摘要:

The use of an ultrasonic accelerometer has led to an empirical correlation between the wave velocity and the static mechanical strength deducted from destructive tests made on intact or lime-treated clays, and to an evaluation of the influence of certain physical soil parameters on wave velocity. The results give a good correlation between the dynamic elastic properties deducted from the shear wave velocity and the static mechanical properties of the intact and the lime-treated clays when measured without confining pressure. The results also confirm that the maximum dynamic shear modulus is proportional to undrained shear strength, independently of soil type. The structure of a lime-treated clay is more favorable to the transmission of shear waves than the same clay in an intact state having the same shear strength; the cause of this difference is associated with the compaction energy and the newly formed minerals resulting from the treatment. Finally, the study of these, treated soils has illustrated the effect of the cementation process on the mechanical behavior of clayey soils.Key words: ultrasonic accelerometer, shear wave velocity, clay, lime treated, cementation, elastic properties, static properties. [Journal translation]

ISSN:0008-3674    

DOI:10.1139/t87-043

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The application of the electric cone penetrometer test in snow has been investigated and compared with results from the ram penetrometer test, which is normally used for snow profiling and slope stability analysis. A special cone penetrometer system was built consisting of a sensitive 1 cm2electric cone, depth transducer, and battery-operated chart recorder. The instruments were tested in April 1985 at three different locations in the Swiss Alps and the test results were compared with those of the ram penetrometer tests.The tests yielded repeatable results up to a depth of 4 m with a high resolution of different snow layers. The electric cone tests show more layers than found in the ram profile and snow pit analyses. In soft snow the ram resistances appear to be, on average, about 30% lower than cone resistance values. Recommendations are given for the future use of electric cone penetration testing in snow.Key words: snow, snowpack analysis, cone penetration test, ram penetrometer, cone resistance, ram resistance, ram number.

ISSN:0008-3674    

DOI:10.1139/t87-044

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Since 1982, extensive use has been made of the self-bored pressuremeter in Arctic offshore site investigations. One finding of this work is that thein situgeostatic stress ratioK0of Beaufort Sea clays is apparently unrelated to the overconsolidation ratio (OCR). The procedures and data to support this finding are documented and the finding is discussed in light of the present geological understanding for the area. It is concluded that the independence ofK0from OCR may be quite widespread, a finding that contradicts the widely held tenet regarding the existence of a single-valued function relatingK0,, and OCR. IfK0is regarded as important, then it should be measuredin situ.Key words: self-bored pressuremeter, geostatic stress ratio (K0), Beaufort Shelf, geologic history, overconsolidation ratio.

ISSN:0008-3674    

DOI:10.1139/t87-045

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The physical processes induced in a bituminous (oil) sand by hot fluid injection consist of the transport of heat and mass and the deformation of the solids skeleton. The roles of heat conduction, convection, and the inelastic stress–strain response of sands in the evolution of stresses in a heated bituminous sand are evaluated in this paper, using the example of hot fluid injection into a vertical slit.Reservoir heating occurs by conduction and convection, whereas heat dissipation occurs mainly by conduction. The heated zone around the slit is small, but, because of stress redistribution due to localized tensile and shear failures, the zone of influence of the induced stresses can be quite large. As a result of the anisotropic temperature gradients caused by the geometry of the heated boundary, rotation of principal stresses occurs in a large area near the slit.Key words: sands, tar sands, injection, fracture, no tension, yielding, strain softening, thermal stress.

ISSN:0008-3674    

DOI:10.1139/t87-046

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Meaningful stress and deformation analysis of soil structures requires an adequate stress–strain law. Herein are presented guidelines for selection of parameters for a simple incremental hyperbolic stress–strain law for sand based upon a tangent stiffness that varies with stress level. The parameters are obtained from an examination of laboratory and field measurements available in the literature, and are presented in terms of both penetration value and relative density. The laboratory results indicate the importance of first-time or primary loading versus repeated loading on modulus values. Back analysis of field observations for monotonic loading conditions indicates that primary loading modulus values obtained from triaxial tests are appropriate at low relative density, whereas perhaps higher values, in the repeated loading range, are appropriate at high relative densities.Key words: sand, deformation, analysis, hyperbolic, tangent stiffness, modulus, relative density, monotonic loading, repeated loading.

