Publications
2018
345.
Forbes, B; Vlachopoulos, N; Diederichs, MS; Hyett, AJ
Spile support performance monitored in a shallow urban tunnel using distributed optical strain sensing Conference
In Proc. 52nd U.S. Rock Mechanics/Geomechanics Symposium, American Rock Mechanics Association Seattle, Washington, USA, 2018.
BibTeX | Tags: Distributed optical strain sensing, Monitoring, Spile support, tunnelling
@conference{Forbes2018,
title = {Spile support performance monitored in a shallow urban tunnel using distributed optical strain sensing},
author = {B Forbes and N Vlachopoulos and MS Diederichs and AJ Hyett},
year = {2018},
date = {2018-06-17},
booktitle = {In Proc. 52nd U.S. Rock Mechanics/Geomechanics Symposium},
journal = {In Proc. 52nd U.S. Rock Mechanics/Geomechanics Symposium},
address = {Seattle, Washington, USA},
organization = {American Rock Mechanics Association},
keywords = {Distributed optical strain sensing, Monitoring, Spile support, tunnelling},
pubstate = {published},
tppubtype = {conference}
}
344.
Vazaios, I; Diederichs, MS; Vlachopoulos, N
Assessment of strain bursting in deep tunnelling by using the finite-discrete element method Journal Article
In: Journal of Rock Mechanics and Geotechnical Engineering, vol. 11, no. 1, pp. 12-37, 2018, ISSN: 1674-7755.
Abstract | Links | BibTeX | Tags: Brittle fracturing, Deep tunnelling, Discrete fracture networks (DFN), finite–discrete element method (FDEM), Hard rock excavations, Rockburst
@article{Vazaios2018b,
title = {Assessment of strain bursting in deep tunnelling by using the finite-discrete element method},
author = {I Vazaios and MS Diederichs and N Vlachopoulos},
url = {https://www.sciencedirect.com/science/article/pii/S167477551830163X},
doi = {https://doi.org/10.1016/j.jrmge.2018.06.007},
issn = {1674-7755},
year = {2018},
date = {2018-06-10},
journal = {Journal of Rock Mechanics and Geotechnical Engineering},
volume = {11},
number = {1},
pages = {12-37},
abstract = {Rockbursting in deep tunnelling is a complex phenomenon posing significant challenges both at the design and construction stages of an underground excavation within hard rock masses and under high in situ stresses. While local experience, field monitoring, and informed data-rich analysis are some of the tools commonly used to manage the hazards and the associated risks, advanced numerical techniques based on discontinuum modelling have also shown potential in assisting in the assessment of rockbursting. In this study, the hybrid finite-discrete element method (FDEM) is employed to investigate the failure and fracturing processes, and the mechanisms of energy storage and rapid release resulting in bursting, as well as to assess its utility as part of the design process of underground excavations. Following the calibration of the numerical model to simulate a deep excavation in a hard, massive rock mass, discrete fracture network (DFN) geometries are integrated into the model in order to examine the impact of rock structure on rockbursting under high in situ stresses. The obtained analysis results not only highlight the importance of explicitly simulating pre-existing joints within the model, as they affect the mobilised failure mechanisms and the intensity of strain bursting phenomena, but also show how the employed joint network geometry, the field stress conditions, and their interaction influence the extent and depth of the excavation induced damage. Furthermore, a rigorous analysis of the mass and velocity of the ejected rock blocks and comparison of the obtained data with well-established semi-empirical approaches demonstrate the potential of the method to provide realistic estimates of the kinetic energy released during bursting for determining the energy support demand.},
keywords = {Brittle fracturing, Deep tunnelling, Discrete fracture networks (DFN), finite–discrete element method (FDEM), Hard rock excavations, Rockburst},
pubstate = {published},
tppubtype = {article}
}
Rockbursting in deep tunnelling is a complex phenomenon posing significant challenges both at the design and construction stages of an underground excavation within hard rock masses and under high in situ stresses. While local experience, field monitoring, and informed data-rich analysis are some of the tools commonly used to manage the hazards and the associated risks, advanced numerical techniques based on discontinuum modelling have also shown potential in assisting in the assessment of rockbursting. In this study, the hybrid finite-discrete element method (FDEM) is employed to investigate the failure and fracturing processes, and the mechanisms of energy storage and rapid release resulting in bursting, as well as to assess its utility as part of the design process of underground excavations. Following the calibration of the numerical model to simulate a deep excavation in a hard, massive rock mass, discrete fracture network (DFN) geometries are integrated into the model in order to examine the impact of rock structure on rockbursting under high in situ stresses. The obtained analysis results not only highlight the importance of explicitly simulating pre-existing joints within the model, as they affect the mobilised failure mechanisms and the intensity of strain bursting phenomena, but also show how the employed joint network geometry, the field stress conditions, and their interaction influence the extent and depth of the excavation induced damage. Furthermore, a rigorous analysis of the mass and velocity of the ejected rock blocks and comparison of the obtained data with well-established semi-empirical approaches demonstrate the potential of the method to provide realistic estimates of the kinetic energy released during bursting for determining the energy support demand.
343.
Vazaios, I; Farahmand, K; Vlachopoulos, N; Diederichs, MS
Effects of confinement on rock mass modulus: a synthetic rock mass modelling (SRM) study Journal Article
In: Journal of Rock Mechanics and Geotechnical Engineering, vol. 10, no. 3, pp. 436-456, 2018, ISSN: 1674-7755.
Abstract | Links | BibTeX | Tags: Composite Geological Strength Index, Confinement, Discrete fracture networks (DFN), Rockmass modulus, Synthetic rockmass modelling (SRM)
@article{Vazaios2018bb,
title = {Effects of confinement on rock mass modulus: a synthetic rock mass modelling (SRM) study},
author = {I Vazaios and K Farahmand and N Vlachopoulos and MS Diederichs},
url = {https://www.sciencedirect.com/science/article/pii/S1674775517302044},
doi = {https://doi.org/10.1016/j.jrmge.2018.01.002},
issn = {1674-7755},
year = {2018},
date = {2018-06-01},
journal = {Journal of Rock Mechanics and Geotechnical Engineering},
volume = {10},
number = {3},
pages = {436-456},
abstract = {The main objective of this paper is to examine the influence of the applied confining stress on the rock mass modulus of moderately jointed rocks (well interlocked undisturbed rock mass with blocks formed by three or less intersecting joints). A synthetic rock mass modelling (SRM) approach is employed to determine the mechanical properties of the rock mass. In this approach, the intact body of rock is represented by the discrete element method (DEM)-Voronoi grains with the ability of simulating the initiation and propagation of microcracks within the intact part of the model. The geometry of the pre-existing joints is generated by employing discrete fracture network (DFN) modelling based on field joint data collected from the Brockville Tunnel using LiDAR scanning. The geometrical characteristics of the simulated joints at a representative sample size are first validated against the field data, and then used to measure the rock quality designation (RQD), joint spacing, areal fracture intensity (P21), and block volumes. These geometrical quantities are used to quantitatively determine a representative range of the geological strength index (GSI). The results show that estimating the GSI using the RQD tends to make a closer estimate of the degree of blockiness that leads to GSI values corresponding to those obtained from direct visual observations of the rock mass conditions in the field. The use of joint spacing and block volume in order to quantify the GSI value range for the studied rock mass suggests a lower range compared to that evaluated in situ. Based on numerical modelling results and laboratory data of rock testing reported in the literature, a semi-empirical equation is proposed that relates the rock mass modulus to confinement as a function of the areal fracture intensity and joint stiffness.},
keywords = {Composite Geological Strength Index, Confinement, Discrete fracture networks (DFN), Rockmass modulus, Synthetic rockmass modelling (SRM)},
pubstate = {published},
tppubtype = {article}
}
The main objective of this paper is to examine the influence of the applied confining stress on the rock mass modulus of moderately jointed rocks (well interlocked undisturbed rock mass with blocks formed by three or less intersecting joints). A synthetic rock mass modelling (SRM) approach is employed to determine the mechanical properties of the rock mass. In this approach, the intact body of rock is represented by the discrete element method (DEM)-Voronoi grains with the ability of simulating the initiation and propagation of microcracks within the intact part of the model. The geometry of the pre-existing joints is generated by employing discrete fracture network (DFN) modelling based on field joint data collected from the Brockville Tunnel using LiDAR scanning. The geometrical characteristics of the simulated joints at a representative sample size are first validated against the field data, and then used to measure the rock quality designation (RQD), joint spacing, areal fracture intensity (P21), and block volumes. These geometrical quantities are used to quantitatively determine a representative range of the geological strength index (GSI). The results show that estimating the GSI using the RQD tends to make a closer estimate of the degree of blockiness that leads to GSI values corresponding to those obtained from direct visual observations of the rock mass conditions in the field. The use of joint spacing and block volume in order to quantify the GSI value range for the studied rock mass suggests a lower range compared to that evaluated in situ. Based on numerical modelling results and laboratory data of rock testing reported in the literature, a semi-empirical equation is proposed that relates the rock mass modulus to confinement as a function of the areal fracture intensity and joint stiffness.
342.
Vazaios, I; Vlachopoulos, N; Diederichs, MS
In: Canadian Geotechnical Journal, vol. 56, no. 1, pp. 35-59, 2018.
