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1.
This paper demonstrates how the use of fracture system modelling can be linked to limit equilibrium analysis of rock slopes susceptible to wedge failure. The use of fracture systems highlights some of the limitations inherent in traditional structural data analysis and representation. Consequently it allows for more comprehensive input data that can be used for stability analysis of rock slopes. In particular the developed methodology addresses important issues such as spatial variability and wedge size distributions. The paper introduces a series of guidelines for interpretation of the results of rock slopes. The proposed techniques arguably result in an improved level of confidence in the design of rock slopes susceptible to wedge failure. 相似文献
2.
M. Grenon 《Astrophysics and Space Science》1999,265(1-4):331-336
Ages and kinematics are revised for SMR stars ([M/H] >+0.30) common to NLTT and HIPPARCOS catalogues. The origin of MR to
SMR stars appears heterogeneous: part of them, of intermediate age, were formed few kpc inside the solar orbit, from slowly
enriched gas, whereas the oldest SMRs were born early, closer to the galactic center where the metal-enrichment had been fast.
Perturbations by the galactic bar explain the peculiar motions of local SMRs as well as their outwards migration.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Summary
The most popular exploitation method used in Canadian hard rock mines is open stope mining. Geomechanical design of open stopes
relies on a range of analytical, numerical and empirical tools. This paper presents an engineering approach for the analysis
and the design of reinforcement for open stopes in jointed rock. The proposed methodology, illustrated by three case studies,
relies on developing 3D joint network models from field data. The 3D joint networks have been successfully linked to a 3D
limit equilibrium software package. The models account for the finite length of joints as well as the influence of random
joints. The integrated approach facilitates comparative analyses of different reinforcement strategies under different degrees
of jointing in the hard rock environment.
Received February 23, 2001; accepted October 11, 2002; Published online January 21, 2003
Acknowledgments The financial support of the National Science and Engineering Council of Canada and the Institut de Recherche en Santé et
Sécurité au Travail of Quebec and Noranda Inc. is greatly appreciated.
Authors' address: Prof. John Hadjigeorgiou, Université Laval, Department of Mining, Metallurgy and Materials Engineering, G1K 7P4 Quebec City,
Quebec, Canada; e-mail: john.hadjigeorgiou@gmn.ulaval.ca 相似文献
4.
This paper presents the results of a series of numerical experiments using the synthetic rock mass (SRM) approach to quantify the behaviour of jointed rock masses. Field data from a massive sulphide rock mass, at the Brunswick mine, were used to develop a discrete fracture network (DFN). The constructed DFN model was subsequently subjected to random sampling whereby 40 cubic samples, of height to width ratio of two, and of varying widths (0.05 to 10 m) were isolated. The discrete fracture samples were linked to 3D bonded particle models to generate representative SRM models for each sample size. This approach simulated the jointed rock mass as an assembly of fractures embedded into the rock matrix. The SRM samples were submitted to uniaxial loading, and the complete stress–strain behaviour of each specimen was recorded. This approach provided a way to determine the complex constitutive behaviour of large‐scale rock mass samples. This is often difficult or not possible to achieve in the laboratory. The numerical experiments suggested that higher post‐peak modulus values were obtained for smaller samples and lower values for larger sample sizes. Furthermore, the observed deviation of the recorded post‐peak modulus values decreased with sample size. The ratio of residual strength of rock mass samples per uniaxial compressive strength intact increases moderately with sample size. Consequently, for the investigated massive sulphide rock mass, the pre‐peak and post‐peak representative elemental volume size was found to be the same (7 × 7 × 14 m). Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
5.
This paper presents the design and development of an enhanced inertial navigation system that is to be integrated into the Morpheus autonomous underwater vehicle at Florida Atlantic University. The inertial measurement unit is based on the off-the-shelf Honeywell HG1700-AG25 3-axis ring-laser gyros and three-axis accelerometers and is aided with ground speed measurements obtained using an RDI Doppler-velocity-log sonar. An extended Kalman filter has been developed, which fuses together asynchronously the inertial and Doppler data, as well as the differential Global Positioning System positional fixes whenever they are available. A complementary filter was implemented to provide a much smoother and stable attitude estimate. Thus far, preliminary study has been made on characterizing the inertial navigation system-based navigation system performance, and the corresponding results and analyzes are provided 相似文献
6.
M. Grenon 《Astrophysics and Space Science》1989,156(1-2):29-37
Members of the Galaxy components are identified according to stellar ages, metallicities and galactic orbits. The local thin disk is found to have a maximum age of 11 billion years and a small abundance scatter partially controlled by the radial gradient of abundances. Metal-rich and old metal-poor stars belong to inner galactic populations and SMRs represent the ultimate star generation in the bulge. The thick disk forms a smooth transition between the halo and thin disk. 相似文献
7.
