Showing papers in "Canadian Geotechnical Journal in 1970"
TL;DR: In this article, the authors compared the natural variabilities of cohesive and frictional components of strength for soil in undisturbed state and as compacted in earth dams, and found that the frictional component of strength is more stable than the cohesive component.
Abstract: For soils exhibiting both cohesive and frictional components of strength, the natural variabilities of the components are compared for soil in the undisturbed state and as compacted in earth dams. ...
238 citations
TL;DR: In this paper, a yield curve for Leda clay is established and the form of the yield curve deviates from that expected for an isotropic material and the pre-yield strains are shown to be different for vertically and horizontally orientated specimens.
Abstract: The pronounced yielding observed in laboratory tests on Leda clay has been associated with the destruction of cementation bonds in the clay. Triaxial test data presented in this paper show that a yield curve can be established for a Leda clay. The form of the yield curve deviates from that expected for an isotropic material and the pre-yield strains are shown to be different for vertically and horizontally orientated specimens.The shear strength of the clay is dependent on the mean normal stress at failure. A portion of the failure envelope is different for specimens orientated in different directions and this 'strength anisotropy' is associated with anisotropic yielding.
115 citations
TL;DR: The more important physical disturbances to the tundra environment are discussed with examples as mentioned in this paper, and it is shown that thermokarst subsidence, not thermal erosion, is the dominant result of man-induced distur...
Abstract: The more important physical disturbances to the tundra environment are discussed with examples. Thermokarst subsidence, not thermal erosion, is shown to be the dominant result of man-induced distur...
112 citations
TL;DR: Using 20 years of storm and ramsonde profile data, the probability of avalanche hazard to the Alta Highway and Village is plotted as a function of ten contributory factors as discussed by the authors.
Abstract: Using 20 years of storm and ramsonde profile data, the probability of avalanche hazard to the Alta Highway and Village is plotted as a function of ten contributory factors Results indicate that th
77 citations
TL;DR: A series of unconfined compression tests have been made on a marine, quick clay and small specimens were extracted for microstructural investigation as discussed by the authors, and the natural micro-structural pattern was characte...
Abstract: A series of unconfined compression tests has been made on a marine, quick clay and small specimens were extracted for microstructural investigation. The natural microstructural pattern was characte...
74 citations
TL;DR: In this article, the influences on the safety margin in earthwork and foundation engineering are considered in relation to soil exploration and tests, analysis of stability under the applied loads, and construction, respectively.
Abstract: The influences on the safety margin in earthwork and foundation engineering are considered in relation to soil exploration and tests, analysis of stability under the applied loads, and construction...
68 citations
TL;DR: In this paper, the pulling capacity of cylindrical concrete piles cast in situ in bored holes is examined for piles constructed in sandy or cohesive soils, and it is concluded that on the basis of the data presented, it was concluded that...
Abstract: The pulling capacity of cylindrical concrete piles cast in situ in bored holes is examined for piles constructed in sandy or cohesive soils. On the basis of the data presented, it is concluded that...
57 citations
TL;DR: In this article, a new appraisal of the strength of LEDA clays under low-effortive normal stresses has been presented, which can be applied to consider the stability of SLOPES.
Abstract: AN APPRAISAL OF THE DRAINED SHEAR STRENGTH OF LEDA CLAY UNDER LOW EFFECTIVE NORMAL STRESSES HAS RESULTED IN A NEW APPRECIATION OF ITS BEHAVIOR IN THIS STRESS RANGE WHICH CAN BE APPLIED TO CONSIDERATION OF THE STABILITY OF SLOPES. CLOSELY SPACED PLANES OF WEAKNESS EXISTING IN THE APPARENTLY INTACT CLAY GIVE RISE TO DILATANT BEHAVIOR AND PREDOMINANTLY FRICTIONAL SHEARING RESISTANCE. THIS MODE OF FAILURE IS CONSISTENT WITH FIELD OBSERVATIONS THAT HAVE BEEN COMPILED FROM NUMEROUS LANDSLIDES; THREE OF THESE LANDSLIDES ARE ANALYZED. /RATAOC/
55 citations
TL;DR: In this article, the authors reported that three inches (7.6 cm) of differential heave has caused severe structural deformation of a lightly loaded building founded on drained black shale bedrock in Ottawa, Canada.
Abstract: Three inches (7.6 cm) of differential heave has caused severe structural deformation of a lightly loaded building founded directly on drained black shale bedrock in Ottawa, Canada. Portions of the building founded on shale below the water table have not heaved.The heave is attributed to oxidation of disseminated iron sulfide in the shale by autotrophic bacteria to produce secondary hydrous sulfates of greater volume. Autotrophic bacteria of the Ferrobacillus and Thiobacillus ferrooxidan types, which cause this type of oxidation in warm, drained, humid environments, were confirmed by laboratory cultures to exist in the rock waters.The potential importance of heave and sulfate attack on future underground concrete structures in areas of Ottawa underlain by black shale is discussed.
54 citations
TL;DR: A detailed inventory of the numerous landslides which have taken place in the Province of Quebec has shown that they are concentrated in given areas as discussed by the authors, and extensive studies carried out in three differen...
Abstract: A detailed inventory of the numerous landslides which have taken place in the Province of Quebec has shown that they are concentrated in given areas. Extensive studies carried out in three differen...
48 citations
TL;DR: A partially confined glaciofluvial aquifer covering 60 square miles (155 square km) occurs to the northeast of the city of Winnipeg as mentioned in this paper, where the karstic bedrock surface is mantled by 30'9'm to 200'ft (60'm) of glacial drift.
Abstract: An extensive confined aquifer, currently pumped at the rate of 3 billion gallons (13.6 billion l) per year, occurs in the fractured and jointed upper 50 ft (15 m) of the thick Paleozoic carbonate rock sequence underlying metropolitan Winnipeg. The karstic bedrock surface is mantled by 30 (9 m) to 200 ft (60 m) of glacial drift. The drift is composed of 20 ft (6 m) of till overlain by lacustrine sediments, mainly clays, that average 40 ft (12 m) in thickness. Two minor water-bearing zones occur in the drift, one in the silt deposits in the upper 5 to 15 ft (1.5 to 4.5 m) of the lacustrine unit and the other in the top few feet of the till. Moderately permeable sandstones interbedded with shales underlie the carbonate rock at depths between 250 and 800 ft (75 and 240 m). The sandstones are aquifers that contain saline water. A partially confined glaciofluvial aquifer covering 60 square miles (155 square km) occurs to the northeast of the city. The karstic bedrock surface, a controlling parameter of the grou...
TL;DR: In this article, the failure behavior of columnar-grained ice during compressive creep and constant strain rate tests was investigated and the role of crack formation in establishing the failure condition was discussed.
Abstract: Information is presented on the failure behavior of columnar-grained ice during compressive creep and constant strain rate tests The role of crack formation in establishing the failure condition i
TL;DR: A building founded on Billings Shale has suffered nearly 4 in. (10 cm) of heave to its basement floor slab as mentioned in this paper, which was thought to be associated with a fault zone in the shale.
Abstract: A building founded on Billings Shale has suffered nearly 4 in. (10 cm) of heave to its basement floor slab. The heaved zone was thought to be associated with a fault zone in the shale, ear which th...
TL;DR: In this article, a 1 FT. (30.5 cm) DIAMETER STEEL PLATE was measured in the field through one winter and the surface force was estimated at 7 to 12 PSI (0.49 to 0.84 KG).
Abstract: THE FROST HEAVING FORCES DEVELOPED UNDER A 1 FT. (30.5 CM.) DIAMETER STEEL PLATE WERE MEASURED IN THE FIELD THROUGHOUT ONE WINTER. THE STEEL PLATE WAS FIXED AT THE GROUND SURFACE WITH A ROCK-ANCHORED REACTION FRAME. HEAVE GAGES AND THERMOCOUPLES WERE INSTALLED AT VARIOUS DEPTHS TO DETERMINE THE POSITION AND TEMPERATURE OF THE ACTIVE HEAVING ZONE. THE GENERAL TREND WAS FOR THE SURFACE FORCE TO INCREASE AS THE WINTER PROGRESSED. WHEN THE FROSTLINE APPROACHED MAXIMUM DEPTH THE FORCE WAS IN EXCESS OF 30,000 LB. (13,608 KG.). ESTIMATES OF THE HEAVING PRESSURE AT THE FROSTLINE RANGED FROM 7 TO 12 PSI (0.49 TO 0.84 KG/CM SQUARED) DURING THIS PERIOD. THE VARIATION OF SURFACE HEAVING FORCE WAS CLOSELY ASSOCIATED WITH WEATHER CONDITIONS. WARMING TRENDS RESULTING IN A TEMPERATURE INCREASE OF THE FROZEN LAYER CAUSED THE FORCES TO DECLINE. /AUTHOR/
TL;DR: In this article, an application of the displacement finite element method to axisymmetric soil-structure interaction problems is described, where the structure and foundation are analyzed as an entity, and the distribution of contact pressure does not have to be assumed.
Abstract: An application of the displacement finite element method to axisymmetric soil–structure interaction problems is described. Since the structure and foundation are analyzed as an entity, the distribution of contact pressure does not have to be assumed. The accuracy of the method is first assessed in the analysis of some simple problems to which other solutions exist. Then a series of laboratory results and one field case record, all involving flexible structures bearing on cohesionless foundations are analyzed, the foundations being treated as elastic but inhomogeneous. Both "Winkler" and elastic solid foundations are considered and it is shown that for the latter type physically reasonable distributions of the elastic modulus do not lead to very good predictions of the deflections of the structure although the deflections within the foundation itself are in agreement with observed values.
TL;DR: Based on data from recent laboratory one-dimensional consolidation tests and evidence of a lowered groundwater level in the past, it can be shown that the St. Clair clay till deposits are, in general, lightly overconsolidated at depth, with a heavily overconstrained crust in the upper 40'ft (12.2'm) of the deposit as discussed by the authors.
Abstract: Over 100 ft (30.4 m) of relatively homogeneous and compressible lacustrine clay and clay till deposits cover a large portion of the St. Clair basin in Southwestern Ontario. The deposit is commonly considered to be normally consolidated at depth with an overconsolidated crust caused by desiccation and weathering.Based on data from recent laboratory one-dimensional consolidation tests and evidence of a lowered groundwater level in the past, it can be shown that the St. Clair clay till deposits are, in general, lightly overconsolidated at depth, with a heavily overconsolidated crust in the upper 40 ft (12.2 m) of the deposit.The evidence of a higher degree of overconsolidation can be used to explain the large discrepancies between predicted and observed settlements of structures founded on the St. Clair clay till.
TL;DR: In this article, an excavation support system that incorporates the retaining of the soil mass by a wall which is held by prestressed anchors (tie-backs) located in the retained soil necessitates...
Abstract: Rational design of an excavation support system that incorporates the retaining of the soil mass by a wall which is held by prestressed anchors (tie-backs) located in the retained soil necessitates...
TL;DR: In this article, it was found that the density after swelling increases linearly with increasing initial density, initial moisture content, and increasing logarithm of applied loading pressure, and the relationships obtained were explained by the influence of particle reorientation and moisture content on swelling tendency.
Abstract: Volume change after saturation was determined on specimens of a statically compacted clay soil. It was found that density after swelling increases linearly with increasing initial density, initial moisture content, and increasing logarithm of applied loading pressure. An empirical equation with five coefficients and a constant, found with the aid of a computer, represents the results with a coefficient of correlation close to 1. An equation for the swelling pressure was also obtained from this equation. Results of specimens which consolidated did not fit the lines obtained for swelling. The relationships obtained were explained by the influence of particle reorientation and moisture content on swelling tendency.
TL;DR: It was recognized that repeated stages and substages of glaciation in Saskatchewan during the Pleistocene Epoch produced a series of overlapping sediments and it was shown that these sediments could b...
Abstract: It was recognized that repeated stages and substages of glaciation in Saskatchewan during the Pleistocene Epoch produced a series of overlapping sediments. It was shown that these sediments could b...
TL;DR: In this article, instability of the base may result from the inflow of water into the excavation, and the most important factors influencing the stability are the ground water anisotropic properties.
Abstract: In excavations below groundwater level, instability of the base may result from the inflow of water into the excavation. The most important factors influencing the stability are the ground water an...
TL;DR: In this article, the effect of gradient at constant relative density is explored, and it is concluded that there is an optimum gradation in terms of both high ultimate strength and high mobilized strength.
Abstract: Comparison of typical results from drained triaxial tests carried out at confining pressures of 50 and 350 p.s.i. (3.52 and 24.61 kg/cm2) on four cohesionless soils are presented.The effect of gradation at constant relative density is explored, and it is concluded that there is an optimum gradation in terms of both high ultimate strength and high mobilized strength. Uniform coarse gravel is shown to have poor mobilized strength, but at confining pressures high enough to cause particle crushing the improvement in gradation and packing leads to a high ultimate strength, although large axial strains are necessarily induced. The optimum gradation is shown to be close to Fuller's curve for maximum density. The effect of increasing the confining pressure from 50 to 350 p.s.i. (3.52 to 24.61 kg/cm2) leads to a decrease in peak of 6 to 10°, but modifications for dilatancy lead to parameters that are sensibly constant for any one material.
TL;DR: A geologic map and stratigraphic sections were drawn which show Upper Cretaceous shales and sandstones overlain by preglacial sands and gravels which, in turn, are overlain with till and glacial lake sediments as mentioned in this paper.
Abstract: The need for new building sites at the University of Alberta required an investigation of the stability of the valley wall of the North Saskatchewan River within the limits of the campus.A geologic map and stratigraphic sections were drawn which show Upper Cretaceous shales and sandstones overlain by preglacial sands and gravels which, in turn, are overlain by till and glacial lake sediments.A large, buried preglacial valley on the western side of the study area enhances slope stability because it lowers the piezometric surface. Landslide analyses in this area indicate that effective strength parameters near peak values are being mobilized.On the eastern side of the study area old landslides are revealed by subdued slump topography. Residual strength parameters used in an infinite slope analysis result in low factors of safety.
TL;DR: In this paper, a mile-long line of piezometers were installed at various depths in a clay terrace system east of the City of Ottawa and measurements indicated a significant downward piezometric gradient through the clay layer to the underlying bedrock.
Abstract: A mile-long line of piezometers were installed at various depths in a clay terrace system east of the City of Ottawa. Measurements indicated a significant downward piezometric gradient through the clay layer to the underlying bedrock. The downward flow of water through the clay affects both existing effective stresses and the stress history of the clay deposit.
TL;DR: In this paper, the finite element method has been used for determining the stress distribution and the displacements due to gravity around an unlined tunnel driven through a semi-infinite medium, characterized by three idealized material behaviors reflecting approximately a short term behavior of natural undisturbed insensitive and sensitive clays.
Abstract: The finite element method has been used for determining the stress distribution and the displacements due to gravity around an unlined tunnel driven through a semi-infinite medium, characterized by three idealized material behaviors reflecting approximately a short term behavior of natural undisturbed insensitive and sensitive clays. The knowledge of stress and displacement fields around an unlined tunnel can be used for evaluating the need for supports according to the acceptability of expected deformations.
TL;DR: In this paper, a method is developed for estimating the rates of permafrost thaw and settlement of dikes constructed on perennially frozen ground, which is important for maintenance and foundation stability.