Abstract | Links | BibTeX | Tags: Brittle failure, excavation damage zone (EDZ), finite–discrete element method (FDEM), spalling, tunnelling
@article{Vazaios2018,
title = {Mechanical analysis and interpretation of excavation damage zone formation around deep tunnels within massive rock masses using hybrid finite–discrete element approach: case of Atomic Energy of Canada Limited (AECL) Underground Research Laboratory (URL) test tunnel},
author = {I Vazaios and N Vlachopoulos and MS Diederichs},
doi = {10.1139/cgj-2017-0578},
year = {2018},
date = {2018-04-19},
journal = {Canadian Geotechnical Journal},
volume = {56},
number = {1},
pages = {35-59},
abstract = {The construction of an underground opening leads to changes in the in situ stress regime surrounding the excavation. The opening influences the rock mass owing to the redistribution of the stresses and results in the disturbance of the surrounding ground. At great depths, massive to slightly or moderately fractured rock masses are usually encountered, and under high stresses, they are more likely to behave in a brittle manner during an excavation. While constitutive models have been developed and proposed for the numerical simulation of such excavations using continuum mechanics, this brittle response cannot be simulated accurately enough, since the material behaviour is governed by fracture initiation and propagation. On the contrary, discontinuum approaches are more suitable in such cases. For the purposes of this paper, the brittle behaviour of hard, massive rock masses and the associated spalling failure mechanisms were simulated by employing a finite–discrete element method (FDEM) approach using Irazu software. The generated numerical model was utilized to replicate field conditions based on the observations at the Atomic Energy of Canada Limited (AECL) Underground Research Laboratory (URL) test tunnel located in Pinawa, Manitoba, Canada. The model results are compared with field observation data to explicitly demonstrate the suitability of the method.},
keywords = {Brittle failure, excavation damage zone (EDZ), finite–discrete element method (FDEM), spalling, tunnelling},
pubstate = {published},
tppubtype = {article}
}
The construction of an underground opening leads to changes in the in situ stress regime surrounding the excavation. The opening influences the rock mass owing to the redistribution of the stresses and results in the disturbance of the surrounding ground. At great depths, massive to slightly or moderately fractured rock masses are usually encountered, and under high stresses, they are more likely to behave in a brittle manner during an excavation. While constitutive models have been developed and proposed for the numerical simulation of such excavations using continuum mechanics, this brittle response cannot be simulated accurately enough, since the material behaviour is governed by fracture initiation and propagation. On the contrary, discontinuum approaches are more suitable in such cases. For the purposes of this paper, the brittle behaviour of hard, massive rock masses and the associated spalling failure mechanisms were simulated by employing a finite–discrete element method (FDEM) approach using Irazu software. The generated numerical model was utilized to replicate field conditions based on the observations at the Atomic Energy of Canada Limited (AECL) Underground Research Laboratory (URL) test tunnel located in Pinawa, Manitoba, Canada. The model results are compared with field observation data to explicitly demonstrate the suitability of the method.
341.
Walton, G; Diederichs, MS; Weinhardt, K; Delaloyle, D; Lato, MJ; Punkkinen, A
Change detection in drill and blast tunnels from point cloud data Journal Article
In: International Journal of Rock Mechanics and Mining Sciences, vol. 105, pp. 172-181, 2018, ISSN: 1365-1609.
Abstract | Links | BibTeX | Tags: change detection, Laser scanning, LiDAR, Mining, tunnelling
@article{WALTON2018172,
title = {Change detection in drill and blast tunnels from point cloud data},
author = {G Walton and MS Diederichs and K Weinhardt and D Delaloyle and MJ Lato and A Punkkinen},
url = {https://www.sciencedirect.com/science/article/pii/S1365160918302430},
doi = {10.1016/j.ijrmms.2018.03.004},
issn = {1365-1609},
year = {2018},
date = {2018-03-13},
journal = {International Journal of Rock Mechanics and Mining Sciences},
volume = {105},
pages = {172-181},
abstract = {During the excavation of underground workings, stress redistribution around the excavation causes the rockmass to deform. The magnitude of this deformation depends on the rockmass conditions, the magnitude, orientation, and anisotropy of the in situ stresses, the excavation method and rate, and the type and location of installed support. Monitoring data which records the deformation of an excavation over time can therefore be used to back analyze information about the rockmass parameters and/or stress state, and can serve as an early warning for more severe failures1.
With the recent profileration of laser scanning technology (and photogrammetry) in geotechnical engineering applications, it is natural that some researchers have begun to study its potential use as a deformation monitoring tool in excavations. By comparing two time-separated point cloud data sets (or attributes of these data sets), rockmass deformation can be mapped. This deformation can be mapped as either relative or absolute. To obtain absolute deformation measurements, georeferencing must be employed. This typically means that the location of the scanner must be surveyed from a known absolute reference for each instance of data collection using a total station. The advantage of absolute positioning when recording deformations is that translations of individual tunnels due to nearby excavation activities can be recorded; in contrast, only closure measurements can be obtained when using relative positioning2. The practical advantage of using relative positioning is that it requires much less time to set up scans, meaning that in an active excavation environment, typical cycle times can be maintained3.
With the exception of closest point approaches, methods for comparing time-separated point cloud data sets have generally used what we refer to as a “global fitting approach”. The global fitting approach for change detection depends on the comparison of 2D or 3D shapes fit to two data sets taken at the same location. Since only a small number of parameters are required to derive the best-fit shape as compared to the large number of data points, anomalous results and random errors can be effectively removed from the analysis. By contrast, algorithms based on closest point distance are significantly influenced by the range error inherent in the instruments used4.
Delaloye5 provides a framework for the comparison of point cloud data sets collected in elliptical excavations (see Walton et al.3 and Delaloye et al.6 for further developments). When fitting an ellipse to data, the long and short axes of the ellipse correspond to the principal deformation directions within the tunnel. To calculate the amount of normalized tunnel convergence, uniform deformation between measurements must be assumed. The orientation of the ellipse can easily be calculated, and is important to identify because a change in the orientation of the ellipse suggests a change in the deformation pattern.
Whereas previous works have focused on excavations with simple geometries (e.g. Wannanmacher et al.7, Nuttens et al.8), this study uses data from the Creighton Mine in Sudbury, Canada to investigate the applicability of various change detection methods for application in an excavation with irregular geometry.},
keywords = {change detection, Laser scanning, LiDAR, Mining, tunnelling},
pubstate = {published},
tppubtype = {article}
}
During the excavation of underground workings, stress redistribution around the excavation causes the rockmass to deform. The magnitude of this deformation depends on the rockmass conditions, the magnitude, orientation, and anisotropy of the in situ stresses, the excavation method and rate, and the type and location of installed support. Monitoring data which records the deformation of an excavation over time can therefore be used to back analyze information about the rockmass parameters and/or stress state, and can serve as an early warning for more severe failures1.
With the recent profileration of laser scanning technology (and photogrammetry) in geotechnical engineering applications, it is natural that some researchers have begun to study its potential use as a deformation monitoring tool in excavations. By comparing two time-separated point cloud data sets (or attributes of these data sets), rockmass deformation can be mapped. This deformation can be mapped as either relative or absolute. To obtain absolute deformation measurements, georeferencing must be employed. This typically means that the location of the scanner must be surveyed from a known absolute reference for each instance of data collection using a total station. The advantage of absolute positioning when recording deformations is that translations of individual tunnels due to nearby excavation activities can be recorded; in contrast, only closure measurements can be obtained when using relative positioning2. The practical advantage of using relative positioning is that it requires much less time to set up scans, meaning that in an active excavation environment, typical cycle times can be maintained3.
With the exception of closest point approaches, methods for comparing time-separated point cloud data sets have generally used what we refer to as a “global fitting approach”. The global fitting approach for change detection depends on the comparison of 2D or 3D shapes fit to two data sets taken at the same location. Since only a small number of parameters are required to derive the best-fit shape as compared to the large number of data points, anomalous results and random errors can be effectively removed from the analysis. By contrast, algorithms based on closest point distance are significantly influenced by the range error inherent in the instruments used4.
Delaloye5 provides a framework for the comparison of point cloud data sets collected in elliptical excavations (see Walton et al.3 and Delaloye et al.6 for further developments). When fitting an ellipse to data, the long and short axes of the ellipse correspond to the principal deformation directions within the tunnel. To calculate the amount of normalized tunnel convergence, uniform deformation between measurements must be assumed. The orientation of the ellipse can easily be calculated, and is important to identify because a change in the orientation of the ellipse suggests a change in the deformation pattern.
Whereas previous works have focused on excavations with simple geometries (e.g. Wannanmacher et al.7, Nuttens et al.8), this study uses data from the Creighton Mine in Sudbury, Canada to investigate the applicability of various change detection methods for application in an excavation with irregular geometry.
With the recent profileration of laser scanning technology (and photogrammetry) in geotechnical engineering applications, it is natural that some researchers have begun to study its potential use as a deformation monitoring tool in excavations. By comparing two time-separated point cloud data sets (or attributes of these data sets), rockmass deformation can be mapped. This deformation can be mapped as either relative or absolute. To obtain absolute deformation measurements, georeferencing must be employed. This typically means that the location of the scanner must be surveyed from a known absolute reference for each instance of data collection using a total station. The advantage of absolute positioning when recording deformations is that translations of individual tunnels due to nearby excavation activities can be recorded; in contrast, only closure measurements can be obtained when using relative positioning2. The practical advantage of using relative positioning is that it requires much less time to set up scans, meaning that in an active excavation environment, typical cycle times can be maintained3.
With the exception of closest point approaches, methods for comparing time-separated point cloud data sets have generally used what we refer to as a “global fitting approach”. The global fitting approach for change detection depends on the comparison of 2D or 3D shapes fit to two data sets taken at the same location. Since only a small number of parameters are required to derive the best-fit shape as compared to the large number of data points, anomalous results and random errors can be effectively removed from the analysis. By contrast, algorithms based on closest point distance are significantly influenced by the range error inherent in the instruments used4.
Delaloye5 provides a framework for the comparison of point cloud data sets collected in elliptical excavations (see Walton et al.3 and Delaloye et al.6 for further developments). When fitting an ellipse to data, the long and short axes of the ellipse correspond to the principal deformation directions within the tunnel. To calculate the amount of normalized tunnel convergence, uniform deformation between measurements must be assumed. The orientation of the ellipse can easily be calculated, and is important to identify because a change in the orientation of the ellipse suggests a change in the deformation pattern.
Whereas previous works have focused on excavations with simple geometries (e.g. Wannanmacher et al.7, Nuttens et al.8), this study uses data from the Creighton Mine in Sudbury, Canada to investigate the applicability of various change detection methods for application in an excavation with irregular geometry.
340.
