No description available.

The design of support systems, comprising rock bolt reinforcement and fabric containment components for tunnels in deep level mining environments does not currently cater well for adverse rock mass conditions. This often results in periodic failure of the support system, particularly under dynamic (rockburst) conditions with the potential for total collapse of the excavation. The design of support systems is currently based either on empirical design guidelines often not applicable to this environment or simple mechanistic models. This thesis details a methodology for the rational design of tunnel support systems based on a mechanistic evaluation of the interaction between the components of a support system and a highly discontinuous rock mass structure. This analysis is conducted under both static and dynamic loading conditions. Due to the highly complex and variable nature of the rock mass structure and the dynamic loading environment, a large component of the practical work on the evaluation of the mechanisms of rock mass deformation and support interaction is based on rockburst case studies. The understanding gained from these investigations is further evaluated by means of laboratory testing of the performance of the components of the support systems and numerical modelling of the interaction of the components of the support system with the rock mass. Due to the complex nature of this design environment the methodology developed in this thesis is but a step towards our greater understanding of the behaviour of the rock mass, and the interaction of support systems in the stabilisation of tunnel excavations. However, in comparison to the current design, this methodology now allows the design engineer to make better estimations of the anticipated demand on the different components of the support systems, under a defined rock mass environment on engineering principles. This understanding will give the design engineer greater flexibility, and confidence to design the appropriate tunnel support system for a specific rock mass and loading condition based on the often limited availability of different support units in the underground mining environment. / Thesis (Ph.D.)-University of Natal, Durban, 1999.

Stories exist throughout S’olh Téméxw, the traditional territory of the Stó:lõ people in the Lower Fraser Valley of British Columbia, of subterranean tunnels connecting disparate locations. These stories, recounted in archival records and by contemporary Stó:lõ community members, provide a gateway into Stó:lõ spiritual connections to place. Through the tunnels, I will explore the complexities of a subterraneous spiritual geography – what is significant about the tunnel stories and what they can say about the way that Stó:lõ people relate to the place world of the valley. Central to this thesis is ideas of imagining and re-imagining space. Through the exploration of the tunnel stories, and the complex and often cross-cultural research relationships that they are recounted in, I hope to show that the connections the tunnels provide can bring distant places, both physical and mental, together in a social imagination. This thesis focuses on the relationships that the tunnel narratives describe – relationships between people and places, researchers and storytellers, physical and metaphysical landscapes, and cultural ways of imagining the space of the valley.

No description available.

Thesis (M.Arch.) - Carleton University, 2006. / Includes bibliographical references (p. 146-147). Also available in electronic format on the Internet.

Thesis (M.A.)--Simon Fraser University, 1998. / Includes bibliographical references (leaves 120-124).

Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2007. / Includes bibliographical references (83-84).

Thesis (Ph. D.)--Florida State University, 2006. / Advisors: Kevin Speer, Martin Wegkamp, Florida State University, College of Arts and Sciences, Dept. of Statistics. Title and description from dissertation home page (viewed Sept. 20, 2006). Document formatted into pages; contains x, 48 pages. Includes bibliographical references.

Uma maneira de analisar a estabilidade de túneis escavados em maciços rochosos fraturados é a baseada na teoria da análise limite utilizando um critério de resistência macroscópico desenvolvido a partir da teoria de homogeneização. Este trabalho primeiramente descreve o comportamento mecânico dos constituintes do maciço rochoso fraturado e os métodos usuais de análise. Posteriormente é descrita a teoria da análise limite e da homogeneização em análise limite, utilizando estas teorias é apresentado o critério de resistência macroscópico para maciços rochosos fraturados em estado plano de deformações desenvolvido por Fréard (2000) e desenvolvido um critério de resistência macroscópico para maciços rochosos fraturados para o caso tridimensional. A partir destes critérios aplicaram-se mecanismos de ruptura para se encontrar limites superiores da função de estabilidade. Assim permitindo a análise da previsibilidade do colapso do túnel estação Pinheiros do metrô de São Paulo o qual os resultados apresentavam a possibilidade de prever o colapso. / One way of analyze the stability of tunnels excavated at fractured rock masses is based on the theory of yield design using a macroscopic strength criterion developed from the theory of homogenization. This dissertation first describes the mechanical behavior of the fractured rock mass constituents and the usual methods of analysis. Later is described the yield design theory and the theory of homogenization applied to the yield design using these theories is presented macroscopic strength criterion for fractured rock masses in a state plan developed by Fréard (2000) and developed a macroscopic strength criterion for rock masses fractured to the three-dimensional case. Based on these criteria were applied failure mechanisms to meet the upper bounding of the stability function. So it’s possible to analyze the predictability of the collapse of the tunnel-station Pinheiros of the Sao Paulo subway which the results showed the possibility of predicting the collapse.

