摘要:

Performance of some structures constructed in rocks in southern Ontario have shown severe distress. It has been hypothesized that the problem is due to the high horizontal stresses existing in the rock formations. As part of a comprehensive investigation into the stress relief and time-dependent behavior of the rocks in this area,in situstress measurements were carried out at a location near the Thorold Tunnel to a depth of 81 ft (25 m). The technique and procedure used are described in detail. It was found that high horizontal stresses, varying from 1200 to 2100 psi (8300 to 14500 kPa) exist in each rock unit encountered. The direction of the major principal stress in the horizontal plane appears to be orientated at N 60° E.

ISSN:0008-3674    

DOI:10.1139/t76-001

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The Frank Slide is the best known of a number of major rock slides in the Canadian Rockies. Seven other slides of the same order of magnitude are described from the Front and Main Ranges between Jasper and the United States border.The geometry and kinematics of the slides are controlled by discontinuities in the rock slide mass. Typically, the major part of the rupture surface is parallel to bedding; the orientation of the lateral margins and the scarp of the slide may be controlled by joint sets.Sliding tends to occur on slopes where bedding dips towards valleys at angles between 30 and 40° and in thickly-bedded, massive weathering rocks such as quartzites, dolomites, and limestones. Major causes of sliding appear to be erosion at the foot and lateral margins of the slide mass.The slides may be easily identified on aerial photographs by their effect on the local vegetation and by the characteristic appearance of their debris. All the slides observed are post-glacial, their frequency seems to have been underestimated and, in places, they may impose major constraints on further development.

ISSN:0008-3674    

DOI:10.1139/t76-002

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A 400 ft (122 m) long, five-span concrete bridge over Mud Creek, supported on end bearing steel piles, was instrumented to measure horizontal movements of its foundations. Fifteen years of observations show that the abutments and piers have moved downslope and rocked back and forth through a small vertical angle about their bases. The net convergence of the abutments is about 4 cm. The horizontal movements were caused by soil creep in the marine clays of the steep valley slopes. The change in verticality of the piers was attributed to the expansion and contraction of the bridge deck due to seasonal temperature variations. The steel end bearing batter piles were ineffective in maintaining the piers and abutments in their original positions.

ISSN:0008-3674    

DOI:10.1139/t76-003

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The expanding consumption of energy has created new demands for coal and increasing activity in the coal mining industry. However, the mining of coal is accompanied by coal wastes which are dumped in the form of coal waste embankments. The present concern for safety and the environment requires an analysis of the geotechnical problems associated with the construction of these embankments to assure acceptable engineering design. This paper discusses the properties of the coal wastes and the behaviour of coal waste embankments which differ from the common earth embankments that the geotechnical engineer has to deal with.

ISSN:0008-3674    

DOI:10.1139/t76-004

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A design philosophy for piles in ice and ice-rich permafrost is proposed, whereby the pile settlements over the design life of the structure are retained within acceptable limits.The secondary creep law for ice is reviewed and the relationships between secondary creep rate, stress, and temperature are obtained using existing creep test data from many different sources. An analysis is performed which relates the steady pile settlement rate to the pile shaft stress and the constant ground temperature.A review of the pile load test data available in the literature is carried out, and the results are compared with the theoretical predictions provided by the pile settlement analysis. Reasonable agreement is obtained between prediction and observation, and it is thought that the analysis presented here provides a conservative (safe) bound on the observed results.The analysis is extended to account for the compression of the pile shaft, varying ground temperature profiles, stress readjustment along the pile shaft, and the end bearing capacity of the pile.The analysis presented here provides a rational basis for pile design in permafrost and, in addition, explains many of the phenomena likely to be observed in the behavior of piles under sustained loading.

ISSN:0008-3674    

DOI:10.1139/t76-005

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The paper reports on the measurement of an arching effect over a large diameter flexible culvert. An arch shape culvert, 51 ft (15.5m) in span, was erected and covered by a 44 ft (13.4m) high embankment. An extensive instrumentation program was laid out in order to check the mobilization of an arching effect during construction by measuring displacements, earth pressures, and stresses in the steel. The instrumentation data indicated that a large portion of the load due to the weight of the soil above the structure was transferred to the adjacent area.

ISSN:0008-3674    

DOI:10.1139/t76-006

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Plane strain problems of consolidation (or poro-elasticity) can be solved using the two displacement functions defined by McNamee and Gibson with the help of a repeated integral transformation technique. The problem of a semi-infinite clay layer whose surface is subjected to an embankment-type of normal trapezoidal pressure applied along an infinite strip is treated here. The general loading pattern selected easily degenerates into a rectangular (uniformly distributed) load for which NcNamee and Gibson gave the solutions, to the triangular loads and also to the line loads. Not only the settlements, but also the pore pressures have been evaluated under these types of loads when the surface is either pervious or impervious.The nondimensional solutions presented are useful to highway and embankment engineers. There is also an example of the use of these solutions.

ISSN:0008-3674    

DOI:10.1139/t76-007

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

At the end of 1974 there were 45 accelerographs and 75 seismoscopes deployed in Canada. The Department of Energy, Mines, and Resources and the National Research Council of Canada have installed most of the instruments but one quarter of them are privately owned. Three quarters of the instruments are located near the west coast with the next largest concentration in the St. Lawrence Valley region. There is one instrument in the Arctic. The majority have been deployed to measure ground motion in populated areas but a few have been deployed in areas of higher seismicity remote from population centers. In western Canada particular emphasis has been placed on measuring the response of different soil types and soil depths. The only major structures in the country that have been instrumented are two large dams.

ISSN:0008-3674    

DOI:10.1139/t76-008

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

In triaxial tests with lubricated enlarged end platens on sand, the internal displacements have been measured using lead shots and x-ray technique. The strain distribution so obtained confirms the homogeneity of deformations. A comparison of the axial strain distribution over the height of the sample obtained with x-ray technique and from surface measurements using a precision theodolite revealed that the much simpler method of surface measurements can be used as a criterion for homogeneity of deformations.In addition a comparison of the volume changes measured using the more accurate x-ray technique and the simpler girth-gauges showed that even the most carefully made girth gauges will underestimate the volume increase and as such are to be used with caution.

ISSN:0008-3674    

DOI:10.1139/t76-009

出版商:NRC Research Press    

年代:1976

数据来源: NRC

ISSN:0008-3674    

DOI:10.1139/t76-010

出版商:NRC Research Press    

年代:1976

数据来源: NRC