Farahmand, K; Vazaios, I; Diederichs, MS; Vlachopoulos, N
In: Computers and Geotechnics, vol. 95, pp. 162-179, 2018, ISSN: 0266-352X.
Abstract | Links | BibTeX | Tags: Deformability, Discrete fracture networks (DFN), LiDAR, Representative elementary volume (REV), Rockmass strength, Scale-dependency, Synthetic rockmass (SRM)
@article{FARAHMAND2018162,
title = {Investigating the scale-dependency of the geometrical and mechanical properties of a moderately jointed rock using a synthetic rock mass (SRM) approach},
author = {K Farahmand and I Vazaios and MS Diederichs and N Vlachopoulos},
url = {https://www.sciencedirect.com/science/article/pii/S0266352X17302677v},
doi = {https://doi.org/10.1016/j.compgeo.2017.10.002},
issn = {0266-352X},
year = {2018},
date = {2018-03-01},
journal = {Computers and Geotechnics},
volume = {95},
pages = {162-179},
abstract = {A synthetic rock mass (SRM) model coupling discrete fracture networks (DFNs) and a discrete element grain-based model (DEM) is used to characterize the mechanical properties of moderately jointed rockmasses under confined and unconfined conditions. The scale dependency of the rockmass properties is investigated using the concept of representative element volume (REV). The numerical results are compared with the estimated values from empirical methods. It is determined that the empirical Hoek-Brown criterion correctly estimates the unconfined strength of the rockmass with non-persistent joints, while it overestimates the strength under confined conditions. An S-shaped strength envelope is obtained from the numerical results.},
keywords = {Deformability, Discrete fracture networks (DFN), LiDAR, Representative elementary volume (REV), Rockmass strength, Scale-dependency, Synthetic rockmass (SRM)},
pubstate = {published},
tppubtype = {article}
}
A synthetic rock mass (SRM) model coupling discrete fracture networks (DFNs) and a discrete element grain-based model (DEM) is used to characterize the mechanical properties of moderately jointed rockmasses under confined and unconfined conditions. The scale dependency of the rockmass properties is investigated using the concept of representative element volume (REV). The numerical results are compared with the estimated values from empirical methods. It is determined that the empirical Hoek-Brown criterion correctly estimates the unconfined strength of the rockmass with non-persistent joints, while it overestimates the strength under confined conditions. An S-shaped strength envelope is obtained from the numerical results.
339.
Diederichs, MS
Early assessment of dynamic rupture hazard for rockburst risk management in deep tunnel projects Journal Article
In: Journal of the Southern African Institute of Mining and Metallurgy, vol. 118, no. 3, pp. 193-204, 2018, ISSN: 2225-6253.
Abstract | Links | BibTeX | Tags: dynamic rupture, hazard assessment, High stress, risk management, Rockburst, tunnelling
@article{Diederichs2018,
title = {Early assessment of dynamic rupture hazard for rockburst risk management in deep tunnel projects},
author = {MS Diederichs},
url = {http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2225-62532018000300004},
doi = {http://dx.doi.org/10.17159/2411-9717/2018/v118n3a1},
issn = {2225-6253},
year = {2018},
date = {2018-03-01},
journal = {Journal of the Southern African Institute of Mining and Metallurgy},
volume = {118},
number = {3},
pages = {193-204},
abstract = {Managing rockbursting conditions in mine development and operational environments is a complex and difficult challenge. The hazard and the associated risks can be managed based on local experience, monitoring, and informed data-rich analysis. On the other hand, blind development for deep tunnelling is being carried out around the world at depths in excess of 2 km and rockbursting has become a common and serious challenge. The rockburst mechanism is predominantly tunnelling-induced dynamic rupture or strain bursting, distinct from the remote or mine-generated events that impact mining excavations. Considerations of rock petrology, fabric, mechanical parameters, and structure allow an estimate of brittle response. The potential for energy storage and rapid release must be accounted for in order to understand the burst potential early in the basic design stage for deep tunnels. Failure to do so can result in unsafe conditions and years of delay. In this paper a multistep semi-empirical approach for early assessment of strain burst or dynamic rupture potential along deep tunnel alignments in variable ground is presented.},
keywords = {dynamic rupture, hazard assessment, High stress, risk management, Rockburst, tunnelling},
pubstate = {published},
tppubtype = {article}
}
Managing rockbursting conditions in mine development and operational environments is a complex and difficult challenge. The hazard and the associated risks can be managed based on local experience, monitoring, and informed data-rich analysis. On the other hand, blind development for deep tunnelling is being carried out around the world at depths in excess of 2 km and rockbursting has become a common and serious challenge. The rockburst mechanism is predominantly tunnelling-induced dynamic rupture or strain bursting, distinct from the remote or mine-generated events that impact mining excavations. Considerations of rock petrology, fabric, mechanical parameters, and structure allow an estimate of brittle response. The potential for energy storage and rapid release must be accounted for in order to understand the burst potential early in the basic design stage for deep tunnels. Failure to do so can result in unsafe conditions and years of delay. In this paper a multistep semi-empirical approach for early assessment of strain burst or dynamic rupture potential along deep tunnel alignments in variable ground is presented.
338.
Ghazvinian, E; Diederichs, MS
Progress of brittle microfracturing in crystalline rocks under cyclic loading conditions Journal Article
In: Journal of the Southern African Institute of Mining and Metallurgy, vol. 118, no. 3, pp. 217-226, 2018, ISSN: 2411-9717.
Abstract | Links | BibTeX | Tags: brittle microfracturing, Crack initiation, crack propogation, cyclic loading
@article{Ghazvinian2018,
title = {Progress of brittle microfracturing in crystalline rocks under cyclic loading conditions},
author = {E Ghazvinian and MS Diederichs},
doi = {http://dx.doi.org/10.17159/2411-9717/2018/v118n3a4},
issn = {2411-9717},
year = {2018},
date = {2018-03-01},
journal = {Journal of the Southern African Institute of Mining and Metallurgy},
volume = {118},
number = {3},
pages = {217-226},
abstract = {The stress at onset of yielding for the walls of deep underground excavations in hard rock is significantly less than the laboratory strength of intact rock samples. The wall stability is rather controlled by the microfracturing strength of the rock (i.e. crack propagation (CD) and initiation (CI) thresholds). Factors such as loading and unloading effect of excavation, glaciation, stress rotation in front of a tunnel face, etc. can contribute to the progressive damage of the rock, influencing the CI and CD thresholds and therefore contributing to the damage intensity around underground openings. The effect of stress rotation and stress fatigue on crack damage thresholds is systematically investigated in this paper through state-of-the-art laboratory testing and monitoring techniques in combination with advanced grain-based numerical modelling.},
keywords = {brittle microfracturing, Crack initiation, crack propogation, cyclic loading},
pubstate = {published},
tppubtype = {article}
}
The stress at onset of yielding for the walls of deep underground excavations in hard rock is significantly less than the laboratory strength of intact rock samples. The wall stability is rather controlled by the microfracturing strength of the rock (i.e. crack propagation (CD) and initiation (CI) thresholds). Factors such as loading and unloading effect of excavation, glaciation, stress rotation in front of a tunnel face, etc. can contribute to the progressive damage of the rock, influencing the CI and CD thresholds and therefore contributing to the damage intensity around underground openings. The effect of stress rotation and stress fatigue on crack damage thresholds is systematically investigated in this paper through state-of-the-art laboratory testing and monitoring techniques in combination with advanced grain-based numerical modelling.
337.
Packulak, TR; Day, JJ; Diederichs, MS
Role of rock direct shear testing in determining geomechanical properties of fractures Journal Article
In: Tunnels and Tunnelling, vol. 2, pp. 32-36, 2018.
Abstract | BibTeX | Tags: Direct shear testing, Discontinuity, Heterogeneous rockmasses, Rockmass
@article{Packulak2018,
title = {Role of rock direct shear testing in determining geomechanical properties of fractures},
author = {TR Packulak and JJ Day and MS Diederichs},
year = {2018},
date = {2018-03-01},
journal = {Tunnels and Tunnelling},
volume = {2},
pages = {32-36},
abstract = {Rockmass discontinuities regularly govern the material behaviour around engineering projects such as natural slopes, surface excavations, and underground openings. Geotechnical laboratory tests, such as direct shear, provide a means to determine stiffness, strength, and post-peak material properties, which are key parameters used to quantify rockmass behaviour. Direct shear tests are typically conducted under constant normal stress (CNL*) and constant normal load (CNL) boundary conditions, which are considered to represent fracture behaviour in near surface gravity-driven environments. Both CNL and CNL* conditions allow the fracture to dilate freely during shear, so there is no feedback between dilation and normal stress. A third boundary condition option in direct shear testing is constant normal stiffness (CNS), which is considered to better reflect behaviours of rock fractures near underground excavations, such as tunnels, mines, and nuclear waste repositories. Assessing geomechanical properties of fractures in granitic rock under CNL* and CNS boundary conditions is the focus of this investigation.},
keywords = {Direct shear testing, Discontinuity, Heterogeneous rockmasses, Rockmass},
pubstate = {published},
tppubtype = {article}
}
Rockmass discontinuities regularly govern the material behaviour around engineering projects such as natural slopes, surface excavations, and underground openings. Geotechnical laboratory tests, such as direct shear, provide a means to determine stiffness, strength, and post-peak material properties, which are key parameters used to quantify rockmass behaviour. Direct shear tests are typically conducted under constant normal stress (CNL*) and constant normal load (CNL) boundary conditions, which are considered to represent fracture behaviour in near surface gravity-driven environments. Both CNL and CNL* conditions allow the fracture to dilate freely during shear, so there is no feedback between dilation and normal stress. A third boundary condition option in direct shear testing is constant normal stiffness (CNS), which is considered to better reflect behaviours of rock fractures near underground excavations, such as tunnels, mines, and nuclear waste repositories. Assessing geomechanical properties of fractures in granitic rock under CNL* and CNS boundary conditions is the focus of this investigation.
336.