Past and present metal abundance gradient in the galactic disc 总被引：1，自引：0，他引：1
M. Grenon 《Journal of Astrophysics and Astronomy》1987,8(2):123-139
A critical discussion of some determinations of metal abundance gradient in the galactic disc is presented with an attempt
to homogenize the results related to local and large-scale gradients. A new estimation of the palaeogradient in intermediate
and old disc population is presented. The gradient is found to depend on galactocentric distance, and to be nearly constant
with time during the lifetime of the galactic disc. 相似文献
8.
Stability Analysis of the 19A Ore Pass at Brunswick Mine Using a Two-Stage Numerical Modeling Approach 总被引：1，自引：0，他引：1
Kamran Esmaieli John Hadjigeorgiou Martin Grenon 《Rock Mechanics and Rock Engineering》2013,46(6):1323-1338
The longevity of ore pass systems is an important consideration in underground mines. This is controlled to a degree by the structural stability of an ore pass which can be compromised by changes in the stress regime and the degree of fracturing of the rock mass. A failure mechanism specific to ore pass systems is damage on the ore pass wall by impact load or wear by material flow. Structural, stress and material flow-induced failure mechanisms interact with severe repercussions, although in most cases one mechanism is more dominant. This paper aims to provide a better understanding of the interaction of ore pass failure mechanisms in an operating mine. This can provide an aid in the design of ore pass systems. A two-stage numerical approach was used for the back analysis of an ore pass at Brunswick mine in Canada. The first stage in the analysis relied on a 3D boundary element analysis to define the stress regime in the vicinity of the ore pass. The second stage used a synthetic rock mass (SRM) model, constructed from a discrete fracture network, generated from quantitative rock mass field data. The fracture network geometry was introduced into a bonded particle model, in a particle flow code (PFC). Subsequently, the ore pass was excavated within the SRM model. A stability analysis quantified the extent of rock mass failure around the ore pass due to the interaction of pre-existing fractures and the failure of the intact rock bridges between these fractures. The resulting asymmetric failure patterns along the length of the ore pass were controlled to a large degree by the in situ fractures. The influence of particle flow impact was integrated into the model by projecting a discrete rock fragment against the ore pass walls represented by the SRM model. The numerical results illustrated that material impact on ore pass walls resulted in localised damage and accelerated the stress-induced failure. 相似文献
9.
A.W. Kirkpatrick M.A. Keaney K. Bentz M. Tyssen C.G. Ball S.M. Grenon T.J. Broderick 《Planetary and Space Science》2010,58(4):717-723
Emergency surgery will be needed to prevent death if humans are used to explore beyond low earth's orbit. Laparoscopic surgery (LS) is envisioned as a less invasive option for space, but will induce further stresses and complicate logistical requirements. Thus, further study into the technology and physiology of LS in weightlessness is required. We recently utilized the National Research Council of Canada's Flight Research Laboratory's Falcon 20 aircraft as a terrestrial analogue space environment (TASE) for space surgery research. The Falcon 20 had never been used for this purpose nor had the involved teams collaborated previously. There were many process challenges including the lack of antecedent surgical studies on this aircraft, a requirement for multiple disciplines who were unfamiliar and geographically distant from each other, flight performance limitations with the Falcon 20, complex animal care requirements, requirements for prototypical in-flight life-support surgical suites, financial limitations, and a need to use non-flight hardened technologies. Stepwise suggested solutions to these challenges are outlined as guidelines for future investigators intending similar research. Overall, the Falcon 20 TASE, backed by the flight resources, especially the design and fabrication capabilities of the NRC-FRL, provide investigators with a versatile and responsive opportunity to pursue research into advanced medical techniques that will be needed to save lives during space exploration. 相似文献
10.
C. Jordi E. Høg A. G. A. Brown L. Lindegren C. A. L. Bailer-Jones J. M. Carrasco J. Knude V. Strai&#;ys J. H. J. de Bruijne J.-F. Claeskens R. Drimmel F. Figueras M. Grenon I. Kolka M. A. C. Perryman G. Tautvai&#;ien&#; V. Vansevi&#;ius P. G. Willemsen A. Brid&#;ius D. W. Evans C. Fabricius M. Fiorucci U. Heiter T. A. Kaempf A. Kazlauskas A. Ku&#;inskas V. Malyuto U. Munari C. Reylé J. Torra A. Vallenari K. Zdanavi&#;ius R. Korakitis O. Malkov A. Smette 《Monthly notices of the Royal Astronomical Society》2006,367(1):290-314