ISSN:0008-3674    

DOI:10.1139/t87-047

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The hydraulic conductivity of natural clays in the 1.5 m contamination zone below a 15 year old domestic waste landfill has been determined.Water-soluble contaminants such as chloride, sodium, and dissolved organic carbon have migrated about 1.0 m compared with only 15 cm for copper, zinc, iron, lead, and manganese. The migration, primarily by diffusion, has rendered the clay perfect for assessment of clay–leachate compatibility with respect to hydraulic conductivity,k.Oedometer tests on tube samples of the clay yieldedkvalues of 1.4 × 10−8 cm/s with a slight decrease to about 1 × 10−8 cm/s in the upper 20 cm of clay at the waste–clay interface. Direct measurement ofkon "undisturbed" tube samples, reconsolidated to their field stress state and permeated with pore fluid squeezed from adjacent contaminated samples, yielded values of 1.5 × 10−8 cm/s at 1 m depth decreasing to 0.75 × 10−8 cm/s at the interface.The decrease inknear the interface seems to correlate directly with increased pollutant concentration of soluble species, total heavy metal concentration, and a slight decrease in void ratio. The changes inkare so small, however, that for the test leachates and undisturbed test soils at this domestic waste site, it is concluded that the hydraulic conductivity has not changed significantly as a result of contamination.Key words: domestic waste, leachate, hydraulic conductivity, clay barriers, compatibility.

ISSN:0008-3674    

DOI:10.1139/t87-048

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The problem of nuclear waste disposal has emphasized the need for research on blast-induced damage around underground excavations. This paper shows how geostatistical methods might be used to delineate zones of damage when the systematic rock testing approach is used. Some basic concepts of the theory of regionalized variables are presented and then illustrated by a typical application. The conclusions drawn from the latter using the theory of regionalized variables are quite different from those drawn from a previously published study based on the same data but using conventional statistical methods.Key words: rock mechanics, regionalized variable, induced damage, geostatistics, dilatometer.

ISSN:0008-3674    

DOI:10.1139/t87-049

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

With the advent of piezocones — penetrometers measuring both the mechanical resistance and induced pore pressures near the tip during penetration into the soil — a new interpretation of penetrometer test data is possible. This paper presents a review of available interpretation methods for obtaining the undrained shear strength of soft soils, and introduces a new interpretation taking into account measured pore pressures. The undrained shear strength is considered to be solely related to the ultimate cavity expansion pressure, which is one of the components of the tip resistance. The other component is calculated assuming that effective friction is developed at the cone–soil interface.Parametric studies on the parameters required for strength determination based on the proposed method are also presented. Special self-boring pressuremeter tests to obtain relevant values of soil rigidity index, which is a key parameter for cavity expansion modelling, are described. Tests were conducted at three sites having the characteristics of soft sensitive clay, stiff sensitive clay, and clayey silt. The operational undrained strength mobilized during the cone insertion derived from the proposed model is equal to or lower than the CK0U triaxial strength, which depends on soil brittleness. The proposed approach yields results consistent with known soil behaviour at all three sites.Key words: piezocone penetrometer, pressuremeter, excess pore-water pressure, undrained shear strength, rigidity index,in situtests, laboratory test.

ISSN:0008-3674    

DOI:10.1139/t87-050

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

A field test for measuring rock modulus was developed and performed at the site of Darlington Generating Station in shaly limestone. The new method yields a value consistent with the rock-mass modulus evaluated from extensometer measurements in the tunnels.A complementary laboratory program to study the effect of specimen size on the elastic parameter was also performed by using compressional and shear wave velocity measurements. It was shown that beyond a threshold value of size, the Poisson's ratio increases, whereas both dynamic shear modulus and Young's modulus decrease with increasing volume of specimen towards the field value of static modulus.Key words: rock-mass modulus, field tests, shear wave velocity, size effect.

ISSN:0008-3674    

DOI:10.1139/t87-051

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Kananaskis Country is situated in the Front Ranges of the Canadian Rockies in southwestern Alberta. Sedimentary rock thrust northeastwards forms mountain ridges that trend northwest–southeast parallel to the major thrust faults. Older, Palaeozoic rocks—mainly limestone and dolomite—form the ridges and peaks. Younger, Mesozoic rocks—sandstones, quartzites, siltstones, shales, conglomerates, and coals—are more easily eroded and form mountain passes and valleys.A reconnaissance mapped 228 rockslides, 8 km2of rockslide debris and 96 km2of talus. The largest rockslide exceeds 50 × 106 m3. Rockslides are most probable in the Devonian Palliser Formation, then in the Permo-Pennsylvanian Rocky Mountain Group, Mississippian Rundle Group, Devonian Fairholme Group, Mississippian Banff Formation, and the younger detrital rocks. Rockslides are most probable on dip and overdip slopes, followed by reverse-dip slopes, oblique and strike-dip slopes, and underdip slopes. Large rock masses have not slid on slopes below their basic friction angle,The reconnaissance shows that certain facilities in valleys below steep mountain slopes are exposed to rockslide hazards, and provides a guide for the location of new facilities. Analyses of two mountain slopes show that there are large, hypothetical hazards in Kananaskis. Rockslides are likely and could be destructive.Key words: Front Ranges, Rocky Mountains, Alberta, rockslides, hazards.

ISSN:0008-3674    

DOI:10.1139/t87-052

出版商:NRC Research Press    

年代:1987

数据来源: NRC