Oke, J; Vlachopoulos, N; Diederichs, MS
Improvement to the Convergence-Confinement Method: Inclusion of Support Installation Proximity and Stiffness Journal Article
In: Rock Mechanics and Rock Engineering, vol. 51, pp. 1495-1519, 2018.
Abstract | Links | BibTeX | Tags: Analytical, Convergence-confinement, Numerical modelling, Support, tunnelling
@article{Oke2018,
title = {Improvement to the Convergence-Confinement Method: Inclusion of Support Installation Proximity and Stiffness},
author = {J Oke and N Vlachopoulos and MS Diederichs},
doi = {10.1007/s00603-018-1418-0},
year = {2018},
date = {2018-02-01},
journal = {Rock Mechanics and Rock Engineering},
volume = {51},
pages = {1495-1519},
abstract = {The convergence-confinement method (CCM) is a method that has been introduced in tunnel construction that considers the ground response to the advancing tunnel face and the interaction with installed support. One limitation of the CCM is due to the numerically or empirically driven nature of the longitudinal displacement profile and the incomplete consideration of the longitudinal arching effect that occurs during tunnelling operations as part of the face effect. In this paper, the authors address the issue associated with when the CCM is used within squeezing ground conditions at depth. Based on numerical analysis, the authors have proposed a methodology and solution to improving the CCM in order to allow for more accurate results for squeezing ground conditions for three different excavation cases involving various excavation-support increments and distances from the face to the supported front. The tunnelling methods of consideration include: tunnel boring machine, mechanical (conventional), and drill and blast.},
keywords = {Analytical, Convergence-confinement, Numerical modelling, Support, tunnelling},
pubstate = {published},
tppubtype = {article}
}
The convergence-confinement method (CCM) is a method that has been introduced in tunnel construction that considers the ground response to the advancing tunnel face and the interaction with installed support. One limitation of the CCM is due to the numerically or empirically driven nature of the longitudinal displacement profile and the incomplete consideration of the longitudinal arching effect that occurs during tunnelling operations as part of the face effect. In this paper, the authors address the issue associated with when the CCM is used within squeezing ground conditions at depth. Based on numerical analysis, the authors have proposed a methodology and solution to improving the CCM in order to allow for more accurate results for squeezing ground conditions for three different excavation cases involving various excavation-support increments and distances from the face to the supported front. The tunnelling methods of consideration include: tunnel boring machine, mechanical (conventional), and drill and blast.
335.
Diederichs, MS; Vazaios, I
Pre-Construction Prediction of Strain-Burst Potential in Blind Tunnelling Conference
Proceedings of the 10th Asian Rock Mechanics Symposium, Singapore, 2018.
BibTeX | Tags: Blind tunnelling, Pre-construction prediction, strain bursting
@conference{Diederichs2018bb,
title = {Pre-Construction Prediction of Strain-Burst Potential in Blind Tunnelling},
author = {MS Diederichs and I Vazaios},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of the 10th Asian Rock Mechanics Symposium},
address = {Singapore},
keywords = {Blind tunnelling, Pre-construction prediction, strain bursting},
pubstate = {published},
tppubtype = {conference}
}
334.
Vazaios, I; Vlachopoulos, N; Diederichs, MS
The effect of jointing in massive highly interlocked rockmasses under high stresses by using a FDEM approach Conference
Proceedings of the IAEG 2018 Conference, International Association of Engineering Geologists San Francisco, California, USA, 2018.
BibTeX | Tags: Finite-discrete element method (FDEM), High stress, Joints, Massive highly interlocked rockmasses
@conference{Vazaios2018bbc,
title = {The effect of jointing in massive highly interlocked rockmasses under high stresses by using a FDEM approach},
author = {I Vazaios and N Vlachopoulos and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of the IAEG 2018 Conference},
address = {San Francisco, California, USA},
organization = {International Association of Engineering Geologists},
keywords = {Finite-discrete element method (FDEM), High stress, Joints, Massive highly interlocked rockmasses},
pubstate = {published},
tppubtype = {conference}
}
333.
Packulak, TR; Day, JJ; Diederichs, MS
Practical aspects of boundary condition selection on direct shear laboratory tests Conference
Proceedings of Geomechanics and geodynamics of rock masses, ISRM-EUROCK 2018, Saint Petersburg, Russia, 2018.
BibTeX | Tags: Boundary conditions, Direct shear testing, Laboratory testing
@conference{Packulak2018b,
title = {Practical aspects of boundary condition selection on direct shear laboratory tests},
author = {TR Packulak and JJ Day and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of Geomechanics and geodynamics of rock masses, ISRM-EUROCK 2018},
address = {Saint Petersburg, Russia},
keywords = {Boundary conditions, Direct shear testing, Laboratory testing},
pubstate = {published},
tppubtype = {conference}
}
332.
Oliveira, DGG; Thewes, M; Diederichs, MS; Langmaack, L
Proposed methodology for clogging evaluation in EPB machines Conference
World Tunnel Congress 2018, Dubai, United Arab Emirates., 2018.
BibTeX | Tags: Clogging, Earth Pressure Balance Machine
@conference{deOliveira2018bb,
title = {Proposed methodology for clogging evaluation in EPB machines},
author = {DGG Oliveira and M Thewes and MS Diederichs and L Langmaack},
year = {2018},
date = {2018-01-01},
booktitle = {World Tunnel Congress 2018},
journal = {World Tunnel Congress 2018},
address = {Dubai, United Arab Emirates.},
keywords = {Clogging, Earth Pressure Balance Machine},
pubstate = {published},
tppubtype = {conference}
}
331.
Paraskevopoulou, C; Diederichs, MS
Analysis of time-dependent deformation in tunnels using the Convergence-Confinement Method Journal Article
In: Tunnelling and Underground Space Technology, vol. 71, pp. 62-80, 2018.
Abstract | Links | BibTeX | Tags: Creep, Long-term behaviour, Time-dependency, Visco-elastic parameters
@article{Paraskevopoulou2018,
title = {Analysis of time-dependent deformation in tunnels using the Convergence-Confinement Method},
author = {C Paraskevopoulou and MS Diederichs},
doi = {10.1016/j.tust.2017.07.001},
year = {2018},
date = {2018-01-01},
journal = {Tunnelling and Underground Space Technology},
volume = {71},
pages = {62-80},
abstract = {During the excavation of a tunnel the accumulated wall displacement and the loading of tunnel support is the result of both the tunnel advance (round length and cycle time) and the time-dependent behaviour of the surrounding rock mass. The current approach to analyze the tunnel wall displacement increase is based on the Convergence-Confinement Method (CCM) performed with either analytical (closed form solutions) or the usage of the Longitudinal Displacement Profiles. This approach neglects the influence of time-dependency resulting in delayed deformation that may manifest even minutes or hours after excavation. Failure to consider the added displacements in the preliminary design can result in false selecting the time of installation and the type of support system causing safety issues to the working personnel, leading to cost overruns and project delivery delays. This study focuses on investigating and analyzing the total displacements around a circular tunnel in a visco-elastic medium by performing an isotropic axisymmetric finite difference modelling, proposing a new yet simplified approach that practitioners can use taking into account the effect of time.},
keywords = {Creep, Long-term behaviour, Time-dependency, Visco-elastic parameters},
pubstate = {published},
tppubtype = {article}
}
During the excavation of a tunnel the accumulated wall displacement and the loading of tunnel support is the result of both the tunnel advance (round length and cycle time) and the time-dependent behaviour of the surrounding rock mass. The current approach to analyze the tunnel wall displacement increase is based on the Convergence-Confinement Method (CCM) performed with either analytical (closed form solutions) or the usage of the Longitudinal Displacement Profiles. This approach neglects the influence of time-dependency resulting in delayed deformation that may manifest even minutes or hours after excavation. Failure to consider the added displacements in the preliminary design can result in false selecting the time of installation and the type of support system causing safety issues to the working personnel, leading to cost overruns and project delivery delays. This study focuses on investigating and analyzing the total displacements around a circular tunnel in a visco-elastic medium by performing an isotropic axisymmetric finite difference modelling, proposing a new yet simplified approach that practitioners can use taking into account the effect of time.
330.
Aubertin, JD; Hoentzsch, S; Diederichs, MS; Milton, H
Influence of the creep law on pillar response based on numerical simulations of an underground salt mine Conference
52nd Rock Mechanics and Geomechanics Symposium, American Rock Mechanics Association Seattle, Washington, USA, 2018.
BibTeX | Tags: Creep, Numerical modelling, Rock pillar
@conference{Aubertin2018,
title = {Influence of the creep law on pillar response based on numerical simulations of an underground salt mine},
author = {JD Aubertin and S Hoentzsch and MS Diederichs and H Milton},
year = {2018},
date = {2018-01-01},
booktitle = {52nd Rock Mechanics and Geomechanics Symposium},
address = {Seattle, Washington, USA},
organization = {American Rock Mechanics Association},
keywords = {Creep, Numerical modelling, Rock pillar},
pubstate = {published},
tppubtype = {conference}
}
329.
Dadashzadeh, N; Diederichs, MS
Prediction of Excavation Damage Zone Depth Variability in Brittle Rocks Conference
Proceedings of Geomechanics and geodynamics of rock masses, ISRM-EUROCK 2018 Saint Petersburg, Russia, 2018.
BibTeX | Tags: Brittle rocks, Depth variability, excavation damage zone (EDZ)
@conference{Dadashzadeh2018bb,
title = {Prediction of Excavation Damage Zone Depth Variability in Brittle Rocks},
author = {N Dadashzadeh and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of Geomechanics and geodynamics of rock masses},
address = {Saint Petersburg, Russia},
organization = {ISRM-EUROCK 2018},
keywords = {Brittle rocks, Depth variability, excavation damage zone (EDZ)},
pubstate = {published},
tppubtype = {conference}
}
328.
Aubertin, JD; Hutchinson, DJ; Diederichs, MS; Triebel, R
Proposed improvements for single blasthole test reporting methodology and observations from a series of tests conducted in underground rock salt mines Conference
12th symposium on rock fragmentation by blasting, Lulea, 2018.
