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This paper quantifies rates of shoreline change and investigates the influence of surficial geology on shoreline dynamics between 1950 and 2018 on Pelly Island, located 10 km off the Mackenzie Delta. Long-term changes in shoreline position were calculated using imagery analysis and Analysing Moving Boundaries Using R (AMBUR). The influence of shoreline exposure to predominant storm direction and influence of surficial geology were examined for northwestern and southeastern zones. The average annual linear regression rate (LRR) rate during the 1950–2018 observation period was −3.8 m·a−1. The end point rate (EPR) was calculated for seven observation periods: 1950–1972, 1972–1985, 1985–2000, 2000–2018, 2000–2013, 2013–2018, and 1950–2018. A mean EPR of −5.5 ± 0.7 m·a−1 was calculated for the 2000–2018 period, and a maximum retreat rate of 46.7 ± 2.1 m·a−1 was recorded during the 2013–2018 observation period. By comparing the rate of change for sections of historical shorelines with differing surficial geology and exposure to storms, it was possible to draw conclusions on why Pelly Island continues to have the highest retreat rates in the Mackenzie–Beaufort region. Greater retreat rates were observed in lacustrine deposits (5.3 m·a−1) compared with moraine deposits (2.7 m·a−1). In addition, shoreline exposure to the predominant storm direction from the northwest was found to be a major influence on rates of shoreline change in all observation periods. [ABSTRACT FROM AUTHOR]

The collaborative federal–provincial Southern Indian Lake project in north-central Manitoba covered an area of more than 3500 km2 of the Trans-Hudson orogen. Regional-scale geological mapping, sampling, and lithogeochemical, isotopic, and geochronological studies resulted in the identification of distinct assemblages of supracrustal rocks and varied episodes of plutonism. A granodiorite gneiss dated at ca. 2520 Ma is interpreted to represent the basement of the Southern Indian domain and is considered a separate crustal domain, named the Partridge Breast block. The Churchill River assemblage is composed of juvenile pillow basalt with intervening clastic sedimentary rocks, possibly a reflection of plume magmatism related to initial rifting of the Hearne craton margin. The Pukatawakan Bay assemblage consists mainly of massive to pillowed, juvenile metabasaltic rocks and associated basinal metasedimentary rocks. The Partridge Breast Lake assemblage is dominated by continental-arc volcanic and volcaniclastic rocks associated with basinal metasedimentary rocks. The Strawberry Island assemblage, consisting of arenite and polymictic conglomerate, is interpreted to have been deposited in a foreland-basin basin or intra-orogen pull-apart basin environment. The Whyme Bay assemblage is characterized by fluvial-alluvial orogenic sediments and is temporally linked to the Sickle Group rocks in the Lynn Lake greenstone belt. Granitoid rocks, dominantly monzogranite and granodiorite, range in age from ca. 1890 to 1830 Ma and occur throughout the Southern Indian domain, and intermediate and mafic intrusions of similar ages are also present. In this paper, we integrate these new data into a tectonic framework for the Southern Indian domain of the Trans-Hudson orogen in Manitoba. [ABSTRACT FROM AUTHOR]

The Esterhazy Member of the western Canada Prairie Evaporite has been mined underground for sylvite (KCl) since the early 1960s. Although the geology of the Esterhazy Member ore body is largely considered a regional flat lying continuous series of thin potash hosting beds, there are numerous occurrences where the ore has been either replaced or removed leaving behind uneconomical halite-rich sections. An explanation of the underlying controls on the formation of these salt anomalies has been somewhat elusive although the overwhelming assumption remains that these features developed in lows on a salina. This paper proposes that salt anomalies formed because of two processes, early compaction of carbonate shoals of the Winnipegosis Formation and tectonics that resulted in multiple stages of block movement during the deposition of the upper Prairie Evaporite. Since these two processes can result in a significantly different size to a salt anomaly, encountering one or the other type can have a significant effect on the economics of the ore body. This paper looks at some of the geological methods that might provide geologists with means to predicting salt anomalies. [ABSTRACT FROM AUTHOR]

