December 2008
As the year draws to a close, we would like to extend to our friends and clients the best wishes for a happy holiday season and a prosperous new year. Itasca has experienced another year of growth, challenges, and change. We have completed numerous consulting projects, released upgrades to four of our six major codes, and have hosted the first international symposium to investigate advanced numerical modeling techniques using all Itasca software products. It has been an eventful year, and already we can expect more of the same for 2009.
– Loren Lorig, Chief Executive Officer
Figure 1. Tunnel (pink) and canister (blue) layout, northern site
Itasca Consultants s.a.s (Ecully, France)–
BEHAVIOR OF REPOSITORY TUNNELS SUPPORT
Numerical modeling was used to compare the support stability for tunnels in two potential nuclear waste disposal sites; the sites had varying rock properties, emplacement depths and storage geometries.
The tunnels were excavated using a Tunnel Boring Machine (TBM). Because both excavation and thermal output are likely to generate sizeable stress increases, the two processes were simulated carefully.
The most significant differences between the sites are their depths, which result in contrasted initial stresses and temperatures, and the clay properties. The southern site is at a depth of 790 m, compared to 330 m for the northern site. Also, the clay in the southern site is weaker, but stiffer, than the one in the northern site. Because initial temperatures were higher in the deep southern site, the thermal power from the canisters is designed to be smaller, and the canister spacing is wider.
Temperatures in the support after 100 years of heating, northern site
Results
The most important difference in behavior between the two sites is the load on the support due to excavation:
These results were included in an overall comparison of the two sites.
Figure 3. Excavation: the TBM (yellow), support, and grout (orange) (above left); Bending moments in the support after 100 years of heating, northern site. (above right)
Update Alert:
Current Versions
updated since
May 15, 2008:
PFC2D 4.0 Available Now
Itasca is pleased to announce that PFC2D version 4.0 has been officially released (its 3D counterpart, PFC3D, was released in October). New features in the code include: 64-bit version, the smooth-joint contact model, simplified model creation facilities, enhanced clump logic, and on-screen help. Complete information on these features, sales information, and examples are available from the PFC section of our web site.
For the first time, demonstration versions of FLAC, 3DEC, PFC2D, and PFC3D are available for download. These demonstrations versions are fully functional versions of the codes, complete with documentation. The demo versions have no time limit, but are limited by the size of the model that may be cycled (for instance, demonstration FLAC can cycle a model of up to 600 zones). Note it is possible, using these versions, to construct larger models, but the demonstration limit prevents cycling them. These demonstration versions are free; a valid name and email address only are required to obtain them. Each version is subject to Itasca's license terms and conditions. If you have been interested in exploring the capabilities of these codes, or simply learning more about them, we invite you to take a look.
An example application showing the ability of FLAC to perform a stability analysis for a slope containing a thin band of soft (weak) material that extends through the slope and diminishes at the toe is newly available online. The example includes a PDF file description of the problem as well as the FLAC project (PRJ) file.
Welcome
Itasca Consulting Canada Inc. is pleased to announce that John Fedorowich has joined the company in the capacity of Senior Structural Geologist. Dr. Fedorowich has 15 years of experience as a structural geologist, and has served for 13 years as an adjunct professor at Laurentian University. His expertise includes: recognition and interpretation of structural features and patterns in underground and open pit mines, drill core, and outcrop; 3D modelling and visualization of structures as applied to ore body development and surface exploration projects; execution of numerous structural mapping projects in a wide variety of structural settings and terrains; and, applied borehole geophysical and other field methods for detection of structures, ore body modelling, and target generation. Please join us in welcoming John to Itasca.
FLAC/DEM Symposium Report
The First International FLAC/DEM Symposium was a success by all accounts. More than 120 attendees had the chance to review the state-of-the-art in the use of advanced numerical modeling techniques using Itasca software. The three day event was attended by participants from more than 23 countries. Photos from the event are available for viewing online.
Symposium Proceedings and Presentations
The Proceedings of the symposium are available directly from Itasca. They are offered in an indexed, searchable CD-ROM format (documents on the disk are PDF files). The Proceedings are $25 plus shipping and handling. In addition, the presentations given at the symposium are available for free (via web download). Please visit the symposium page — see the "Proceedings" and "Presentations" sections — if you are interested in obtaining either.
The annual Spring FLAC, FLAC3D, UDEC, 3DEC, and PFC2D and PFC3D introductory software training courses at Itasca Consulting Group Inc. in Minneapolis are now open for enrollment. Registration is available on a first-come, first-served basis. The deadline for registration is one month prior to the start of each class. Please see the "Schedule of Courses" on the Training page for dates and times. Also please note there are still spaces available in the training courses on FLAC3D and PFC3D/CCFD that are being offered in February and March, respectively, in Ecully France at the offices of Itasca Consultants s.a.s. In addition, Itasca Australia Pty Ltd. is offering software training courses in early 2009. Training for FLAC3D is scheduled for Jan 28-30, 2009. Training for FLAC and UDEC is planned for February 2-6, 2009. For complete details contact Itasca Australia at software@itasca.com.au.
Andrieux, P., and J. Hadjigeorgiou. (2008) "The Destressability Index Methodology for the Assessment of the Likelihood of Success of a Large-Scale Confined Destress Blast in an Underground Mine Pillar," Int. J. Rock Mech. Min. Sci., 45, 407-421.
Bourdeau, C., D. Billaux and A. Chraibi. (2008) "Deplacements d'un Barrage Sous l'Effet Des Variations de Temperatures et de la Retenue/Displacements of a Dam with Variations of the Airand Water Temperatures and of the Reservoir Level (in French)," in Insertion Des Grands Ouvrages dans Leur Environment (Insertion of Large Civil Engineering Structures in the Environment, JNGG'08, Nantes, France, June 2008), pp. 411-418. Paris: Laboratoire Central des Ponts et Chaussés.