Este trabalho estuda os resultados obtidos da aplicação de um modelo tridimensional de previsão de comportamento de túneis profundos em rocha reforçados com tirantes passivos. Utiliza-se o método dos elementos finitos e simula-se a escavação pelo sistema de ativação e desativação de elementos. Os tirantes são tratados com uma lei de comportamento elastoplástica e o maciço reforçado com tirantes é considerado um meio homogêneo anisotrópico em escala macroscópica, através do método de homogeneização dos meios periódicos. Para a análise paramétrica foi verificada a influência dos parâmetros do sistema de reforço e do maciço. Resultados em termos de convergência do túnel e tensões são apresentados e indicam que, para o caso analisado, o comprimento dos tirantes é um fator de reduzida influência. A densidade de tirantes possui maior importância, porém, esta não é afetada por modificações na coesão e no módulo de elasticidade do maciço. A distância de aplicação dos tirantes à face de escavação se mostrou significativa somente para valores abaixo de 1/3 do raio do túnel, para valores acima, os deslocamentos já ocorreram e, portanto, não mobilizavam mais os tirantes. Verificou-se que a concentração de tensões σrr acontece na parte superior e inferior do túnel e, também, antes da frente de escavação. O ângulo de atrito demonstrou influência irrisória na convergência, diferentemente da coesão que diminui a convergência, tanto do teto como da parede do túnel, à medida que seu valor aumenta. O empuxo lateral exibiu ainda maior significância, revelando o quanto é importante sua correta determinação, especialmente na convergência lateral do túnel. Ainda, constatou-se a grande importância da combinação de tirantes com revestimento em concreto, que juntos, diminuíram em aproximadamente 25% os deslocamentos no teto do túnel. / This work studies the results obtained from the application of a three-dimensional model to predict the behavior of bolted reinforced rock mass deep tunnel. The finite element method is used to model and simulate the excavation through the activation and deactivation of elements. The bolts are treated with an elastoplastic law and the rock mass is considered as a homogenized anisotropic medium on the macroscopic scale through the homogenization method of periodic media. In the parametric analysis was studied the influence of the parameters of the reinforcement system and the rock mass. Results in terms of convergence of the tunnel and stresses are presented and indicate that, for the studied case, the length of the bolts is a factor of little influence. The density of bolts has a greater importance, however, its influence was not affected by changes in cohesion and elasticity modulus of the rock mass. The distance between the bolted zone and the facing of the tunnel was a significant parameter only for values below 1/3 of the tunnel’s radius, for distances greater than this, the displacements had already occurred and did not mobilize the bolts anymore. It was verified that stress concentration σrr occurs in the top and bottom of the tunnel, and also before the facing of the excavation. The friction angle demonstrated negligible influence on the convergence, unlike the cohesion, which decreases the convergence of the roof and tunnel’s wall as its value increases. The coefficient of lateral earth pressure at rest, k0, exhibited even greater significance, revealing how important its correct determination is, especially for the lateral convergence of the tunnel. Still, it was observed the great importance of the combination of bolts and concrete lining, which together decreased by approximately 25% the displacement of the tunnel’s roof.