摘要:

Erodibility drill hole tests have been conducted on three Eastern Canadian clays on intact structured specimens, on specimens destructured by consolidation, and on remolded and reconsolidated specimens. The intact structured clay is highly resistant to erosion; links between particles can resist high tractive stresses. The resistance to erosion is drastically decreased however when the clay is destructured by consolidation or remolding. The decrease varies from one clay to the other; after consolidation the resistance to erosion is very low for the St. Hyacinthe clay but still high for the St. Leon clay. The clays are even more erodible after remolding and reconsolidation, but important differences are still observed between the clays tested. The pore water salinity appears as a significant factor in the understanding of the different behaviour observed after destructuration of the clay by consolidation or remolding.Key words: erosivity, rate of erosion, critical tractive stress, structured clay, destructuration, consolidation, remolding, pore water salinity.

ISSN:0008-3674    

DOI:10.1139/t86-072

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Presented herein is a comparison of the results of laboratory model tests used to study the bearing capacity of geogrid and geotextile reinforced earth slabs. The parameters studied were the coefficient of friction between the geotextile and the soil, pull-out resistance between the geogrid and the soil, depth below the footing of the first layer of reinforcement, vertical spacing of the layers, number of layers, width size of a square sheet of reinforcement, and tensile strength of the reinforcement. For both geogrids and geotextiles, after an optimum number of layers or width of reinforcement, the bearing capacity did not increase. In addition, the bearing capacity was largest for those geogrid and geotextile reinforced earth slabs where the first layer was closest to the footing and the spacing between the layers was the smallest. Bearing capacity increased directly with increasing reinforcement tensile strength for the geotextile; however, for the geogrid, aperture size and reinforcement tensile strength must be looked at simultaneously.Key words: reinforced earth slab, geogrid, geotextile, bearing capacity, pull-out, friction.

ISSN:0008-3674    

DOI:10.1139/t86-073

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Flexibility coefficients of single piles and interaction factors established for groups of two piles are presented to facilitate analysis of arbitrary pile groups exposed to static horizontal loads. Such an analysis may yield pile group flexibility, stiffness, deflection, and distribution of loads on individual piles. The data given are complete in that they include horizontal translation, rotation in the vertical plane, and cross effects between the two, making it possible to establish complete stiffness and flexibility matrices of pile groups provided with either rigid caps or arbitrarily flexible caps. Homogeneous, parabolic, and linear (Gibson's) soil profiles are considered and the piles may have a free length sticking above the ground surface. The methods of group evaluation based on superposition of interaction factors are reviewed and compared and numerical examples are given.Key words: piles, pile groups, lateral loads, flexibility, stiffness, load distribution.

ISSN:0008-3674    

DOI:10.1139/t86-074

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The lateral soil pressures, ultimate bearing capacity, and displacements of instrumented vertical single rigid model piles in a layered system consisting of soft clay overlying loose sand and subjected to vertical eccentric and central inclined loads have been investigated. The variation of lateral soil pressures and the tip resistance of the pile are analysed with respect to the total load or moment on the pile. Theoretical estimates of pile capacity in homogeneous soils under pure moment and under horizontal load have been extended to piles in a layered system. For intermediate eccentricities and inclinations of the load, the pile capacity can be estimated from simple interaction relations or semiempirical eccentricity and inclination factors. The pile displacements are analysed in the light of linear elastic theory and nondimensionalp − ycurves. Reasonable agreement has been found between the measured and predicted values.Key words: bearing capacity, clay, displacements, eccentric load, horizontal load, lateral pressure, layered system, model test, pile, sand.

ISSN:0008-3674    

DOI:10.1139/t86-075

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

A new highway crossing of the Fraser River at Annacis Island near Vancouver, British Columbia, is currently under construction. It involves a major cable-stayed bridge with a main span of 465 m. Support for the bridge is provided by piles driven into dense overconsolidated Quaternary sediments: on the south bank they are found essentially at ground surface while on the north (Annacis Island) side they are encountered at a depth of 80–85 m overlain by sequences of weak deltaic and alluvial materials. This paper describes the geotechnical investigation for the bridge and describes the design of six foundations including those for the two main piers. The north main pier is founded on unusually deep pipe piles about 85 m long.Key words: bridge, case history, earthquake, geological investigations, liquefaction, negative skin friction, pile, settlement analysis, site investigation.

