Publications

45.

Whipple, R; Banton, CJ; Diederichs, MS

Current Shotcrete Testing at Inco Conference

Proceedings of the International Workshop & Seminar on Surface Support Liners, Quebec City, QC, Canada, 2003.

BibTeX | Tags: shotcrete lining

44.

Coulson, A; Diederichs, MS; Falmagne, VF; Rizkala, M; Simser, B

Qualitative Risk Assessment for Mine Openings in Varying Stress Conditions Conference

Proceedings of the North American Rock Mechanics Conference, UTP Press Toronto, Ontario, Canada, 2002.

BibTeX | Tags: mine support, Risk assessment, Stress conditions

43.

Diederichs, MS

Rock damage under low confinement conditions: Implications for design of underground openings in both relaxed and high stress conditions Conference

Proceedings of the North American Rock Mechanics Conference, UTP Press Toronto, Ontario, Canada, 2002.

BibTeX | Tags: High stress, low confinement, Rockmass damage, underground excavations

42.

Diederichs, MS; Coulson, A; Falmagne, VF; Rizkala, M; Simser, B

Application of rock damage limits to pillar analysis at Brunswick Mine Conference

Proceedings of the North American Rock Mechanics Conference, Toronto, Ontario, Canada, 2002.

BibTeX | Tags: Rock pillar, Rockmass damage

41.

Guerard, B; Diederichs, MS; Hutchinson, DJ; Falmagne, V; Nickson, S

A Rockmass System Approach to Prediction of Ground Performance in Underground Mines Conference

Proceedings of the Canadian Geotechnical Conference, Niagara Falls, ON, Canada, 2002.

BibTeX | Tags: Rockmass, underground mines

40.

Essex, RJ; Diederichs, MS; Giles, EL

Managing geotechnical and financial risk in underground construction Journal Article

In: International Society of Rock Mechanics News Journal, vol. 6, no. 3, pp. 38-39, 2001.

BibTeX | Tags: Risk assessment, underground excavations

39.

Diederichs, MS; Espley, S; Hutchinson, DJ

Method for performing wedge analysis for assessing wedge instabilities in underground openings Patent

2001.

BibTeX | Tags: underground excavations, Wedge analysis, Wedge instabilities

38.

Kaiser, PK; Diederichs, MS; Martin, D

Brittle rock mass failure and tunnelling at depth Conference

Proceedings of the Morgenstern Symposium, Edmonton, AB, Canada, 2001.

BibTeX | Tags: Brittle damage, Brittle rocks, Deep tunnelling

37.

Steiner, W; Diederichs, MS; Kaiser, PK

Probabilistic evaluation of the stability of a bridge foundation in a rock cliff Conference

Proceedings of the International Symposium: Landslides – Causes, Impacts and Countermeasures, Switzerland, 2001.

BibTeX | Tags: bridge foundation, probability, rock cliff, Stability

36.

Kaiser, PK; Diederichs, MS; Martin, CD; Sharp, J; Steiner, W

Underground works in hard rock tunnelling and mining Conference

ISRM international symposium, International Society for Rock Mechanics and Rock Engineering International Society for Rock Mechanics and Rock Engineering, Melbourne, Australia, 2000.

Abstract | Links | BibTeX | Tags: Artificial Intelligence, brittle rock, mining induced stress change, pillar strength, reservoir geomechanics, shotcrete lining, structural geology, underground work

@conference{Kaiser2000,

title = {Underground works in hard rock tunnelling and mining},

author = {PK Kaiser and MS Diederichs and CD Martin and J Sharp and W Steiner},

url = {https://onepetro.org/ISRMIS/proceedings-abstract/IS00/All-IS00/ISRM-IS-2000-021/50702},

year  = {2000},

date = {2000-11-19},

booktitle = {ISRM international symposium},

publisher = {International Society for Rock Mechanics and Rock Engineering},

address = {Melbourne, Australia},

organization = {International Society for Rock Mechanics and Rock Engineering},

abstract = {The rock mass around an underground opening is subjected to a unique stress path that results in low radial confinement and both tangential loading and unloading conditions near the wall. As a result, the rock mass strength near underground excavations is controlled by failure mechanisms dominating at low confinement. Hence, when constructing underground works in hard rock, two general scenarios are encountered: 

1. structurally controlled gravity-driven failures; and 

2. stress-induced failure with spalling and slabbing. 

