摘要:

A major landslide of the flow variety took place in the fall of 1924 in the Lake St. John region of the Province of Quebec, Canada. The slide involved 2.5 million cubic yards (2.0 × 106 m3) of clay and resulted in loss of life and considerable damage to property. A review of the circumstances preceding failure, the geotechnical properties of the clay and the mechanism of the slide movements is presented in the paper.

ISSN:0008-3674    

DOI:10.1139/t71-001

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

As part of the design of an important pile foundation, an extensive testing program has been carried out in order to determine the type and the necessary characteristics of the pile best suited to the site and the structure to be designed. Three types of piles have been tested, i.e. timber piles, a steel H-pile, and a Herkules precast concrete pile. The Herkules and H-piles were equipped with deformation gauges and driven in 10-ft (3-m) increments to a total length of 70 ft (21 m), a loading test being carried out at the end of each increment. Thus, it was possible to determine the variations of the bearing capacity, the point–resistance, and the skin-friction as functions of the embedded pile length.The aim of this paper is to present the technique used and the results obtained.

ISSN:0008-3674    

DOI:10.1139/t71-002

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Consideration is given to the prediction of undrained movements which may occur due to contained yielding beneath embankments on muskegs. The study shows that insignificant improvement in the predicted undrained movements can be expected by assuming the soil to be an elastic cross-anisotropic material unless the independent shear modulus is measured. All predictions were made using the finite element technique and assuming the soil to be an elastic isotropic yielding material. The settlement predictions are in good agreement with the recorded construction movements of the two case records studied.The first analysis clearly shows that the yielded zone is restricted to a soft clay layer immediately beneath about 20 ft (6.1 m) of peat and marl. The predictions show that berms have a beneficial effect in containing this zone and reducing differential settlement. Horizontal movements are significant in comparison with the vertical movements except near the centerline.In the second case, analysis of a shallow peat layer underlain by stiff clay shows that the predicted settlement and shape of yield zone are largely dependent on whether the lower boundary is assumed perfectly rough or shearless.

ISSN:0008-3674    

DOI:10.1139/t71-003

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

There is no classification of river and lake ice that simultaneously takes into account the history of ice formation, the structure of the ice cover, and the texture of the various ice types. Such fundamental information is a prerequisite to the determination and discussion of their physical and mechanical properties.The first part of this classification is a brief description of the formation and the physical properties of the three important ice layers making up the ice cover. The second aspect of the classification deals with the texture of various ice types.It is possible to determine certain meteorological conditions which have occurred during formation of primary ice from on-site observations and the study of ice profiles. Hydrodynamic information can be obtained from the study of secondary or superimposed ice. Presently, major events causing layers of frazil slush, congealed frazil slush, and drained snow ice can easily be recognized and interpreted.The evaluation and eventual prediction of the mechanical properties of the various ice types according to such a classification will be helpful in solving engineering and navigation problems.

ISSN:0008-3674    

DOI:10.1139/t71-004

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Experimental creep data on model cylindrical retaining structures formed from two frozen soils, saturated Ottawa sand and Ontonagon (Sault Ste. Marie) clay, are presented. The sand–ice behavior in the model barrier is analyzed using a constitutive relationship which includes the state of stress, state of strain, time, and temperature. Displacement rates at the inner wall surface calculated according to the creep relationship agree with measured rates for properly chosen values of a parameter which modifies the contribution of the deviatoric stress component to the creep rate.The axial force observed at the sample ends provided information as to the soil–ice behavior during primary and secondary creep. For the sand–ice material this axial force did not reach its final value until steady-state creep was approximated. This indicates that Poisson's ratio may change depending on the stage or development of the creep deformations. This behavior was not observed for the frozen clay. The stress – strain – time behavior for the two soils differed considerably due to the greater amounts of unfrozen water in the frozen clay (about 50 %) as compared with the saturated Ottawa sand (little or none).

ISSN:0008-3674    

DOI:10.1139/t71-005

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

In situvane tests were carried out in a number of different muskeg deposits to examine the mechanism of failure and the effect of variation in vane size and speed of testing. The failure mechanism in peat was found to be similar to that in soft clays. The apparent shear strength varied with vane size but was independent of testing speed. There was an optimum vane size of 10 cm diameter.Block samples were obtained from one site for laboratory vane tests to investigate anisotropy in the strength of the peat.In situtests for anisotropy using vanes of varying shape confirmed the laboratory results, and showed that strengths on the vertical plane could be 100 % higher than those on the horizontal plane.

ISSN:0008-3674    

DOI:10.1139/t71-006

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Construction of the Empress Hotel began in 1904 on a site reclaimed from the sea. The combined load of the fill and the structure has caused several feet of compression in the underlying marine silty clay. Fortunately, settlement observations have been made regularly since1912 and the nature of the foundations and the structure allow reliable extrapolation back to the first loading. This paper describes the site, the applied loading, the settlements observed, and the results of laboratory tests on samples recently obtained. The observed primary and secondary consolidation settlements are compared with computed values.

ISSN:0008-3674    

DOI:10.1139/t71-007

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A slurry trench cut-off was constructed for the Duncan Dam. Two failures of the trench wall occurred during construction, one of which required relocation of a portion of the cut-off to avoid delaying construction of the dam. The relocated cut-off was successfully constructed from a higher ground elevation, using a denser slurry, produced by mixing in more silt. To analyze the failures a nomograph was developed which can be used to determine the required slurry density for trench wall stability. The stability analysis, first developed by Morgenstern and Amir-Tahmasseb was confirmed. The hydrostatic head drop across the cut-off varies from 85 to 90 % of the gross head on the dam. Differential settlement of almost 10 ft (3 m) has occurred along the cut-off after completion without detrimental effects. Readings over the last 3 years indicate no reduction in the efficiency of the cut-off.

ISSN:0008-3674    

DOI:10.1139/t71-008

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The formulation is presented of the equations governing the solution of true three-dimensional consolidation problems by means of finite element methods. The numerical procedure for handling the resulting algebraic equations is described briefly and detailed results from the solution of several problems are given. Excellent agreement is found between the numerical analysis and existing closed form solutions.

ISSN:0008-3674    

DOI:10.1139/t71-009

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Triaxial extension tests were carried out on hollow cylinder sand specimens of identical external geometry under identical test boundary conditions. For reference, solid cylinder sand specimens were tested under identical boundary conditions. The radial width of the hollow cylinders was varied and the test parameters of specimen strength and deformation were found to vary systematically with the specimen radial width. The hollow cylinder extension strengths were significantly lower than the corresponding solid cylinder strengths. In the extreme case, a difference in shearing angle values of 11° was found. However, the behavior of these specimens was found to be quite consistent, when allowance was made for energy spent in volume dilatation and approximately constant frictional strengths were obtained, independent of specimen configuration. The differing modes of behavior of the hollow cylinder sand specimens is considered to be an inherent property of the specimen configuration and this finding has important implications for the interpretation of the conventional extension test.Method of test specimen fabrication and the test procedures are described as well as the hollow cylinder apparatus and an internal load transducer which was used for the measurement of the axial load in these experiments.

ISSN:0008-3674    

DOI:10.1139/t71-010

出版商:NRC Research Press    

年代:1971

数据来源: NRC