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This paper presents the failure analysis of layered clayey slopes with emphasis on the combined effect of the clay's weakening behavior and the seismic loading using the particle finite element method (PFEM). Diverse failure mechanisms have been disclosed via the PFEM modelling when the strain-weakening behavior of clay is concerned. In contrast to a single layered slope exhibiting either a shallow or a deep failure mode, a layered slope may undergo both failure modes with a time interval in between. Seismic loadings also enlarge the scale of slope failure in clays with weakening behavior. The failure of a real layered slope (i.e. the 1988 Saint-Adelphe landslide, Canada) triggered by the Saguenay earthquake is also studied in this paper. The simulation results reveal that the choice of the strain-softening value controls the slip surface of the landslide and the amplification effect is important in the triggering of the landslide. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The alternative shear and torsion design method (the general method) in the current AASHTO-LRFD specifications and the Canadian A23.3 CSA building code requires a check on the adequacy of the longitudinal steel to resist the stresses not only from bending and axial loads, but also from shear and torsion. This paper presents an evaluation of the general method equation for the calculation of the stresses in the longitudinal steel in members with adequate transverse reinforcement. Longitudinal steel strain readings from tests are compared with the values calculated based on the general method equation for longitudinal force. The study covers the cases of nonprestressed members subjected to combined shear and/or torsion and to prestressed and nonprestressed members subjected to combined torsion and bending. The general method equation is found to give satisfactory results. [ABSTRACT FROM AUTHOR]

Oil sands are natural deposits of sand materials that are rich in bitumen. Limited studies have been conducted to determine the dynamic behavior of oil sand materials. Recent difficulties encountered in oil sand mine fields in Canada substantiated the need to characterize the stress dependent, visco-elastic, and plastic behavior of oil sand materials under dynamic loading of off-road construction and mining equipment. This paper introduces a new cyclic triaxial test procedure for determining shear modulus and deformation characteristics of oil sand materials. The test procedure was used to characterize shear moduli of three oil sand materials with varying bitumen contents. From the test results, nonlinear shear modulus models were successfully developed to characterize temperature and stress dependent behavior of the tested oil sand materials. The research findings indicate that the new laboratory approach is an improvement on conventional tests, especially when oil sand materials need to be evaluated in the field for subgrade construction and equipment mobility. [ABSTRACT FROM AUTHOR]

Abstract: A major international experiment, demonstrating technologies for use in sealing the rooms and tunnels of a nuclear waste repository was conducted at Canada’s Underground Research Laboratory between 1998 and 2004. Two bulkheads separated by 12m were installed in a 3.5-m-high by 4.25-m-wide tunnel located 420m below the surface in an intact volume of rock within a granitic pluton. These bulkheads isolated a section of tunnel that was subsequently flooded, stepwise pressurized to 4MPa and then following extended operation at ambient temperature the water in the flooded tunnel was heated. Heating occurred for a period of approximately one year prior to decommissioning of the TSX. One bulkhead consisted of high-performance concrete and the other of blocks of compacted sand-bentonite material. The performance of these two bulkheads was monitored throughout the experiment in order to evaluate the influence of elevated hydraulic head and tunnel temperature on these materials. This paper provides a brief overview of the evolution of the clay bulkhead portion of the TSX and generally discusses the water uptake, physical deformation and stresses developed and monitored in the course of TSX operation. At the end of 5 years of operation the TSX was dismantled and extensively sampled allowing for development of detailed density and water content profiles for the clay bulkhead. This also allowed the instrument responses to be compared to the physical state at the time of decommissioning. The majority of the very limited seepage past the clay bulkhead occurred at the outer perimeter regions of the clay bulkhead and that this was the region that will require particular attention when it comes time to construct bulkheads in an actual repository. Continual swelling at the upstream face of the bentonite-based clay bulkhead as downstream compression occurred meant that a positive contact was maintained between the clay bulkhead and the surrounding rock and other confining media. It also provided an excellent demonstration of the self-sealing capacity of bentonite-based materials. [Copyright &y& Elsevier]

This article discusses on the new Canadian Highway Bridge Design Code, the design provisions for fiber-reinforced structures. It provides a more rational and detailed design procedures for fiber-reinforced structures. It discusses the progress in the study relevant to this area that has been conducted by the research community worldwide and by the ISIS Canada Research Network, in particular. It also provides several comments related to the shear design of fiber-reinforced polymer and fiber-reinforced polymer-reinforced concrete beams. Moreover, the longitudinal strain parameter is also discussed.