 

The former process is predominant when both the radial and the tangential stresses are low, where as the latter is prevalent when high tangential stresses drive rock mass failure. Whereas structurally controlled failures are most frequently observed at shallow depths and slabbing failure is commonly found at great depth, mining and tunnelling experience shows that these failure processes may be encountered at essentially any depth. In this keynote the authors provide an overall framework for assessing the stability of underground openings in hard rocks, regardless whether the excavations are required for mining, nuclear waste or civil engineering applications. For the prediction of stress-induced slabbing, a bi-linear failure envelope cut-off is introduced. The resulting failure envelope, combined with numerical modelling, is used to determine the depth of failure near excavations and in pillars, and to examine the effect of rock mass bulking of the failed rock on the displacement demand for support selection. An assessment of rock mass relaxation on structurally controlled failure processes is made with respect to support demand and support capacity. This keynote also includes a brief review of violent failure processes, i.e., rockbursting. Where possible, examples from mining and civil engineering projects are provided to illustrate the design challenges of underground excavations in hard rocks. Guidelines for support design are provided.},

keywords = {Artificial Intelligence, brittle rock, mining induced stress change, pillar strength, reservoir geomechanics, shotcrete lining, structural geology, underground work},

pubstate = {published},

tppubtype = {conference}

}

Close

The rock mass around an underground opening is subjected to a unique stress path that results in low radial confinement and both tangential loading and unloading conditions near the wall. As a result, the rock mass strength near underground excavations is controlled by failure mechanisms dominating at low confinement. Hence, when constructing underground works in hard rock, two general scenarios are encountered:
1. structurally controlled gravity-driven failures; and
2. stress-induced failure with spalling and slabbing.

The former process is predominant when both the radial and the tangential stresses are low, where as the latter is prevalent when high tangential stresses drive rock mass failure. Whereas structurally controlled failures are most frequently observed at shallow depths and slabbing failure is commonly found at great depth, mining and tunnelling experience shows that these failure processes may be encountered at essentially any depth. In this keynote the authors provide an overall framework for assessing the stability of underground openings in hard rocks, regardless whether the excavations are required for mining, nuclear waste or civil engineering applications. For the prediction of stress-induced slabbing, a bi-linear failure envelope cut-off is introduced. The resulting failure envelope, combined with numerical modelling, is used to determine the depth of failure near excavations and in pillars, and to examine the effect of rock mass bulking of the failed rock on the displacement demand for support selection. An assessment of rock mass relaxation on structurally controlled failure processes is made with respect to support demand and support capacity. This keynote also includes a brief review of violent failure processes, i.e., rockbursting. Where possible, examples from mining and civil engineering projects are provided to illustrate the design challenges of underground excavations in hard rocks. Guidelines for support design are provided.

Close

35.

Diederichs, MS; Kaiser, PK

Authors' reply to Discussion by A.L. Sofianos regarding Diederichs MS. and Kaiser P.K. Stability of large excavations in laminated hard rock masses Journal Article

In: International Journal of Rock Mechanics and Mining Sciences, vol. 36, no. 7, pp. 995-997, 2000.

Links | BibTeX | Tags: Hard rockmasses, laminated rockmasses, Voussoir beam analogue

34.

Diederichs, MS

Instability of hard rockmasses: the role of tensile damage and relaxation PhD Thesis

the University of Waterloo, 2000.

Abstract | Links | BibTeX | Tags: Brittle damage, Crack initiation, Discrete element method, Hard rockmasses, Relaxation, Tensile Strength

@phdthesis{Diederichs1999,

title = {Instability of hard rockmasses: the role of tensile damage and relaxation},

author = {MS Diederichs},

url = {http://hdl.handle.net/10012/480},

year = {2000},

date = {2000-01-01},

address = {University of Waterloo Library 200 University Avenue West Waterloo, Ontario, Canada N2L 3G1},

school = {the University of Waterloo},

abstract = {In low stress environments, stability of rockmasses around underground excavations is typically controlled by rockmass structure. At depth and in highly stressed areas the rockmass strength controls stability. Tensile strength and tensile damage processes as well as abutment relaxation or reduced confinement often play dominant roles as agents of rockmass conditioning and failure control. This study focusses primarily on stability issues related to underground excavations in "hard" rockmasses, rockmasses that are sparsely to moderately jointed with rock of high strength, high stiffness, and brittle response.