This paper focusses on obtaining a better understanding of the subsurface geology of the Chibougamau area, in the northeast of the Abitibi greenstone belt (Superior craton), using geophysical data collected along a 128 km long traverse with a rough southwest–northeast orientation. We have constructed two-dimensional (2D) models of the study area that are consistent with newly collected gravity data and high-resolution magnetic data sets. The initial models were constrained at depth by an interpretation of a new seismic section and at surface by the bedrock geology and known geometry of lithological units. The attributes of the model were constrained using petrophysical measurements so that the final model is compatible with all available geological and geophysical data. The potential-field data modelling resolved the geometry of plutons and magnetic bodies that are transparent on seismic sections. The new model is consistent with the known structural geology, such as open folding, and provides an improvement in estimating the size, shape, and depth of the Barlow and Chibougamau plutons. The Chibougamau pluton is known to be associated with Cu–Au magmatic-hydrothermal mineralisation and, as the volume and geometry of intrusive bodies is paramount to the exploration of such mineralisation, the modelling presented here provides a scientific foundation to exploration models focused on such mineralisation. [ABSTRACT FROM AUTHOR]

Our paper reports the detrital zircon record from Late Devonian to late Carboniferous foreland basin deposits in the Rheno-Hercynian (RH) Variscides of Germany. Together with a review of petrography and detrital mineral ages from the literature, the data permit to reconstruct accretion and exhumation along the RH active margin. From Frasnian to latest Carboniferous, the main source (now eroded) was a north-Armorican microcontinent (Franconia) with magmatic rocks representing late Neoproterozoic arc or back-arc, Cambro-Ordovician rift and Silurian–Early Devonian subduction of the Rheic ocean and (or) RH rifting. At ca. 380 Ma, detrital magmatic zircons combined with high- to medium-pressure mica and detrital glaucophane suggest the existence of a paired metamorphic belt at the RH tectonic front. From the Viséan onwards, zircons reveal younging of granitoid debris from ca. 380–360 Ma in Late Devonian sediments to ca. 320–300 Ma in the Westphalian C–D and Stephanian. Greywackes of the Namurian A record a change from dominant magmatic clasts toward meta-arenites associated with Baltoscandian zircons, which document accretion to and exhumation from the base of the orogenic wedge. Their source must be sought in metamorphosed Devonian sandstones of the type presently encountered in parts of the active margin crystallines (Mid-German Crystalline High), but in eroded higher units. Basal accretion implies heating of the lower plate beyond the brittle–ductile boundary and supports the model of a high-temperature regime before and during Variscan collision. Palinspastic restoration of the estimated volume of recycled material yields >100 km of distal shelf deposits lost in the process, which adds to the known shortening of the RH basin. The Variscan geology of southwestern England and southern Portugal and provenance studies in those areas are compatible with a geodynamic evolution similar to that in Germany. [ABSTRACT FROM AUTHOR]

Western North America preserves a rich record of Eocene life and environments under globally warm climates, and represents an interval where significant coal and other minerals were deposited. The Eocene is of interest to biologists and paleontologists for its record of the appearance and rise to dominance of many plant, insect, and mammal groups now typical of the temperate forests of North America, admixed with groups now well represented in tropical areas or restricted to eastern Asia. This record is also of interest for its potential contribution to our understanding of interactions between climate, the biota, and the ecosystems they occupied, under atmospheric carbon dioxide levels much higher than today. Documentation of the Eocene in western North America offers insights into the effects of future greenhouse climates. A special symposium held at the 2014 Annual Meeting of the Geological Society of America in Vancouver, British Columbia, brought together geologists, paleontologists, and biologists with an interest in these questions. This paper introduces the special issue that includes a selection of papers drawn from that symposium as well as on related topics, spanning the Early to Late Eocene, and geographically from British Columbia to Colorado. [ABSTRACT FROM AUTHOR]

