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dc.contributor.authorGhazvinian, Ehsan
dc.contributor.otherQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))en
dc.date2010-09-23 13:59:28.795en
dc.date.accessioned2010-09-24T19:06:24Z
dc.date.available2010-09-24T19:06:24Z
dc.date.issued2010-09-24T19:06:24Z
dc.identifier.urihttp://hdl.handle.net/1974/6083
dc.descriptionThesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2010-09-23 13:59:28.795en
dc.description.abstractThe failure of brittle rocks around deep underground excavations due to the high induced stress is controlled by the crack accumulation in the rock. The study shows that the damage initiation strength, CI, corresponds to the long-term strength, and the short-term strength of the brittle rocks in-situ is the crack interaction strength, CD. Therefore the damage thresholds that are being used for the calibration and validation of numerical models are important parameters in the design of underground structures. The accurate detection of the damage thresholds is important as they define the in-situ behaviour of the brittle rocks. The two most common methods of detecting damage thresholds are the Acoustic Emission method and the strain measurement method. Apparent discrepancy that exists between the accuracy of these methods was the author’s motivation for comparing these two methods on Stanstead and Smaland granites. The author introduced two new parameters based on the measured strains for improving the strain measurement method. Based on the comparisons, the author is of the opinion that the Acoustic Emission method is a more accurate method of detecting damage thresholds. Numerical models are an important tool in the design of underground structures. The numerical methods that are able to simulate fractures explicitly have the ability to predict the brittle failure, the density and the extension of the microcracks around the opening. Itasca’s Particle Flow Code (PFC) was used in this study due to its potential to simulate fractures explicitly. Calibration of PFC models to Unconfined Compressive Strength properties of the rock does not mean that the model will behave correctly under other confining stresses or in tension. The author has tried to solve this problem by different methods and developing new procedures. Improvements in the model behaviour have been achieved but more work is required. The definition, and detection and calibrated simulation of rock damage thresholds for calibration of numerical models is helpful for a successful design of underground excavations and long term, lower bound strength, a critical design parameter for deep geological repositories for the storage of nuclear wastes, for example.en
dc.languageenen
dc.language.isoenen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectBrittle Rocken
dc.subjectDamage Thresholden
dc.subjectParticle Flow Codeen
dc.subjectAcoustic Emissionen
dc.subjectRock Mechanicsen
dc.subjectMicrocracksen
dc.titleModelling and Testing Strategies for Brittle Fracture Simulation in Crystalline Rock Samplesen
dc.typethesisen
dc.description.degreeMasteren
dc.contributor.supervisorDiederichs, Marken
dc.contributor.departmentGeological Sciences and Geological Engineeringen


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