This thesis is divided into two parts. In Part 1, the author examines structurally dominated failure modes, investigating the role of residual tensile rockmass strength and relaxation on the stability of tunnels and mining stopes. Because of the demonstrated significance of these mechanisms, the results of this study are used to modify empirical design tools for stability assessment.

In Part 2, the author investigates the importance of microscopic and mesoscopic tensile crack growth on compression-induced damage near-excavation fracturing of heterogenous rockmasses at depth. The sensitivity of insitu rockmass compressive strength to low near-excavation confining stress is examined. It is demonstrated that tensile failure processes, even under moderately compressive stress fields, control rockmass failure and fracture development near excavations in hard rock. The findings of this work explain the success of empirical strength criteria and damage prediction tools, improving confidence for future design applications.

Two simple numerical analogues for rock and rockmass behaviour are used in this study. The voussoir beam model is applied to the study of structurally controlled instability while an elastic-brittle bonded-contact discrete element model is used to study damage processes of stressed rock.

For excavations in sparsely to moderately jointed hard rockmasses, the extent of the gravity driven failures can be prevented or limited if the joints, which bound the potentially unstable blocks, are even slightly discontinuous. That is, even in small proportion of intact area (rock bridge) over the plane of a joint can generate significant self-supporting, load bearing capacity. The support pressure achieved for most practical support systems can be matched by a very small proportion of rock bridges as demonstrated using example analyses of wedge and jointed beam (voussoir) stability. This observation has implications for short-term or first-pass support design as well as for accurate back analysis of failures and stability assessment of areas that are affected by mining.

Limit equilibrium analyses of rock blocks and wedges are highly conservative if the effects of clamping (compressive stresses) are ignored. Conservatively, abutment relaxation or unclamping of excavation backs and walls may also be a significant factor controlling rockmass stability and failure. This relaxation can be the result of geometry change, mining induced local stress change, e.g., undercutting or inappropriate wall design, or abutment deterioration. Empirical stope and tunnel design guidelines are modified in this work to account for the effects of relaxation.

An empirical insitu damage criteria for use with elastic models, based on a reduced uniaxial compressive strength intercept (σ1 = 30 to 50% of laboratory UCS) and a limited dependency on confining stress σ3 (Δσ1 = 1 to 1.5 times Δσ3), has proven useful and dependable for the prediction of rockmass damage around excavations. This criterion closely resembles the experimentally determined threshold for crack initiation in laboratory and field scale tests. The success of this approach is related to the nature of the damage process in hard rock.

Two important aspects of this process, investigated in this thesis, are the tensile nature of damage mechanisms and the consequent sensitivity to low confinement conditions. Mechanisms of extension crack initiation, accumulation and interaction and the impact of low effective confining stress are explored through a review of the nature of solid bonding and damage, a study of granite behaviour in laboratory strength tests, and through the use of a bonded contact analogue. In particular, the numerical model, Particle Flow Code (discrete element) is used to examine, as a baseline case, a damage accumulation process in which individual crack extension is restricted.

While such accumulation in a heterogenous solid shows first order sensitivity to confinement, it is then demonstrated that increased sensitivity, to low confinement, of actual rockmass yield strength is related to the mechanics of crack extension. Rock yield strength is shown to be coincident with the onset of crack interaction. Mechanisms which cause individual nucleating cracks to extend further, do significantly increase the interaction potential and reduce the yield strength. A number of mechanisms affecting this process are addressed in this work.

