摘要:

Thermal conductivities were determined for 10 fine-grained soils obtained from potential borrow pit areas along the proposed route of the Mackenzie Highway, N.W.T., and from the nearly completed section of the Mackenzie Highway, just south of Inuvik. The moisture contents and densities of the test specimens were based on the standard Proctor density curves. The measurements were made by the transient heat-flow method using a line heat source. The values were in good agreement with Kersten's data obtained by the steady-state heat flow method.Grain-size, mineralogical analyses of the clay-size fraction, Atterberg limits, and standard Proctor density determinations are given for all 10 soils.

ISSN:0008-3674    

DOI:10.1139/t75-033

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Laboratory model pullout tests were conducted with a cylindrical object, 1 sediment, 1 objectin situtime, 3 electrode configurations, and electric potential gradients of 0, 0.25, and 0.5 V/cm to determine the effect of electroosmosis on reducing force and time requirements for breaking objects free of soft sediments.Results show electroosmosis to be very effective in reducing breakout times. The relationship between the breakout force ratio and breakout time can be expressed in terms of 2 empirical parameters. Electrical power requirements to achieve breakout appear to be independent of electrode configurations but do depend on electric potential gradients.

ISSN:0008-3674    

DOI:10.1139/t75-034

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A detailed terrain classification was carried out as part of a study on the Dempster Highway from Mile 166 to Mile 290.5, the Yukon–Northwest Territories Border. The objective was to establish a rational basis for field testing and subsurface exploration programs in the future and the evaluation of the potential effects upon the physical environment of the construction of highways and other transportation facilities in the Arctic, on terrain composed of sedimentary rocks which have not been glaciated. Terrain units were established on the basis of geology, vegetation, topography, and patterned ground. The subsurface sediments were mapped mainly as outcrops of weathered shale and sandstone. The sandstone was found to be the most stable foundation and borrow material. The shale was found to be mainly clay with high ice contents near the surface, and was observed to be very unstable when thawed. A number of plant communities, which differed significantly from a geotechnical point of view, were identified.

ISSN:0008-3674    

DOI:10.1139/t75-035

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Traditional methods of mine tailings disposal are shown to compromise public safety and protection of the environment. Two designs are described which more closely meet these concerns. They represent a departure from the traditional methods and should stimulate a re-appraisal of previously held concepts of tailings disposal.

ISSN:0008-3674    

DOI:10.1139/t75-036

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The Scandinavian and Canadian experiences are reviewed and analyzed in the light of recent experiments involving the effects of added salts on the remolded shear strength and the liquid limits of two Ottawa area clays, both of which had low porewater salinity in their natural state. The response was similar to that observed in the Scandinavian marine clays where the sensitivity decreases as the salinity increases. It is concluded that the similarities relating to the influence of chemical factors are greater than previous interpretations have indicated. The precise relationship between porewater salinity and sensitivity in Leda clay appears to be unique to each sample and a broad geographic relationship should not be expected. Even short range similarities may be obscured by the generally low salinities of the Canadian marine clays and the great variability in other factors, such as texture and degree of cementation, which also affect the sensitivity.

ISSN:0008-3674    

DOI:10.1139/t75-037

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The penetration rate effect on the strength of clay and sand was studied by constant velocity penetration tests performed with various velocities up to 2.662 f.p.s. (81.14 cm/s). The clay and sand targets were of various strengths and moisture contents. The construction of the penetrometer is similar to that used in static tests, and in each test the cone resistance, sleeve friction, and penetration velocity were recorded.Experimental results indicated that for granular soils the effects of penetration velocity on cone and sleeve friction resistances are insignificant, whereas, for cohesive soils, the increase in penetration velocity causes an increase in the cone and friction resistances. It is found that for the cohesive soils the ratio of dynamic to static strength is directly proportional to the logarithm of the penetration velocity ratio. The proportionality constant of this relationship defined as soil viscosity coefficient depends on the physical properties of the soil and the soil strength and its value increases as the strength of the soil decreases. For the tested soils various values of the soil viscosity coefficient are proposed for different strength ranges. The validity of the analytical relationship is established for penetration velocities ranging from 0.0044 f.p.s. (0.13 cm/s) to 18 f.p.s. (550 cm/s).

