Two methods of laboratory measurements of time-dependent deformations of rocks due to the relief of in situ stresses are described. Experiments were performed on specimens taken from seven rock formations in southern Ontario. It was found that some rock types exhibit considerable time-dependent deformation, generally consistent with observed field behaviour. In addition, the swelling behaviour of the shaly rocks is anisotropic and constituent layers of the same rock formation may possess very different swelling characteristics. Mineralogical tests performed showed that the observed swelling behaviours are related to the composition and clay fabric of the rock.For detailed analysis of the test results, a rheological model was employed to represent the time-dependent deformation. Model parameters for three rock types have been obtained.Because the tests are simple and inexpensive to perform, it becomes practical to carry out a large number of tests for the evaluation of potential problems due to time-dependent deformation.

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur.Energy Research, 7, 3, pp. 265-278, 1983 Heat transfer characteristics of in-ground heat exchangers Svec, O. J.; Goodrich, L. E.; Palmer, J. H. L.

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. Geotechnical Journal, 15, 4, pp. 573-583, 1978-11 Results of a program of instrumentation involving a precast, segmented concrete-lined tunnel in clay Belshaw, D. J.; Palmer, J. H. L. In Thunder Bay, Ontario, a 2.16 m diameter tunnel is nearing completion in a soft to firm clay using a full-face tunnel boring machine and an unbolted precast segmented concrete lining. The lining consists of rings composed of four trapezoidal sections of unreinforced concrete, 1 m in length and 11 cm thick. Each ring is assembled within the protection of the tailpiece of the tunnel boring machine and clay grout is injected behind the ring as the machine advances by thrusting on the completed lining. CanadianBecause of the uniqueness of this method of construction, an extensive field instrumentation program was undertaken to evaluate the tunnelling procedure and the performance of the completed tunnel. The first phase of instrumentation involved a 60m length of the tunnel and included observations of ground surface deformation, soil deformation (as measured by slope indicators, magnetic extensometers, and deep settlement points), total pressure on the lining, and deformation of the lining. The information also included tunnelling procedure and weight of spoil removed as the tunnel boring machine passed through the instrumented area.These observations are presented and discussed. Some problems of instrumentation are considered, particularly as they related to the second array of instrumentation which was designed to provide detailed information on spatial deformations and pore pressure changes. Par suite de la nouveaute de cette methode de construction, un programme elabore d'instrumentation a ete entrepris pour evaluer la procedure d'excavation et la performance du tunnel completi. La premiere phase de I'instrumentation implique une longueur de 60m de tunnel et comprend des observations des deformations de sol (tel que mesurees au moyen d'inclinometres, d'extensometres magnetiques, de points de tassement en profondeur), de la pression totale sur le blindage et de la deformation du blindage. L'information incluait egalement la procedure d'excavation et le poids des materiaux de deblais enleves alors que I'appareil d'excavation passait a travers la zone instrumentee.Ces observations sont presentees et discutees. Des problemes d'instrumentation sont consideres particulierement en regard du deuxieme reseau d'instrumentation qui avait ete conGu pour...

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 situ stress 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.

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. Geotechnical Journal, 17, 2, pp. 174-184, 1980-05 Deformations and pore pressures in the vicinity of a precast, segmented, concrete-lined tunnel in clay Palmer, J. H. L.; Belshaw, D. J. Canadian----National Research Conseil national During construction of a 2.16 m diameter tunnel in a soft to firm clay deposit in Thunder Bay, Ontario, an initial array of instrumentation to provide data indicating overall performance and a second array to provide detailed spatial deformation and pore-water pressure distribution were installed. The tunnel lining consisted of unbolted rings composed of four trapezoidal, unreinforced concrete sections assembled within the tailpiece of the tunnel boring machine.This paper presents and discusses detailed observations of soil deformation, pore-water pressure changes, and total pressure on the lining obtained from the second array of instrumentation. The soil stratigraphy was similar to that at the first array and the data obtained are compared with the earlier data. Monitoring of the instruments is continuing and data from the first year of observations are presented. Cet article prCsente les observations dCtaillCes de dkformations du sol, de variations de pressions interstitielles et de contraintes totales sur le revetement, obtenues I'aide de la deuxikme sCrie d'instruments. La stratigraphie du sol Ctant semblable ?i celle prevalent ?i proximitt de la premikre sCrie; les donn&s obtenues sont comparkes. On continue ?i faire le relev6 des instruments, et les donnCes relatives ?i la premikre annCe d'observation sont prCsenttes.[Traduit par la revue]