Finally, it is shown that many of these mechanisms act together insitu, reducing the yield strength of rockmasses to the crack initiation threshold. These findings improve our understanding of the rockmass failure process and explain the success, in near-excavation conditions, of the empirical damage threshold described above. Now, verified mechanistically, this threshold, used with robust three dimensional boundary element analyses, can be applied with confidence to determine the potential extent of excavation-induced rockmass damage and associated support requirements for complex mine openings or underground civil works.},

keywords = {Brittle damage, Crack initiation, Discrete element method, Hard rockmasses, Relaxation, Tensile Strength},

pubstate = {published},

tppubtype = {phdthesis}

}

Close

In low stress environments, stability of rockmasses around underground excavations is typically controlled by rockmass structure. At depth and in highly stressed areas the rockmass strength controls stability. Tensile strength and tensile damage processes as well as abutment relaxation or reduced confinement often play dominant roles as agents of rockmass conditioning and failure control. This study focusses primarily on stability issues related to underground excavations in "hard" rockmasses, rockmasses that are sparsely to moderately jointed with rock of high strength, high stiffness, and brittle response.

This thesis is divided into two parts. In Part 1, the author examines structurally dominated failure modes, investigating the role of residual tensile rockmass strength and relaxation on the stability of tunnels and mining stopes. Because of the demonstrated significance of these mechanisms, the results of this study are used to modify empirical design tools for stability assessment.

In Part 2, the author investigates the importance of microscopic and mesoscopic tensile crack growth on compression-induced damage near-excavation fracturing of heterogenous rockmasses at depth. The sensitivity of insitu rockmass compressive strength to low near-excavation confining stress is examined. It is demonstrated that tensile failure processes, even under moderately compressive stress fields, control rockmass failure and fracture development near excavations in hard rock. The findings of this work explain the success of empirical strength criteria and damage prediction tools, improving confidence for future design applications.

Two simple numerical analogues for rock and rockmass behaviour are used in this study. The voussoir beam model is applied to the study of structurally controlled instability while an elastic-brittle bonded-contact discrete element model is used to study damage processes of stressed rock.

For excavations in sparsely to moderately jointed hard rockmasses, the extent of the gravity driven failures can be prevented or limited if the joints, which bound the potentially unstable blocks, are even slightly discontinuous. That is, even in small proportion of intact area (rock bridge) over the plane of a joint can generate significant self-supporting, load bearing capacity. The support pressure achieved for most practical support systems can be matched by a very small proportion of rock bridges as demonstrated using example analyses of wedge and jointed beam (voussoir) stability. This observation has implications for short-term or first-pass support design as well as for accurate back analysis of failures and stability assessment of areas that are affected by mining.

Limit equilibrium analyses of rock blocks and wedges are highly conservative if the effects of clamping (compressive stresses) are ignored. Conservatively, abutment relaxation or unclamping of excavation backs and walls may also be a significant factor controlling rockmass stability and failure. This relaxation can be the result of geometry change, mining induced local stress change, e.g., undercutting or inappropriate wall design, or abutment deterioration. Empirical stope and tunnel design guidelines are modified in this work to account for the effects of relaxation.
An empirical insitu damage criteria for use with elastic models, based on a reduced uniaxial compressive strength intercept (σ1 = 30 to 50% of laboratory UCS) and a limited dependency on confining stress σ3 (Δσ1 = 1 to 1.5 times Δσ3), has proven useful and dependable for the prediction of rockmass damage around excavations. This criterion closely resembles the experimentally determined threshold for crack initiation in laboratory and field scale tests. The success of this approach is related to the nature of the damage process in hard rock.

Two important aspects of this process, investigated in this thesis, are the tensile nature of damage mechanisms and the consequent sensitivity to low confinement conditions. Mechanisms of extension crack initiation, accumulation and interaction and the impact of low effective confining stress are explored through a review of the nature of solid bonding and damage, a study of granite behaviour in laboratory strength tests, and through the use of a bonded contact analogue. In particular, the numerical model, Particle Flow Code (discrete element) is used to examine, as a baseline case, a damage accumulation process in which individual crack extension is restricted.

While such accumulation in a heterogenous solid shows first order sensitivity to confinement, it is then demonstrated that increased sensitivity, to low confinement, of actual rockmass yield strength is related to the mechanics of crack extension. Rock yield strength is shown to be coincident with the onset of crack interaction. Mechanisms which cause individual nucleating cracks to extend further, do significantly increase the interaction potential and reduce the yield strength. A number of mechanisms affecting this process are addressed in this work.

Finally, it is shown that many of these mechanisms act together insitu, reducing the yield strength of rockmasses to the crack initiation threshold. These findings improve our understanding of the rockmass failure process and explain the success, in near-excavation conditions, of the empirical damage threshold described above. Now, verified mechanistically, this threshold, used with robust three dimensional boundary element analyses, can be applied with confidence to determine the potential extent of excavation-induced rockmass damage and associated support requirements for complex mine openings or underground civil works.

Close

33.

Diederichs, MS; Espley, S; Langille, C; Hutchinson, DJ

A semi-empirical hazard assessment approach to wedge instability in mine openings Conference

GeoEng2000, Melbourne, Australia, 2000.

BibTeX | Tags: hazard assessment, mine support, Wedge instabilities

32.

(Ed.)

The use of discrete element simulation to illuminate brittle rock failure processes Collection

Montreal, QC, Canada, 2000.

BibTeX | Tags: Brittle failure, Discrete element method

31.

Diederichs, MS; Kaiser, PK; Suorineni, F

The impact of abutment relaxation on stability of underground mine openings Conference

Pacific Rocks 2000, NARMS Symposium, Seattle, Washington, USA, 2000.

BibTeX | Tags:

30.

Hutchinson, DJ; Knight, M; Cascante, G; Diederichs, MS

What is a Geological Engineer? Lessons from Canadian Education Experience Conference

GeoEng2000, Melbourne, Australia, 2000.

BibTeX | Tags:

29.

Hutchinson, DJ; Nickson, S; Diederichs, MS

Auditing Cablebolting Practice for Underground Mines Conference

Invited lecture to MASHA Mining Health and Safety Conference, Sudbury, ON, Canada, 2000.

BibTeX | Tags:

28.

Diederichs, MS; Kaiser, PK

Stability of large excavations in laminated hard rock masses: the voussoir analogue revisited Journal Article

In: International Journal of Rock Mechanics and Mining Sciences, vol. 36, no. 1, pp. 97-117, 1999, ISSN: 1365-1609.

Abstract | Links | BibTeX | Tags: compression arch geometry, deflection threshold, Discrete element method, Hard rockmasses, laminated rockmasses, Stability, support pressure, Voussoir beam analogue

@article{DIEDERICHS199997,

title = {Stability of large excavations in laminated hard rock masses: the voussoir analogue revisited},

author = {MS Diederichs and PK Kaiser},

url = {https://www.sciencedirect.com/science/article/pii/S0148906298001806},

doi = {https://doi.org/10.1016/S0148-9062(98)00180-6},

issn = {1365-1609},

year  = {1999},

date = {1999-01-01},

journal = {International Journal of Rock Mechanics and Mining Sciences},

volume = {36},

number = {1},

pages = {97-117},

abstract = {The voussoir beam analogue has provided a useful stability assessment tool for more than 55 years and has seen numerous improvements and revisions over the years. In this paper, a simplified and robust iterative algorithm is presented for this model. This approach includes an improved assumption for internal compression arch geometry, simplified displacement determination, support pressure and surcharge analysis and a corrected stabilizing moment in the two dimensional case. A discrete element simulation is used to verify these enhancements and to confirm traditional assumptions inherent in the model. In the case of beam snap-through failure, dominant in hard rock excavations of moderately large span, design criteria are traditionally based on a stability limit which represents an upper bound for stable span estimates. A deflection threshold has been identified and verified through field evidence, which corresponds to the onset of non-linear deformation behaviour and therefore, of initial instability. This threshold is proposed as a more reasonable stability limit for this failure mode in rockmasses and particularly for data limited cases. Design charts, based on this linearity limit for unsupported stability of jointed rock beams, are presented here summarizing critical span–thickness–modulus relationships.},

keywords = {compression arch geometry, deflection threshold, Discrete element method, Hard rockmasses, laminated rockmasses, Stability, support pressure, Voussoir beam analogue},

pubstate = {published},

tppubtype = {article}

}

Close

27.

Diederichs, MS; Kaiser, PK

Tensile strength and abutment relaxation as failure control mechanisms in underground excavations Journal Article

In: International Journal of Rock Mechanics and Mining Sciences, vol. 36, no. 1, pp. 69-96, 1999, ISSN: 1365-1609.

