摘要:

A long overpass structure with 32 piers between abutments was founded on strip footing and friction pile foundations in a deep marine clay subsoil of firm consistency. The piles were steel H-sections which were provided at the construction stage at 6 pier locations in lieu of footings because of unfavorable soil conditions exposed during excavation. A load test to failure on a single pile indicated the pile–soil adhesion to be considerably lower than the undrained shear strength of the clay.Post-construction observations indicated the settlement of the pile-supported piers to be about 50% that of the adjacent footing supported piers. The settlements of both types of foundations were small and within tolerable limits. The design approaches used for prediction of footing settlements and the group action of friction piles in bearing capacity and settlement are presented in the paper.

ISSN:0008-3674    

DOI:10.1139/t69-039

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

This paper presents a critical review of the current theories of predicting pore pressures in saturated clays. These theories are generalized and examined and their limitations discussed. It is shown mathematically that the pore pressure induced by shear may be expressed as a sole function of major principal strain, and this approach eliminates the anomalies inherent in the "stress theories" for pore pressure. A hypothesis is also developed to provide a possible mechanism of pore pressure set up in undisturbed normally-consolidated clays.

ISSN:0008-3674    

DOI:10.1139/t69-040

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Experimental results on normally-consolidated undisturbed clays of various sensitivities are presented and analyzed using the approach developed in Part I. It is shown that, both for isotropically and anisotropically consolidated samples, the pore pressure ratio – strain relationship is independent of the magnitude of consolidation pressures, time of sustained stress, time of consolidation and intrinsic anisotropy under both plane strain and axially-symmetric stress conditions. The effect of the intermediate principal stress may be taken easily into account so that the pore pressure set up under plane strain condition may be estimated from results of laboratory triaxial tests. The effect of strain rate was found to be small for the clays tested, and becomes insignificant at large strains.The relevance of each of these conclusions in relation to practical problems are discussed. The use of the pore pressure – strain approach in practice in general, and for some class of field problems in which the approach is especially suited, are pointed out.

ISSN:0008-3674    

DOI:10.1139/t69-041

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The experimental behavior of remolded layered clays undergoing both one-dimensional vertical flow and three-dimensional combined vertical and radial flow is shown to be in close agreement with exact solutions formulated in terms of Terzaghi theory. The accuracy of a number of approximate solutions for layered clays is assessed, confirming the importance of the interface flow condition.

ISSN:0008-3674    

DOI:10.1139/t69-042

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A side-wall sampler which is capable of taking samples from the walls of test-holes to a depth of 1000 ft or more is described. Samples have been extracted from till, clay, silt, and fine- to coarse-grained sands in drift and non-indurated bedrock from more than 1000 test-holes in southern Saskatchewan. Side-hole sampling is faster and cheaper than conventional sampling methods and is ideally suited for geological investigations. Mineralogical, paleontological, and radio-carbon analyses have been determined on side-hole cores.

ISSN:0008-3674    

DOI:10.1139/t69-043

出版商:NRC Research Press    

年代:1969

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t69-044

出版商:NRC Research Press    

年代:1969

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t69-045

出版商:NRC Research Press    

年代:1969

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t69-046

出版商:NRC Research Press    

年代:1969

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t69-047

出版商:NRC Research Press    

年代:1969

数据来源: NRC