Infestation by the mountain pine beetle, Dendroctonus ponderosae, decimated the forests of central British Columbia from 1999 to 2012, severely impacting the forest industry of the Nechako-Chilcotin plateau. In response, all levels of government recognized the value in developing other areas of economic activity, such as hydrocarbon and mineral exploitation, to support local economies. Exploration for resources beneath the Nechako-Chilcotin plateau has historically been constrained by Tertiary volcanic sequences and Quaternary glacial deposits that obscure the underlying geology and limit geophysical imaging. Thus, a coordinated program comprising additional geological mapping, borehole data analysis, and modern geophysical surveys of the area was initiated in 2006, with the objective of better defining the subsurface geology, solving problems of imaging through the complex near-surface, and developing improved regional geological and tectonic models. An initial set of papers arising from this fieldwork, which focused on issues relevant to mineral and hydrocarbon exploration, was published in June 2011 in a Special Issue of the Canadian Journal of Earth Sciences. This Introduction to the second 'Mountain Pine Beetle' Special Issue summarizes a set of scientific papers that focus on topics more related to hydrocarbon exploration and the large-scale structure of the crust. The papers deal with the development, thickness, and present distribution of the most prospective Cretaceous sedimentary rocks, as well as characterizing the physical properties of the near-surface volcanic units. [ABSTRACT FROM AUTHOR]

Based on the excessive deformations and support failure encountered during tunnel construction at the Driskos Twin Tunnel site in Northern Greece, this paper provides insight on how tunnels designed in such weak rock environments can be realistically analyzed with a view of determining better analytical tools to predict deformations and improving current design methods. Specific factors that were assessed include rock strength based on the geological strength index (GSI), tunnel deformation, numerical analysis techniques employed, three-dimensional model type, support considerations, dilation, sequencing of tunnel excavation, influence of single bore construction on twin bore, and homogenization of tunnel faces. This work involves the use of nominally identical two- and three-dimensional numerical models of tunnel sequencing for analytical simulation of weak material behaviour and sequential tunnel deformation response with the goal of investigating the strength and deformation of such weak rock masses. These have been used in combination with monitoring data that were obtained in the field during the Driskos Twin Tunnel construction. A discussion of the geological conditions, material property determination, monitoring data, and model calibration strategy is given. This paper provides insight into these issues and poses many more fundamental questions regarding the analysis of tunnel excavation within weak rock masses requiring further investigation. [ABSTRACT FROM AUTHOR]

This paper investigates the significant curling that occurs when thin soil layers undergo desiccation. Curling deformations, in the form of (1) lifting off from the edges (generating a concave surface), or (2) lifting off from the middle (creating a convex surface), are reported in the drying of soft soil and concrete pavements in the field. This paper presents experimental observations of significant curling of both forms 1 and 2 in wet soil specimens under controlled drying conditions. A theoretical explanation for curling is presented on the basis of unsaturated soil mechanics. The curling was primarily attributed to differential shrinkage strain increments that occur down the soil profile and their variation with the progression of desiccation. Making use of nonlinear elasticity theory under large deformations and measured properties, the shrinkage and curling deformations were modelled using the FLAC (Fast Lagrangian Analysis of Continua) computer program. The modelling approach appears to capture the observed behaviour of curling during desiccation. [ABSTRACT FROM AUTHOR]

Mineral and petroleum exploration in the Cariboo-Chilcotin region of British Columbia is hampered by widespread and extensive cover of Pleistocene glacial deposits and Tertiary volcanic successions. Seeing through this geological cover is critical to reducing exploration risk and enhancing exploration activity. Also critical to exploration is effective community engagement, hopefully resulting in endorsement and support for exploration initiatives. The forests in the Cariboo-Chilcotin region have been extensively destroyed by an infestation of the mountain pine beetle, , disrupting established communities and greatly affecting economic activity in the region. Governments of all levels recognized that geological exploration activity could provide a ready and appreciable stimulus to economic activity, but only if local communities endorsed such programs. Relatively little oil and gas exploration and research has taken place in the region, and its effects have been poorly understood locally. Consequently, an extended effort was undertaken to establish an integrated geoscience program for the Cariboo-Chilcotin region, focused on mineral and petroleum exploration-related research and coupled with engagement with local communities to inform them of exploration benefits and risks. This Introduction to the 'Mountain Pine Beetle' Special Issue of Canadian Journal of Earth Sciences provides a brief overview of the scientific papers included in the issue and also a review of the community engagement process that was undertaken to establish working relationships with First Nations and other communities in the region. [ABSTRACT FROM AUTHOR]

