Posicionamento geodésico com GPS no suporte a detecção de deslocamento em barragens
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2017-09-27
Autores
Rocha, Rodrigo Santos Mendes da
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Universidade Estadual Paulista (Unesp)
Resumo
Grandes corpos artificiais têm potencial catastrófico em casos de colapso de sua estrutura. Como ocorrido em Mariana – MG, o colapso da barragem trouxe prejuízos socioeconômicos e ambientais incalculáveis o que justifica a importância da prevenção de acidentes conforme imposto na Lei nº 12.334/2010 que trata da segurança de barragens. Um ponto importante de verificação da saúde da estrutura tange ao monitoramento da mesma que deve ser acompanhada periodicamente a fim de detectar deslocamentos e/ou deformações. Este monitoramento é realizado através de métodos geotécnicos, métodos geodésicos, como o posicionamento por satélites artificiais, Global Navigation Satellite Systems (GNSS), ou, por equipamentos medidores de distâncias e ângulos, além do nivelamento geométrico de precisão e a gravimetria. Tendo como estudo de caso uma barragem de concreto de uma usina hidrelétrica (UHE), a dissertação visa utilizar os sinais GNSS para detectar a ocorrência de deslocamento de pontos sobre a barragem ao longo de quatro campanhas de coleta de dados entre os anos de 2012 e 2015. O Teste de Congruência Global (TCG) será utilizado para detectar os vértices que podem ser considerados estáveis. Todo o processamento dos dados GNSS foi realizado utilizando somente os sinais do Global Positioning System (GPS) no software científico Bernese, v5.2. Para a realização do TCG foi implementado o TCGunesp, um software capaz de utilizar os resultados provenientes do processamento de dados do Bernese e informar se as estações geodésicas deslocaram ao longo do tempo. Os resultados dos processamentos de dados GPS apontaram uma alta precisão das coordenadas que foi confrontada com a repetitividade dos resultados das seções de processamento, no qual constatou-se uma diferença no modelo estocástico o que possibilitou o cálculo de um coeficiente de escala. Através das análises do TCG 3D, 2D (planimétrico) e 1D (altimétrico e no eixo do fluxo da barragem) utilizando o TCGunesp foram constatadas estações que sofreram deslocamento quando utilizado o modelo estocástico original. Ao ser realizado o reescalonamento do modelo estocástico a partir do coeficiente de escala, aumentou sensivelmente a quantidade de estações consideradas estáveis pelo teste.
Large artificial bodies have catastrophic potential in cases of collapse of their structures. As occurred in Mariana - MG, the collapse of the dam brought incalculable socioeconomic and environmental damages, which justifies the importance of accident prevention, as required by Law No. 12,334/2010, which deals with dam safety. An important point of verification of the health of the structure refers to the monitoring of the same that must be monitored periodically in order to detect displacements or deformations. This monitoring is carried out using geotechnical methods and geodetic methods, such as positioning by artificial satellites, Global Navigation Satellite Systems (GNSS) or by distance and angle measuring equipment. in addition to precision geometric leveling and gravimetry Having as a case study a concrete dam of a hydroelectric plant, the dissertation aims to use the GNSS signals to detect the occurrence of displacement of points in the dam 's structural body during four campaigns of data collection between the years of 2012 and 2015. The Global Congruence Test (TCG) will be used to detect the vertices that can be considered stable. All GNSS data processing was performed using only the Global Positioning System (GPS) signals in the scientific software Bernese, v5.2. For the implementation of the TCG, the TCGunesp was implemented, a software capable of using the results from the Bernese data processing and informing if the geodesic stations have moved over time. The results of the GPS data processing showed a high precision of the coordinates that was confronted with the repeatability of the results of the processing sections, in which a difference in the stochastic model was verified, which enabled the calculation of a scale coefficient. Through the analysis of TCG 3D, 2D (planimetric) and 1D (altimetric and in the axis of the dam flow) using TCGunesp, stations were observed that were displaced when using the original stochastic model. When the stochastic model was rescheduled from the scale coefficient, the number of stations considered stable by the test was significantly increased.
Large artificial bodies have catastrophic potential in cases of collapse of their structures. As occurred in Mariana - MG, the collapse of the dam brought incalculable socioeconomic and environmental damages, which justifies the importance of accident prevention, as required by Law No. 12,334/2010, which deals with dam safety. An important point of verification of the health of the structure refers to the monitoring of the same that must be monitored periodically in order to detect displacements or deformations. This monitoring is carried out using geotechnical methods and geodetic methods, such as positioning by artificial satellites, Global Navigation Satellite Systems (GNSS) or by distance and angle measuring equipment. in addition to precision geometric leveling and gravimetry Having as a case study a concrete dam of a hydroelectric plant, the dissertation aims to use the GNSS signals to detect the occurrence of displacement of points in the dam 's structural body during four campaigns of data collection between the years of 2012 and 2015. The Global Congruence Test (TCG) will be used to detect the vertices that can be considered stable. All GNSS data processing was performed using only the Global Positioning System (GPS) signals in the scientific software Bernese, v5.2. For the implementation of the TCG, the TCGunesp was implemented, a software capable of using the results from the Bernese data processing and informing if the geodesic stations have moved over time. The results of the GPS data processing showed a high precision of the coordinates that was confronted with the repeatability of the results of the processing sections, in which a difference in the stochastic model was verified, which enabled the calculation of a scale coefficient. Through the analysis of TCG 3D, 2D (planimetric) and 1D (altimetric and in the axis of the dam flow) using TCGunesp, stations were observed that were displaced when using the original stochastic model. When the stochastic model was rescheduled from the scale coefficient, the number of stations considered stable by the test was significantly increased.
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Palavras-chave
Monitoramento, Auscultação, GNSS, Ajustamento, Monitoring, Auscultation, Adjustment