Abstract | Links | BibTeX | Tags: boundary parallel relaxation, instability, residual tensile capacity, rock bridges, stress driven failure, underground excavations, Voussoir beam analogue

26.

Tannant, DD; Espley, S; Barclay, R; Diederichs, MS

Field trials of a thin sprayed-on membrane for drift support Conference

Proceedings of the 9th ISRM Congress on Rock Mechanics, vol. 1, Balkema, Rotterdam Paris, France, 1999.

BibTeX | Tags:

25.

Diederichs, MS; Hutchinson, DJ; Kaiser, PK

Cablebolt layouts using the Modified Stability Graph Journal Article

In: Canadian Institution of Mining Bulletin, vol. 92, no. 1035, pp. 81-85, 1999.

BibTeX | Tags: cablebolting, Modified stability graph

24.

Tannant, DD; Diederichs, MS; Seldon, S

Hangingwall relaxation and cablebolt support for deep stopes at Kidd Mine Conference

100th Canadian Institute of Mining AGM, Montreal, QC, Canada, 1998.

BibTeX | Tags:

23.

Diederichs, MS; Espley, S; Langille, C

Optimizing support design for wedge instability - the Viability Index Conference

100th Canadian Institute of Mining AGM, Montreal, QC, Canada, 1998.

BibTeX | Tags:

22.

Martin, D; Diederichs, MS; Hajiabdolmajid, V

Damage mechanisms in brittle rock masses Conference

Proceedings of the 51st Canadian Geotechnical Conference, Edmonton, AB, Canada, 1998.

BibTeX | Tags:

21.

Kaiser, PK; Falmagne, V; Suorineni, F; Diederichs, MS; Tannant, DD

Incorporation of rockmass relaxation and degradation into empirical stope design Conference

99th Canadian Institute of Mining Annual General Meeting, Vancouver, British Columbia, Canada, 1997.

BibTeX | Tags:

20.

Diederichs, MS; Kaiser, PK

Rock instability and risk analyzes in open stope mine design Journal Article

In: Canadian Geotechnical Journal, vol. 33, no. 3, pp. 431-439, 1996.

Abstract | Links | BibTeX | Tags: Design, Empirical, Mining, Risk, Stability

19.

Diederichs, MS

Semi-empirical design of cablebolt arrays: Overlays for the modified stability graph Conference

98th Canadian Institute of Mining Annual General Meeting, Edmonton, AB, Canada, 1996.

BibTeX | Tags:

18.

Hutchinson, DJ; Diederichs, MS

Engineering underground support systems - the cablebolting cycle Conference

98th Can Institute of Mining Annual General Meeting, Edmonton, AB, Canada, 1996.

BibTeX | Tags:

17.

Hutchinson, DJ; Diederichs, MS

Cablebolting in Underground Mines Book

BiTech Publishers, Vancouver, 1996, ISBN: 0921095376.

BibTeX | Tags: cablebolting, underground mines

16.

Hutchinson, DJ; Diederichs, MS

The cablebolt cycle - underground support engineering Journal Article

In: Canadian Institute of Mining Bulletin, vol. 89, no. 1001, pp. 117-123, 1996.

BibTeX | Tags: cablebolting, Underground support

15.

Shimizu, N; Kaiser, PK; Diederichs, MS; Hutchinson, DJ

Overview of cablebolting in tunnels Journal Article

In: Journal of the Japan Tunnelling Association, vol. 28, no. 4, pp. 43-52, 1996.

BibTeX | Tags: cablebolting, tunnelling

14.

Diederichs, MS; Vasak, P

Mine-Map Overlay - Risk Management for Drifts Book Chapter

In: Canadian Rockburst Handbook, vol. 2, Chapter 9, pp. 43, CAMIRO, 1995.

BibTeX | Tags: risk management

13.

Diederichs, MS; Kaiser, PK

Confidence, sensitivity and risk analysis in open stope mine design Conference

Proceedings of the 48th Canadian Geotechnical Conference, Vancouver, British Columbia, Canada, 1995.

BibTeX | Tags:

12.

Hutchinson, DJ; Diederichs, MS

Observational design of cablebolt support systems Conference

Proceedings of the 48th Canadian Geotechnical Conference, Vancouver, British Columbia, Canada, 1995.