BibTeX | Tags: Blasthole testing, In situ measurements, Rock salt
@conference{Aubertin2018b,
title = {Proposed improvements for single blasthole test reporting methodology and observations from a series of tests conducted in underground rock salt mines},
author = {JD Aubertin and DJ Hutchinson and MS Diederichs and R Triebel},
year = {2018},
date = {2018-01-01},
booktitle = {12th symposium on rock fragmentation by blasting},
journal = {12th symposium on rock fragmentation by blasting},
address = {Lulea},
keywords = {Blasthole testing, In situ measurements, Rock salt},
pubstate = {published},
tppubtype = {conference}
}
327.
Diederichs, MS
Reopening a Canadian Landmark: The rehabilitation repurposing of the Brockville Tunnel Conference
NW Conference, no. TT2018-TAC/NASTT, Edmonton, 2018.
BibTeX | Tags: Brockville tunnel, Historical, Rehabilitation
@conference{Diederichs2018b,
title = {Reopening a Canadian Landmark: The rehabilitation repurposing of the Brockville Tunnel},
author = {MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {NW Conference},
number = {TT2018-TAC/NASTT},
pages = {8},
address = {Edmonton},
keywords = {Brockville tunnel, Historical, Rehabilitation},
pubstate = {published},
tppubtype = {conference}
}
326.
Dadashzadeh, N; Diederichs, MS
Effect of Rock Strength Components’ Evolution Rate on the Mechanism of Failure in Brittle Rocks Conference
Proceedings of the Tunneling and Trenchless Conference, no. TT2018 – TAC/NASTT-NW, Edmonton, AB, Canada, 2018.
BibTeX | Tags: Brittle failure, Evolution rate, Rock strength, Time-dependency
@conference{Dadashzadeh2018,
title = {Effect of Rock Strength Components’ Evolution Rate on the Mechanism of Failure in Brittle Rocks},
author = {N Dadashzadeh and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of the Tunneling and Trenchless Conference},
number = {TT2018 – TAC/NASTT-NW},
address = {Edmonton, AB, Canada},
keywords = {Brittle failure, Evolution rate, Rock strength, Time-dependency},
pubstate = {published},
tppubtype = {conference}
}
325.
Oliveira, D; Thewes, M; Diederichs, MS
Laboratory assessment of flow behavior and clogging associated with EPB excavation Conference
NW Conference, no. TT2018-TAC/NASTT, North American Society For Trenchless Technology Edmonton, AB, Canada, 2018.
BibTeX | Tags: Clogging, Earth Pressure Balance Machine, Flow behaviour, Laboratory testing
@conference{Oliveira2018,
title = {Laboratory assessment of flow behavior and clogging associated with EPB excavation},
author = {D Oliveira and M Thewes and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {NW Conference},
number = {TT2018-TAC/NASTT},
address = {Edmonton, AB, Canada},
organization = {North American Society For Trenchless Technology},
keywords = {Clogging, Earth Pressure Balance Machine, Flow behaviour, Laboratory testing},
pubstate = {published},
tppubtype = {conference}
}
324.
Dadashzadeh, N; Diederichs, MS
Reliability of Prediction for Tunnel Excavation Damage Zone Depth in Brittle Rocks Conference
Proceedings of the 10th Asian Rock Mechanics Symposium, Singapore, 2018.
BibTeX | Tags: Brittle damage, excavation damage zone (EDZ), Reliability methods, tunnelling
@conference{Dadashzadeh2018b,
title = {Reliability of Prediction for Tunnel Excavation Damage Zone Depth in Brittle Rocks},
author = {N Dadashzadeh and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of the 10th Asian Rock Mechanics Symposium},
address = {Singapore},
keywords = {Brittle damage, excavation damage zone (EDZ), Reliability methods, tunnelling},
pubstate = {published},
tppubtype = {conference}
}
323.
Vazaios, I; Vlachopoulos, N; Diederichs, MS
A multidisciplinary approach in modelling hard rocks with natural discontinuities: From data collection to numerical simulation Conference
Proceedings of the ARMA 2018 Conference, American Rock Mechanics Association Seattle, Washington, USA, 2018.
BibTeX | Tags: Discontinuity, Hard rockmasses, Multidisciplinary, Numerical simulation
@conference{Vazaios2018bbb,
title = {A multidisciplinary approach in modelling hard rocks with natural discontinuities: From data collection to numerical simulation},
author = {I Vazaios and N Vlachopoulos and MS Diederichs},
year = {2018},
date = {2018-01-01},
booktitle = {Proceedings of the ARMA 2018 Conference},
address = {Seattle, Washington, USA},
organization = {American Rock Mechanics Association},
keywords = {Discontinuity, Hard rockmasses, Multidisciplinary, Numerical simulation},
pubstate = {published},
tppubtype = {conference}
}
2017
322.
Day, JJ; Diederichs, MS; Hutchinson, DJ
New direct shear testing protocols and analyses for fractures and healed intrablock rockmass discontinuities Journal Article
In: Engineering Geology, vol. 229, pp. 53-72, 2017.
Abstract | Links | BibTeX | Tags: Cobourg limestone, Direct shear testing, Healed (intrablock) structure, Normal stiffness, Shear stiffness, Shear strength
@article{Day2017,
title = {New direct shear testing protocols and analyses for fractures and healed intrablock rockmass discontinuities},
author = {JJ Day and MS Diederichs and DJ Hutchinson},
doi = {10.1016/j.enggeo.2017.08.027},
year = {2017},
date = {2017-11-07},
journal = {Engineering Geology},
volume = {229},
pages = {53-72},
abstract = {Modern geotechnical numerical design is limited by conventional characterization and data collection practices, which do not capture detailed parameters of intact rock and rockmass structure that are necessary for input to sophisticated and powerful simulation tools. Furthermore, as modern underground excavations go deeper and enter into more high stress environments with complex excavation geometries and associated stress paths, healed structures within initially intact rock blocks such as sedimentary nodules and hydrothermal veins (termed intrablock structure, where conventional fractures are termed interblock structure) are having an increasing influence on rockmass behaviour and should be included in modern geotechnical design. The role of sedimentary nodular intrablock structure in the Cobourg limestone on rockmass behaviour is an important consideration for the design of Canadian Deep Geological Repositories (DGRs) for the permanent storage of nuclear waste. This direct shear test program provides valuable laboratory data results for mechanical properties of targeted fracture surfaces and intrablock features in the Cobourg limestone for application to the numerical geotechnical design of prospective DGRs. Measurements of normal stiffness (Kn), shear stiffness (Ks), shear strength (in terms of cohesion (c) and friction angle (ϕ) from the Mohr-Coulomb shear strength criterion), and initial dilation angle (ψ) parameters are assessed and critically evaluated. These established parameters for fractures are applied to the tests on intrablock structures to provide a consistent basis for comparison and to enable the use of existing mechanical parameters in numerical model inputs. The implications of normal and shear stiffness property selection are evaluated at the excavation scale using finite element models with explicit rockmass structure. The critical analyses of conventional calculations of parameters results in improved calculation methods with mechanistic reasoning for the ultimate application of the data to sophisticated numerical models with explicit or discrete rockmass structure.},
keywords = {Cobourg limestone, Direct shear testing, Healed (intrablock) structure, Normal stiffness, Shear stiffness, Shear strength},
pubstate = {published},
tppubtype = {article}
}
Modern geotechnical numerical design is limited by conventional characterization and data collection practices, which do not capture detailed parameters of intact rock and rockmass structure that are necessary for input to sophisticated and powerful simulation tools. Furthermore, as modern underground excavations go deeper and enter into more high stress environments with complex excavation geometries and associated stress paths, healed structures within initially intact rock blocks such as sedimentary nodules and hydrothermal veins (termed intrablock structure, where conventional fractures are termed interblock structure) are having an increasing influence on rockmass behaviour and should be included in modern geotechnical design. The role of sedimentary nodular intrablock structure in the Cobourg limestone on rockmass behaviour is an important consideration for the design of Canadian Deep Geological Repositories (DGRs) for the permanent storage of nuclear waste. This direct shear test program provides valuable laboratory data results for mechanical properties of targeted fracture surfaces and intrablock features in the Cobourg limestone for application to the numerical geotechnical design of prospective DGRs. Measurements of normal stiffness (Kn), shear stiffness (Ks), shear strength (in terms of cohesion (c) and friction angle (ϕ) from the Mohr-Coulomb shear strength criterion), and initial dilation angle (ψ) parameters are assessed and critically evaluated. These established parameters for fractures are applied to the tests on intrablock structures to provide a consistent basis for comparison and to enable the use of existing mechanical parameters in numerical model inputs. The implications of normal and shear stiffness property selection are evaluated at the excavation scale using finite element models with explicit rockmass structure. The critical analyses of conventional calculations of parameters results in improved calculation methods with mechanistic reasoning for the ultimate application of the data to sophisticated numerical models with explicit or discrete rockmass structure.
321.
Diederichs, MS
An overview of geomechanics field-based training in Europe Journal Article
In: Tunnels and Tunnelling, vol. 6, pp. 30-33, 2017.
BibTeX | Tags: Field-based training, geomechanics
@article{Diederichs2017bb,
title = {An overview of geomechanics field-based training in Europe},
author = {MS Diederichs},
year = {2017},
date = {2017-11-01},
journal = {Tunnels and Tunnelling},
volume = {6},
pages = {30-33},
keywords = {Field-based training, geomechanics},
pubstate = {published},
tppubtype = {article}
}
320.
Paraskevopoulou, C; Perras, MA; Diederichs, MS; Loew, S; Lam, T; Jensen, M
Time-dependent behaviour of brittle rocks based on static load laboratory tests Journal Article
In: Geotechnical and Geological Engineering, vol. 36, pp. 337-376, 2017.
