de barragens de aterro por galgamento: caracterizaĆ§Ć£o laboratorial do hidrograma efluente da rotura. Lisboa: Instituto Superior de Engenharia de Lisboa, 2017. DissertaĆ§Ć£o de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa