ABSTRACT
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ABSTRACT
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One of the primary objectives of the Canadian Liquefaction Experiment (CANLEX) project was to develop and evaluate undisturbed sampling techniques as part of the overall goal to focus and coordinate Canadian geotechnical expertise on the... more
One of the primary objectives of the Canadian Liquefaction Experiment (CANLEX) project was to develop and evaluate undisturbed sampling techniques as part of the overall goal to focus and coordinate Canadian geotechnical expertise on the topic of soil liquefaction. Six sites were selected by the CANLEX project in an attempt to characterize various deposits of loose sandy soil. The sites consisted of a variety of soil deposits, including hydraulically placed sand deposits associated with the oil sands industry, natural sand deposits in the Fraser River Delta, and hydraulically placed sand deposits associated with the hard-rock mining industry. At each site, a target zone was selected and various methods of ground sampling were performed. These included ground freezing and sampling, fixed piston tube sampling, Christensen double-tube core sampling, large-diameter sampling using the Laval sampler, and sonic (rotary-vibratory) continuous coring. Ground freezing and sampling was performe...
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A geogrid reinforced cohesive soil test embankment 12 metres high with 1:1 side slopes is under construction in the province of Alberta. Three different types of geogrids are being evaluated at the site, including tensar SR2, signode... more
A geogrid reinforced cohesive soil test embankment 12 metres high with 1:1 side slopes is under construction in the province of Alberta. Three different types of geogrids are being evaluated at the site, including tensar SR2, signode tnx-5001, and paragrid 50s. This paper outlines the geometric layout for the test fill and the design methods currently used for this type of reinforced slope. Instrumentation has been installed to monitor pore pressure responses and the deformations of both the in situ foundation soils and the compacted fill material. Through the analysis of the soil-geogrid interaction performance, a rational design approach will be developed for high geogrid reinforced slopes constructed with cohesive soils. For the covering abstract of the conference see IRRD 807201.
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Several mix &signs of a Ciment Fondu based grout were tested in the laboratory to develop a grout which would perform adequately as a pile back611 material in permafrost as wld as -lO°C. The test procedure and results of thermal,... more
Several mix &signs of a Ciment Fondu based grout were tested in the laboratory to develop a grout which would perform adequately as a pile back611 material in permafrost as wld as -lO°C. The test procedure and results of thermal, compressive strength. and workability performance of the different mix designs are described in &tail. Resume Plusieurs m6langes de codis B base de ccciment Fondu* ont 6t6s exp6riment6s en laboratoire afrn de dbvelopper un coulis pouvant se wmporter de fapn adequate comme mat6riel de remplissage pour des pieux implant6s dam le perg6lisol jusqu'B -lO°C. L'exp6rimentation ainsi que les rbsultats en terme & performance thermique. de rbsistance en compression et de maniabilit6 pour les diffbrent m6langes sont
This paper presents the results of a laboratory study undertaken to examine the effect of hydraulic variables on the scour of a cohesive soil produced by submerged plane turbulent wall jets. The velocity and thickness of the jet were... more
This paper presents the results of a laboratory study undertaken to examine the effect of hydraulic variables on the scour of a cohesive soil produced by submerged plane turbulent wall jets. The velocity and thickness of the jet were varied in tests with one cohesive soil in part to determine if repeatable scour experiments by these jets could be performed
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Spray freezing technology has been used in ice building construction in cold regions and artificial snow making. The spray freezing process involves heat and mass transfer and ice nucleation. The freezing temperature of the sprayed water... more
Spray freezing technology has been used in ice building construction in cold regions and artificial snow making. The spray freezing process involves heat and mass transfer and ice nucleation. The freezing temperature of the sprayed water is influenced by many factors, such as droplet size (volume), ambient air temperature, and impurity content of the water. An experimental study was carried out to investigate the influence of the droplet size (volume) and the ambient air temperature on the ice nucleation temperature of the freely suspended droplets of different qualities—piggery wastewater, pulp mill effluent, and oil sands tailings pond water. The time required to initiate freezing in the freely suspended wastewater droplets was measured under various experimental conditions using video-image technology. The ice nucleation temperature of the droplets were predicted based on the required freezing time and the rate of heat and mass transfer.
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This study was carried out to investigate organic and inorganic contaminant removal from melting spray ice produced from aerated stabilization basin treated pulp mill wastewater and the oil sands tailings pond water. The influence of the... more
This study was carried out to investigate organic and inorganic contaminant removal from melting spray ice produced from aerated stabilization basin treated pulp mill wastewater and the oil sands tailings pond water. The influence of the feedwater characteristics and the ice column contaminant concentration and distribution patterns induced by the degree of freezing during the spraying on the release of impurities were examined. The contaminant separation efficiency was not significantly influenced by the characteristics of the wastewaters. A dramatic decrease of chemical oxygen demand, total organic carbon, conductivity, color (pulp mill effluent), and Cl\u-. and SO-\(2/4) (oil sands tailings pond water) concentration in the early meltwater occurred in all ice columns produced with drainwater formation during spraying. Most impurities entrapped within the ice columns had moved to the bottom of the columns, therefore a greater volume of high-quality meltwater was produced. Release of impurities from these ice columns was best described using a power equation. Reduction of meltwater impurity concentration was much slower when the impurities were distributed uniformly in the ice columns as occurred when no drainwater was produced during spraying. In this case, the decay of the meltwater impurity concentration was best predicted using an exponential function. Preferential release of one type of contaminant over others occurred under some experimental conditions.
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... Scott, EA Richards & Y.(Bill) Liu University of Alberta, Edmonton, Alb., Canada ABSTRACT: A 12 m high geogrid reinforced test embankment constructed of cohesive soil, which contains three reinforced and one un-reinforced test... more
... Scott, EA Richards & Y.(Bill) Liu University of Alberta, Edmonton, Alb., Canada ABSTRACT: A 12 m high geogrid reinforced test embankment constructed of cohesive soil, which contains three reinforced and one un-reinforced test section has been built near Devon, Albcna The ...
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Large volumes of the tailings produced as a result of mineral and energy production are disposed of on the Earth's surface. A major concern of mining operations is how to minimize the environmental impact and reduce the storage... more
Large volumes of the tailings produced as a result of mineral and energy production are disposed of on the Earth's surface. A major concern of mining operations is how to minimize the environmental impact and reduce the storage volume of tailings. In addition, pressure to optimally use scarce water resources, especially in arid regions, is critical. Maximum recycle and reuse
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A grout for use in pile installation in permafrost is described. The high alumina cement (Ciment Fondu) based grout cures by rapidly evolving heat which maintains it above 0 °C until it hydrates and hardens. The laboratory development... more
A grout for use in pile installation in permafrost is described. The high alumina cement (Ciment Fondu) based grout cures by rapidly evolving heat which maintains it above 0 °C until it hydrates and hardens. The laboratory development program of the mix design along with the cement admixtures which allows the grout to cure at temperatures as low as −10 °C and to remain workable during field use is reviewed. The development of installation procedures for the grout during construction of short range radar foundations is described along with field measurements of the compressive strength and the temperature profiles of the grout after placement in permafrost as cold as −14 °C. The Ciment Fondu grout performed according to the design requirement of hardening without freezing in permafrost colder than −10 °C during the installation of about 2000 piles for part of the short range radar project. Key words: permafrost, grout, laboratory, field, installation procedure, mix design.
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The effect of a temperature gradient on the process of moisture movement within the landfill environment has not been studied in cold-climatic regions. A laboratory study investigating the migration and accumulation of moisture within... more
The effect of a temperature gradient on the process of moisture movement within the landfill environment has not been studied in cold-climatic regions. A laboratory study investigating the migration and accumulation of moisture within shredded municipal refuse subjected to a temperature gradient is reported. The laboratory study consisted of four series of experiments involving three samples in each series. The measured parameters included water intake rate from a free water source, final moisture content profiles, and temperature gradient. In each series of experiments, water intake to the sample was attributed to the freezing process. The parameter which characterizes the relationships between the measured water intake rate and temperature gradient is the segregation potential. The results of the tests showed that moisture migrates through the freezing refuse to form ice lenses. The significance of this moisture movement during the cold weather is the increase in the leachate prod...
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In situ ground freezing to obtain undisturbed samples of a loose sand beneath the Duncan Dam in British Columbia is described. This was the first known use of ground freezing to assist in obtaining samples at depth greater than 10 m in... more
In situ ground freezing to obtain undisturbed samples of a loose sand beneath the Duncan Dam in British Columbia is described. This was the first known use of ground freezing to assist in obtaining samples at depth greater than 10 m in Canada. Once frozen, the sand was cored and brought to the surface using a Cold Regions Research and Engineering Laboratory core barrel, which is used extensively in permafrost regions. The design, installation, and performance of the liquid nitrogen freezing systems are described in detail. The drilling, sampling, and preparation of the frozen core for transport to the testing facility are also outlined. The quality of the core retrieved during the sampling was judged to be excellent, and good agreement was found between the void ratios measured using both the frozen core and high-quality gamma–gamma density logging techniques, which were performed adjacent to ground-freezing and sampling locations. Key words : ground freezing, cohesionless soils, un...
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A study has been carried out to investigate the influence of fines and gradation on the skeletal collapse behaviour of loosely prepared sand samples. Loose sand samples, formed by moist tamping and consolidated to the same effective... more
A study has been carried out to investigate the influence of fines and gradation on the skeletal collapse behaviour of loosely prepared sand samples. Loose sand samples, formed by moist tamping and consolidated to the same effective stress level, were prepared with varying percentages of both plastic and non-plastic fines (< 74 μm) and non-plastic fine sand (> 74 μm). Samples were isotropically consolidated and subjected to monotonic undrained triaxial compression. Results indicate that increased percentages of fines (< 74 μm) have a pronounced effect on the monotonic undrained behaviour at large strains (> 0.5%). This change is represented by a decreased strain softening behaviour and a shifting of the steady-state line. Variation of the gradation of the host sand appears to have little effect on the monotonic undrained behaviour. A supplemental study, involving use of the scanning electron microscope, was carried out to evaluate the findings of the test program in term...
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Loose cohesionless materials can collapse during either static or dynamic loading, resulting in a rapid buildup of pore pressure and associated reduction in shear resistance. As the cohesionless material collapses, it rapidly looses... more
Loose cohesionless materials can collapse during either static or dynamic loading, resulting in a rapid buildup of pore pressure and associated reduction in shear resistance. As the cohesionless material collapses, it rapidly looses resistance until the acting shear stress decreases to the available residual or steady-state strength. Specially designed stress-path testing has been performed on sand to investigate this collapse process. Results from this test program and previously published data show that a state boundary can be defined when a cohesionless material moves from peak to steady state along a constant void ratio stress path regardless of whether it is loaded drained or undrained. Further, it is demonstrated that the state boundary represents a surface in the effective mean normal stress–deviator stress–void ratio space. Hence, flow slides and liquefaction can be initiated when the stress path followed during either drained or undrained loading attempts to cross this stat...
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This note presents the results of a limited number of laboratory-scale pile load tests to establish those modifications to current pile construction procedures that would be most effective in increasing pile capacity. The results indicate... more
This note presents the results of a limited number of laboratory-scale pile load tests to establish those modifications to current pile construction procedures that would be most effective in increasing pile capacity. The results indicate that the properties of the backfill (ice content, salinity, and size of annulus) have a significant influence on short-term pile capacity, while the properties of the native soil are less important. The results demonstrate that the pile capacity can be maximized through the use of nonsaline sand backfill. In saline soils, the shear strength at the backfill - native soil interface may govern the design, and must be evaluated together with the adfreeze strength at the pile-backfill interface. The results also demonstrate that the roughness of the outside surface of the pile has a significant influence on adfreeze strength. Sandblasting the pile surface doubled the adfreeze strength at the pipe-backfill interface. This effect appears to be due to incr...
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The procedure of obtaining design ice loads on arctic structures using the American Petroleum Institute (API) Bulletin 2N is first outlined. Then a summary of ice forces measured in the Beaufort Sea and in the laboratory is given,... more
The procedure of obtaining design ice loads on arctic structures using the American Petroleum Institute (API) Bulletin 2N is first outlined. Then a summary of ice forces measured in the Beaufort Sea and in the laboratory is given, followed by an examination of the physical principles underlying ice–structure interaction. The current trend of advocating a lower design ice pressure is noted and argued against. It is felt that the indentation formula presented in API Bulletin 2N may be capable of providing a simple, reasonable estimate for the design ice pressure provided a modified definition of strain rate is used. Key words: ice pressure, ice forces, indentation, arctic offshore structures.
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A pile load test program carried out in Iqaluit, Northwest Territories, to provide design information for the Short Range Radar sites is described. The program consisted of testing 10 steel pipe piles with various surface modifications... more
A pile load test program carried out in Iqaluit, Northwest Territories, to provide design information for the Short Range Radar sites is described. The program consisted of testing 10 steel pipe piles with various surface modifications backfilled with clean sand and 4 Dywidag bars backfilled with Ciment Fondu™ grout. All tests were performed in saline permafrost. This paper describes the site conditions, installation procedures and pile uplift load testing procedures, and results of the pile load tests. The beneficial effect of modifications to the pile surface and backfill material is identified. The analysis and discussions of the results are presented in a companion paper. Key words : permafrost, saline, piles, load tests, field, in situ, capacity.
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The Canadian geotechnical engineering community has completed a major collaborative 5 year research project entitled the Canadian Liquefaction Experiment (CANLEX). The main objective of the project was to study the phenomenon of soil... more
The Canadian geotechnical engineering community has completed a major collaborative 5 year research project entitled the Canadian Liquefaction Experiment (CANLEX). The main objective of the project was to study the phenomenon of soil liquefaction, which can occur in saturated sandy soils and is characterized by a large loss of strength or stiffness resulting in substantial deformations. In many areas of Canada, large structures are constructed on or comprise sandy soils, e.g., some major hydroelectricity earth dams and many tailings impoundments in the mining industry. The behaviour of loose sandy soils can be difficult to predict, but can have a significant financial impact on these types of engineering structures. Consequently, the intent of the CANLEX project was to improve the overall understanding of soil liquefaction. This paper provides an overview of the CANLEX project, outlining the project objectives, major achievements, and conclusions. Four companion papers describe diff...
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To study the mechanical behaviour of ice rubble, triaxial compression tests are performed on broken ice samples. Using the phenomenological approach, the stress–strain curves of normally consolidated broken ice are compared and contrasted... more
To study the mechanical behaviour of ice rubble, triaxial compression tests are performed on broken ice samples. Using the phenomenological approach, the stress–strain curves of normally consolidated broken ice are compared and contrasted with those of other geomaterials that display high plastic compressibility. Key words: broken ice, geomaterials, mechanical behaviour, stress–strain curves.
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The results of a laboratory study to determine the influence of soil salinity, pile surface treatment, pile backfill material, and temperature on the adfreeze bond strength and deformation of model piles are presented. The influence of... more
The results of a laboratory study to determine the influence of soil salinity, pile surface treatment, pile backfill material, and temperature on the adfreeze bond strength and deformation of model piles are presented. The influence of salinity and temperature on the adfreeze strength is shown to be related through the unfrozen water, and similar strength results were obtained at similar unfrozen water contents. Salinity in the backfill material of 10 and 30 ppt caused reductions in the adfreeze bond strength of 80–99%. Similar salinities within the native soil reduced its shear strength causing the location of the failure to change from the pile–backfill interface to the backfill – native soil interface when nonsaline backfill was used. Sandblasting of the pile surface to remove any surface coating resulted in adfreeze bond strengths two to three times greater than those measured on nonsandblasted piles. The use of cementitious grout to replace the sand slurry backfill resulted in ...
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The construction of an underpass in the City of Edmonton required the temporary relocation of the CNR main-line prior to the construction of a permanent bridge. The line was placed close to the underpass excavation which was supported by... more
The construction of an underpass in the City of Edmonton required the temporary relocation of the CNR main-line prior to the construction of a permanent bridge. The line was placed close to the underpass excavation which was supported by a tie-back sheet pile wall. Because of the stringent requirements associated with the presence of the railway line, the supports were designed on a conservative basis and observations of tie-back loads were taken over a period of 7 months.This note presents the observations of tie-back loads from January to July, 1977. Following installation in accordance with the design requirements, substantial fluctuations in tie-back load were observed for about 3 months. Then the loads fell off gradually to about 50% of the originally applied values. The variation of the load with time bears a strong correlation with average air temperature and is accounted for by the alternate freezing and thawing of the ground adjacent to the sheet pile wall. The ultimate dec...
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As part of an overall study to evaluate the properties and processes influencing the rate and magnitude of consolidation for oil sand tailings produced using different extraction processes, laboratory flume deposition tests were carried... more
As part of an overall study to evaluate the properties and processes influencing the rate and magnitude of consolidation for oil sand tailings produced using different extraction processes, laboratory flume deposition tests were carried out with the objective to hydraulically deposit oil sand tailings and compare the effects of caustic and noncaustic extraction processes on the nature of beach deposits in terms of geometry, grain-size distribution, and density. The characteristics of the beaches from this research study were compared with other flume deposition test results performed using a variety of tailings materials. A good correlation exists between flume deposition test results using oil sand tailings and the various other tailings materials, especially those with appreciable fines contents with respect to parameters that govern beach slope. These comparisons show the reliability and effectiveness of flume deposition tests in terms of establishing general relationships and ca...
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A state-boundary surface defines a boundary in stress – void-ratio space above which no stress state can exist. The applicability of the state-boundary surface for sand has not gained widespread attention primarily because sand is not... more
A state-boundary surface defines a boundary in stress – void-ratio space above which no stress state can exist. The applicability of the state-boundary surface for sand has not gained widespread attention primarily because sand is not generally considered to be a difficult soil from a design point of view apart from liquefaction. Liquefaction is a phenomenon usually encountered in very loose cohesionless materials. An experimental study relating the drained and undrained behavior of very loose saturated sand is presented. It is shown that the post-peak portion of undrained stress paths travels along the state boundary and that the state boundary can be approximated by a straight line. The slope of this straight line appears to stay constant for very loose sand. There are potentially an infinite number of these lines, which form a three-dimensional surface in deviator stress – effective mean normal stress – void-ratio space. Previously published results by various researchers are use...
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The performance of a 6 m high anchored steel sheet pile retaining wall, constructed to allow CN Rail to twin its main-line track, is presented. The instruments installed gave measurement of the load and its variation along the tieback... more
The performance of a 6 m high anchored steel sheet pile retaining wall, constructed to allow CN Rail to twin its main-line track, is presented. The instruments installed gave measurement of the load and its variation along the tieback anchors; the distribution of the strain along the height of the wall which allowed an earth-pressure distribution to be postulated; and the lateral deflection of the wall. The earth-pressure distributions, inferred from the field measurements, were adequately predicted using the Terzaghi and Peck recommendation coupled with the Boussinesq procedure to account for the train loads. The best-fit lateral pressure distributions were in turn used to calculate displacement profiles by modelling the wall as a beam. The results matched the measured profiles reasonably well, thus endorsing a simplified technique for predicting displacements of an anchored wall. Key words : retaining wall, tieback, earth-pressure distribution, wall deflection, railway.
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The level to gently undulating ground on backfilled mined-out areas is referred to as reclaimed mine spoil. This paper deals with model footings for light structures placed on such soil. For the case considered, the spoil is dominated by... more
The level to gently undulating ground on backfilled mined-out areas is referred to as reclaimed mine spoil. This paper deals with model footings for light structures placed on such soil. For the case considered, the spoil is dominated by a disaggregated clay shale. Settlement of the spoil arises from self-weight, an increase in overburden, and saturation. This last source takes place as the water table rises or when surface infiltration occurs. This latter cause is the source of potentially damaging settlement and is the focus of the research work. Four footings, each 1 × 1 m, were placed on a 1 m thick mat composed of either preloaded, compacted soil, compacted soil/flyash mixture, or compacted flyash. Each footing was loaded to 61 kPa. The settlement was small under this load but every footing settled intolerably when the soil below the footing was saturated. However, the results have merit. Further design consideration needs to be devoted to obviating the ingress of surface water...
