Publications

@article{nokey,

title = {Calibration of a 2D built-in rockbolt model using pre-yield axial load distribution data for fully grouted rebar rockbolts},

author = {CP Fischer and B Forbes and MS Diederichs},

doi = {https://doi.org/10.1016/j.jrmge.2025.11.051},

year  = {2026},

date = {2026-04-15},

journal = {Journal of Rock Mechanics and Geotechnical Engineering},

volume = {In Press},

keywords = {Built-in Rockbolt models, Fiber-optic sensing, Finite element method (FEM), Fully grouted rebar (FGR) rockbolts, Rockbolt axial load distribution, Rockbolt numerical modelling},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {The practicality of quality assessment metrics for millimeter-scale digital image correlation speckle patterns},

author = {É Gagnon and JJ Day},

doi = {https://doi.org/10.1111/str.12491},

year  = {2024},

date = {2024-12-16},

urldate = {2024-12-16},

journal = {Strain},

volume = {61},

issue = {1},

pages = {e12491},

keywords = {Brazilian tensile strength test, digital image correlation, Quality assessment, rock mechanics, speckle pattern},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Measurement of true tensile strength from Brazilian tensile strength laboratory tests},

author = {TRM Packulak and JJ Day and MR McDonald and AC Jacksteit and MS Diederichs},

doi = {https://doi.org/10.1139/cgj-2023-0204},

year  = {2024},

date = {2024-11-13},

journal = {Canadian Geotechnical Journal},

volume = {62},

pages = {1-14(2025)},

keywords = {Brazilian tensile strength test, Direct tensile strength, Laboratory testing procedures, Lithological variability, True tensile strength},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Effects of Foliation Type and Orientation on Tensile Strength of Low Porosity Rocks},

author = {TRM Packulak and É Gagnon and JJ Day and MS Diederichs},

doi = {https://doi.org/10.1007/s10706-024-02847-9},

year  = {2024},

date = {2024-06-10},

journal = {Geotechnical and Geological Engineering},

volume = {42},

pages = {5557–5585},

keywords = {Anisotropic tensile strength failure criterion, Brazilian tensile strength test, digital image correlation, Geological anisotropy, Laboratory testing, True tensile strength},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Elasto-plastic and post-yield weakening jointed rockmass response in a comparison of equivalent-continuum and explicit structural models},

author = {CP Fischer and MS Diederichs},

doi = {https://doi.org/10.1139/cgj-2022-0190},

year  = {2024},

date = {2024-02-01},

urldate = {2023-01-01},

journal = {Canadian Geotechnical Journal},

volume = {61},

issue = {4},

pages = {611-626},

keywords = {elasto-plastic, explicit structure models, joint networks, post-yield weakening, rockmass dilation},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Veined Rock Performance under Uniaxial and Triaxial Compression Using Calibrated Finite Element Numerical Models},

author = {GA Rudderham and JJ Day},

doi = {https://doi.org/10.3390/geotechnics3040067},

year  = {2023},

date = {2023-11-07},

journal = {Geotechnics},

volume = {3},

issue = {4},

pages = {1219-1250},

keywords = {Finite element method numerical models, Geomechanics numerical modelling, Hydrothermal veined rocks, Model validation, Numerical calibration, Triaxial compressive stress experiments, Vein geometry},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {The Impact of Axial Load Distribution on Brazilian Tensile Testing on Rock},

author = {TRM Packulak and JJ Day},

doi = {https://doi.org/10.1007/s00603-023-03583-x},

year  = {2023},

date = {2023-10-23},

journal = {Rock Mechanics and Rock Engineering},

volume = {57},

pages = {979–991 (2024)},

keywords = {Brazilian tensile strength test, Crack initiation, Laboratory testing procedures, Platen configuration, Strain measurement, True tensile strength, Uneven loading},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Paint Speckle Application Recommendations for Digital Image Correlation Analysis of Brazilian Tensile Strength Tests on Low-Porosity Rocks},

author = {SK Woodland and É Gagnon and TRM Packulak and A Dobosz and JJ Day},

doi = {https://doi.org/10.1007/s00603-023-03604-9},

year  = {2023},

date = {2023-10-20},

journal = {Rock Mechanics and Rock Engineering},

volume = {57},

pages = {1495–1507 (2024)},

keywords = {Brazilian tensile strength test, digital image correlation, speckle pattern, Strain measurement, True tensile strength},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Critical Review of Current States of Practice in Direct Shear Testing of Unfilled Rock Fractures Focused on Multi-Stage and Boundary Conditions},

author = {NR MacDonald and TRM Packulak and JJ Day},

doi = {https://doi.org/10.3390/geosciences13060172},

year  = {2023},

date = {2023-06-08},

journal = {Geosciences},

volume = {13},

issue = {6},

pages = {172},

keywords = {Boundary conditions, Dilation, Direct shear testing, Joint stiffness, Multi-stage direct shear testing, Rock fracture, Shear strength},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Transformation of geological sciences and geological engineering field methods course to remote delivery using manual, virtual, and blended tools in fall 2020},

author = {JJ Day},

doi = {https://doi.org/10.5194/gc-5-381-2022},

year  = {2022},

date = {2022-12-20},

journal = {Geoscience Communication},

volume = {5},

issue = {4},

pages = {381–395},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Packulak2022,

title = {Enhancement of Constant Normal Stiffness Direct Shear Testing Protocols for Determining Geomechanical Properties of Fractures},

author = {TR Packulak and JJ Day and MS Diederichs},

doi = {10.1139/cgj-2021-0576},

year  = {2022},

date = {2022-03-03},

urldate = {2022-03-03},

journal = {Canadian Geotechnical Journal},

volume = {59},

issue = {9},

pages = {1643-1659},

abstract = {Discontinuity behaviour can have a large impact on geotechnical engineering design; therefore, it is essential to determine their geomechanical properties in order to predict rockmass behaviour and mitigate any potential failure that may affect personnel safety or damage property. Geotechnical numerical software programs that discretely simulate discontinuities rely on direct shear laboratory tests to provide the properties needed as inputs to these tools. This study presents valuable direct shear laboratory test results for the mechanical properties and behaviours of fresh, unweathered, rough fractures in the Pointe du Bois granite. The testing program considers three separate boundary conditions: constant normal stress (CNL*) and two variations of constant normal stiffness (CNS). A new machine stiffness model is proposed to estimate the machine stiffness for tunnelling applications. Measurements of shear strength, and a proposed secant dilation angle are assessed and critically evaluated. It is found in this study that there is no significant difference between shear strength parameters determined from direct shear data from CNL* and CNS boundary conditions when comparing maximum strength and residual strength. In addition, it is found that the proposed secant dilation angle, critical shear displacement, and total dilation potential all have a negative relationship with increasing normal stress.},

keywords = {Constant normal stiffness, Constant normal stress, Dilation, Direct shear testing, Granite, Machine normal stiffness, Rough fractures, Shear strength},

pubstate = {published},

tppubtype = {article}

}

@article{Aubertin2021,

title = {Towards Blast Design Guidelines for Underground},

author = {JD Aubertin and DJ Hutchinson and MS Diederichs},

year  = {2021},

date = {2021-12-14},

journal = {Blasting and Fragmentation},

volume = {13},

number = {2},

pages = {77-101},

keywords = {Blast design, underground excavations},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Reliability of excavation damage zone prediction in brittle rocks through continuum modeling},

author = {N Dadashzadeh and MS Diederichs},

year  = {2021},

date = {2021-08-24},

urldate = {2021-08-24},

journal = {Journal of Rock Mechanics and Geotechnical Engineering},

number = {JRMGE_2019_618},

keywords = {Brittle rocks, continuum modelling, excavation damage zone (EDZ)},

pubstate = {published},

tppubtype = {article}

}

@article{FARAHMAND202160,

title = {Calibration of coupled hydro-mechanical properties of grain-based model for simulating fracture process and associated pore pressure evolution in excavation damage zone around deep tunnels},

