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Introducing: Laboratory Testing Services
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H-M coupling

We are excited to announce a new business activity for Geomechanica: rock laboratory testing services. Geomechanica’s personnel have extensive rock laboratory testing experience, which enabled Geomechanica to begin offering rock testing services in 2015. These services provide clients with the data needed for the design and analyses of various civil and mining engineering projects.

From weak shales to hard crystalline rocks, Geomechanica offers a full array of standard rock mechanics laboratory testing services, including:

  • Uniaxial compression testing
  • Triaxial compression testing
  • Brazilian disc testing
  • Direct shear testing
  • Slake durability testing
  • Cerchar abrasivity testing
  • Point load testing

Email us at lab@geomechanica.com or call us at +1-647-478-9767 for more information about our testing capabilities or to request a brochure.




 
ARMA 2017: Short Course on 2D and 3D Modeling of Rock Fracturing Processes in Geomechanics
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Geomechanica is looking forward to teaching a short course on 2D and 3D Modeling of Rock Fracturing Processes in Geomechanics at the 51st US Rock Mechanics/Geomechanics Symposium (ARMA 2017) to be held in San Francisco, California, USA on 25-28 June 2017 External link. The one-day course, instructed by Dr. Bryan Tatone and Mr. Aly Abdelaziz will be held at the The Westin St. Francis on Sunday, 25 June 2017 from 8:30 am to 4:00 pm.

This one-day course will combine theoretical lectures on the fundamental principles of Irazu FDEM software with practical modeling sessions where participants will be guided through several simulation cases. The course will start with a general introduction to the FDEM modelling philosophy and its application to engineering geology, rock mechanics, and geophysics problems. After a quick review of the basic algorithms, such as finite element deformation, contact detection, and contact interaction, the fracture model will be discussed in more depth. More advanced features of Irazu, including: in-situ stress initialization, rock excavation, Discrete Fracture Networks (DFNs), and hydro-mechanical coupling will also be introduced. In the second part of the course, participants will gain valuable hands-on experience through a series of practical modelling exercises using Geomechanica’s Irazu software to model practical rock fracturing problems. Please review the course flyer below for more information (or this link PDF-icon):



We encourage geotechnical, geological, mining and petroleum engineers, as well as undergraduate and post-graduate students and researchers to attend this short course. The registration fee of $400 includes lunch/refreshments, course slides, Irazu manuals, and related references.




 
FEM Solver
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The computational engine of Irazu simulation software is based on the finite-discrete element method. This inherently means that Irazu is equipped with a finite element solver (FEM). The FEM solver uses linear elastic constitutive laws (isotropic and transversely isotropic) and solves the equations of motion using an explicit time integration scheme. Therefore, it is well suited to model dynamic problems. In addition to being a simulation tool on its own, the FEM solver can be used together with the FDEM solvers of Irazu: an Irazu simulation can be started from a prescribed FEM state. This can greatly reduce the computational demands of Irazu simulations and thus save simulation time.

Some examples of the application of the FEM solver include:

  • Elastic stress-strain analysis of many practical engineering applications
  • Application of geostatic in-situ stresses to the domain
  • Modelling stress variations caused by mining operations, including staged excavations
  • Simulation of dynamic problems, including stress wave propagation in heterogeneous media

Below is an example of an open pit mine. Firstly, the far-field in-situ stresses are applied to the pre-mining domain based on available stress data. Afterwards the excavation of the pit is considered in 3 stages. Notice the changes in stress distribution and principal stress rotations (gray lines). These results can be used on their own or as a starting point for a full FDEM analysis with Irazu in which large deformations and possible fracturing in the slope can be simulated.

Staged excavation of an open pit slope. The simulation started by applying far-field in-situ stresses (top left), then three stages of excavations. The gray lines indicate the direction of major principal stress, σ1. Compressive stresses are negative. Stress unit: Pascals.
 

This feature is currently available in the latest versions of both Irazu 2D and Irazu 3D. We also plan to release a standalone FEM version of Irazu in the future. Please get in touch with us by expressing your interest to info@geomechanica.com email_icon.