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A vast amount and variety of mine tailings are produced around the world each day. These mining wastes must be properly managed. To evaluate mine tailings disposal technology, the appropriate engineering properties of the tailings must be... more
A vast amount and variety of mine tailings are produced around the world each day. These mining wastes must be properly managed. To evaluate mine tailings disposal technology, the appropriate engineering properties of the tailings must be ascertained. The results of a laboratory investigation on the engineering properties of four different tailings are presented. First, some of the basic properties of the tailings are described. Large-strain consolidation tests and hydraulic conductivity tests are then described. The techniques for saturating and placing the tailings sample prior to carrying out the consolidation tests are given. Column drying and shrinkage tests for investigating the desiccation behavior of mine tailings are outlined. Furthermore, water retention characteristic tests using both the pressure-plate extractor and the saturated salt solution desiccator are outlined. Finally, shear strength parameter tests are described. The engineering properties derived from these tes...
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Shear wave velocity (Vs) measurements were carried out in a triaxial testing program on three different cohesionless soils. The Vswas measured using bender elements during consolidation and at ultimate steady state. After consolidation... more
Shear wave velocity (Vs) measurements were carried out in a triaxial testing program on three different cohesionless soils. The Vswas measured using bender elements during consolidation and at ultimate steady state. After consolidation the soil samples were loaded in shear under constant strain rate triaxial compression either drained or undrained to determine their ultimate steady or critical state (USS) at large strains. The Vsmeasurements were used to develop relationships between the void ratio (e), mean normal effective stress (p′), and Vs. The shear loading results were expressed within the framework of critical state soil mechanics. The results of the Vsand USS information were combined with the state parameter concept to develop an equation to use field measured Vsto estimate the in situ consolidation state within a soil. Thus, the contractive–dilative boundary with respect to vertical effective stress for large strain loading can be determined from in situ measurements of V...
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The Canadian geotechnical engineering community has completed a major collaborative 5 year research project entitled the Canadian Liquefaction Experiment (CANLEX). The main objective of the project was to study the phenomenon of soil... more
The Canadian geotechnical engineering community has completed a major collaborative 5 year research project entitled the Canadian Liquefaction Experiment (CANLEX). The main objective of the project was to study the phenomenon of soil liquefaction, which can occur in saturated sandy soils and is characterized by a large loss of strength or stiffness resulting in substantial deformations. The intent of this paper is to compare, interpret, and summarize the large amount of field and laboratory data obtained for six sites in Western Canada as part of the CANLEX project. The sites are compared in terms of both flow-liquefaction and cyclic-softening considerations. The paper presents a number of conclusions drawn from the project as a whole, in terms of both fundamental and practical significance.Key words: sand, flow liquefaction, cyclic softening, CANLEX.
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Helical Anchors, also known as Screw Anchors, have been used in many engineering applications. They provide structural stability against axial compression, uplift, overturning, and lateral forces. Predicting the loading capacity of... more
Helical Anchors, also known as Screw Anchors, have been used in many engineering applications. They provide structural stability against axial compression, uplift, overturning, and lateral forces. Predicting the loading capacity of helical anchors installed in Alberta is difficult because of the complexity of the sediments found in Alberta due to the glacial history. Therefore, a testing program, including compression, tension, and lateral pile loading tests, was carried out on screw anchors installed in typical Alberta soil. The Cone Penetration test (CPT) was adopted as the site investigation method for determining the soil parameters within the soil profile. The program is focused on developing a more reliable approach that incorporates an in situ testing method (CPT) into the design. This paper presents the development of the field testing program including site characterization using CPT, instrumentation, and installation of the test anchors.