The goal of this paper is to propose input energy spectra applicable to seismic design of structures based on Iranian earthquakes. In terms of input energy, these spectra represent the load effects of a strong earthquake that a structure may encounter during its lifetime. For this purpose, from among 1800 existing earthquake records in Iran, 110 records were selected. By using these records and through dynamic response analyses, the design input energy spectra for four ground types, defined by the Iranian earthquake code of practice, have been derived. L’objectif de cet article est de proposer des spectres d’énergie induite applicables à la conception sismique de structures basée sur des séismes Iraniens. En termes d’énergie induite, ces spectres représentent les effets de charge d’un séisme fort qu'une structure pourrait subir au cours de sa durée de vie. À cet effet, parmi les 1800 enregistrements de séismes existants en Iran, 110 enregistrements ont été sélectionnés. En utilisant ces enregistrements et des analyses de réponse dynamique, les spectres d’énergie induite par conception, pour quatre types de sol, définis par le Code de la pratique des séismes Iranien, ont été dérivés. [ABSTRACT FROM AUTHOR]

This is the follow-up paper to Vassallo et al. (2007), which discussed the experimentally observed small-strain behaviour of an unsaturated compacted silt. The influence that suction and, more in general, mean net stress – suction history has on the initial shear stiffness was analysed and ascribed to the accumulation of irreversible volumetric strains. In this study, a model able to predict the observed behaviour is proposed, based on classical unsaturated soil volumetric hardening elastoplastic formulations. Starting from the interpretation of the results relative to simple stress paths, such as preliminary equalization and loading–unloading compression, the results of "complex" stress paths, such as those including drying–wetting cycles, have subsequently been modelled by introducing some additional parameters. [ABSTRACT FROM AUTHOR]

Mountain building in the western part of the Archean Superior Province culminated with the formation of regional strike-slip faults. This paper reports on the kinematics and timing of several major faults at the juncture between the Uchi, English River, Winnipeg River, and western Wabigoon subprovinces. Sinistral-oblique mylonitization along the northeast-striking Miniss River fault occurred at 2681 [ABSTRACT FROM AUTHOR]

Canadian society faces a significant decline in the number of active mines and in the discovery rate of base and precious metal deposits. Exploring in the shadows of active and former mines with improved metallogenic models and new technologies is one way to address this problem. Another way is to diversify mineral exploration outside known mining camps and target prospective but underexplored settings and nonconventional mineral deposits. In Canadian terms, diversifying exploration commonly translates into targeting gneissic and granitic terrains where modern geoscience knowledge may be rare or only at reconnaissance scale and where key regional and local indicators and vectors to ore may be missing in the geological record. Though underexplored settings abound in Canada, only one orogen has an aura that discourages exploration: the Grenville Province. Consequently, even though the Grenville Province provides the best model of a deep continental-collision zone so far studied anywhere on Earth and constitutes a microcosm of continental accretion, it remains underexplored, underprospected, undermapped and underestimated. It is thus essential to revisit the mineral potential of the most accessible orogen of the Canadian Shield, search for its missing volcanic belts, reexamine its ore deposits and mineral occurrences, and explore new research avenues using the best remote-sensing device on Earth: human eyes. This special issue captures advances associated with regional field investigations by government that played a special role in opening up frontier areas for mineral exploration. Papers stemming from academia and government–university–industry consortiums investigate further some of the topics covered by these and earlier surveys and others contribute structural and metamorphic insights that will be valuable in future mapping projects. The advances reported here for the Grenville Province may provide impetus to revisit other Grenville-age terrains worldwide, just as metallogenic models developed in other countries have provided the means to look in a different manner at the Grenville orogen for mineral deposits. Collectively all the various approaches presented in this volume help us to revamp our way of looking at the mineral potential of the Grenville orogen. [ABSTRACT FROM AUTHOR]

Concrete structures are becoming more and more sophisticated and submitted to severe conditions, for example: high stresses and temperatures, cyclic loadings, earthquakes, etc. It is therefore necessary to simulate correctly the behaviour and damage of such structures. However, the behaviour of this material is among the most complex ones: various phenomena are observed experimentally, such as, loss of stiffness, irreversible strains, stiffness recovery and dissymmetric behaviour to mention a few. If all these effects are taken into consideration, it would lead to models that use numerous parameters. In this paper, a framework for damage mechanics of concrete is presented and used to simulate the nonlinear behaviour of concrete using finite element method (FEM). A relatively simple isotropic damage model, containing essentially no adjustable parameters is shown to produce results in remarkably good agreement with experimental results. Indeed, the damage law requires only the fracture energy to be completely defined. A special form of damage surfaces is constructed to illustrate the application of the model. A new damage criterion, defined as an equivalent strain norm, is proposed to take into consideration the dissymmetric behaviour of concrete. To verify the FEM program including the model, the predicted deformations are compared with experimental results and results from other nonlinear constitutive models. [ABSTRACT FROM AUTHOR]

