摘要:

A series of unconfined compression tests has been made on a marine, quick clay and small specimens were extracted for microstructural investigation. The natural microstructural pattern was characterized by a network of small aggregates connected by links of particles. The links broke down successively at increasing shear deformation and formed domain-like groups of particles. In the macroscopic shear zone the shear forces tended to orient and deform the aggregates.The aggregates behaved as rigid bodies to a certain stress level during the shear process. The concept of residual strength may correspond to the state where the majority of the links have been broken while the aggregates are still intact.

ISSN:0008-3674    

DOI:10.1139/t70-001

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The frost heaving forces developed under a 1 ft (30.5 cm) diameter steel plate were measured in the field throughout one winter. The steel plate was fixed at the ground surface with a rock-anchored reaction frame. Heave gauges and thermocouples were installed at various depths to determine the position and temperature of the active heaving zone.The general trend was for the surface force to increase as the winter progressed. When the frostline approached maximum depth the force was in excess of 30 000 lb (13 608 kg). Estimates of the heaving pressure at the frostline ranged from 7 to 12 psi (0.49 to 0.84 kg/cm2) during this period.The variation of surface heaving force was closely associated with weather conditions. Warming trends resulting in a temperature increase of the frozen layer caused the forces to decline.

ISSN:0008-3674    

DOI:10.1139/t70-002

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The following article deals with the design and construction of the main dam at the Outardes 4 development. The structure is an earth and rockfill dam reaching a maximum height of 400 ft (~121.9 m). The characteristics of the site, the choice of the type of structure, the principal properties of the materials, the typical cross-section, and stability analysis are either mentioned or described. The construction and control methods are discussed and a brief description of the instrumentation in the dam is also given.

ISSN:0008-3674    

DOI:10.1139/t70-003

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The aim of this paper is to present a method of investigation of submerged sand deposits based on undisturbed sampling by an ancient but not widely used technique. After a rapid description of the equipment and technique, three case histories where this method was used are considered. These lead to some important remarks concerning the quality of the samples, the limits of applicability of the method, and finally the validity of the well-known relationships between standard penetration index and relative density, friction angle, or modulus of elasticity of sands.

ISSN:0008-3674    

DOI:10.1139/t70-004

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The finite element method has been used for determining the stress distribution and the displacements due to gravity around an unlined tunnel driven through a semi-infinite medium, characterized by three idealized material behaviors reflecting approximately a short term behavior of natural undisturbed insensitive and sensitive clays. The knowledge of stress and displacement fields around an unlined tunnel can be used for evaluating the need for supports according to the acceptability of expected deformations.

ISSN:0008-3674    

DOI:10.1139/t70-005

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Comparison of typical results from drained triaxial tests carried out at confining pressures of 50 and 350 p.s.i. (3.52 and 24.61 kg/cm2) on four cohesionless soils are presented.The effect of gradation at constant relative density is explored, and it is concluded that there is an optimum gradation in terms of both high ultimate strength and high mobilized strength. Uniform coarse gravel is shown to have poor mobilized strength, but at confining pressures high enough to cause particle crushing the improvement in gradation and packing leads to a high ultimate strength, although large axial strains are necessarily induced. The optimum gradation is shown to be close to Fuller's curve for maximum density. The effect of increasing the confining pressure from 50 to 350 p.s.i. (3.52 to 24.61 kg/cm2) leads to a decrease inpeak of 6 to 10°, but modifications for dilatancy lead toparameters that are sensibly constant for any one material.

ISSN:0008-3674    

DOI:10.1139/t70-006

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The results of laboratory studies of the frost susceptibility characteristics of pulverized fuel ash are presented. Four different ashes were investigated, in their plain state, and also after stabilization with ordinary Portland cement and calcitic hydrated lime. Measurements were made of frost heave, permeability, compressive and tensile strength, and heaving pressure. Frost heave was shown to decrease as the strength increased and as the permeability decreased. Values of strength and permeability were found at which the frost heave was reduced to an acceptable value, and the relative importance of strength and permeability in reducing frost heave is discussed. The heaving pressures mobilized are compared with the corresponding compressive and tensile strengths of the ashes.

ISSN:0008-3674    

DOI:10.1139/t70-007

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Volume change after saturation was determined on specimens of a statically compacted clay soil. It was found that density after swelling increases linearly with increasing initial density, initial moisture content, and increasing logarithm of applied loading pressure. An empirical equation with five coefficients and a constant, found with the aid of a computer, represents the results with a coefficient of correlation close to 1. An equation for the swelling pressure was also obtained from this equation. Results of specimens which consolidated did not fit the lines obtained for swelling. The relationships obtained were explained by the influence of particle reorientation and moisture content on swelling tendency.

ISSN:0008-3674    

DOI:10.1139/t70-008

出版商:NRC Research Press    

年代:1970

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t70-009

出版商:NRC Research Press    

年代:1970

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t70-010

出版商:NRC Research Press    

年代:1970

数据来源: NRC