Geomechanics Research Group

logoDr. Davide Elmo
#513 Frank Forward Building
Telephone t: 604 822 9304
email: delmo@mining.ubc.ca

 

 

RESEARCH ACTIVITIES

Discrete fracture network modelling applied to fragmentation processes and engineering problems. Determining the likely distribution of rock mass fragmentation is one of the most critical elements in pre caving assessment of rock mass fragmentation, with the impact of poor or unexpected fragmentation upon cave operations being significant. Over the last 5 years, it has been demonstrated that Discrete Fracture Network (DFN) tools could assist in the fragmentation assessment, primarily through providing a better description of the pre caving in situ fragmentation distribution.

fragmentaition

Analysis of natural fragmentation for slopes and caving problems (Elmo et al., 2008)

breakage

Analysis of rock breakage and flow (Elmo et al., 2014)

 

 

 

 

 

 

 

 

 

 

 

 

Numerical simulations of the mechanical behaviour of hard rock pillars and synthetic rock mass modelling. An approach for modelling fractured rock masses has been developed which has two main objectives: to maximise the quality of representation of the geometry of existing rock jointing and to use this within a loading model which takes full account of this style of jointing (see also the paper by Elmo & Stead, 2010, awarded the 2010 Golder Associates Milligan Award).

scaleeffects

Analysis of pillar behaviour and scale effects (Elmo & Stead, 2010)

 

jointinclination1

Analysis of pillar behaviour abd varying joint inclination (Elmo & Stead, 2010)

 

 

Advanced numerical modelling of block cave mining and interaction between surface and underground mining. Analysis of the critical factors in the transition from surface to underground mining, showing how Induced deformation and/or failure of the crown pillar between the pit floor and the cave back may trigger slope instability on the pit walls. Research carried out as part of a joint UBC-SFU project (e.g. Elmo et al, 2010 and Vyazmensky et al., 2009).

cavedevelopement

2D FDEM analysis of cave development (Elmo et al., 2010)

 

Laboratory and numerical analysis of brittle fracture and damage using FEM and FEM/DEM techniques. Characterisation of brittle fracture damage and study of the effects of progressive damage in rock with respect to design processes (e.g. progressive damage within pit slope as the pit is excavated and step-path failure).

Understanding hydraulic fracture geometry and interactions through Discrete fracture network modelling and FEM/DEM modelling. Simulation of hydraulic fracture development through using DFN models and a rule based approach that allows for the rapid modelling of the interaction between the hydraulic fracture and the natural fracture system. Geomechanical models using a hybrid FEM-DEM code to investigate critical design factors (e.g. Rogers et. al., 2011 and Elmo et al., 2013).

LABORATORY FACILITIES
To be updated soon – Page under construction

DIRECTORY
To be updated soon – Page under construction
The Geomechanics Research Groups currently includes 3 MASs Students, 3 PhD students (shared) and 1 Postdoctoral Fellow (shared).

SELECTED PUBLICATIONS (for the period 2010 to 2015)

Journals

1. Zhang Y., D. Stead D. Elmo. 2015. Characterization of strength and damage of hard rock pillars using a synthetic rock mass method. Computers and Geotechnics. Vol. 65. pp 56 – 72.
2. Mitelman A. and Elmo D. 2014. Modelling of blast induced damage in tunnels using a hybrid finite-discrete numerical approach. Journal of Rock mechanics and Geotechnical Engineering. In Press. doi:10.1016/j.jrmge.2014.09.002
3. Elmo D., S. Rogers, D. Stead and E. Eberhardt. 2014. A Discrete fracture network approach to characterise rock mass fragmentation and implications for geomechanical upscaling. Transactions of the Australian Inst. Mining Metallurgy. Volume 123, Issue 3.
4. Woo K.S., E. Eberhardt, D. Elmo, D. Stead and P. Kaiser. 2014. Benchmark testing of numerical capabilities for modelling the influence of undercut depth on caving, fracture initiation and subsidence angles associated with block cave mining. Transactions of the Australian Inst. Mining Metallurgy. Volume 123, Issue 3. DOI 10.1179/1743286314Y.0000000063.
5. Rogers S., D. Elmo, G. Webb and A. Catalan. 2014. Volumetric Fracture Intensity Measurement for Improved Rock Mass Characterisation and Fragmentation Assessment in Block Caving Operations. Rock Mechanics and Rock Engineering. DOI 10.1007/s00603-014-0592-y
6. Hamdi P., D. Stead and D. Elmo. 2014. Damage characterization during laboratory strength testing: A 3D-finite-discrete element approach. Computers and Geotechnics. Vol. 60, 33-46.
7. Elmo D., D. Stead, E. Eberhardt and A. Vyazmensky. 2013. Applications of Finite Discrete Element Modelling to Rock Engineering Problems. International Journal of Geomechanics. Vol. 13(5).
8. Woo K-S., E. Eberhardt, D. Elmo and D Stead. 2013. Empirical investigation and characterization of surface subsidence related to block cave mining. International Journal of Rock Mechanics and Mining Sciences: Vol. 61. Pages 31-42.
9. Coggan J., F. Gao, D. Stead and D. Elmo. 2012. Numerical modelling of the effects of weak immediate roof lithology on coal mine roadway stability. International Journal of Coal Geology, volume 90-91, pages 100-109, DOI:10.1016/j.coal.2011.11.003.
10. Sturzenegger M., D. Stead and D. Elmo. 2011. Terrestrial remote sensing-based estimation of discontinuity frequency, mean trace length, block size/shape and dependence on observation scale. Engineering Geology. Vol. 119(3-4). Pages 96-111.
11. Vyazmensky A., D. Elmo and D. Stead. 2010. Role of Rock Mass Fabric and Faulting in the Development of Block Caving Induced Surface Subsidence. Rock Mechanics and Rock Engineering. Vol. 43(5), 533-556, DOI: 10.1007/s00603-009-0069-6.
12. Vyazmensky A., D. Stead, D. Elmo and A. Moss. 2010 Numerical Analysis of Block Caving Induced Instability in Large Open Pit Slopes: A Finite Element / Discrete Element Approach. Rock Mechanics and Rock Engineering. Vol. 43(1), 21-39, DOI: 10.1007/s00603-009-0035-3.
13. Elmo D. and D. Stead. 2010. An integrated numerical modelling – discrete fracture network approach applied to the characterisation of rock mass strength of naturally fractured pillars. Rock Mechanics and Rock Engineering, Vol. 43(1), 3-19. DOI 10.1007/s00603-009-0027-3.

