摘要:

Increased urbanization and a more intense land use tends to emphasize the landslide problem. This report discusses landslides within the City of Edmonton in general terms and detailed analyses are not presented.Thirty-seven landslide sites are enumerated. Old coal mine subsidence, lateral erosion by the North Saskatchewan River, and construction activity are considered to be the major causes. Man induced landslides account for nearly three-quarters of the slides listed.About one half of the landslides have their seat of failure in the poorly indurated clay shales of Upper Cretaceous age that forms the bedrock. A few are located in fill sections and the remainder are in the glacial lake clays that form the surface deposits of the area.

ISSN:0008-3674    

DOI:10.1139/t77-001

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The methods of probability theory are used to develop probabilistic models for predicting the total settlement (based on either consolidation test data or the results of standard penetration tests) and the time rate of settlement for a compressible clay layer in terms of uncertain values for soil compressibility and loads. The total settlement and the time rate of settlement are well approximated by log-normal distributions. Results calculated by use of the probabilistic approach are compared with settlement values measured in a well documented case history with good supporting laboratory test data.

ISSN:0008-3674    

DOI:10.1139/t77-002

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Based on the information gathered during a design pile testing program and the subsequent construction of a large pile foundation in Quebec City, the potential and limitation of the wave equation method for analysing pile driving behaviour are demonstrated.The application of the wave equation method to instrumented precast concrete piles driven under well controlled conditions leads to excellent predictions both in terms of driving stresses and of ultimate bearing capacities.The same high quality of prediction is obtained for a steel H-pile and a precast concrete pile driven incrementally to a depth of 53 ft (16.2 m) in a uniform sand deposit. However, proper simulation of the joints is required for the precast concrete pile.On the contrary, a very poor correlation between computed and observed ultimate capacities is obtained for the production piles. This is attributed to the poor reliability of the blow counts used as input data in the classical wave equation method of analysis.

ISSN:0008-3674    

DOI:10.1139/t77-003

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Undrained cyclic loading of triaxial samples of a sensitive Champlain Sea clay at deviatoric stress levels in excess of 50% of the static shear strength is shown to produce large deformations and eventual shear failure. Continued deformation of the clay under repeated loadings is believed to result from a progressive destruction of the cemented soil structure. Effective stress failures result from an increase in the excess pore water pressures within the sample.

ISSN:0008-3674    

DOI:10.1139/t77-004

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The overconsolidated soils and soft rocks which form a large proportion of foundation materials in Western Canada typically have a substantial component of their total deformation of an immediate (time independent) nature. This makes them particularly suitable for application of pressuremeter testing when deformation characteristics are sought for settlement or heave analysis.The presented study is a continuation of work on pressuremeter testing carried out at the University of Alberta systematically since 1971 with a view to developing a pragmatic approach to a complex problem of foundation deformation analysis.Described in detail are pressuremeter testings on three sites in Western Canada where documented case histories of deformation behavior were available. The first case history analysed was a settlement of Mount Blackstrap near Saskatoon, Saskatchewan, which is a man-made ski hill founded on very deep till strata. The second case was the settlement of concrete silos in Calgary, Alberta, founded on a layer of dense, coarse gravel. The third study was concerned with an analysis of a load test on a bored pile embedded in Cretaceous bedrock at the Calgary Airport.At all three sites the pressuremeter derived moduli were used in back-analysis of foundation behavior and the results were compared with previously recorded field data. An agreement between the back-analysis and field data in some cases and discrepancies in others indicate the limitations of this approach to pressuremeter testing in these types of foundation materials. The results are discussed and conclusions are drawn on the basis of these as well as the previously studied case histories.

ISSN:0008-3674    

DOI:10.1139/t77-005

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A method for thein situmeasurement of the horizontal and vertical coefficients of permeability and consolidation is presented in this paper.Following a brief review of the theories developed by Gibson for the constant and falling head tests, the results of the integration of the consolidation equations are given in the case of a cylindrical permeameter in an orthotropic soil. An experimental method for measuringkv,kh,cv, andchis described. The main difficulties are related to the placement of the permeameter with the least possible disturbance of the soil and to the accurate measurement of the flow.The first problem has found a satisfactory solution by using the self-boring technique for the placement of the permeameters. The flow is measured with an automated unit, described in this paper, which allows for a rigorous stabilisation of the applied depression and a resolution of 10 mm3in the measurement of the volumes.[Journal translation]

ISSN:0008-3674    

DOI:10.1139/t77-006

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Various theories for determining the earth pressure on shaft linings in cohesionless soils are discussed, and results are presented for a Coulomb-type analysis with a conical sliding surface. The assumed shape of the failure surface approximates closely the one given in published results obtained by the method of characteristics. The simplicity of the cone permits an investigation of a number of parameters,e.g. the earth pressure coefficient on radial planes, which turns out to be a decisive parameter in the analysis, and accounts for the widely differing published values for earth pressures on shaft linings. Certain theories could lead, especially at greater depths, to rather conservative designs.A similar theory is also presented for earth pressures on shafts in cohesive soils. In this case the possibility of base failure must be considered as well, and it is shown that this might be the deciding failure mechanism.

ISSN:0008-3674    

DOI:10.1139/t77-007

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The safety factor for piping by heave was conceived as a minimum criterion (probably in 1929 by Baumgart and Davidenkoff, certainly in 1943 by Terzaghi). The minimum condition of the criterion is frequently omitted. This paper gives the relation of the criterion to first principles and indicates solutions for the piece-wise homogeneous and linear inhomogeneous soil. Theoretical and experimental evidence shows that the omission of the minimum condition yields upper bound estimates for the safety factor and is equivalent to assuming homogeneity. It is concluded that in general the assumption of homogeneity is significantly on the unsafe side.

ISSN:0008-3674    

DOI:10.1139/t77-008

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Samples of Winnipeg tan silt, brown clay, grey clay, and grey plastic clay were examined using X-ray diffraction and the scanning electron microscope (SEM). These same samples from the Winnipeg Floodway test site had been the subject of an extensive investigation by Freeman, who had shown that they were anisotropic in shear strength and permeability.Evidence was obtained that the presence of non-clay minerals in varves, veins, and inclusions in otherwise clayey material was a cause of anisotropy. Clay particle horizontal orientation and the presence of horizontal planes of uniformly graded silt are further reasons for anisotropy. In addition photographic data were obtained of shape, size, and grouping of the soil particles.

ISSN:0008-3674    

DOI:10.1139/t77-009

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The paper presents the results of model tests concerning the bearing capacity of a strip foundation resting on stratified subsoil. The foundation was loaded with vertical and inclined forces, acting axially and eccentrically. The subsoil assumed for the testing consisted of a strong layer overlying a weak one. Three principal problems were analysed based on results obtained from the model tests as follows: the effect of stratified subsoil on the foundation's bearing capacity, the effect of the loading system on the foundation's bearing capacity, and the effect of stratified subsoil on the settlement of the foundation. In the concluding remarks the mechanism of failure for stratified subsoil and practical notes on the soil bearing capacity under the analysed conditions are presented.

ISSN:0008-3674    

DOI:10.1139/t77-010

出版商:NRC Research Press    

年代:1977

数据来源: NRC