Abstract | Links | BibTeX | Tags: Creep, Laboratory testing, Long-term behaviour, Static load testing, Time-dependency, Visco-elastic parameters
@article{Paraskevopoulou2017,
title = {Time-dependent behaviour of brittle rocks based on static load laboratory tests},
author = {C Paraskevopoulou and MA Perras and MS Diederichs and S Loew and T Lam and M Jensen},
url = {https://link.springer.com/article/10.1007/s10706-017-0331-8},
doi = {https://doi.org/10.1007/s10706-017-0331-8},
year = {2017},
date = {2017-08-22},
journal = {Geotechnical and Geological Engineering},
volume = {36},
pages = {337-376},
abstract = {Cumulative elastic and inelastic strain and associated internal stress changes as well as damage evolution over time in brittle rocks control the long-term evolution of the rockmass around underground openings or the land surface settlement. This long-term behaviour is associated with time-dependent deformation and is commonly investigated under static load (creep) conditions in laboratory scale. In this study, low Jurassic and Cobourg limestone samples were tested at different static load levels in unconfined conditions to examine the time to failure. Comparisons are made with longterm testing data in granites and limestones associated with the Canadian nuclear waste program and other data from the literature. Failure typically occurred within the time limits of the test program (4 months) with axial (differential) stress levels near or above the crack damage threshold (CD) estimated from baseline testing. The results also suggest that the time to failure of limestone is longer than that of granite at a given driving stress. Further insight into samples that did not reach failure was investigated and it was found that there was a clear division between failure and no failure samples based on the Maxwell viscosity of the samples tested (indicating that viscosity changes near the yield threshold of these rocks. Furthermore, samples showed a clear tendency towards failure within minutes to hours when loaded above CD and no failure was shown for samples loaded below CI (crack initiation threshold). Samples loaded between CD and CI show a region of uncertainty, with some failing and other not at similar driving stress-ratios. Although such testing is demanding in terms of setup, control of conditions, continuous utilization of test and data acquisition equipment and data processing, it yields important information about the long-term behaviour of brittle rocks, such as the expect time to failure and the visco-elastic behaviour. The information presented in this paper can be utilized for preliminary numerical studies to gain an understanding of potential impact of long-term deformations.},
keywords = {Creep, Laboratory testing, Long-term behaviour, Static load testing, Time-dependency, Visco-elastic parameters},
pubstate = {published},
tppubtype = {article}
}
Cumulative elastic and inelastic strain and associated internal stress changes as well as damage evolution over time in brittle rocks control the long-term evolution of the rockmass around underground openings or the land surface settlement. This long-term behaviour is associated with time-dependent deformation and is commonly investigated under static load (creep) conditions in laboratory scale. In this study, low Jurassic and Cobourg limestone samples were tested at different static load levels in unconfined conditions to examine the time to failure. Comparisons are made with longterm testing data in granites and limestones associated with the Canadian nuclear waste program and other data from the literature. Failure typically occurred within the time limits of the test program (4 months) with axial (differential) stress levels near or above the crack damage threshold (CD) estimated from baseline testing. The results also suggest that the time to failure of limestone is longer than that of granite at a given driving stress. Further insight into samples that did not reach failure was investigated and it was found that there was a clear division between failure and no failure samples based on the Maxwell viscosity of the samples tested (indicating that viscosity changes near the yield threshold of these rocks. Furthermore, samples showed a clear tendency towards failure within minutes to hours when loaded above CD and no failure was shown for samples loaded below CI (crack initiation threshold). Samples loaded between CD and CI show a region of uncertainty, with some failing and other not at similar driving stress-ratios. Although such testing is demanding in terms of setup, control of conditions, continuous utilization of test and data acquisition equipment and data processing, it yields important information about the long-term behaviour of brittle rocks, such as the expect time to failure and the visco-elastic behaviour. The information presented in this paper can be utilized for preliminary numerical studies to gain an understanding of potential impact of long-term deformations.
319.
Forbes, B; Vlachopoulos, N; Hyett, A; Diederichs, MS
A new optical sensing technique for monitoring shear of rock bolts. Tunnelling and Underground Space Technology Journal Article
In: Tunnelling and Underground Space Technology, vol. 66, pp. 34-46, 2017, ISBN: 0886-7798.
Abstract | Links | BibTeX | Tags: Instrumentation, Optical sensing, Physical testing, Rock bolt, Shear, Strain analysis
@article{Forbes2017,
title = {A new optical sensing technique for monitoring shear of rock bolts. Tunnelling and Underground Space Technology},
author = {B Forbes and N Vlachopoulos and A Hyett and MS Diederichs},
url = {https://www.sciencedirect.com/science/article/pii/S0886779816307313},
doi = {https://doi.org/10.1016/j.tust.2017.03.007},
isbn = {0886-7798},
year = {2017},
date = {2017-06-21},
journal = {Tunnelling and Underground Space Technology},
volume = {66},
pages = {34-46},
abstract = {In addressing limitations of conventional ground support measurement, a novel optical strain sensing technique is presented that is capable of measuring strain at increments as low as 0.65mm along the entirety of an optical sensor affixed to a support element. The technique considers monitoring three sensing lengths along the profile of a fully grouted rock bolt element using a single optical fiber, which, in turn, allows the derivation of both the principle strain and principle strain direction along the bolt. A series of three experiments, which include: symmetric bending, combined axial load and bending, and double shear loading are presented and highlight the potential of the technique to capture bolt behaviour under such generalized rock bolt loading conditions. Analogized as a distributed strain rosette, the optical technique can distinguish both the coaxial and bending induced constituents of the total strain in the bolt regardless of load orientation.},
keywords = {Instrumentation, Optical sensing, Physical testing, Rock bolt, Shear, Strain analysis},
pubstate = {published},
tppubtype = {article}
}
In addressing limitations of conventional ground support measurement, a novel optical strain sensing technique is presented that is capable of measuring strain at increments as low as 0.65mm along the entirety of an optical sensor affixed to a support element. The technique considers monitoring three sensing lengths along the profile of a fully grouted rock bolt element using a single optical fiber, which, in turn, allows the derivation of both the principle strain and principle strain direction along the bolt. A series of three experiments, which include: symmetric bending, combined axial load and bending, and double shear loading are presented and highlight the potential of the technique to capture bolt behaviour under such generalized rock bolt loading conditions. Analogized as a distributed strain rosette, the optical technique can distinguish both the coaxial and bending induced constituents of the total strain in the bolt regardless of load orientation.
318.
Day, JJ; Diederichs, MS; Hutchinson, DJ
The influence of mineralogy and grain scale features in healed intrablock structure on direct shear properties in the Cobourg limestone Conference
Proceedings of ARMA San Francisco, June 2017, American Rock Mechanics Association San Francisco, California, USA, 2017.
BibTeX | Tags: Cobourg limestone, Direct shear testing, Grain scale features, Healed intrablock structures
@conference{Day2017bb,
title = {The influence of mineralogy and grain scale features in healed intrablock structure on direct shear properties in the Cobourg limestone},
author = {JJ Day and MS Diederichs and DJ Hutchinson},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of ARMA San Francisco, June 2017},
pages = {8},
address = {San Francisco, California, USA},
organization = {American Rock Mechanics Association},
keywords = {Cobourg limestone, Direct shear testing, Grain scale features, Healed intrablock structures},
pubstate = {published},
tppubtype = {conference}
}
317.
Cain, S; Diederichs, MS
The impact of tunnel shape, orientation and blast round length on excavation damage development in brittle rock Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Brittle rocks, excavation damage zone (EDZ), Tunnel orientation, Tunnel shape
@conference{Cain2017b,
title = {The impact of tunnel shape, orientation and blast round length on excavation damage development in brittle rock},
author = {S Cain and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Brittle rocks, excavation damage zone (EDZ), Tunnel orientation, Tunnel shape},
pubstate = {published},
tppubtype = {conference}
}
316.
Diederichs, MS
Progressive and time-dependent brittle damage processes and failure in rock Conference
Proceedings of Progressive Rock Failure Conference, Ascona, Switzerland, 2017.
BibTeX | Tags: Brittle damage, progressive failure, Time-dependency
@conference{Diederichs2017bbb,
title = {Progressive and time-dependent brittle damage processes and failure in rock},
author = {MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of Progressive Rock Failure Conference},
address = {Ascona, Switzerland},
keywords = {Brittle damage, progressive failure, Time-dependency},
pubstate = {published},
tppubtype = {conference}
}
315.
Paraskevopoulou, C; Diederichs, MS
How time-dependanct influences the longitudinal displacement profile during the construction of deep tunnels Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Deep tunnelling, Longitudinal displacement profiles, Time-dependency
@conference{Paraskevopoulou2017bb,
title = {How time-dependanct influences the longitudinal displacement profile during the construction of deep tunnels},
author = {C Paraskevopoulou and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Deep tunnelling, Longitudinal displacement profiles, Time-dependency},
pubstate = {published},
tppubtype = {conference}
}
314.
Oliveira, DGG; Diederichs, MS; Thewes, M; Friemann, S; Aguiar, G
EPB Conditioning of Mixed Transitional Ground: Investigating Preliminary Aspects Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Earth Pressure Balance Machine, Mixed soils
@conference{deOliveira2017,
title = {EPB Conditioning of Mixed Transitional Ground: Investigating Preliminary Aspects},
author = {DGG Oliveira and MS Diederichs and M Thewes and S Friemann and G Aguiar},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Earth Pressure Balance Machine, Mixed soils},
pubstate = {published},
tppubtype = {conference}
}
313.
Blacklock, N; Diederichs, MS
Applications of scout hole programs in tunnelling operations under high stress Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: High stress, Scout hole programs, tunnelling
@conference{Blacklock2017,
title = {Applications of scout hole programs in tunnelling operations under high stress},
author = {N Blacklock and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {High stress, Scout hole programs, tunnelling},
pubstate = {published},
tppubtype = {conference}
}
312.
Day, JJ; Diederichs, MS; Hutchinson, DJ
Application of Composite Geological Strength Index for healed rockmass structure to deep mining tunnels Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Composite Geological Strength Index, Deep mining, Deep tunnelling, Healed intrablock structures
@conference{Day2017bbb,
title = {Application of Composite Geological Strength Index for healed rockmass structure to deep mining tunnels},
author = {JJ Day and MS Diederichs and DJ Hutchinson},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Composite Geological Strength Index, Deep mining, Deep tunnelling, Healed intrablock structures},
pubstate = {published},
tppubtype = {conference}
}
311.