There are two unreconciled interpretations for the age and character of the boundary separating the Cambrian–Ordovician Potsdam and Beekmantown groups that underlie the Ottawa Embayment in eastern Ontario. These stratal groups consist of interior facies of the central Laurentian Platform. As exposed in the type section of the Nepean Formation (upper Potsdam Group), located in the City of Ottawa, the boundary was previously interpreted to be conformable and of Early Ordovician age. This intepretation was of enormous impact on subsequent regional geology compilations that showed a diachronous boundary across the platform interior. From recent subsurface analysis across eastern Ontario, the contact was interpreted to be disconformable, a sequence boundary separating Late Cambrian and Early Ordovician strata. This paper reexamines the type section. Lithologically, the group boundary should be repositioned downsection by ~1.5 m. The contact now lies coincident with a disconformity that has a paleorelief of < 10 cm. The proposed revision is geologically significant. Previous collections of Early Ordovician conodonts from the type section, used to define the age of what had been interpreted to be upper Potsdam strata, now fall entirely within the lower Beekmantown Group. Nepean (Potsdam) strata exposed in the type section remain undated. Regional correlation of the disconformity across the Laurentian platform suggests that Nepean strata at the type section are likely of Late Cambrian age. There now exists a regionally coherent separation of Cambrian and Ordovician sedimentation patterns in the Ottawa Embayment. [ABSTRACT FROM AUTHOR]

The Newfoundland Fracture Zone, the southwest Grand Banks transform, and the Cobequid–Chedabucto fault zone form a linked strike-slip fault system from the Atlantic Ocean to southeastern Canada. This paper suggests that several large-scale geological features in southeastern Canada are the result of a small amount of strike-slip motion on the system during the mid Cretaceous and Oligocene. Regional extension features developed in the releasing bend in the Laurentian sub-basin during the mid Cretaceous, but the same area experienced Oligocene compression. This tectonic model accounts for the distribution of mid-Cretaceous volcanism, fault-bounded basins, and regional unconformities, as well as mid to late Cretaceous subsidence of the Scotian basin and Oligocene uplift of the eastern Scotian Shelf. [ABSTRACT FROM AUTHOR]

This paper employs a simplified analytical method to investigate the influence of reaction piles on the load–displacement behaviour of a test pile in static load testing. A parametric study is conducted to examine the effects of factors such as pile spacing ratio, pile slenderness ratio, and pile soil stiffness ratio. Several soil profiles are considered in the study. The parametric study also includes the cases of static load testing in the lateral direction. The correction factors for the initial pile head stiffness obtained from static pile load tests with the use of reaction piles are given in charts. Furthermore, analyses of centrifuge modelling of axially loaded piles are carried out using the simplified analytical method. Good agreements between the test results and the analysis results are demonstrated, and the applicability of the correction factors is verified. [ABSTRACT FROM AUTHOR]

The mechanical behaviour of natural clays is influenced by the degradation of the microstructure induced by the applied loads. The consequence of progressive damage to the natural microstructure is that it is not possible to describe the state of the soil in terms of effective stress components and void ratio only, and therefore it is not possible to locate a unique state boundary surface by normalizing stresses with respect to the equivalent pressure. In this paper it is shown that, by defining a normalizing pressure that accounts for the progressive loss of structure occurring during a test, the state of the soil during loading can be completely described in a normalized stress space. The laws linking the normalizing pressure to the degree of microstructure disruption are derived from the isotropic hardening laws of two constitutive models recently proposed for natural soils. The normalizing procedure is applied to the experimental results obtained on three natural clays of different depositional origin and with different mechanical properties. For the three clays, the parameters describing structure degradation permit the assessment of the rate of loss of structure with plastic strains. For the clays examined, the volumetric plastic strains are seen to play a major role, compared to the deviatoric plastic strains, in causing progressive disruption of the microstructure. Lastly, it is shown that the initial degree of structure and the rate of structure degradation can be related to the depositional conditions and the stress history of the clay deposits. [ABSTRACT FROM AUTHOR]

