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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of reliability methods to the design of underground structures

Langford, John Connor 18 September 2013 (has links)
Uncertainty in rockmass and in situ stress parameters poses a critical design challenge in geotechnical engineering. This uncertainty stems from natural variability (aleatory) due to the complex history of formation and continual reworking of geological materials as well as knowledge-based uncertainty (epistemic) due to a lack of site specific information and the introduction of errors during the testing and design phases. While such uncertainty can be dealt with subjectively through the use of conservative design parameters, this leads to a lack of understanding of the variable ground response and the selection of an over-conservative design that can have a negative impact on both the project cost and schedule. Reliability methods offer an alternative approach that focuses on quantifying the uncertainty in ground conditions and utilizing it directly in the design process. By doing so, a probability of failure can be calculated with respect to a prescribed limit state, providing a measure of design performance. When multiple design options are considered, reliability methods can be paired with a quantitative risk analysis to determine the optimum design on the basis of safety and minimum cost rather than subjective conservatism. Despite the inherent benefits of such an approach, the adoption of reliability methods has been slow in geotechnical engineering due to a number of technical and conceptual challenges. The research conducted pertaining to this thesis aims to address these issues and remove the perceived “cloak of mystery” that surrounds the use of reliability methods. The scientific and engineering research in this thesis was divided into four sections: (1) the assessment of uncertainty in geotechnical input parameters, (2) a review of reliability methods in the context of geotechnical problems, (3) the development of a reliability-based, quantitative risk approach for underground support design and (4) the application of such a method to existing case studies. The completion of these areas is critical to the design of underground structures and may bring about a shift in design philosophy in the geotechnical industry. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2013-09-18 10:35:26.265
2

Performance of Support Systems Subjected to Dynamic Loads at Two Underground Nickel Mines

Liang, Grace Ya Chih 23 July 2012 (has links)
The consequences of mine seismicity can be mitigated by installing support systems capable of absorbing the energy generated by seismic events. Recent work has focused on the testing of individual support or reinforcement units under laboratory impact loads; this, however, does not render itself to easy extrapolation to field conditions. Hence, this thesis focuses on improving the understanding of the performance of support systems in real-world applications through passive monitoring of past rockburst events. 14 years of rockburst history were collected from Coleman Mine and Copper Cliff Mine, two of Vale’s underground (nickel) operations in Sudbury Ontario. Statistical analysis, principal component analysis (PCA) and partial least square projection (PLS) were utilized to find relation between collected parameters and performance capacity. This thesis discusses the adequacy of various support systems and investigates the validity of perceived support performance as compared to the actual performance based on analyses of field data.
3

Performance of Support Systems Subjected to Dynamic Loads at Two Underground Nickel Mines

Liang, Grace Ya Chih 23 July 2012 (has links)
The consequences of mine seismicity can be mitigated by installing support systems capable of absorbing the energy generated by seismic events. Recent work has focused on the testing of individual support or reinforcement units under laboratory impact loads; this, however, does not render itself to easy extrapolation to field conditions. Hence, this thesis focuses on improving the understanding of the performance of support systems in real-world applications through passive monitoring of past rockburst events. 14 years of rockburst history were collected from Coleman Mine and Copper Cliff Mine, two of Vale’s underground (nickel) operations in Sudbury Ontario. Statistical analysis, principal component analysis (PCA) and partial least square projection (PLS) were utilized to find relation between collected parameters and performance capacity. This thesis discusses the adequacy of various support systems and investigates the validity of perceived support performance as compared to the actual performance based on analyses of field data.
4

Research on construction materials of the Witwatersrand region

Blight, Geoffrey Eustace January 1985 (has links)
A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Science to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, 1985 / This volume contains a record of research carried out over the past two decades into problems associated with civil engineering and mining construction materials. Although the various parts of the work were initiated as a result of problems that arose in the Witwatersrand region, the results of the research have in many cases evoked intense interest from other parts of the world. For example, the work on soluble salts in road bases has been taken up in Saudi Arabia and other desert regions, while that on the stability of waste rock dumps has been adopted as a basis for rock dump design in the United States of America. The research revolves entirely about materials, usually, waste, either produced by the mines and reused or disposed of by civil engineers; or reused to provide support by the mines · themselves. The main aim and end result of the research has been a more effective and efficient use of materials and better protection and control of the local environment. / Andrew Chakane 2021

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