摘要:

An electrical analog of two-dimensional heat transfer systems, easily constructed of small resistors and capacitors, has many uses in the shady of heat transfer in soils. Scale factors are established and a 146-node model is applied to the design of a pit to be used for inserting thermistor probes laterally into a soil mass. The model is also used to obtain general solution maps to other soil systems with results displayed on generalized graphs ofequivalent depths. This graphical approach, explained herein, is useful for illustrating the effect of local anomalies in two-dimensional soil systems having sinusoidal surface temperatures. Limitations of this simple analog model are discussed.

ISSN:0008-3674    

DOI:10.1139/t68-021

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The principal aim of this paper is to compare laboratory settlement and pore pressure dissipation rates of undisturbed Leda clay with those predicted from a modified consolidation theory developed by Raymond (1966a). The theoretical curves have been computed using directly measured values of the soil permeability and incorporate the variation with void ratio of both permeability and compressibility. The experimental data (obtained from the triaxial apparatus) indicate that the predicted rates of consolidation, and especially of pore water dissipation, are likely to be grossly in error owing to the cemented nature of the soil structure. This factor appears to be partially described by the theory of Barden (1965), although quantitative evaluation of the constants involved in this theory has not been possible.The paper also considers two other aspects of the consolidation of Leda clay. (1) The rate of secondary consolidation varies significantly with consolidation pressure and appears to reflect the changes in compressibility revealed by the void ratio vs. log pressure curve. (2) The variation of soil properties with depth at the Ottawa treatment plant site influences all aspects of the consolidation behaviour of the clay.Available field data have been included in the paper where relevant to the discussion.

ISSN:0008-3674    

DOI:10.1139/t68-022

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Experimental results of swell pressure under complete inundation show that the curve of pressure against log of time has a typical reversed S shape, similar to that of consolidation. No endeavour, however, has been made to explain this behaviour theoretically.The paper deals with the mathematical derivation of the swell pressure function and the definition of the parameters involved. Under certain simplified assumptions, it is shown that the dissipation of the suction during a swelling test is proportional to the development of the swell pressure and that the dissipation function is mathematically identical with that of the consolidation process. The solution of this function yielded a rather simple expression for the swell pressure, which agrees with values obtained when the clay is saturated and results in a fraction of the initial suction when the clay is partly saturated.

ISSN:0008-3674    

DOI:10.1139/t68-023

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The ultimate uplift capacity of foundations with special reference to transmission tower footings is evaluated. A number of model uplift tests made by the authors and by others were studied and compared with full-scale tests. These tests showed a complex failure mechanism which varied with the depth of the foundation. Using simplifying assumptions a general theory was produced. It was shown that with suitable modification for shape and depth a useful relationship was available for computing the full-scale uplift capacity of foundations. It was further shown by model tests that the theory could be modified to take into account group action. Further research is required to evaluate the effect of combined loads and long-term effects.

ISSN:0008-3674    

DOI:10.1139/t68-024

出版商:NRC Research Press    

年代:1968

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t68-025

出版商:NRC Research Press    

年代:1968

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t68-026

出版商:NRC Research Press    

年代:1968

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t68-027

出版商:NRC Research Press    

年代:1968

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t68-029

出版商:NRC Research Press    

年代:1968

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t68-030

出版商:NRC Research Press    

年代:1968

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t68-031

出版商:NRC Research Press    

年代:1968

数据来源: NRC