 
2017 ISRM Rocha Medal Recipient: Dr. Bryan Tatone
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Since 1982 a bronze medal and a cash prize have been awarded annually by the International Society for Rock Mechanics (ISRM) for an outstanding doctoral thesis in rock mechanics or rock engineering, to honour the memory of Past President Manuel Rocha while stimulating young researchers.


From the ISRM news release External link following its Council meeting on August 28th, 2016 in Ürgüp, Turkey, we have learned that another member of the Geomechanica’s team, Dr. Bryan Tatone, will receive this prestigious award. Dr. Tatone follows the path of his colleague, Dr. Andrea Lisjak External link, who was awarded the Rocha Medal in 2015. A PDF of Dr. Tatone’s Ph.D. Thesis entitled “Investigating the evolution of rock discontinuity asperity degradation and void space morphology under direct shear” can be downloaded here External link. Dr. Tatone will be awarded the medal at the ISRM International Symposium Rock Mechanics for Africa in Cape Town, South Africa (October 2-7, 2017) where he will also give a plenary lecture on his Ph.D. research.

Dr. Tatone joins an impressive list External link of previous recipients that have made significant contributions to the field of rock mechanics and rock engineering. We at Geomechanica congratulate Dr. Tatone, an invaluable member of our team, on this prestigious achievement!




 
Numerical simulation of discontinuity shearing behaviour
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The multi-facetted experimental and numerical investigation forming the PhD thesis of Geomechanica’s Dr. Bryan Tatone entitled “Investigating the evolution of rock discontinuity asperity degradation and void space morphology under direct shear External link” demonstrated the first experimentally-supported simulation of discontinuity shearing using a FDEM modelling approach. Dr. Tatone’s work coupled micro-Computed Tomography (micro-CT) with FDEM modelling to better understand the failure mechanisms of asperities and identify the limitations of numerically simulating the shearing process.

Geomechanica is continuing work on the modelling of discontinuity shearing using our Irazu FDEM software. In particular, the substantial speed-up offered by GPU acceleration allows one to consider larger-scale problems. This ability to explicitly capture realistic discontinuity morphology is of potential benefit to a wide range of rock engineering problems, including those concerned with enhancing rock mass permeability (e.g. well stimulation) and those concerned with minimizing changes to rock mass permeability (e.g., nuclear waste storage). We look forward to working together with fellow researchers to exploit this capability of our software.

Asperity damage evolution
Results from the thesis of Dr. Bryan Tatone showing agreement between experimental and numerical observations: (a) Damage evolution in discontinuity replicas as observed using micro-CT imagery; (b) Numerically simulated damage evolution of a single asperity showing the principal stress distribution together with the mode of fracturing.




 
Irazu computational performance
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Irazu makes use of state-of-the-art high performance computing techniques to speed-up computations. In particular, we use GPU (graphics processing unit) computing on consumer-grade AMD graphics cards. To demonstrate the improvement in computation speed, five uniaxial compression strength (UCS) tests with an increasing number of finite elements were simulated using Irazu and the sequential CPU code Y-Geo. The number of elements, nominal element size, and time step size are summarized in the table below. Each of these models was executed for 10,000 time steps and the elapsed time between the first and last output (i.e., time step = 0 and time step = 10,000) were compared. All simulations were performed on a standard desktop computer equipped with an Intel Core i7 CPU @ 3.4 GHz (over clocked to 4.0 GHz), 16 GB of RAM, and AMD Radeon R9 200 series GPU with 3 GB of on-board memory.

Number of finite elements Element size (mm) Time step size (ms)
3,630 2.00 10-5
14,600 1.00 10-6
58,524 0.50 10-7
232,128 0.25 10-8
504,756 0.10 10-9

The relative speed-up of Irazu over Y-Geo, defined by the ratio of Y-Geo simulation time divided by Irazu simulation time, is presented in the figure below (left). Full contact detection refers to an Irazu simulation where contact detection is performed at each time step. In contrast, fixed contact topology at t=0 refers to a simulation where contact detection is only performed once at the beginning of the simulation. The latter approach is only suitable for models with small displacements, where new contacts among elements are not formed during the simulation (for instance, hydraulic fracturing applications). As the figure below shows, Irazu exhibited a substantial speed-up over Y-Geo, starting at around 5 times for the smallest model, but increasing to 30 times for the largest model. The speed-up for models with fixed topology was even greater, peaking at over 42 times for the largest model. This trend shows that a greater GPU performance boost is realized when more elements and, thus, more parallel working groups are employed.

