HCItasca's sustained commitment to research as an integral part of its consulting practice and software development is leading us in new directions: partnerships yielding novel modeling and analytical techniques (see Consulting below), a new office (see HCItascaWorld), and prospects to integrate our modeling codes with other software. At HCItasca, research provokes innovation and drives inquiry. On occasion, it leads nowhere. But, as Einstein said, "If we knew what it was we were doing, it would not be called research, would it?" We're pleased our track record shows that it's worth the effort.

—John Markham, Executive Officer

 

Long view and detail of a two-dimensional SRM made of 330,000 particles & 40,225 discontinuities, resulting in 38,656 clusters


A slice through a FLAC3D model employing SRM-derived properties. The predicted extent of microseismicity (within the dark gray isosurface) compares favorably with the location of recorded events (black dots). The predicted extent of caving (light gray isosurface) and yield (dark blue) are also shown. Itasca Consulting Group, Inc. and ASC (Applied Seismology Consultants) are in an ongoing partnership to apply advanced numerical modeling tools and microseismic data analysis techniques to caving prediction. The work is part of the Mass Mining Technology (MMT) Project, an industrially funded project supporting fundamental research into the mechanics of caving, blasting, and flow in underground mass mining. Itasca studies rock mass strength and brittleness, using the Particle Flow Code (PFC) to create and test "Synthetic Rock Mass" samples (SRM) and subjecting these to induced stresses expected in situ. Using advanced tools for microseismic data analysis, ASC compares the predicted spatial temporal trends in fracturing within the samples directly with microseismic data obtained in the field. This represents a powerful combination of tools that can be applied to a wide range of rock mechanics problems and a potentially significant advancement past traditional, empirical methods of estimating rock mass properties.

Linking PFC to microseismic data is a technique that has been successfully employed within pioneering research projects to reproduce in situ seismicity measured in massive brittle rock (Hazzard and Young, 2004) and has been applied to the analysis of damage around underground excavations (Young et al., 2004). The current MMT research objectives are to extend the technique to the prediction of jointed rock mass behavior in three dimensions. The complete project description describes the techniques used, the results to date, and full citations for the references above.

Comparison of fracture orientations predicted by SRM testing and those inferred from microseismic data.

HCItasca is pleased to announce the formation of a new office, Itasca Houston, Inc., that will extend HCItasca's geomechanical and hydrological expertise and software products to the oil and gas industry. Itasca Houston, Inc. expects to be able to make significant contributions to understanding current challenges in the industry through application of HCItasca's advanced modeling capabilities. The office will offer consulting services independently and in conjunction with other HCItasca offices with the goal of developing a wider profile for HCItasca within the oil and gas industry.

 

Update Alert:
Current Versions
updated since
January 30, 2007:






PFC 4.0 Pre-Release available now
The final release is expected this summer. New features in version 4.0 include:

• Fluid-particle simulation capability by coupling PFC3D to a new computational fluid dynamics code developed by Itochu Techno-Solutions Corporation (CTC) that computes fluid flow through arbitrarily shaped volumes (use of this feature requires separate purchase of the CTC code);
• 64 bit version;
• Enhanced Fishtank to support solids-based modeling including genesis of multiple clumped and bonded material regions with particle-size refinement;
• Enhanced clump logic including measurement-logic support;
• Sliding-joint contact model to simulate the behavior of a through-going interface regardless of the local particle contact orientations along the interface (requires C++/UDM option);
• Help File containing the Command Reference, FISH Reference, and Example Applications volumes from the PFC Manual.

Note on Availability
With PFC2D and PFC3D Version 4.0 targeted for release this summer, the following changes have been adopted for sale and distribution of the code:

• For new purchases - As of April 15, we will no longer sell Version 3.1. Between April 15 and the date of release, clients who purchase Version 4.0 will receive Version 3.1 at the time of purchase and will automatically receive Version 4.0 when it is officially released.
• For current version 3.1 users - Current users have until May 15 to pre-purchase at a significantly discounted rate over the price of upgrading after release.

 

The annual round of spring introductory training courses in Minneapolis is approaching fast, and the courses are filling up. The FLAC training course on April 2, 3, and 4 has space for only two more trainees. The FLAC3D course for following week (April 9, 10, and 11) has five spots available. If you are interested in attending either of these courses, don't wait - sign up now.

 

Conference information
online FLAC/DEM Conference Update
The initial preparations for the conference are underway. The date for the conference has been set - August 25-27, 2008. The call for papers has been issued, and abstracts are due June 15, 2007. Arrangements for a venue in Minneapolis are in the works, and we expect to be able to supply this information, as well as other details, in the next issue of Groundworks. More information, including the conference timetable and the instructions supplied in the call for papers, is available online.

 

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

Barnett, W. P., and L. Lorig. "A Model for Stress-Controlled Pipe Growth," J. Volcanol. Goeth. Res., 159, 108-125 (2007).

Corkum, A. G., and C. D. Martin. "Analysis of Tunnel Deformations in Opalinus Clay Using a Stress-Dependent Modulus Model," in Sea to Sky Geotechnique (CD Proceedings of the 59th Canadian Geotechnical Conference & 7th Joint CGS/IAH-CNC Groundwater Specialty Conference, Vancouver, October 2006), Paper no. 022-29, pp. 461-468.

Corkum, A. G., and C. D. Martin. "The Mechanical Behaviour of Weak Mudstone (Opalinus Clay) at Low Stresses," Int. J. Rock Mech. Min. Sci., 44, 196-209 (2007).

Damjanac, B., M. Board, M. Lin, D. Kicker, and J. Leem."Mechanical Degradation of Emplacement Drifts at Yucca Mountain — A Modeling Case Study, Part II: Lithophysal Rock," Int. J. Rock Mech. Min. Sci., 44, 368-399 (2007).

Fairhurst, C., B. Damjanac and T. Brandshaug. "Rock Mass Strength and Numerical 'Experiments',", in Publications of the Geotechnical Institute No. 2006-5, Proceedings 35 (Geomechanics Colloquium, November 2006), pp. 1-20. Freiberg, Germany: Technical University Mining Academy Freiberg, 2007.

Lin, M., D. Kicker, B. Damjanac, M. Board, and M. Karakouzian. "Mechanical Degradation of Emplacement Drifts at Yucca Mountain — A Modeling Case Study, Part I: Nonlithophysal Rock," Int. J. Rock Mech. Min. Sci., 44, 351-367 (2007).

Potyondy, D. O. "Simulating Stress Corrosion with a Bonded-Particle Model for Rock," Int. J. Rock Mech. Min. Sci., 44, 677-691 (2007).

Schegel, R., J. Will and H. Konietzky. "Optimization and Sensitivity Analysis in Mining and Geotechnical Engineering Using Numerical Approaches," Buletin Resurse Minerale, 2, 47-54 (2006).