Conference Proceedings

1. Hamdi P., D. Stead, D. Elmo, J. Töyrä and B.M. Stöckel. 2014. Use of an integrated Finite/Discrete Element Method-Discrete Fracture Network Approach (FDEM-DFN) in characterizing surface subsidence associated with sub-level caving. Proc. 1st Conference on Discrete Fracture Network Engineering. Vancouver, Canada.
2. Hamdi P., D. Stead and D. Elmo. 2014. Characterizing the influence of micro-heterogeneity on the strength and fracture of rock using an FDEM-nDFN approach. ISRM Rock Mechanics Symposium. 27th to 29th May, Vigo, Spain. (Conference award for the best paper written by a PhD student, Hamdi P.)
3. Elmo D., R. Pakalnis and D. Stead. 2014. A comparison between simulated results and empirical formulae using a hybrid modelling approach. 1St Int. Conference on Applied Empirical Design Methods in Mining. 9-11nt June, Lima, Peru.
4. Panton B., D. Elmo, P. Schlotfeldt and J. Carvalho. 2014. Design of rock foundation anchorage Using Discrete Fracture Networks. Proc. 1st Conference on Discrete Fracture Network Engineering. Vancouver, Canada.
5. Dorador L., E. Eberhardt and D. Elmo. 2014. Assessment of broken ore density variations in a block cave draw column as a function of fragment size distributions and fines migration. Proc. 3rd Int. Symp. on Block and Sublevel Caving. Santiago. Chile. June 5th – 6th. pp. 109-117.
6. Dorador L., E. Eberhardt and D. Elmo. 2014. Influence of secondary fragmentation and column height on block size distribution and fines migration reaching drawpoints. Proc. 3rd Int. Symp. on Block and Sublevel Caving. Santiago. Chile. June 5th – 6th. pp. 128-137.
7. Elmo D., S. Rogers, R. Dunphy and D. Bearinger. 2013. An initial assessment of the impact of varying perf cluster Design on hydraulic fracture effectiveness. Proc. 47th US Rock Mechanics Symposium, San Francisco, CA, June 27-30, 2013. Paper 13-716.
8. Hamdi P., D. Stead and D. Elmo. 2013. Numerical simulation of damage during laboratory testing on rock using a 3D-FEM/DEM approach. Proc. 47th US Rock Mechanics Symposium, San Francisco, CA, June 27-30, 2013. Paper 13-583.
9. Rogers S., D. Elmo, G. Webb and A. Catalan. 2013. Volumetric Fracture Intensity Measurement for improved rock mass characterisation and fragmentation assessment in block caving operations. Proc. 47th US Rock Mechanics Symposium, San Francisco, CA, June 27–30, 2013. Paper 13-487.
10. Elmo D., C. Clayton, S. Rogers, R. Beddoes and S. Greer. 2012. Numerical simulations of potential rock bridge failure within a naturally fractured rock mass. Proceedings International Symposium on Rock Slope Stability in Open Pit Mining and Civil Engineering, Vancouver, Canada.
11. Elmo D., P. Schlotfeldt, R. Beddoes and D. Roberts. 2011. Numerical simulations of scale effects under varying loading conditions for naturally fractured rock masses and implications for rock for rock mass strength characterization and the design of overhanging rock slopes. Proc. 45th US Rock Mechanics Symposium, San Francisco, CA, June 27–30, 2011.
12. Elmo D., S. Rogers and R. Beddoes. 2011. Numerical analysis of caving mechanism using a hybrid FEM/DEM approach: experience gained and lessons learned. Proc. 45th US Rock Mechanics Symposium, San Francisco, CA, June 27–30, 2011.
13. Elmo D., D. Roberts, S. Rogers and T. Yanske. 2010. Simulations of roof collapse and cave development using a hybrid finite/discrete approach. Proc. 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Salt Lake City, UT June 27–30, 2010.
14. Styles T. D., Y. Zhang, D. Stead, D. Elmo, D. Roberts and T. Yanske. 2010. A photogrammetric approach to brittle fracture characterization in mine pillars. Proc. 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Salt Lake City, UT June 27–30, 2010.
15. Elmo D., S. Rogers, R. Beddoes and A. Catalan. 2010. An Integrated FEM/DEM – DFN synthetic rock mass approach for the modelling of surface subsidence associated with panel cave mining at the Cadia East Underground Project. 2nd Int. Symp. on Block and Sublevel Caving. Perth, Australia.
16. Rogers S., D. Elmo, G. Webb and A. Catalan. 2010. A DFN based approach to defining in situ, primary and secondary fragmentation distributions for the Cadia East panel cave. 2nd Int. Symp. on Block and Sublevel Caving. Perth, Australia.
17. Rogers S., D. Elmo, G. Webb and A. Catalan. 2010. Simulating the impacts of hydro fracture pre-conditioning on cavability and fragmentation at the planned Cadia East Panel Cave. 2nd Int. Symp. on Block and Sublevel Caving. Perth, Australia.