Vibrating-wire earth pressure cells are often used to measure soil pressure in fills and embankments or contact pressure between soil and buried structures. Instrumentation companies provide each cell with a formula to calculate pressure based on frequency and temperature readings. This paper presents the calibration work that was carried out on a series of 76 mm diameter cells and four 228 mm diameter cells with temperatures ranging from –10 to +30 °C with and without the effect of applied pressure. Based on this work and additional data from two field sites, it was found that temperature calibration factors given on the calibration sheet specific to each cell largely underestimated the temperature effect. It was also found that the correction factors were dependent not only on temperature, but also on the pressure applied to the cell. The temperature calibration factor, which is given as a linear correction on the calibration datasheet, becomes parabolic as a pressure is applied on the cell. Based on the findings, recommendations are provided for minimizing the temperature effect on pressure cell readings and improving the accuracy of the temperature calibration factor. [ABSTRACT FROM AUTHOR]

The implementation of unsaturated soil mechanics into engineering practice is dependent, to a large extent, upon an ability to estimate unsaturated soil property functions. The soil-water characteristic curve (SWCC), along with the saturated soil properties, has proven to provide a satisfactory basis for estimating the permeability function and shear strength functions for an unsaturated soil. The volume change functions have not been totally defined nor applied in geotechnical engineering. The objective of this paper is to present a procedure for estimating the SWCC from information on the grain-size distribution and the volume–mass properties of a soil. SWCCs represent a continuous water content versus soil suction relationship. The proposed method provides an approximate means of estimating the desorption curve corresponding to a soil initially slurried near the liquid limit. The effects of stress history, fabric, confining pressure, and hysteresis are not addressed. A database of published data is used to verify the proposed procedure. The database contains independent measurements of the grain-size distribution and the SWCC. The level of fit between the estimated and measured SWCCs is analyzed statistically. The proposed procedure is compared to previously proposed methods for predicting the SWCC from the grain-size distribution. The results show that the proposed procedure is somewhat superior to previous methods.Key words: soil-water characteristic curve, grain-size distribution, volume-mass properties, pedo-transfer function, unsaturated soil property functions.L'introduction de la mécanique des sols non saturés dans la pratique de l'ingénieur est dépendante jusqu'à un certain point de l'habileté à estimer les fonctions des propriétés des sols non saturés. La courbe caractéristique sol-eau, avec les propriétés des sols saturés, s'est avérée pouvoir fournir une base satisfaisante pour évaluer la fonction de perméabilité et les fonctions de résistance au cisaillement d'un sol non saturé. Les fonctions de changement de volume n'ont pas été totalement définies ni appliquées à la géotechnique de l'ingénieur. L'objectif de cet article est de présenter une procédure pour évaluer la courbe caractéristique sol-eau en partant de l'information sur la distribution granulométrique et les propriétés masse-volume d'un sol. Les courbes caractéristiques sol-eau représentent une relation continue de teneur en eau en fonction de la succion du sol. La méthode proposée fournit des moyens approximatifs pour évaluer la courbe de désorption correspondant à un sol initialement en boue près de la limite de liquidité. On n'a pas traité des effets de l'histoire des contraintes, de la fabrique, de la pression de confinement et de l'hystérèse. Une base des données publiées est utilisée pour vérifier la méthode proposée. La base de données contient des mesures indépendantes de la distribution granulométrique et de la courbe caractéristique sol-eau. Le niveau de lissage entre les courbes caractéristiques sol-eau mesurées est analysé statistiquement. La procédure proposée est comparée à des méthodes proposées antérieurement pour prédire la courbe caractéristique sol-eau en partant de la distribution granulométrique. Les résultats montrent que la procédure proposée est quelque peu supérieure aux méthode antérieures.Mots clés : courbe caractéristique sol-eau, distribution granulométrique, propriétés masse-volume, fonction pédo-transfert, fonctions de propriétés des sols non saturés.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