ISSN:0008-3674    

DOI:10.1139/t86-076

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Many railways have been making increasing use of the heavier mass per unit area geotextiles, bringing into question the financial viability of their use. In order to assess the viability of turnout geotextiles, two closely spaced turnouts, positioned on an embankment constructed of compacted clay at Rosser, near Winnipeg, were rehabilitated in September 1981. Under one turnout, a Turn Out Pack System (TOPS) geotextile of variable mass per unit area (550–1100 g/m2(16–32 oz/yd2)) was used; with the other, no geotextile was used. The ballast was a metamorphic granodioritic gneiss known locally as Kenora granite. This article summarizes the findings of excavations made to assess the performance of the geotextile. The assessment excavations were made in August 1984 after an average of 13.6 × 106gross tonnes (15 × 106gross tons) per year per track of traffic. The results clearly show the damage penalty to the ballast from fouling caused at the nongeotextile locations.Key words: railways, ballast, subballast, geotextile, fouling, pumping, fines, equivalent opening size (EOS).

ISSN:0008-3674    

DOI:10.1139/t86-077

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The dimensioning of anchor bars grouted in rock takes into account the mechanical properties of the three components steel, grout, and rock. The allowable bond strength at the rock–grout interface recommended by different national codes is generally selected according to the type of rocks and assuming an ordinary cement grout. In the present approach, the influence of the type of grout on the pull-out strength of anchor bars in a sound rock mass with mechanical properties equal or higher than the grout is considered. This experimental study shows that certain cement grouts can develop pull-out strength clearly higher than those obtained with epoxy grouts for example.Key words: rock mass, grouted anchors, cement grouts, epoxy grouts, pull-out test, creep test. [Journal translation]

ISSN:0008-3674    

DOI:10.1139/t86-078

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Anin situanalysis of naturally occurring creep has been carried out in ice-rich permafrost soils underlying a slope at the proposed Canadian Arctic Gas pipeline crossing of Great Bear River in the Northwest Territories. This is the second of four papers that describe the study. Field investigation and instrument installation techniques are described and geological, geotechnical, and geothermal results are presented. The data presented here are intended to facilitate clear interpretation of deformation observations in the third paper. The data are representative of ice-rich glaciolacustrine clay deposits that are widespread in the mid-Mackenzie Valley area.Key words: Mackenzie Valley, pipelines, slopes, permafrost, soils, drilling, sampling, geotechnical, geothermal.

ISSN:0008-3674    

DOI:10.1139/t86-079

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Anin situanalysis of naturally occurring creep has been carried out at the proposed Canadian Arctic Gas pipeline crossing of Great Bear River in the Northwest Territories. This is the third of four papers that describe the study. The borehole inclinometer system and monitoring procedures used to determinein situmovement are described. Significant factors affecting the accuracy of the system are assessed. External factors causing movement of the inclinometer casing are also assessed and movements caused by these factors are separated from natural ground movements. The magnitude and nature of naturally occurring creep deformations are discussed.Key words:Mackenzie Valley, pipelines, slopes, permafrost, soils, geotechnical, inclinometers, creep.

ISSN:0008-3674    

DOI:10.1139/t86-080

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Anin situanalysis of naturally occurring creep has been carried out at the proposed Canadian Arctic Gas pipeline crossing of Great Bear River in the Northwest Territories. This is the last of four papers that describe the study. Creep properties of natural and reconstituted frozen soils are briefly reviewed. A laboratory programme to measure creep properties of undisturbed ice-rich glaciolacustrine clay samples from the Great Bear River site is described in detail. The results are analysed to determine empirical parameters for constitutive equations that describe the stress–strain–time behaviour of the material.Key words: Mackenzie Valley, pipelines, slopes, ice-rich, soils, permafrost, geotechnical, creep, laboratory.

ISSN:0008-3674    

DOI:10.1139/t86-081

出版商:NRC Research Press    

年代:1986

数据来源: NRC