Abstract: Prediction of permafrost thaw and settlement of dikes constructed on perennially frozen ground is important for maintenance and foundation stability. A method is developed for estimating the rates ...
TL;DR: In this paper, the authors present a method of investigation of submerged sand deposits based on undisturbed sampling by an ancient but not widely used technique, which is based on an ancient technique.
Abstract: The aim of this paper is to present a method of investigation of submerged sand deposits based on undisturbed sampling by an ancient but not widely used technique. After a rapid description of the ...
TL;DR: In this article, a finite difference technique is used to calculate temperature variations in layered systems as a function of position and time under conditions of position, position, and time, under finite difference.
Abstract: Based on a finite difference technique, computer programs have been developed whereby temperature variations in layered systems as a function of position and time may be computed under conditions o...
TL;DR: In this paper, the authors have presented the results of a very interesting and valuable study stressing the significance of the groundwater level changes in the past history of the soil, which is of great regret that we have lost the senior author, who in his lifetime had contributed very much to a better understanding of soils from both the engineering and the geological points of view.
Abstract: The authors have presented the results of a very interesting and valuable study stressing the significance of the groundwater level changes in the past history of the soil It is of great regret that we have lost the senior author of this paper, who in his lifetime had contributed very much to a better understanding of soils from both the engineering and the geological points of view I can comment only on the geologic aspects of this investigation Being in full agreement, that the over-consolidation of the crust of the soil in this area was most probably due to the lowering of the groundwater table, I see the history of this lowering in a slightly different light First, according to the latest data on the development of Lake Huron and Lake Erie (Lewis et al 1966; Lewis 1969), the longest lasting lowering of the lake levels began quite early (about 12 600 years ago in Lake Erie, slightly later in Lake Huron); it lasted for a period probably three times as long as listed in their Table 11, and the maximum drop of the water level was also greater: 133 ft (405 m) in Lake Erie, 415 ft (1265 m) in Lake Huron As a result, Lake St Clair also experienced a lengthier period of lowering of its level, because of its connection with Lake Erie and Lake Ontario All these additional facts seem to support the authors' explanation that the drawdown of the groundwater table was due to the lowering of the Erie and the Huron levels However, the Windsor and Tilbury sites discussed in this paper were probably too far from Lake Erie (10-20 miles (16-32 km) ) and even farther from Lake Huron for having been influenced directly by the changes in these lake levels, particularly if we consider the low permeability of the clay till in this area These sites are only a couple of miles from Lake St Clair Therefore, let us pay closer attention to the possible level changes in the St Clair basin Lake St Clair is very shallow (maximum depth 20 ft ( 6 m ) according to Wightman (1961)) , and its outlet area appears to be even shallower than that, on the map of the Canadian Hydrographic Service ( 1956) Thus, if the precipitation was in excess of the evapotranspiration, as it is now, also during the lowering of the Lake St Clair level, the drop of the water level still would be small, probably in a range of about 5 ft (-13 m ) This figure is based upon the sharp break in the lake bottom profiles, found by Wightman (1961) However, borings in this lake bottom have encountered peat and weathering of the underlying clay at depths up to 15 ft (46 m) below the lake level, as already mentioned by the authors Thus, we have to look for an evidence of decrease in precipitation and/or increase in evapo-transpiration, in order to explain the temporary drying out of the lake Dry climate existed in the Great Lakes Region about l l 000 to 9000 years ago, as indicated by the predominance of pine in pollen diagrams during this period (Cushing 1965), and also by other evidence, such as drying of some lakes and increased wind-transport of sand This dry climate, in addition to the lowering of lake levels due to isostatic causes, may be the main reason for the maximum lowering of the Lake St Clair level, and also for the lowering of the groundwater table in the clay till area adjoining the Lake Judging from the elevations of the base of the over-consolidated brown oxidized zone of the till (Fig 1, based upon Table I of Soderman and Kim) the groundwater table at the time of this desiccation and oxidation was