author = {K Farahmand and MS Diederichs},

url = {https://www.sciencedirect.com/science/article/pii/S1674775520301219},

doi = {https://doi.org/10.1016/j.jrmge.2020.06.006},

issn = {1674-7755},

year  = {2021},

date = {2021-06-20},

journal = {Journal of Rock Mechanics and Geotechnical Engineering},

volume = {13},

number = {1},

pages = {60-83},

abstract = {The objective of this paper is to develop a methodology for calibration of a discrete element grain-based model (GBM) to replicate the hydro-mechanical properties of a brittle rock measured in the laboratory, and to apply the calibrated model to simulating the formation of excavation damage zone (EDZ) around underground excavations. Firstly, a new cohesive crack model is implemented into the universal distinct element code (UDEC) to control the fracturing behaviour of materials under various loading modes. Next, a methodology for calibration of the components of the UDEC-Voronoi model is discussed. The role of connectivity of induced microcracks on increasing the permeability of laboratory-scale samples is investigated. The calibrated samples are used to investigate the influence of pore fluid pressure on weakening the drained strength of the laboratory-scale rock. The validity of the Terzaghi's effective stress law for the drained peak strength of low-porosity rock is tested by performing a series of biaxial compression test simulations. Finally, the evolution of damage and pore pressure around two unsupported circular tunnels in crystalline granitic rock is studied.},

keywords = {Cohesive crack model, Coupled hydro-mechanical properties, excavation damage zone (EDZ), Grain-based model, Stress-dependent permeability, Stress-fracturing model},

pubstate = {published},

tppubtype = {article}

}

@article{ClarkDay2021,

title = {Mineralogical implications for geotechnical properties of intact heterogeneous and veined rocks from the Legacy skarn deposit},

author = {MD Clark and JJ Day},

doi = {10.1016/j.enggeo.2021.106067},

year  = {2021},

date = {2021-02-22},

journal = {Engineering Geology},

volume = {285},

pages = {21},

abstract = {Predicting the geomechanical behaviour of rockmasses is key to the economic success and safety of rock engineering projects including surface and underground excavations. For these projects, unconfined compressive stress (UCS) laboratory testing provides fundamental geomechanical properties of intact rocks. It is currently standard practice for UCS testing to consider only homogeneous specimens that are free of defects and discard heterogeneous specimens such as those that contain intrablock structures (e.g. veins) or extra-granular defects (e.g. phenocrysts). Understanding the complexities of these heterogeneous rocks and rockmasses is critical for excavation projects such as deep cave mines where extensive tunnel networks, caves, and stopes are regularly excavated through heterogeneous rockmasses. This paper presents the test results and analyses of UCS tests conducted on 29 matrix-type and 21 veined drill core specimens from the Legacy Skarn deposit located in northern New Brunswick, Canada. These specimens are sorted into five lithological units: beige, red, and black varieties of quartz-plagioclase granodiorite, calcareous mudstone, and garnet-pyroxene skarn. Mineralogical compositions of these units are determined using field identification techniques and microscopic laboratory methods including petrographic thin section analysis, powdered X-Ray Diffraction, and micro-X-Ray Fluorescence. Significant effects of hydrothermal veining and phenocrysts on the UCS test results are discussed in this study to highlight the significant influence of mineralogy on the variability of geomechanical properties. For example, vein mineralogy dominated by calcite weakened the granodiorites but strengthened the calcareous mudstone. Vein mineralogy dominated by quartz in the skarn unit had a mixed influence on geomechanical properties. Vein thickness primarily influenced geomechanical properties of specimens with single veins, whereas vein density was more useful to characterize specimens that contained vein networks or stockwork. The effects of vein orientation only partially agree with the established Jaeger model for shear failure through critically oriented foliations. The disseminated alteration in the granodiorites (plagioclase phenocrysts) and skarn (garnet crystals) typically increased stiffness and strength as the large grains arrest crack propagation when under load. Lastly, the effects of sample selection on reported UCS test results using four sample selection methods are presented. The results demonstrate the importance of including heterogeneous veined specimens in UCS sample selection and testing programs to capture rock variability and improve the accuracy of numerical geomechanical design. Recommendations are made to improve geotechnical core logging and sample selection protocols when characterizing heterogeneous complex rockmasses.},

