摘要:

A bridge across the river Thames has existed at London for 1000 years and possibly more. The early bridges were built on timber piles but these were subject to constant erosion. In 1176 Peter of Colechurch built a masonry bridge on piers which rested on starlings and this lasted through various vicissitudes for over 600 years. Constant maintenance of the foundations was required and in 1831 this was eventually replaced by Rennie's famous bridge which lasted for 140 years. This bridge was founded on a timber grillage which rested on timber piles. Immediately after it was completed it was carefully examined by three independent engineers, relative levels were taken and the same points on the piers were re-levelled after 30 years and again after 130 years. Due to high applied stresses, continuing secondary compression of the clay took place and the resulting differential settlement eventually led to the bridge being replaced. Rennie's bridge was rebuilt in Arizona in 1973.

ISSN:0008-3674    

DOI:10.1139/t81-042

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Principles for designing piles in permafrost on the basis of both ultimate capacity and limiting deformations are reviewed. Procedures developed previously for predicting settlement of piles in ice-rich soils are extended to ice-poor materials and shown to be in reasonable agreement with the modest amount of field data currently available. A compilation of data on allowable adfreeze strength data, frozen soil creep data, and pile design procedures has been undertaken to facilitate selecting allowable loads on piles in a broad range of permafrost soils. Illustrative examples are given in an Appendix.

ISSN:0008-3674    

DOI:10.1139/t81-043

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The dynamic behaviour of some cohesive soils of southwestern Ontario is experimentally investigated using a resonant column apparatus. Attention is concentrated particularly on the dynamic shear modulus, Young's modulus, and damping ratio. The variation of these characteristics with void ratio, confining pressure, strain, and stress history is studied. Data are presented that can be utilized in the design of foundations and structures exposed to dynamic loads.

ISSN:0008-3674    

DOI:10.1139/t81-044

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Winnipeg is built on lacustrine, swelling, plastic clays, and is intersected by two major rivers, and other smaller rivers. The riverbanks are used for commercial, residential, and public utility purposes, and many are unstable. This paper reviews the conditions of topography, river flooding, and soil properties which have produced sliding in the riverbanks. The framework of legislation which governs riverbank development is reviewed, and procedures for stability analyses are outlined. The paper concludes by discussing current design practices, and their application to stabilising measures for common practical problems in the city.

ISSN:0008-3674    

DOI:10.1139/t81-045

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The St. Lawrence Seaway passes through the St. Lawrence River, the Great Lakes, and three Canadian canals: South Shore and Beauharnois Canals in Quebec, and the Welland Canal across the Niagara Peninsula in Ontario. The varied geological conditions and the continuous growth of navigation traffic through its 150 year history influenced the need for and the type and extent of protection for the canal slopes. The methods used include cut stone, riprap, concrete slabs, grouted riprap, soil–cement, gabions, mattresses filled with mortar slurry, and in special cases armour stone and protective rolls. This paper presents their design, construction, behaviour, and cost, with supporting background information. Riprap has proved, so far, to be the most reliable and economical general slope protection method, since suitable rock materials are still readily available locally.

ISSN:0008-3674    

DOI:10.1139/t81-046

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

It is generally admitted that the long term stability of clay slopes should be analysed in terms of effective stresses, which necessitates the knowledge of the pore pressure conditions and of the relationship between the shear strength and the effective stresses. This paper deals with the determination of shear strength for stability analysis of clay slopes in Eastern Canada. First the various concepts pertinent to slope stability in soft clay are examined and a certain justification of the use of the post-peak or large strain strength is demonstrated. In a second part, 14 case records of natural slopes or permanent excavation slopes are presented and analysed in terms of the post-peak strength. Finally, values of post-peak strength determined in the laboratory for more than 30 sites are presented and it is attempted to derive correlations by which the shear strength parameters could be readily approximated from other properties such as the apparent preconsolidation pressure or the vane strength.

ISSN:0008-3674    

DOI:10.1139/t81-047

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Air-acceptance testing of a coal aquifer was conducted prior to a field test of underground coal gasification to investigate the characteristic flow parameters of the aquifer and the flow patterns developed in the vicinity of the injection well. Pressure distributions developed during air injection were found to be similar to those developed during prior hydrogeological testing, but gave a more local indication of permeability anisotropy. Values ofkL/μ from the initial pressure build up during the air-acceptance tests were 4.8–9.5 times those from the hydrogeological tests, indicating that significant differences between the permeability, pumping well height, and viscosity exist for the two flow situations.

ISSN:0008-3674    

DOI:10.1139/t81-048

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A resonant column apparatus was modified to facilitate dynamic testing of cohesive soils. To alleviate the difficulties caused by air penetration into the confining medium and the sample, a small telescopic plexiglass cell is placed in the main large cell. In this inner cell, mercury is used as a substitute confining medium for long term and high pressure tests. The apparatus was used to study the behaviour of cohesive soils of Ontario. The results are described in a companion paper.

ISSN:0008-3674    

DOI:10.1139/t81-049

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

In situpressuremeter tests have in recent years come into wide use in the determination of the parameters to be used for foundation design. Although theoretically correct analytical expressions have been developed for the radial expansion pressure versus radial strain relationship, these are generally cumbersome and difficult to use and in practice a graphical procedure is commonly used to derive the maximum undrained shear stress and the undrained modulus value from the test data.To overcome the disadvantages that this graphical procedure involves an empirically-derived analytical relationship based on Kondner's hyperbolic stress–strain relationship is presented here, by means of which all the derived parameters can be obtained simply and without recourse to graphical construction.

ISSN:0008-3674    

DOI:10.1139/t81-050

出版商:NRC Research Press    

年代:1981

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t81-051

出版商:NRC Research Press    

年代:1981

数据来源: NRC