Vazaios, I; Vlachopoulos, N; Forbes, B; Diederichs, MS
A DFN-LiDAR-optical sensor method for the estimation of rockmass conditions in underground projects Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Discrete fracture networks (DFN), LiDAR, Rockmass conditions, underground work
@conference{Vazaios2017b,
title = {A DFN-LiDAR-optical sensor method for the estimation of rockmass conditions in underground projects},
author = {I Vazaios and N Vlachopoulos and B Forbes and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Discrete fracture networks (DFN), LiDAR, Rockmass conditions, underground work},
pubstate = {published},
tppubtype = {conference}
}
310.
Jaczkowski, E; Ghazvinian, E; Diederichs, MS
The influence of scale and loading rate on the crack damage thresholds of Cobourg limestone Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Cobourg limestone, Crack damage thresholds, Loading rate, Scale-dependency
@conference{Jaczkowski2017,
title = {The influence of scale and loading rate on the crack damage thresholds of Cobourg limestone},
author = {E Jaczkowski and E Ghazvinian and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Cobourg limestone, Crack damage thresholds, Loading rate, Scale-dependency},
pubstate = {published},
tppubtype = {conference}
}
309.
LeRiche, A; Kalenchuk, KS; Diederichs, MS
Estimation of in situ stress from borehole breakout in brittle rock for the prediction of shaft overbreak Conference
Proceedings of the World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Borehole breakout, Brittle rocks, in situ stresses, Shaft overbreak
@conference{LeRiche2017,
title = {Estimation of in situ stress from borehole breakout in brittle rock for the prediction of shaft overbreak},
author = {A LeRiche and KS Kalenchuk and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {Proceedings of the World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Borehole breakout, Brittle rocks, in situ stresses, Shaft overbreak},
pubstate = {published},
tppubtype = {conference}
}
308.
Dadashzadeh, N; Diederichs, MS
Investigation of Factor of Safety in Squeezing Ground Conference
World Tunnelling Conference, Bergen, Norway, 2017.
BibTeX | Tags: Factor of Safety, squeezing
@conference{Dadashzadeh2017,
title = {Investigation of Factor of Safety in Squeezing Ground},
author = {N Dadashzadeh and MS Diederichs},
year = {2017},
date = {2017-06-01},
booktitle = {World Tunnelling Conference},
pages = {8},
address = {Bergen, Norway},
keywords = {Factor of Safety, squeezing},
pubstate = {published},
tppubtype = {conference}
}
307.
Vazaios, I; Vlachopoulos, N; Diederichs, MS
Integration of Lidar-based Structural Input and Discrete Fracture Network Generation for Underground Applications Journal Article
In: Geotechnical and Geological Engineering, vol. 35, pp. 2227–2251, 2017.
Abstract | Links | BibTeX | Tags: DFN Model Size, DFN Number of Realizations, Discrete fracture networks (DFN), LiDAR, Representative elementary volume (REV), underground work, Virtual Mapping
@article{Vazaios2017,
title = {Integration of Lidar-based Structural Input and Discrete Fracture Network Generation for Underground Applications},
author = {I Vazaios and N Vlachopoulos and MS Diederichs},
doi = {https://doi.org/10.1007/s10706-017-0240-x},
year = {2017},
date = {2017-04-27},
journal = {Geotechnical and Geological Engineering},
volume = {35},
pages = {2227–2251},
abstract = {In this study the authors present an approach of establishing and validating discrete fracture networks (DFNs) for underground projects using LiDAR (Light Detection and Ranging) as the source data. With the use of LiDAR in geotechnical and geological engineering becoming increasingly popular, it is necessary to establish the interactive application of this technology with other tools. Such a tool is the generation of DFNs and their integration into the geomechanical design, with a specific focus on underground projects such as tunnels, caverns, repositories etc. This paper attempts to show an approach in which LiDAR data from the Brockville Tunnel, located in Ontario, Canada, is used as the source for the determination of input parameters of DFN modelling based on manual and automatic mapping techniques. Having determined a representative set of input parameters, a deterministic DFN model is created in order to calibrate other modelling parameters associated with the generation process, leading to the creation of multiple DFN models. By employing the representative elementary volume (REV) concept, these models are used in order to examine the effect of the different joint sets on the estimated REV, and to introduce an approach of determining the required number of DFN realizations and the size of the DFN models.},
keywords = {DFN Model Size, DFN Number of Realizations, Discrete fracture networks (DFN), LiDAR, Representative elementary volume (REV), underground work, Virtual Mapping},
pubstate = {published},
tppubtype = {article}
}
In this study the authors present an approach of establishing and validating discrete fracture networks (DFNs) for underground projects using LiDAR (Light Detection and Ranging) as the source data. With the use of LiDAR in geotechnical and geological engineering becoming increasingly popular, it is necessary to establish the interactive application of this technology with other tools. Such a tool is the generation of DFNs and their integration into the geomechanical design, with a specific focus on underground projects such as tunnels, caverns, repositories etc. This paper attempts to show an approach in which LiDAR data from the Brockville Tunnel, located in Ontario, Canada, is used as the source for the determination of input parameters of DFN modelling based on manual and automatic mapping techniques. Having determined a representative set of input parameters, a deterministic DFN model is created in order to calibrate other modelling parameters associated with the generation process, leading to the creation of multiple DFN models. By employing the representative elementary volume (REV) concept, these models are used in order to examine the effect of the different joint sets on the estimated REV, and to introduce an approach of determining the required number of DFN realizations and the size of the DFN models.
306.
Oliveira, D; Diederichs, MS
Tunnel support for stress induced failures in Hawkesbury Sandstone Journal Article
In: Tunnelling and Underground Space Technology, vol. 64, pp. 10-23, 2017, ISBN: 0886-7798.
Abstract | Links | BibTeX | Tags: Brittle failure, Deep excavations, Hard rock excavations, in situ stresses, Sandstone
@article{Oliveira2017,
title = {Tunnel support for stress induced failures in Hawkesbury Sandstone},
author = {D Oliveira and MS Diederichs},
url = {https://www.sciencedirect.com/science/article/pii/S0886779816308665},
doi = {https://doi.org/10.1016/j.tust.2017.01.003},
isbn = {0886-7798},
year = {2017},
date = {2017-04-01},
journal = {Tunnelling and Underground Space Technology},
volume = {64},
pages = {10-23},
abstract = {Underlying much of Sydney, Australia is a composite rock formation known as the Hawkesbury Sandstone. This unit is composed of clastic layers of variable competency including a number of thick and strong layers. The presence of very high horizontal stresses within these layers is widely accepted. Deep excavations such as basements or open cuts in Hawkesbury Sandstone often experience moderate horizontal movements in excess of 1 mm per metre of rock excavation. These movements can result in various scales of damage and excess loads on supporting elements. Stress induced failures in tunnels and underground excavations have also been observed in a number of projects and include crushing, spalling and or slabbing of intact rock blocks or shear failures associated with planes of weakness. While most design approaches in ground engineering account for shear failure mechanisms, the assessment of brittle failure is less common and less well understood. Conventional models and failure criteria do not appropriately describe such behaviour and consequently the impacts on ground support may not always be appropriately addressed. This paper presents some discussions on the modelling and assessment of brittle failure in Hawkesbury Sandstone and some of the impacts of high in-situ stresses on tunnel support design.},
keywords = {Brittle failure, Deep excavations, Hard rock excavations, in situ stresses, Sandstone},
pubstate = {published},
tppubtype = {article}
}
Underlying much of Sydney, Australia is a composite rock formation known as the Hawkesbury Sandstone. This unit is composed of clastic layers of variable competency including a number of thick and strong layers. The presence of very high horizontal stresses within these layers is widely accepted. Deep excavations such as basements or open cuts in Hawkesbury Sandstone often experience moderate horizontal movements in excess of 1 mm per metre of rock excavation. These movements can result in various scales of damage and excess loads on supporting elements. Stress induced failures in tunnels and underground excavations have also been observed in a number of projects and include crushing, spalling and or slabbing of intact rock blocks or shear failures associated with planes of weakness. While most design approaches in ground engineering account for shear failure mechanisms, the assessment of brittle failure is less common and less well understood. Conventional models and failure criteria do not appropriately describe such behaviour and consequently the impacts on ground support may not always be appropriately addressed. This paper presents some discussions on the modelling and assessment of brittle failure in Hawkesbury Sandstone and some of the impacts of high in-situ stresses on tunnel support design.
305.
Cain, S; Diederichs, MS
Shape matters: the impact of geometry on brittle damage for repository engineering Journal Article
In: Tunnels and Tunnelling, vol. 2, pp. 32-37, 2017.
BibTeX | Tags: Brittle damage, Deep geological repository (DGR), geometry
@article{Cain2017,
title = {Shape matters: the impact of geometry on brittle damage for repository engineering},
author = {S Cain and MS Diederichs},
year = {2017},
date = {2017-03-01},
journal = {Tunnels and Tunnelling},
volume = {2},
pages = {32-37},
keywords = {Brittle damage, Deep geological repository (DGR), geometry},
pubstate = {published},
tppubtype = {article}
}
304.
Diederichs, MS; Walton, G; Duran, F
Rockmass Stiffness Modification and Post-Yield Behaviour Book Chapter
In: Chapter 4.2, pp. 51-53, Canadian Institute of Mining, Metallurgy and Petroleum, 2017.
BibTeX | Tags: Post-yield
@inbook{Diederichs2017b,
title = {Rockmass Stiffness Modification and Post-Yield Behaviour},
author = {MS Diederichs and G Walton and F Duran},
year = {2017},
date = {2017-01-01},
pages = {51-53},
publisher = {Canadian Institute of Mining, Metallurgy and Petroleum},
chapter = {4.2},
series = {S.U.M.I.T Program},
keywords = {Post-yield},
pubstate = {published},
tppubtype = {inbook}
}
303.