keywords = {Drill core sample selection, extra-granular heterogeneous rocks, Geomechanical laboratory testing, hydrothermal veins, Intrablock structures, Unconfined compressive stress},

pubstate = {published},

tppubtype = {article}

}

@article{AUBERTIN2021103985,

title = {Horizontal single hole blast testing – Part 2: Field observations and experimental trends from SHB campaigns at two underground salt mines},

author = {JD Aubertin and DJ Hutchinson and MS Diederichs},

url = {https://www.sciencedirect.com/science/article/pii/S0886779821001760},

doi = {https://doi.org/10.1016/j.tust.2021.103985},

issn = {0886-7798},

year  = {2021},

date = {2021-01-04},

journal = {Tunnelling and Underground Space Technology},

volume = {114},

pages = {103-985},

abstract = {Large scale Single Hole Blast (SHB) testing is used to characterize blasting behavior in a cost-effective manner. SHB testing provides the means to assess the effect of blasting specifications (e.g. burden dimension, explosive used, borehole diameter) on rock cratering and blast efficiency. The observed behavior depends significantly on the testing procedure and measurements recorded. Crater characteristics are commonly described by the displaced volume of rock and breakout shape. Analysis of SHB test results relies on reproducible measurements. This paper proposes a method for analysis of horizontal SHB tests using data collected via terrestrial laser scanning (TLS) surveys. The procedural algorithms, point cloud manipulations, and analysis facilitate systematic SHB testing, including the use of a reference axis aligned with the blasthole orientation. The definition of crater extents, absolute burden measurements, methods for crater slicing, and filtering are developed to maintain consistency with the plane strain assumption. Crater partitioning protocols are elaborated to enhanced details of captured data. A detailed workflow of the analysis is provided with examples from compiled field testing. The conventional SHB measurement approach for crater breakout angle is refined to account for superficial surface roughness, and to capture the full crater shape. Data captured for the craters is represented along the blasthole length to capture the plane-strain component of single blasthole cratering. Comprehensive results from full scale field experiments are presented in a companion paper.},

keywords = {LiDAR, Point cloud processing, Rock blasting, Single hole blast test, terrestrial laser scanning, Underground Mining},

pubstate = {published},

tppubtype = {article}

}

@article{CLARK2021106067,

title = {Mineralogical and sample selection implications for geomechanical properties of intact heterogeneous and veined rocks from the Legacy skarn deposit},

author = {MD Clark and JJ Day},

url = {https://www.sciencedirect.com/science/article/pii/S0013795221000788},

doi = {https://doi.org/10.1016/j.enggeo.2021.106067},

issn = {0013-7952},

year  = {2021},

date = {2021-01-01},

journal = {Engineering Geology},

volume = {285},

pages = {106067},

abstract = {Predicting the geomechanical behaviour of rockmasses is key to the economic success and safety of rock engineering projects including surface and underground excavations. For these projects, unconfined compressive stress (UCS) laboratory testing provides fundamental geomechanical properties of intact rocks. It is currently standard practice for UCS testing to consider only homogeneous specimens that are free of defects and discard heterogeneous specimens such as those that contain intrablock structures (e.g. veins) or extra-granular defects (e.g. phenocrysts). Understanding the complexities of these heterogeneous rocks and rockmasses is critical for excavation projects such as deep cave mines where extensive tunnel networks, caves, and stopes are regularly excavated through heterogeneous rockmasses. This paper presents the test results and analyses of UCS tests conducted on 29 matrix-type and 21 veined drill core specimens from the Legacy Skarn deposit located in northern New Brunswick, Canada. These specimens are sorted into five lithological units: beige, red, and black varieties of quartz-plagioclase granodiorite, calcareous mudstone, and garnet-pyroxene skarn. Mineralogical compositions of these units are determined using field identification techniques and microscopic laboratory methods including petrographic thin section analysis, powdered X-Ray Diffraction, and micro-X-Ray Fluorescence. Significant effects of hydrothermal veining and phenocrysts on the UCS test results are discussed in this study to highlight the significant influence of mineralogy on the variability of geomechanical properties. For example, vein mineralogy dominated by calcite weakened the granodiorites but strengthened the calcareous mudstone. Vein mineralogy dominated by quartz in the skarn unit had a mixed influence on geomechanical properties. Vein thickness primarily influenced geomechanical properties of specimens with single veins, whereas vein density was more useful to characterize specimens that contained vein networks or stockwork. The effects of vein orientation only partially agree with the established Jaeger model for shear failure through critically oriented foliations. The disseminated alteration in the granodiorites (plagioclase phenocrysts) and skarn (garnet crystals) typically increased stiffness and strength as the large grains arrest crack propagation when under load. Lastly, the effects of sample selection on reported UCS test results using four sample selection methods are presented. The results demonstrate the importance of including heterogeneous veined specimens in UCS sample selection and testing programs to capture rock variability and improve the accuracy of numerical geomechanical design. Recommendations are made to improve geotechnical core logging and sample selection protocols when characterizing heterogeneous complex rockmasses.},

keywords = {Drill core sample selection, extra-granular heterogeneous rocks, Geomechanical laboratory testing, hydrothermal veins, Intrablock structures, Unconfined compressive stress},

pubstate = {published},

tppubtype = {article}

}

@article{Hegger2021,

title = {Measuring the full-field strain response of uniaxial compression test specimens using distributed fiber optic sensing},

author = {S Hegger and N Vlachopoulos and T Poles and MS Diederichs},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Rock Mechanics and Rock Engineering},

keywords = {Distributed fiber optic sensing, Strain response, Uniaxial compressive strength of intact rock},

pubstate = {published},

tppubtype = {article}

}

@article{Packulak2021,

title = {New Data Processing Protocols to Isolate Fracture Deformations to Measure Normal and Shear Joint Stiffness},

author = {TR Packulak and JJ Day and MTA Labeid and MS Diederichs},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Rock Mechanics and Rock Engineering},

keywords = {Fracture deformations, Laboratory testing, Normal stiffness, Shear stiffness, Testing protocols},

pubstate = {published},

tppubtype = {article}

}

@article{Diederichs2021,

title = {An illustrative study on the sensitivity of EDZ development to layered and nodular sedimentary structure},

author = {MS Diederichs and JJ Day},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Rock Mechanics and Rock Engineering},

keywords = {excavation damage zone (EDZ), Nodular structure, Three-dimensional sensitivity analysis},

pubstate = {published},

tppubtype = {article}

}

@article{nokeyb,

title = {On the interaction between emitted and reflected pulses as a blast cratering mechanism in rock salt},

author = {JD Aubertin and DJ Hutchinson and MS Diederichs},

year  = {2020},

date = {2020-09-01},

urldate = {2020-09-01},

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

keywords = {blast cratering mechanism, emitted pulses, reflected pulses, Rock salt},

pubstate = {forthcoming},

tppubtype = {article}

}

@article{Innocente2020,

title = {Review of Long-Term Strength and Time-to-Failure of Brittle Rocks: Lab Testing and Interpretation},

author = {J Innocente and MS Diederichs and C Paraskevopoulou},

year  = {2020},

date = {2020-08-01},

journal = {Rock Mechanics and Geotechnical Engineering},

keywords = {Brittle rocks, Laboratory testing, Long-term behaviour},

pubstate = {forthcoming},

tppubtype = {article}

}

@article{OConnor2020,

title = {The geo-mechanical response of axial loaded fully grouted rock bolts using a distributed fiber optic sensor technique},

author = {T O'Connor and N Vlachopoulos and MS Diederichs and B Forbes},

year  = {2020},

date = {2020-08-01},

urldate = {2020-08-01},

journal = {Tunnelling and Underground Space Technology},

keywords = {Distributed fiber optic sensing, Fully grouted rock bolt, Geo-mechanical response},

pubstate = {forthcoming},

tppubtype = {article}

}

@article{DiFrancesco2020,

title = {The implications of M3C2 projection diameter on 3-D semi-automated rockfall extraction from sequential terrestrial laser scanning point clouds},

