The mechanical behavior of fractures in geological media is important to geotechnical and geoenvironmental engineering. Considerable investigations have been conducted on, firstly, the characterization of the fracture topography and secondly, on the assessment of the influence of fracture topography on the mechanical behavior, particularly the dilatancy of the discontinuity. The studies of the mechanical behavior of fracture surfaces have invariably been concerned with the examination of the mechanics of the contact surfaces, to the virtual exclusion of the progress of failure zones into regions adjacent to the contacting fracture surfaces. This thesis conducts a computational assessment of the role of geomaterial plasticity and surface topography on the behavior of a fracture. The computational modelling takes accounts of the irregularity of the joint surface, the frictional and elasticity characteristics of the contact zones, the elasto-plastic failure of the material and incompatible deformations that arise during shear of an irregular fracture surface. The computational shear responses are compared for the cases where a regular fracture surface exhibits identical shear behavior in the presence of geomaterial plasticity. For an irregular joint, it is observed that the shear behavior is relatively unaffected by material plasticity. Variation of dilatancy with shear cycles, however, can be directly attributed to the presence of material plasticity. Plastic energy dissipation is related to the normal restraints specified. Shear behavior of a specific joint appears to depend mainly on the interfacial behavior of the limited number of asperity contact during shear. The surface geometry of these asperities governs the dilatancy and their slopes control the peak shear resistance. The thesis also examines briefly the influence of initial separation of joints on the shear behavior.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.34003 |
| Date | January 2001 |
| Creators | Yu, Qifeng, 1977- |
| Contributors | Selvadurai, A. P. S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Civil Engineering and Applied Mechanics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001874542, proquestno: MQ79106, Theses scanned by UMI/ProQuest. |
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