This paper addresses the behaviour of compacted expansive soils under swell–shrink cycles. Laboratory cyclic swell–shrink tests were conducted on compacted specimens of two expansive soils at surcharge pressures of 6.25, 50.00, and 100.00 kPa. The void ratio and water content of the specimens at several intermediate stages during swelling until the end of swelling and during shrinkage until the end of shrinkage were determined to trace the water content versus void ratio paths with an increasing number of swell–shrink cycles. The test results showed that the swell–shrink path was reversible once the soil reached an equilibrium stage where the vertical deformations during swelling and shrinkage were the same. This usually occurred after about four swell–shrink cycles. The swelling and shrinkage path of each specimen subjected to full swelling – full shrinkage cycles showed an S-shaped curve (two curvilinear portions and a linear portion). However, the swelling and shrinkage path occurred as a part of the S-shaped curve, when the specimen was subjected to full swelling – partial shrinkage cycles. More than 80% of the total volumetric change and more than 50% of the total vertical deformation occurred in the central linear portion of the S-shaped curve. The volumetric change was essentially parallel to the saturation line within a degree of saturation range of 50–80% for the equilibrium cycle. The primary value of the swell–shrink path is to provide information regarding the void ratio change that would occur for a given change in water content for any possible swell–shrink pattern. It is suggested that these swell–shrink paths can be established with a limited number of tests in the laboratory.Key words: expansive soils, oedometer tests, swell–shrink behaviour, shrinkage tests.Cet article traite du comportement des sols gonflants compactés sous des cycles de gonflement–retrait. Les essais en laboratoire de gonflement–retrait ont été réalisés sur des spécimens compactés de deux sols gonflants à des pressions de surcharge de 6,25, 50,00, et 100,00 kPa. On a déterminé l'indice des vides et la teneur en eau des spécimens à plusieurs étapes intermédiaires durant le gonflement jusqu'à la fin du gonflement, et durant le retrait jusqu'à la fin du retrait, pour tracer le cheminement de la teneur en eau en fonction de l'indice des vides avec le nombre croissant de cycles de gonflement–retrait. Les résultats d'essais ont montré que le cheminement gonflement–retrait était réversible une fois que le sol avait atteint une étape d'équilibre où les déformations verticales durant le gonflement et le retrait étaient les mêmes. Cette étape était généralement atteinte après environ quatre cycles de gonflement–retrait. Le cheminement de gonflement et retrait de chaque spécimen assujetti à des cycles de gonflement complet et retrait complet ont montré une courbe en forme de « S » (deux portions curvilignes et une portion linéaire). Cependant, le cheminement de gonflement et retrait se produisait le long de la courbe en forme de « S » lorsque le spécimen était soumis à des cycles de gonflement–retrait partiel. Plus de 80 % du changement volumétrique total et plus de 50 % de la déformation verticale totale se sont produits le long de la portion centrale linéaire de la courbe en forme de « S ». On a trouvé que le changement volumétrique était essentiellement parallèle à la ligne de saturation à l'intérieur d'un degré de saturation variant dans la plage de 50 à 80 % pour le cycle d'équilibre. La valeur première du cheminement gonflement–retrait est de fournir de l'information quant au changement de l'indice des vides qui se produirait pour un changement donné de teneur en eau pour n'importe quel schéma possible de gonflement–retrait. On croit que ces cheminements gonflement–retrait peuvent être établis avec un nombre limité d'essais en laboratoire.Mots clés : sols expansifs, essais oedométriques, comportement gonflement–retrait, essais de retrait.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

This paper presents a method to obtain the constitutive relationships of sand from drained self-boring pressuremeter tests. Plane-strain conditions and Rowe's stress–dilatancy theory are assumed to hold to determine stress and finite strain distributions and paths. The proposed method, which has been validated using both calibration chamber studies and field tests, appears to correctly render the response behaviour of relatively loose to dense sands.Key words: stress–strain relations, self-boring pressuremeter tests, sands, finite strains, stress distributions, paths.Cet article présente une méthode qui permet d'obtenir les relations constitutives des sols à partir d'essais pressiométriques drainés. Des conditions de déformation plane et la théorie de la dilatance de Rowe sont assumées être valides afin de déterminer les distributions de contraintes et de déformations finies, ainsi que leurs cheminements. La méthode proposée, qui a été validée à l'aide d'essais de calibration en cuve et sur place, semble reproduire correctement le comportement des sables lâches et denses.Mots clés : relations contrainte–déformation, essais pressiométriques autoforeurs, sables, déformations finies, distributions de contraintes, cheminements. [ABSTRACT FROM AUTHOR]