author = {PM DiFrancesco and D Bonneau and DJ Hutchinson},

doi = {10.3390/rs12111885},

year  = {2020},

date = {2020-06-10},

journal = {Remote Sensing},

volume = {12},

number = {11},

pages = {28},

abstract = {Rockfall inventories are essential to quantify a rockfall activity and characterize the hazard. Terrestrial laser scanning and advancements in processing algorithms have resulted in three-dimensional (3D) semi-automatic extraction of rockfall events, permitting detailed observations of evolving rock masses. Currently, multiscale model-to-model cloud comparison (M3C2) is the most widely used distance computation method used in the geosciences to evaluate 3D changing features, considering the time-sequential spatial information contained in point clouds. M3C2 operates by computing distances using points that are captured within a projected search cylinder, which is locally oriented. In this work, we evaluated the effect of M3C2 projection diameter on the extraction of 3D rockfalls and the resulting implications on rockfall volume and shape. Six rockfall inventories were developed for a highly active rock slope, each utilizing a different projection diameter which ranged from two to ten times the point spacing. The results indicate that the greatest amount of change is extracted using an M3C2 projection diameter equal to, or slightly larger than, the point spacing, depending on the variation in point spacing. When the M3C2 projection diameter becomes larger than the changing area on the rock slope, the change cannot be identified and extracted. Inventory summaries and illustrations depict the influence of spatial averaging on the semi-automated rockfall extraction, and suggestions are made for selecting the optimal projection diameter. Recommendations are made to improve the methods used to semi-automatically extract rockfall from sequential point clouds.},

keywords = {change detection, frequency-magnitude, M3C2, rockfall, spatial averaging, terrestrial laser scanning},

pubstate = {published},

tppubtype = {article}

}

@article{Forbes2020,

title = {An in situ monitoring campaign of a hard rock pillar at great depth within a Canadian mine},

author = {B Forbes and N Vlachopoulos and MS Diederichs and AJ Hyett and A Punkkinen},

doi = {10.1016/j.jrmge.2019.07.018},

year  = {2020},

date = {2020-06-01},

journal = {Journal of Rock Mechanics and Geotechnical Engineering},

volume = {12},

number = {3},

pages = {427-448},

abstract = {A recent research campaign at a Canadian nickel-copper mine involved instrumenting a hard rock sill drift pillar with an array of multi-point rod extensometers, distributed optical fibre strain sensors, and borehole pressure cells (BHPCs). The instrumentation spanned across a 15.24 m lengthwise segment of the relatively massive granitic pillar situated at a depth of 2.44 km within the mine. Between May 2016 and March 2017, the pillar's displacement and pressure response were measured and correlated with mining activities on the same level as the pillar, including: (1) mine-by of the pillar, (2) footwall drift development, and (3) ore body stoping operations. Regarding displacements of the pillar, the extensometers provided high temporal resolution (logged hourly) and the optical fibre strain sensors provide high spatial resolution (measured every 0.65 mm along the length of each sensor). The combination of sensing techniques allowed centimetre-scale rock mass bulking near the pillar sidewalls to be distinguished from microstrain-scale fracturing towards the core of the pillar. Additionally, the influence and extent of a mine-scale schistose shear zone transecting the pillar was identified. By converting measured rock mass displacement to velocity, a process was demonstrated which allowed mining activities inducing displacements to be categorised by time-duration and cumulative displacement. In over half of the analysed mining activities, displacements were determined to prolong for over an hour, predominately resulting in submillimetre cumulative displacements, but in some cases multi-centimetre cumulative displacements were observed. This time-dependent behaviour was more pronounced within the vicinity of the plumb shear zone. Displacement measurements were also used to assess selected support member load and elongation mobilisation per mining activity. It was found that a combined static load and elongation capacity of reinforcing members was essential to maintaining excavation stability, while permitting gradual shedding of stress through controlled pillar sidewall displacements.},

keywords = {Distributed optical fibre strain sensing, Dynamic support, Extensometer, Hard rock pillar, High stress, In situ monitoring, Rock mass bulking, Rockburst},

pubstate = {published},

tppubtype = {article}

}

@article{Forbes2020b,

title = {Augmenting the in-situ rock bolt pull test with distributed optical fiber strain sensing},