ISSN:0008-3674    

DOI:10.1139/t75-038

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

For the past 2 years, detailed field and laboratory studies have focused on the hydrogeologic investigation of a proposed, subsurface, radioactive waste management site in Alberta at the Defence Research Establishment Suffield. The basic approach has involved test drilling and sampling augmented by down-hole geophysical techniques to establish stratigraphic sequences. In addition, piezometers and soil moisture – temperature blocks have been emplaced to define the saturated–unsaturated flow regime. Laboratory studies of drift and bedrock samples have characterized variations in mineralogy, texture, and sorptive properties.Piezometric data indicate that the site is predominantly a recharge area with median values of permeability ranging from 2.8 × 10−2to 2.8 × 10−4 ft/day (1 × 10−5to 1 × 10−7 cm/s). To reach the zone of saturation, recharge water must pass downward through a maximum of 120 ft (36.3 m) of unsaturated, glacial drift with cation exchange capacities ranging from 25 to 105 mequiv per 100 g. The absence of water level fluctuations in observation wells and the soil moisture block data indicate that the quantity of water moving downward through the waste management site is small.

ISSN:0008-3674    

DOI:10.1139/t75-039

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Hydraulically placed cemented tailings, with a 30:1 tailings–cement ratio, have been used to backfill large blast-hole stopes at Fox Mine in Northern Manitoba. Heavily reinforced concrete bulkhead supports were provided to prevent intrusion of hydraulic fill materials into the mine drifts. Instrumentation was installed through several of these bulkheads to measure horizontal stresses on the bulkheads and pore water pressures at several points in the fill. Fill quantities, fill levels, and water balance were monitored in conjunction with the instrumentation. Measured bulkhead stresses were much less than anticipated due, apparently, to the effects of arching and cementation. Timber bulkheads, designed on the field measurements, were found to perform satisfactorily in subsequent stope pours. Backfill drainage appeared to follow the general predictions made from laboratory permeability tests on control cylinders.

ISSN:0008-3674    

DOI:10.1139/t75-040

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

When the basement floor of a church in the New Edinburgh area of Ottawa heaved, it was discovered that the concrete under the floor had been reduced to a mushy consistency due to attack by sulfate solution formed by the oxidation of pyrite in the underlying shale. Gypsum was the main product in the weathered zone of the shale. It is shown that heaving resulted from the growth of gypsum crystals between the lamellae in the shale. Jarosite, which is formed by a series of oxidation reactions from pyrite, was also found in the weathered shale. Some oxidation reactions occur only in the presence of sulfur bacteria. The cementitious portion of the concrete was leached out by acid, leaving a weak porous material. The importance of safeguarding concrete in contact with potentially expansive shales from sulfate attack is emphasized.

ISSN:0008-3674    

DOI:10.1139/t75-041

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The west abutment of the Little Smoky River bridge in central Alberta showed evidence of movement toward the river. Subsequent investigations revealed that the landslide on which the bridge was built was moving slowly. The Little Smoky River occupies a broad preglacial valley eroded in Upper Cretaceous clay shales and is re-excavating tills deposited during glaciation. The site was instrumented with tiltmeters to define the failure planes. Soil strength parameters were determined on samples obtained from boreholes. Analysis revealed that the failure mechanism consisted of a series of blocks each acting as a separate entity but all merging to a common lower shear zone. The key to understanding the failure is the failure of the individual blocks progressively from the toe to the scarp. The slow movement allows the bridge to be kept in service. Since the first block is subject to river erosion, its stabilization would be a step in stabilizing the slope.

ISSN:0008-3674    

DOI:10.1139/t75-042

出版商:NRC Research Press    

年代:1975

数据来源: NRC