Connectivity, permeability, and channeling in randomly
distributed and kinematically defined discrete fracture network
models
A major use of DFN models for industrial applications is to evaluate permeability and flow structure in hardrock aquifers from geological observations of fracture networks. The relationship between the statistical fracture density distributions and permeability has been extensively studied, but there has been little interest in the spatial structure of DFN models, which is generally assumed to be spatially random (i.e., Poisson). We compare the predictions of Poisson DFNs to new DFN models where fractures result from a growth process defined by simplified kinematic rules for nucleation, growth, and fracture arrest. This so-called ‘‘kinematic fracture model’’ is characterized by a large proportion of T intersections, and a smaller number of intersections per fracture.
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Three-dimensional picture of flow in the sequential kinematic DFN model colored by total flow per fracture
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Several kinematic models were tested and compared with Poisson DFN models with the same density, length, and orientation distributions. Connectivity, permeability, and flow distribution were calculated for 3-D networks with a self-similar power law fracture length distribution. For the same statistical properties in orientation and density, the permeability is systematically and significantly smaller by a factor of 1.5–10 for kinematic than for Poisson models. In both cases, the permeability is well described by a linear relationship with the areal density p32, but the threshold for kinematic models is 50% larger than for Poisson models. Flow channeling is also enhanced in kinematic DFN models. This analysis demonstrates the importance of choosing an appropriate DFN structure for predicting flow properties from fracture network parameters. |
 Software
Training & Seminars
Itasca will host introductory training courses in Europe:
Code |
Location |
Dates |
Contact |
| Griddle v1.0 Training course |
Ecully, France |
January 16-18, 2017 |
Itasca France |
| FLAC3D Training course |
Ecully, France |
January 24-26, 2017 |
Itasca France |
| Itasca Info Days dedicated to FLAC3D 6.0 |
Germany |
Quarter 1, 2017 |
Itasca Germany |
| Workshop Itasca/ENPC |
ENPC, Paris |
March 7, 2017 |
Itasca France |
| FLAC3D/Griddle Training course |
Gelsenkirchen and Freiberg, Germany |
March/April, 2017 |
Itasca Germany |
Please visit www.itascacg.com/training for full details.
For users who envisage the need for substantial amounts of assistance, consulting support or customized training course are available.
Accordingly, users are encouraged to submit sample problems prior to the training session for our review and preparation. These problems would then be used as practical applications of the code during the training sessions. |
Conferences
Itasca and/or representatives will be attending the following conferences:
| Swedish Rock Mechanics Day ("Bergmekanikdagen") |
March 13, 2017 |
Stockholm, Sweden |
| Swedish Foundation Day ("Grundläggningsdagen") |
March 16, 2017 |
Stockholm, Sweden |
| Deep and High Stress Mining |
March 28-30, 2017 |
Perth, Australia |
| World Tunnel Congress |
June 9-15, 2017 |
Bergen, Norway |
| BCRRA 2017 |
June 28-30, 2017 |
Athens, Greece |
| Powders & Grains 2017 |
July 3-7, 2017 |
Montpellier, France |
| Congress International AFTES Paris 2017 "The value is underground" |
November 13-16, 2017 |
Paris, France |
Slope Stability 2018
Jonny Sjöberg appointed Keynote Speaker : |
April 11-13, 2018 |
Seville, Spain |
Recent Publications
Maillot, J., P. Davy, R. Le Goc, C. Darcel, and J.R. de Dreuzy -– (2016), Connectivity, permeability, and channeling in randomly distributed and kinematically defined discrete fracture network models, Water Resour. Res., 52.
Mäkitaavola, K., B-M Stöckel, J. Sjöberg, S. Hobbs, J. Ekman, M. Henschel and A. Wickramanyake – (2016) "Application of InSAR for Monitoring Deformations at the Kiirunavaara Mine". In: Proceedings ISMS 2016, 3rd International Symposium on Mine Safety, Science and Engineering (Montreal, Canada, Aug 15–17, 2016), Paper No. 250.
Perman, F., T. Wettainen, C. Gonzalo and J. Sjöberg – (2016) "Three-dimensional modeling and stress calibration for a complex mining geometry". In: Proceedings RS2016, 7th International Symposium on In-Situ Rock Stress (Tampere, Finland, May 10-12, 2016), pp. 127–138. ISBN 978-951-758-606-1.
Lope Álvarez, D., J. Sjöberg, M. Eriksson, R. Bertilsson, D. Mas Ivars – (2016) "Tunnelling and reinforcement in heterogeneous ground – A case study". In: Proceedings Eight International Symposium on Ground Support in Mining and Underground Construction (Luleå, Sweden, September 12-14, 2016), Paper No. 193.
Vatcher, J., S. D. McKinnon and J. Sjöberg (2016) – "Developing 3-D mine-scale geomechanical models in complex geological environments, as applied to the Kiirunavaara Mine", in Engineering Geology, Vol 203, pp. 140–150 (http://dx.doi.org/10.1016/j.enggeo.2015.07.020)
J. J. Oetomo, E. Vincens, F. Dedecker, J-C. Morel (2016) - "Modeling the 2D behavior of drystone retaining walls by a fully discrete element method", in Int. Journal for Numerical and Analytical Methods in Geomechanics, to publish |