Oliveira, DGG; Diederichs, MS; Silva, MAA Peixoto
nteração de tuneladoras com terreno transicional solo-rocha Conference
Proceedings 4°CBT–Brazilian Tunnelling Congress, Sao Paulo, Brazil, 2017.
BibTeX | Tags: Tunnel boring machine (TBM)
@conference{deOliveira2017bb,
title = {nteração de tuneladoras com terreno transicional solo-rocha},
author = {DGG Oliveira and MS Diederichs and MAA Peixoto Silva},
year = {2017},
date = {2017-01-01},
booktitle = {Proceedings 4°CBT–Brazilian Tunnelling Congress},
address = {Sao Paulo, Brazil},
keywords = {Tunnel boring machine (TBM)},
pubstate = {published},
tppubtype = {conference}
}
302.
Oliveira, DGG; Diederichs, MS; Rasmussen, LL; Jr, M Cecillio
Tropical residual soil data compilation as guidance for laboratory tests and modelling the EPB excavation process Conference
Proceedings of the 9th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground, Sao Paulo, Brazil, 2017.
BibTeX | Tags: Earth Pressure Balance Machine, Laboratory testing, Modelling, Tropical residual soil
@conference{deOliveira2017b,
title = {Tropical residual soil data compilation as guidance for laboratory tests and modelling the EPB excavation process},
author = {DGG Oliveira and MS Diederichs and LL Rasmussen and M Cecillio Jr},
year = {2017},
date = {2017-01-01},
booktitle = {Proceedings of the 9th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground},
address = {Sao Paulo, Brazil},
keywords = {Earth Pressure Balance Machine, Laboratory testing, Modelling, Tropical residual soil},
pubstate = {published},
tppubtype = {conference}
}
301.
LeRiche, A; Kalenchuk, KS; Diederichs, MS
Estimation of in situ stress from borehole breakout for improved understating of excavation overbreak in brittle-anisotropic rock Conference
Proceedings of Deep Mining Conference, Perth, Australia, 2017.
BibTeX | Tags: Anisotropy, Borehole breakout, brittle rock, Excavation overbreak, in situ stresses
@conference{LeRiche2017b,
title = {Estimation of in situ stress from borehole breakout for improved understating of excavation overbreak in brittle-anisotropic rock},
author = {A LeRiche and KS Kalenchuk and MS Diederichs},
year = {2017},
date = {2017-01-01},
booktitle = {Proceedings of Deep Mining Conference},
journal = {Proceedi},
pages = {14},
address = {Perth, Australia},
keywords = {Anisotropy, Borehole breakout, brittle rock, Excavation overbreak, in situ stresses},
pubstate = {published},
tppubtype = {conference}
}
300.
Eberhardt, E; Diederichs, MS; Rahjoo, M
Pre‐Peak Brittle Fracture Damage. Rock Mechnics and Rock Engineering Book Chapter
In: Feng,; Hudson, (Ed.): vol. 1: Principles, Chapter 20, pp. 623-658, CRC Press, 2017.
BibTeX | Tags: Brittle damage, Brittle fracturing
@inbook{Eberhardt2017,
title = {Pre‐Peak Brittle Fracture Damage. Rock Mechnics and Rock Engineering},
author = {E Eberhardt and MS Diederichs and M Rahjoo},
editor = {Feng and Hudson},
year = {2017},
date = {2017-01-01},
volume = {1: Principles},
pages = {623-658},
publisher = {CRC Press},
chapter = {20},
series = {Rock Mechnics and Rock Engineering},
keywords = {Brittle damage, Brittle fracturing},
pubstate = {published},
tppubtype = {inbook}
}
299.
Day, JJ; Diederichs, MS; Hutchinson, DJ
Investigating normal and shear stiffness properties of fractures and healed sedimentary nodular structure in the Cobourg limestone Conference
Canadian Geotechnical Society Conference, GeoOttawa 2017 Ottawa, ON, Canada, 2017.
BibTeX | Tags: Cobourg limestone, Healed intrablock structures, Nodular structure, Normal stiffness, Rock fracture, Shear stiffness
@conference{Day2017b,
title = {Investigating normal and shear stiffness properties of fractures and healed sedimentary nodular structure in the Cobourg limestone},
author = {JJ Day and MS Diederichs and DJ Hutchinson},
year = {2017},
date = {2017-01-01},
booktitle = {Canadian Geotechnical Society Conference},
pages = {8},
address = {Ottawa, ON, Canada},
series = {GeoOttawa 2017},
keywords = {Cobourg limestone, Healed intrablock structures, Nodular structure, Normal stiffness, Rock fracture, Shear stiffness},
pubstate = {published},
tppubtype = {conference}
}
298.
Paraskevopoulou, C; Perras, MA; Diederichs, MS; Amann, F; Loew, S; Lam, T
The three stages of stress-relaxation - Observations for the time-dependent behaviour of brittle rocks based on laboratory testing Journal Article
In: Engineering Geology, vol. 216, no. 12, pp. 56-75, 2017, ISBN: 0013-7952.
Abstract | Links | BibTeX | Tags: Brittle rocks, Creep, Laboratory testing, stages of stress relaxation, Static load testing, stress relaxation testing, Time-dependency, time-dependent behaviour
@article{Paraskevopoulou201756,
title = {The three stages of stress-relaxation - Observations for the time-dependent behaviour of brittle rocks based on laboratory testing},
author = {C Paraskevopoulou and MA Perras and MS Diederichs and F Amann and S Loew and T Lam},
url = {https://www.sciencedirect.com/science/article/pii/S0013795216306573},
doi = {https://doi.org/10.1016/j.enggeo.2016.11.010},
isbn = {0013-7952},
year = {2017},
date = {2017-01-01},
journal = {Engineering Geology},
volume = {216},
number = {12},
pages = {56-75},
abstract = {nderground openings can experience time-dependent deformations and stress changes. Studying time-dependent rock behaviour is commonly done with static load (creep) tests in the laboratory which typically exhibit three distinct stages of behaviour. In this study relaxation tests were conducted to examine if three stages also exist under constant strain boundary conditions and to understand how the relaxation behaviour changes as the driving stress to strength ratio is increased. Tests were conducted on two types of limestone. At different load levels similar stress-time responses were measured indicating three distinct stages of stress relaxation. The first stage of stress relaxation (RI) where the stress relaxes with a decreasing rate is followed by the second stage (RII) in which the stress decrease approaches a constant rate and in the third stage (RIII) no further stress relaxation takes place. In the first stage 55% to 95% of the total stress relaxation takes place. The test results are compared with literature data to understand the influence of the stiffness on the magnitude and time to reach the maximum stress relaxation. Relaxation tests could be used to derive numerical model inputs to describe the time-dependent behaviour in a manner similar to static load tests.},
keywords = {Brittle rocks, Creep, Laboratory testing, stages of stress relaxation, Static load testing, stress relaxation testing, Time-dependency, time-dependent behaviour},
pubstate = {published},
tppubtype = {article}
}
nderground openings can experience time-dependent deformations and stress changes. Studying time-dependent rock behaviour is commonly done with static load (creep) tests in the laboratory which typically exhibit three distinct stages of behaviour. In this study relaxation tests were conducted to examine if three stages also exist under constant strain boundary conditions and to understand how the relaxation behaviour changes as the driving stress to strength ratio is increased. Tests were conducted on two types of limestone. At different load levels similar stress-time responses were measured indicating three distinct stages of stress relaxation. The first stage of stress relaxation (RI) where the stress relaxes with a decreasing rate is followed by the second stage (RII) in which the stress decrease approaches a constant rate and in the third stage (RIII) no further stress relaxation takes place. In the first stage 55% to 95% of the total stress relaxation takes place. The test results are compared with literature data to understand the influence of the stiffness on the magnitude and time to reach the maximum stress relaxation. Relaxation tests could be used to derive numerical model inputs to describe the time-dependent behaviour in a manner similar to static load tests.
297.
Aubertin, JD; Hutchinson, DJ; Diederichs, MS
Single blasthole testing in soft rocks Conference
CIM convention, Montreal, QC, Canada, 2017.
BibTeX | Tags: Blasthole testing, Soft rocks
@conference{Aubertin2017b,
title = {Single blasthole testing in soft rocks},
author = {JD Aubertin and DJ Hutchinson and MS Diederichs},
year = {2017},
date = {2017-01-01},
booktitle = {CIM convention},
journal = {CIM convention},
address = {Montreal, QC, Canada},
keywords = {Blasthole testing, Soft rocks},
pubstate = {published},
tppubtype = {conference}
}
296.
Diederichs, MS; Hutchinson, DJ; Walton, G; Day, JJ; Langford, JC; Vazaios, I; Palleske, C; Delaloyle, D; Duran, F; Kraan, M; O'Connor, S
Automated Characterization and Change Detection Within 3D Digitally Scanned Virtual Excavation Boundary and Borehole Models to Quantify Rockmass Deformation Response to Mining Over Time Book Chapter
In: Chapter 2.3, pp. 24-26, Canadian Institute of Mining, Metallurgy and Petroleum, 2017.
BibTeX | Tags: Deformation analysis
@inbook{Diederichs2017,
title = {Automated Characterization and Change Detection Within 3D Digitally Scanned Virtual Excavation Boundary and Borehole Models to Quantify Rockmass Deformation Response to Mining Over Time},
author = {MS Diederichs and DJ Hutchinson and G Walton and JJ Day and JC Langford and I Vazaios and C Palleske and D Delaloyle and F Duran and M Kraan and S O'Connor},
year = {2017},
date = {2017-01-01},
pages = {24-26},
publisher = {Canadian Institute of Mining, Metallurgy and Petroleum},
chapter = {2.3},
series = {S.U.M.I.T Program},
keywords = {Deformation analysis},
pubstate = {published},
tppubtype = {inbook}
}
Queen's Geomechanics and Geohazards Group
36 Union Street, Miller Hall
Queen's University
Kingston, Ontario
K7L 3N6
Canada
36 Union Street, Miller Hall
Queen's University
Kingston, Ontario
K7L 3N6
Canada
phone:
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