Greetings to all at the start of 2007. The past year has been a busy time of growth and accomplishment for HCItasca, with the addition of new personnel and the expansion of operations and opportunities in a number of our offices. We wish you a happy and prosperous coming year, and we look forward to continuing to develop our relationships with new and existing clients.

—John Markham, Executive Officer

 

Relative locations of road tunnels, exit ramps and weakness zones Z1 to Z6 from 3DEC model Recently, Itasca Consulting Group, Inc. has conducted several 3D stability analyses of complex geometry tunnel infrastructure for road as well as rail tunnels by applying both the continuum code FLAC3D and discontinuum code 3DEC. The analyses addressed various objectives such as:

• Evaluation of alternative designs with respect to excavation stability
• Influence of new tunnel infrastructure on the stability of existing near proximity tunnels
• Determining the affects of pervasive chlorite schist zones on tunnel deformations and stability
• Estimating the influence of multiple large-scale shear zones/faults on overall and local tunnel stability
• Determining the influence of local joint structure on local tunnel stability
• Determination of ground support response (shotcrete and grouted rock bolts) and its affect on stability

The investigations benefited from good information about ground conditions from local site characterization studies. The site information included ranges in ground conditions, the effects of which were also evaluated in the 3D models. Innovative analysis techniques were developed to demonstrate that the total utilization of all rock bolts is quite low with respect to characteristic strength and strain capacities. In one case 1740 rock bolts were used with 9 bolts predicted to yield. The yielding bolts were located across a weakness zone.



Left: Excavation geometry evaluated for stability in 3DEC model. Sequence of excavation considered as well as a locally jointed region. Right: Contours of major principal stress (Pa) (most compressive) in shotcrete liner for supported section of rail tunnels (from 3DEC model). Stress pattern affected by block displacements in the jointed region.

 

Update Alert:
Current Versions
updated since
October 12, 2006:






Upcoming Conference
HCItasca will host the first-ever FLAC/DEM Conference in the Spring of 2008 in Minneapolis. The conference will feature topics and discussions covering the spectrum of HCItasca software: FLAC, FLAC3D, UDEC, 3DEC, PFC2D, and PFC3D. Where past HCItasca-sponsored conferences have limited their scope to a single 2D/3D code pair, this conference, in considering all the codes, will offer a complete look at the state of numerical modeling with HCItasca software. A call for papers will be forthcoming in the next month, and complete details regarding registration, accommodations, and conference-related events will be made available online as preparations for the conference go forward.

 

New Office Location
Itasca Consulting China Ltd. has relocated its office. Please note the new address (the phone and the fax are the same as previously).

Itasca Consulting China Ltd.
T1, Guanshan Second Road, Suite 5-301-1
International Enterprise Center, Phase II
Wuhan City, Hubei Province 430070
People's Republic of China
phone/fax: 86-27-8786-2349
iccl@itasca.cn
web: www.itasca.cn

 

Visit the Conference Site Personnel from the HCItasca offices Hydrologic Consultants Inc. (HCI) and Itasca Consulting Group, Inc. (ICG) will be in attendance at the 2007 Society of Mining Engineers annual meeting in Denver, February 25 to 28. Marc Ruest of ICG will present papers in the "Careful Blast Excavation and Rapid Development" and "Geomechanics: Rock Mechanics in Digital Age – State of the Art of Modeling in Design Practices" sessions. HCItasca will also have a booth in the exhibit hall. If you are going to be attending the conference, please stop by the booth to visit.

 

Spring Training
The annual round of introductory training courses for HCItasca software is approaching. The course offerings are:

• FLAC: April 2, 3, 4
• FLAC3D: April 9, 10, 11
• 3DShop: April 16, 17, 18
• UDEC: April 23, 24, 25
• 3DEC: April 30; May 1, 2
• PFC2D/PFC3D: May 7, 8, 9, 10

Registration deadlines are four weeks prior to the start of each course. Reserve your space now. Further information about training and course outlines is available online. Purchasers of new FLAC3D 3.1 licenses are reminded that one free registration for the FLAC3D and 3DShop courses is available to them.

 

When installing a new license of HCItasca software using a USB SentinelPro key for security, startup errors can result if the key is plugged into the computer prior to the software installation. One simple way to fix this problem is to remove the USB key and cycle it through the other USB ports available on the machine until it is recognized. (On Windows XP, the message "Found New Hardware: Sentinel SuperPro" will appear in the lower right corner.) After doing so, the key should work correctly on all the computer's USB ports.

 

Literature by HCItasca personnel recently published or acquired in the HCItasca library.

Board, M., and B. Damjanac. (2003) "Development of a Methodology for Analysis of Instability in Room and Pillar Mines," in 2003 Swedish Rock Mechanics Day Conference, pp. 1-22, O. Stephansson, Ed. Stockholm: SveBeFo.

Damjanac, B., P. A. Cundall and T. Brandshaug. (2006) "Itasca Presentations at the Menlo Park Workshop, August 23-24, 2004," in Report of the Workshop on Extreme Ground Motions at Yucca Mountain, August 23-25, 2004, U.S. Geological Survey, USGS Open-File Report 2006-1277, T. C. Hanks et al., Eds. Reston, Virginia: USGS.

Davy P., C. Darcel, O. Bour, R. Munier, J. R. de Dreuzy , "A note on the angular correction applied to fracture intensity profiles along drill core," J. Geophys. Res., Vol. 111, No. B11, 30 November 2006.

Fairhurst, C. (2006) "Fundamental Considerations Relating to the Strength of Rock," in Report of the Workshop on Extreme Ground Motions at Yucca Mountain, August 23-25, 2004 Open-File Report 2006-1277, U.S. Geological Survey, USGS Open-File Report 2006-1277, T. C. Hanks et al., Eds. Reston, Virginia: USGS.

Han, Y., and B. Liu. (2006) "FLAC Numerical Modeling on Poroelastic Responses of Saturated Solid Cylindrical Rock Samples (in Chinese)," in Proceedings of the 9th China National Rock Mechanics & Engineering Conference, pp. 236-243. Beijing: Science Publishing Co.

Wang, T. (2006) "Research on Simulation of Rupture of Rock Mass of Tunnel Based on Particle Flow Method (in Chinese)," in Proceedings of the 9th China National Rock Mechanics & Engineering Conference, pp. 464-471. Beijing: Science Publishing Co.

Zhu, H., H. Li and C. O'Connor. (2006) "Numerical Modeling of Brittle Rock Failure (in Chinese)," in Proceedings of the 9th China National Rock Mechanics & Engineering Conference, pp. 260-266. Beijing: Science Publishing Co.