Previous studies on unconformity-related uranium deposits in the Athabasca Basin (Canada) suggest that egress flow and ingress flow can develop along single fault systems at different stages of compressional deformation. This research aims to examine whether or not both ingress and egress flow can develop at the same time within an area under a common compressional stress field, as suggested by the reverse displacement of the unconformity surface by the basement faults. The study considers the Phoenix and Gryphon uranium deposits in the Wheeler River area in the southeastern part of the Athabasca Basin. Two-dimensional numerical modeling of fluid flow, coupled with compressional deformation and thermal effects, was carried out to examine the fluid flow pattern. The results show that local variations in the basement geology under a common compressional stress field can result in both egress and ingress flow at the same time. The fault zone at Phoenix underwent a relatively low degree of deformation, as reflected by minor reverse displacement of the unconformity, and egress flow developed, whereas the fault zone at Gryphon experienced a relatively high degree of deformation, as demonstrated by significant reverse displacement of the unconformity, and ingress flow was dominant. The correlation between strain development and location of uranium mineralization, as exemplified by Gryphon and Phoenix uranium deposits, suggests that the localization of dilation predicted by numerical modeling may represent favourable sites for uranium mineralization in the Athabasca Basin. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article focuses on the new Canadian Highway Bridge Design Code, the design provisions for fiber-reinforced structures. The Canadian Highway Bridge Design Code Technical Subcommittee 16 on Fiber Reinforced Structures has been investigating the level of conservatism in the shear equation as part of its continuous work in the calibration of the design provisions for fiber-reinforced polymer structures. Internal committee documents have been produced dealing with developments of a reliability-based health monitoring system for fiber-reinforced structures.

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geometry and timing of deformation affecting Ordovician bedrock and overlying Pleistocene sediments in the Rouge River valley near Scarborough, Ontario, are analysed to evaluate whether or not the structures are a result of glacial action or neotectonic activity. Extensive data on local and regional ice-flow directions are used to evaluate the kinematic compatibility between the observed faults and folds and the local ice-flow directions. Jointing and multiple episodes of faulting affect both the Ordovician bedrock and the overlying Pleistocene sediments. At one site, the bedrock is displaced by a normal fault by a minimum of 1.2 m. Crosscutting relationships constrain the majority of the faulting in the Rouge River valley as being coeval with deposition of the lower Bowmanville till during the Nissouri phase (ca. 23–15 ka), and possibly younger at one locality. The youngest regional ice-flow direction is northwestward; however, local ice-flow directions are highly variable. This can be explained by local perturbation enhanced by the presence of drumlinoid features in the area. Most deformation features are compatible with local and regional ice-flow directions. Glaciotectonic ice-push and ice-thrust deformation affected the Thorncliffe Formation after about 23 ka. Although some faults appear to be kinematically incompatible with ice-flow directions, six boreholes drilled to 52 m depth revealed only minor vertical offsets of bedrock strata in the uppermost 20 m, and an absence of obvious fault offsets deeper, precluding the possibility that the faults observed in the surface exposures were caused by deep-seated neotectonic stresses.Nous avons analysé la géométrie et le moment de la déformation touchant le socle ordovicien et les sédiments sus-jacents du Pléistocène dans la vallée de la rivière Rouge près de Scarborough, en Ontario, afin de déterminer si les structures résultent d'une action glaciaire ou d'une activité néotectonique. De nombreuses données sur les directions locales et régionales de l'écoulement glaciaire ont servi pour évaluer la compatibilité cinématique entre les failles et les plis observés et les directions locales des écoulements glaciaires. Le réseau de diaclases et les nombreux épisodes de failles affectent à la fois le socle ordovicien et les sédiments sus-jacents du Pléistocène. À un site, le socle est déplacé d'au moins 1,2 mètres par une faille normale. Des relations d'entrecroisements restreignent la plupart des failles de la vallée de la rivière Rouge à être contemporaines de la déposition du till Bowmanville inférieur au cours de la phase Nissouri (vers 23–15 ka) et possiblement plus jeunes à une localité. La direction de l'écoulement régional le plus jeune est vers le nord-ouest; toutefois, les directions locales de l'écoulement glaciaire sont hautement variables. Cela peut être expliqué par une perturbation locale rehaussée par la présence de formes drumlinoïdes dans la région. La plupart des paramètres de déformation sont compatibles avec les directions locales et régionales de l'écoulement glaciaire. La déformation glaciotectonique et de chevauchement glaciaire a affecté la Formation de Thorncliffe un peu après 23 ka. Bien que quelques failles semblent être incompatibles d'un point de vue cinétique avec les directions d'écoulement, six forages à une profondeur de 52 mètres ont révélé seulement de mineurs déplacements verticaux des strates du socle dans les 20 mètres supérieurs et une absence de déplacement évident de failles à de plus grandes profondeurs, écartant ainsi la possibilité que les failles observées dans les affleurements de surface aient été causées par des contraintes néotectoniques à de grandes profondeurs.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]