BibTeX | Tags:

11.

Hutchinson, DJ; Diederichs, MS

The role of training in effective cable bolt installation Conference

CIM Mine Operators' Conference, no. 23, Timmins, Ontario, Canada, 1995.

BibTeX | Tags:

10.

McCreath, DR; Diederichs, MS

Assessment of near-field rockmass fracturing around a potential nuclear fuel waste repository Journal Article

In: International Journal of Rock Mechanics and Mining Sciences, vol. 31, no. 5, pp. 457-470, 1994, ISSN: 0148-9062.

Abstract | Links | BibTeX | Tags: Canadian Shield, Deep geological repository (DGR), fracture mechanics, Plutonic rocks

@article{McCreath1994457,

title = {Assessment of near-field rockmass fracturing around a potential nuclear fuel waste repository},

author = {DR McCreath and MS Diederichs},

url = {https://www.sciencedirect.com/science/article/pii/014890629490149X},

doi = {HTTPS://DOI.ORG/10.1016/0148-9062(94)90149-X},

issn = {0148-9062},

year  = {1994},

date = {1994-10-01},

journal = {International Journal of Rock Mechanics and Mining Sciences},

volume = {31},

number = {5},

pages = {457-470},

abstract = {Atomic Energy of Canada Limited (AECL) is developing a concept for the permanent storage of Canada's nuclear fuel wastes. As of 1992, the concept was based on in-floor emplacement of waste canisters within an engineered repository constructed at depths of 500–1000 m in plutonic rocks of the Canadian Shield. Canadian law requires that the Federal Environmental Assessment Review Office (FEARO) undertake a formal review of the concept before AECL proceed with site selection and design. In preparation for this upcoming review, the federal ministry which is responsible for the environment, Environment Canada, commissioned a small panel to undertake an overview of the concept. The sole purpose of the panel's work was to identify issues of potential importance to the safety and acceptability of the storage concept, so that the future review process could be appropriately focused on these key issues. Although fracture mechanics research has made much progress in understanding rock mass failure in terms of fundamental fracture initiation, propagation and interaction processes, there is still no generally accepted method by which to evaluate the actual fracturing response of a real rock mass in situ. Nevertheless, public review of the repository concept must address the issue of potential rock mass fracturing around the underground openings. The challenge is to do so despite the lack of a generally agreed methodology, in a manner which is practical within tight budgetary limits, acceptable in the context of normal engineering practice, and sensible from a fracture mechanics perspective. The key question is whether simple rock engineering analyses, based on conventional stress-strength comparisons, can be used to assess the potential for near-field fracturing of the rock mass. The goal of the work reported in this paper was to undertake a realistic but limited pre-feasibility level engineering evaluation of the potential for near-field fracturing of the rock mass, particularly in the vicinity of the canister emplacement holes. The approach chosen was based on simple parametric modelling using boundary element analyses. Input parameters were selected to reflect a range of conditions appropriate to batholiths of the Canadian Shield. The results, based on conventional rock engineering stress-strength analyses, were evaluated within the context of current fracture mechanics research views and of engineering judgement derived from experience with rock mass fracturing around deep underground openings in the mines of the Canadian Shield. Results indicate that stress concentration effects will cause fracturing beneath the room floors, and experience suggests that rock damage will be mainly in the form of horizontal slabbing. With time, rock damage may extend over the full 5 m depth of the emplacement holes. These findings suggest that the concept of in-floor storage of the waste canisters must undergo detailed critical review before being accepted as an inherent part of the AECL disposal concept.},

keywords = {Canadian Shield, Deep geological repository (DGR), fracture mechanics, Plutonic rocks},