Carr, C. et al. (2008) "Investigation of Underground Mining Potential at Xstrata Copper's Ernest Henry Copper-Gold Mine," in MASSMIN 2008 (5th International Conference on Mass Mining, Luleå, Sweden, June 2008), pp.423-432, H. Schunnesson and E. Nordlund, Eds. Luleå: Division of Mining & Geotechnical Engineering, Luleå University of Technology.
Connell, L.D., and C. Detournay. (2009) "Coupled flow and geomechanical processes during enhanced coal seam methane recovery through CO2 sequestration" Int. J. Coal Geol., 77, 222-233.
Cundall, P. (2008) "Recent Advances in Numerical Modelling for Large-Scale Mining Projects," ACG News., 30,1-7 (June).
Cundall, P. A., M. E. Pierce and D. Mas Ivars. (2008) "Quantifying the Size Effect of Rock Mass Strength," in SHIRMS 2008 (Proceedings, 1st Southern Hemisphere International Rock Mechanics Symposium, Perth, Western Australia, September 2008), Vol. 2, pp. 3-15, Y. Potvin et al., Eds. Nedlands, Western Australia: Australian Centre for Geomechanics.
Deisman, N. et al. (2008) "Geomechanical Characterization of Coal seam Reservoirs: The SRM Approach," in Proceedings, Asia Pacific CBM Conference (Brisbane, September 2008). Paper No. 003.
Deisman, N., D. Mas Ivars and M. Pierce. (2008) "PFC2D Smooth Joint Contact Model Numerical Experiments," in GeoEdmonton '08: A Heritage of Innovation (61st Canadian Geotechnical Conference, Edmonton, September 2008). Paper No. 83.
Deisman, N., R. J. Chalaturnyk and D. Mas Ivars. (2009) "An Adaptive Continuum/Discontinuum Coupled Reservoir Geomechanics Simulation Approach for Fractured Reservoirs," in 2009 SPE Reservoir Simulation Symposium (The Woodlands, Texas, February 2009). Paper No. SPE119254.
Detournay, C. (2008) "Numerical Modeling of the Slit Mode of Cavity Evolution Associated with Sand Production," in CD Proceedings, SPE Annual Technical Conference & Exhibition (Denver,September 2008). Paper No. SPE 116168. Houston: SPE.
Hakami, H., and R. Christiansson. (2008) "A Numerical Study of the Stress Field at Forsmark Based on the Shearing Behaviour of Major Deformation Zones," in Geomechanics in the Emerging Social & Technological Age (CD Proceedings, 12th IACMAG Conference, Goa, India, October 2008). Paper No. I01. Toronto: X-CD Technologies Inc.
Hudyma, M., and Y. Potvin. (2008) "Characterizing Caving Induced Seismicity at Ridgeway Gold Mine," in MASSMIN 2008 (5th International Conferenceon Mass Mining, Luleå, Sweden, June 2008), pp. 931-942, H. Schunnesson and E. Nordlund, Eds. Luleå: Division of Mining& Geotechnical Engineering, Luleå University of Technology.
Lorig, L. J. (2008) "Using Numbers from Geology," in The Second Half Century of Rock Mechanics (11th Congress of the International Society for Rock Mechanics, Lisbon, July 2007), pp.1369-1377, L. Ribeiro e Sousa, C. Olalla, and N. Grossmann, Eds. London: Taylor and Francis Group.
Mas Ivars, D. et al. (2008)"The Smooth-Joint Contact Model (Abstract)," in Proceedings, WCCM8 - ECCOMAS 2008 (8th World Congress on Computation Mechanics/5th European Congress on Computational Methods in Applied Sciences & Engineering, Venice, Italy, June-July 2008). Paper No. a2735, B. A. Schrefler and U. Perego, Eds. Barcelona: International Center for Numerical Methods in Engineering (CIMME).
Naidoo, K., M. F. Handley and A. R. Leach. (2008) "Applying Numerical Modelling to Pillar Design in South African Mines — An Initial Study," in SHIRMS 2008 (Proceedings, 1st Southern Hemisphere International Rock Mechanics Symposium, Perth, Western Australia, September 2008), Vol. 1, pp. 379-390, Y. Potvin et al., Eds. Nedlands, Western Australia: Australian Centre for Geomechanics.
Potvin, Y., and M. Hudyma. (2008) "Interpreting Caving Mechanisms Using Microseismic Monitoring Data," in MASSMIN 2008 (5th International Conference on Mass Mining, Luleå, Sweden, June 2008), pp. 971-981, H. Schunnesson and E. Nordlund, Eds. Luleå: Division of Mining& Geotechnical Engineering, Luleå University of Technology.
Sainsbury, B., M. E. Pierce and D. Mas Ivars. (2008) "Analysis of Caving Behaviour Using a Synthetic Rock Mass — Ubiquitous Joint Rock Mass Modelling Technique," in SHIRMS 2008 (Proceedings, 1st Southern Hemisphere International Rock Mechanics Symposium, Perth, Western Australia, September 2008), Vol. 1, pp. 343-252, Y. Potvin et al., Eds. Nedlands, Western Australia: Australian Centre for Geomechanics.
Sainsbury,D. P. (2008) "Analysis of River Bed Cracking Above Longwall Extraction Panels in the Southern Coalfield of New South Wales, Australia," in SHIRMS2008 (Proceedings, 1st Southern Hemisphere International Rock Mechanics Symposium, Perth, Western Australia, September 2008), Vol. 1, pp.325-338, Y. Potvin et al., Eds. Nedlands, Western Australia: Australian Centre for Geomechanics.