As depicted in the right figure, Irazu showed a linear increase in simulation time as a function of the number of elements (R2=0.99). Although the simulation time in Y-Geo is also linearly proportional to the number of elements (see inset of right figure), the slope of the line defining simulation time versus number of elements is significantly lower for Irazu (approximately 36 times), indicating the computational efficiency is far superior. Overall, the results show that GPU-powered computations in Irazu lead to an impressive reduction in simulation time compared to the sequential Y-Geo CPU code.

TimeSpeedComp-landscape

This text is part of our paper for the ARMA rock mechanics symposium in Houston, Texas, June 26-29, 2016. You can download the full paper here PDF-icon.




 
Introducing Geomechanica: Lassonde Institute PhD Graduates Pursue Entrepreneurship in Rock Mechanics
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Geomechanica’s Dr. Andrea Lisjak and Dr. Omid Mahabadi were recently interviewed by the Lassonde Institute of Mining of the University of Toronto. In this interview, we discussed our endeavours in founding Geomechanica and developing our state-of-the-art geomechanical simulation software, Irazu.

“Three Lassonde Institute of Mining PhD graduates— Andrea Lisjak (CivE PhD 2013), Omid Mahabadi (CivE PhD 2012), and Bryan Tatone (CivE PhD 2014) —have combined rock mechanics, computer science, and entrepreneurship in Geomechanica, a three-pronged startup company that develops geomechanical simulation software and provides rock-engineering consulting and rock mechanics laboratory testing services. Their software, Irazu, which launched commercially in December 2015, is a state-of-the art rock mechanics simulation tool that offers a fast, unique method to model mine operations.”

You can read the full interview at: http://lassondeinstitute.utoronto.ca/news/introducing-geomechanica-lassonde-institute-phd-graduates-pursue-entrepreneurship-in-rock-mechanics/External link




 
ARMA 2016: Short course on Modeling of Coupled Hydro-Mechanical Deformation and Fracturing Processes in Geomechanics
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Geomechanica is looking forward to teaching a short course on Modeling of Coupled Hydro-Mechanical Deformation and Fracturing Processes in Geomechanics at the 50th US Rock Mechanics/Geomechanics Symposium (ARMA 2016) to be held in Houston, Texas, USA on 26-29 June 2016 External link. The one-day course External link, instructed by Dr. Andrea Lisjak and Dr. Omid Mahabadi, will be held at the The Westin Galleria Houston on Sunday June 26, 2016 from 8:30 am to 4:30 pm.

This one-day course will combine theoretical lectures on the fundamental principles of Irazu FDEM software with practical modeling sessions where participants will be guided through several simulation cases. The course will start with a general introduction to the FDEM modelling philosophy and its application to engineering geology, rock mechanics, and geophysics problems. After a quick review of the basic algorithms, such as finite element deformation, contact detection, and contact interaction, the fracture model will be discussed in more depth. More advanced features of Irazu, including: in-situ stress initialization, rock excavation, and the incorporation of rock-reinforcement and Discrete Fracture Networks (DFNs), and hydro-mechanical coupling will also be introduced. In the second part of the course, participants will gain valuable hands-on experience through a series of practical modelling exercises using Geomechanica’s Irazu software to model practical H-M-coupled problems in oil & gas, geothermal, and civil engineering applications. Please review the course flyer below for more information:



We encourage geotechnical, geological, mining and petroleum engineers, as well as undergraduate and post-graduate students and researchers to attend this short course. The registration fee of $400 includes lunch/refreshments, course slides, Irazu manuals, and related references.