pubstate = {published},

tppubtype = {article}

}

Close

Atomic Energy of Canada Limited (AECL) is developing a concept for the permanent storage of Canada's nuclear fuel wastes. As of 1992, the concept was based on in-floor emplacement of waste canisters within an engineered repository constructed at depths of 500–1000 m in plutonic rocks of the Canadian Shield. Canadian law requires that the Federal Environmental Assessment Review Office (FEARO) undertake a formal review of the concept before AECL proceed with site selection and design. In preparation for this upcoming review, the federal ministry which is responsible for the environment, Environment Canada, commissioned a small panel to undertake an overview of the concept. The sole purpose of the panel's work was to identify issues of potential importance to the safety and acceptability of the storage concept, so that the future review process could be appropriately focused on these key issues. Although fracture mechanics research has made much progress in understanding rock mass failure in terms of fundamental fracture initiation, propagation and interaction processes, there is still no generally accepted method by which to evaluate the actual fracturing response of a real rock mass in situ. Nevertheless, public review of the repository concept must address the issue of potential rock mass fracturing around the underground openings. The challenge is to do so despite the lack of a generally agreed methodology, in a manner which is practical within tight budgetary limits, acceptable in the context of normal engineering practice, and sensible from a fracture mechanics perspective. The key question is whether simple rock engineering analyses, based on conventional stress-strength comparisons, can be used to assess the potential for near-field fracturing of the rock mass. The goal of the work reported in this paper was to undertake a realistic but limited pre-feasibility level engineering evaluation of the potential for near-field fracturing of the rock mass, particularly in the vicinity of the canister emplacement holes. The approach chosen was based on simple parametric modelling using boundary element analyses. Input parameters were selected to reflect a range of conditions appropriate to batholiths of the Canadian Shield. The results, based on conventional rock engineering stress-strength analyses, were evaluated within the context of current fracture mechanics research views and of engineering judgement derived from experience with rock mass fracturing around deep underground openings in the mines of the Canadian Shield. Results indicate that stress concentration effects will cause fracturing beneath the room floors, and experience suggests that rock damage will be mainly in the form of horizontal slabbing. With time, rock damage may extend over the full 5 m depth of the emplacement holes. These findings suggest that the concept of in-floor storage of the waste canisters must undergo detailed critical review before being accepted as an inherent part of the AECL disposal concept.

Close

9.

Kazakidis, VN; Diederichs, MS

Understanding jointed rock mass behaviour using a ubiquitous joint approach Journal Article

In: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, vol. 30, no. 2, pp. 163-172, 1993, ISSN: 0148-9062.

Links | BibTeX | Tags: Joints, Rockmass

8.

Diederichs, MS; Pieterse, E; Nose, J; Kaiser, PK

A model for evaluating cable bolt bond strength Conference

Eurock '93, 1993.

BibTeX | Tags:

7.

Hoek, E; Carvalho, JL; Diederichs, MS

Tunnel support design software Conference

Tunnelling Association of Canada Annual General Meeting, Tunneling Association of Canada 1993.

BibTeX | Tags:

6.

Hutchinson, DJ; Diederichs, MS

An instrumentation program for performance monitoring of a cable bolt reinforced rockmass Conference

Geotechnical Instrumentation and Monitoring in Open Pit and Underground Mining, Rotterdam: A.A. Balkema 1993.

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5.

Hutchinson, DJ; Falmagne, V; Diederichs, MS

An instrumentation program to monitor cablebolt reinforced rockmass performance at Ansil Mine: program description and results Conference

Proceedings of the Canadian Geotechnical Conference, Toronto, Ontario, Canada, 1992.

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4.

Kaiser, PK; Diederichs, MS; Yazici, S

Cable bolt performance during mining induced stress change - Three case examples Conference

Rock Support, Rotterdam: A.A. Balkema 1992.

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3.

McCreath, DR; Diederichs, MS

The Canadian concept for a nuclear fuel waste disposal facility: assessing the potential for near field fracturing of the rockmass Conference

Proceedings of the 45th Canadian Geotechnical Conference, Toronto, Ontario, Canada, 1992.

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2.

Hoek, E; Grabinsky, MW; Diederichs, MS

Numerical modelling for underground excavation design Journal Article

In: Transportation, Mining and Metallurgy, vol. 100, no. A1-50, pp. A22-A30, 1991.

BibTeX | Tags: Numerical modelling, underground excavations

1.

Innocente, J; Paraskevopoulou, C; Diederichs, MS

Time-Dependent Model for Brittle Rocks Considering the Long-Term Strength Determined from Lab Data Bachelor Thesis

0000.

BibTeX | Tags: Laboratory testing, Long-term behaviour, Time-dependency, time-dependent behaviour