ISSN:0008-3674    

DOI:10.1139/t63-001

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Construction of spillways on clay shale in Western Canada has resulted in some serious heave problems. This paper briefly describes the clay shales of the area and gives typical laboratory swelling test results. It has not yet been possible to predict total heave and rate of heave from laboratory tests. Observational programs to check the performance of existing structures as well as special tests were undertaken to provide information required for design. Typical heave observations at spillways showing the effect of seepage, frost action, and hold-down piles are included.

ISSN:0008-3674    

DOI:10.1139/t63-002

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The first part of the paper summarizes the results of recent research on the bearing capacity of spread foundations of various shapes under a central vertical load and outlines the effects of foundation depth, eccentricity and inclination of the load. Simple formulae have been derived for use in practice and their application to the design of rigid and flexible foundations is briefly indicated.The second part of the paper discusses the bearing capacity of single piles under vertical and inclined loads. The bearing capacity of piled foundations and free-standing pile groups is outlined, and the results of model tests on pile groups under central and eccentric loads are briefly analysed in relation to some problems in practice.

ISSN:0008-3674    

DOI:10.1139/t63-003

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

As part of an over-all study of the performance of building foundations in highly plastic soil areas of western Canada, the Division of Building Research has been measuring ground movements and changes in soil moisture conditions in grass-covered, undisturbed soil profiles under climatic conditions ranging from sub-humid to semi-arid. Results of measurements begun in 1951 in Winnipeg, Manitoba, and more recently those in Regina, Eston, and Tisdale, Saskatchewan, are reported. Results of a theoretical soil moisture depletion calculation, based on Thornthwaite's potential evapo-transpiration concept, are presented. It is proposed as a more rational way of measuring the vegetation-climate factor in humid to sub-humid climates than simply comparing air temperature and precipitation with long-term averages. Empirical relationships are suggested between calculated soil moisture depletion, the depth of free water table, and the depth of frost penetration under similar thermal conditions but different soil moisture conditions. Shrinkagein situof undisturbed, unsaturated soils at temperatures well below 32° F has been observed and is attributed to thermal air-void volume change.

ISSN:0008-3674    

DOI:10.1139/t63-004

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The construction of the Ottawa Sewage Treatment Plant provided an opportunity to measure bottom heave in two large excavations in clay. With gauges installed prior to excavation, elastic heave, swelling, and heave due to pile driving were measured in an excavation 31.5 ft. deep. Using a Poisson's ratio of 0.4, the modulus of elasticity determined from field measurements compared favourably with the initial tangent modulus from the best unconfined compression strength tests. In the other excavation a drop in the ground water table produced an elastic settlement that exceeded the elastic heave resulting from unloading by excavation.

ISSN:0008-3674    

DOI:10.1139/t63-005

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t63-006

出版商:NRC Research Press    

年代:1963

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t63-007

出版商:NRC Research Press    

年代:1963

数据来源: NRC