A parcel of land just south of Ottawa at Gloucester has been the site of an unusual amount of geotechnical research over the past 45 years. The parcel was recently to have been placed on the open real estate market but has been saved for scientific purposes and is now designated as "Canadian Geotechnical Research Site No. 1 at Gloucester". This paper presents an outline of the research that has been conducted at the site, in four general divisions, namely compressibility, strength, deformation, and soil property improvement. It is hoped that the site will stimulate the development and evaluation of new tools and techniques, foster scientific cooperation and information exchange, and allow the results of research involving the site to improve the state of practice, education, and research.Key words: sensitive clay, compressibility research, strength research, deformation research, soil improvement research.Un montant exceptionnel de recherche en géotechnique a été faite durant les 45 dernières années sur un morceau de terrain juste au sud d'Ottawa à Gloucester. Ce terrain devait jusqu'à récemment être vendu mais il a été sauvegardé à des fins scientifiques et est maintenant connu sous le nom « Site No. 1 de recherche canadienne en géotechnique à Gloucester ». Cet article présente les grandes lignes de la recherche effectuée, en quatre divisions générales, soit la compressibilité, la résistance, la déformation et l'amélioration des propriétés des sols. Il y a bon espoir que ce site va stimuler le développement et l'évaluation de nouveaux outils et techniques, entretenir une coopération scientifique et un échange d'information, et permettre à améliorer l'état de la pratique, l'éducation ainsi que la recherche avec les résultats obtenus à même les essais effectués sur le site.Mots clés : argile sensible, recherche sur la compressibilité, recherche sur la résistance, recherche sur la déformation, recherche sur l'amélioration des propriétés des sols. [ABSTRACT FROM AUTHOR]

While the Cardium Formation (Turonian–Coniacian, Upper Cretaceous) is one of the major hydrocarbon sources, and consequently one of the most intensely studied siliciclastic formations in the Western Canada Sedimentary Basin, it remains one of the more controversial units in terms of understanding the depositional environments and processes it represents, and correlations between subsurface and outcrop. Proposed subsurface subdivisions based on sequence stratigraphic concepts, and relation of these allomembers to long-established members of the outcrop belt, have provoked further disagreements. The general lack of biostratigraphic data within the Cardium Formation makes it difficult to test different models and to resolve conflicting proposals. This paper provides stratigraphic and taxonomic information on all known scaphitid ammonoids from the Cardium Formation and correlation of these faunas with the Turonian and Coniacian zonal scheme established in the United States Western Interior; future publications will provide similar treatments of the collignoniceratid ammonites and inoceramid bivalves.Bien que la Formation de Cardium (Turonien–Coniacien; Crétacé supérieur) soit l'une des sources majeures d'hydrocarbures et, par conséquent, l'une des formations siliciclastiques les plus intensément étudiées du bassin sédimentaire de l'Ouest canadien, elle demeure l'une des unités les plus controversées en termes de compréhension des environnements et des processus de déposition qu'elle représente et des corrélations entre le roc souterrain et les affleurements. Les subdivisions proposées pour la subsurface, basées sur des concepts de séquences stratigraphiques, et les relations de ces allomembres à des membres de la ceinture d'affleurements établis depuis longtemps ont causé de nouvelles divergences d'opinion. Le manque de données biostratigraphiques à l'intérieur de la formation complique l'essai de différents modèles et la résolution de propositions contradictoires. Cet article fournit des informations stratigraphiques et taxonomiques sur tous les Ammonoïdés scaphitidae de la Formation de Cardium ainsi qu'une corrélation de ces faunes avec le schéma zonal du Turonien et du Coniacien établi dans l'Ouest américain intérieur; des publications à venir traiteront de façon similaire des Ammonites collignoniceratidae et des bivalves Inoceramidae.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The article presents a response to a commentary on the paper "Rock Quality Designation (RQD): Time to Rest in Peace," published in the 2018 issue of this journal. Topics discussed include the necessity of using RQD in rock mass classifications systems, limitations of the existing classification systems and continuous profiles of shear waves. The advantage of using RQD is emphasized.