[pt] Ao longo das últimas décadas, a cidade do Rio de Janeiro vem sofrendo com vários eventos de queda de blocos de rochas que não podem ser relacionados a quaisquer fatores desencadeantes evidentes, como temporadas de chuva ou eventos sismicos. Assim, outros possíveis fenômenos iniciais ou causas foram avaliados e as variações térmicas naturais parecem ser um dos fatores desencadeantes que contribuem para esses eventos. O mecanismo associado à flutuação diária de temperatura é capaz de gerar deslocamentos irreversíveis, sendo um fator preparatório para as quedas de rochas. Em maciços rochosos fraturados, os blocos de rochas se expandem, empurram outros blocos em sua volta, se contraem, podendo ou não voltar para sua posição de origem, gerando movimentos cíclicos. O proposito principal deste trabalho é estudar o comportamento mecânico e hidráulico de descontinuidades de rochas gnáissicas sob carregamento cíclico cisalhante pré-pico para diferentes tipos de JRC (Joint Roughness Coefficient), variações da tensão normal entre 100 e 1000 kPa e da frequência entre 0,1 e 0,01 Hz, garantindo uma velocidade quase estática, simulando as condições de temperatura no campo. Foi possível verificar que o comportamento dos deslocamentos irreversíveis das amostras ensaiadas foi influenciado pela tensão cisalhante de pré-pico para tensões normais e frequências baixas e para tensões normais altas o deslocamento foi constante e quase estático, diminuindo pouco a resistência ao cisalhamento em 2000 ciclos e gerando níveis de deslocamentos irreversíveis bem mais baixos. / [en] Over the last few decades, the city of Rio de Janeiro has been suffering from several rockfall events that cannot be related to any obvious triggering factors such as rainy seasons or earthquakes. Thus, other possible initial phenomena or causes were evaluated and natural thermal variations seem to be one of the triggering factors that contribute to these events. The mechanism associated with the daily fluctuation of temperature is capable of generating irreversible displacements, being a preparatory factor for rockfalls. In fractured rock mass, rock blocks expand, push other blocks around them, contract, and may or may not return to their original position, generating cyclical movements. The main purpose of this work is to study the mechanical and hydraulic behavior of gneiss rock discontinuities under pre-peak cyclic shear loading for different types of JRC (Joint Roughness Coefficient), normal stress variations between 100 and 1000 kPa and frequency variations between 0.1 and 0.01 Hz, ensuring an almost static speed, simulating the temperature conditions in the field. It was possible to verify that the behavior of the irreversible displacements of the tested samples was influenced by the pre-peak cyclic shear for normal stresses and low frequencies and for high normal stresses the displacement was constant and almost static, decreasing the shear strength in 2000 cycles and generating much lower levels of irreversible displacements.

The main goal of the grouting is to seal the fractures in the rock mass,improve the strength properties of the rock mass and decrease deformability. However,the overuse of the grouting should be avoided due mainly to economic reasons,optimizing the project time and sometimes severe environmental issues.Insufficient grout spread can cause worse sealing results and decreasedurability. To control the process of grouting and predict the penetrationlength an analytical solution called Real Time Grouting Control theory (RTGC) hasbeen developed. This thesis aimed to evaluate RTGC theory on the equipmentrepresenting a one-dimensional model of a fracture called Varying Aperture LongSlot - VALS. The evaluation was based on a comparison between the calculated(predicted) penetration length according to RTGC theory and the realpenetration obtained in the experiments. Results of the tests show that the RTGCtheory is a good tool to predict the penetration length of the grout at thejoints with apertures close to the hydraulic apertures. At the apertures,significantly less than the hydraulic aperture, the results of the test andRTGC theory differ a lot.