author = {B Forbes and N Vlachopoulos and MS Diederichs and JD Aubertin},

url = {https://www.sciencedirect.com/science/article/pii/S1365160919309918},

doi = {https://doi.org/10.1016/j.ijrmms.2019.104202},

issn = {1365-1609},

year  = {2020},

date = {2020-02-01},

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

volume = {126},

pages = {104-202},

abstract = {A high spatial resolution distributed optical fiber strain sensing technology is demonstrated to advance the assessment of support element behaviour during in-situ pull tests. A technique to instrument typical tendon support elements with a fiber optic sensor is discussed and was trialed at an underground salt mine through a series of pull tests on instrumented rebar elements. It is shown that a continuous strain profile can be measured along the length of a support element under pull test load, which, in turn, allows the interfacial shear stress distribution and deformation of the support element to be resolved. In comparison to load and displacement measurements solely at the support element head, which is what is traditionally reported for in-situ pull tests, the optical fiber strain sensor is found to provide significantly more insight into the mechanistic behaviour of the support element by readily measuring highly variable strain distributions and by quantifying the load development length of the support element. The sensor arrangement allowed the conventional handling and installation procedures to be followed without any implication to the integrity of the sensor. Accordingly, an instrumented reinforcement element can be installed with minimal interruption to on-going mining/construction procedures at the given project.},

keywords = {Distributed optical fiber strain sensing, Fully grouted rock bolt, Pull-out testing, Quality assessment, Strain measurement, Support Performance},

pubstate = {published},

tppubtype = {article}

}

@article{nokeyc,

title = {Assessing 3-Dimensional Joint Roughness with Structure-from-Motion Photogrammetry},

author = {D Bonneau and TR Packulak and DJ Hutchinson and MS Diederichs},

year  = {2020},

date = {2020-01-01},

urldate = {2020-01-01},

journal = {International Journal of Geo-information},

keywords = {joint roughness, Photogrammetry, structure-from-motion},

pubstate = {published},

tppubtype = {article}

}

@article{Aubertin2020,

title = {Horizontal Single Blasthole Testing – Part 1: Systematic measurements using TLS surveys},

author = {JD Aubertin and DJ Hutchinson and MS Diederichs},

doi = {10.1016/j.tust.2021.103985},

year  = {2020},

date = {2020-01-01},

journal = {Tunnelling and Underground Space Technology},

volume = {114},

number = {103985},

keywords = {terrestrial laser scanning},

pubstate = {published},

tppubtype = {article}

}

@article{Bonneau2019,

title = {3-Dimensional Rockfall Shape Back-Analysis: Methods and Implications},

author = {D Bonneau and DJ Hutchinson and PM DiFrancesco and M Coombs and Z Sala},

doi = {10.5194/nhess-19-2745-2019},

year  = {2019},

date = {2019-12-04},

journal = {Natural Hazards and Earth System Sciences},

volume = {19},

pages = {2745–2765},

abstract = {Rockfall is a complex natural process that can present risks to the effective operation of infrastructure in mountainous terrain. Remote sensing tools and techniques are rapidly becoming the state of the practice in the characterization, monitoring and management of these geohazards. The aim of this study is to address the methods and implications of how the dimensions of three-dimensional rockfall objects, derived from sequential terrestrial laser scans (TLSs), are measured. Previous approaches are reviewed, and two new methods are introduced in an attempt to standardize the process. The approaches are applied to a set of synthetic rockfall objects generated in the open-source software package Blender. Fifty rockfall events derived from sequential TLS monitoring in the White Canyon, British Columbia, Canada, are used to demonstrate the application of the proposed algorithms. This study illustrates that the method used to calculate the rockfall dimensions has a significant impact on how the shape of a rockfall object is classified. This has implications for rockfall modelling as the block shape is known to influence rockfall runout.},

keywords = {rockfall, terrestrial laser scanning},

pubstate = {published},

tppubtype = {article}

}

@article{deOliveira2019,

title = {Clogging and flow assessment of cohesive soils for EPB tunnelling: Proposed laboratory tests for soil characterisation},

author = {DGG Oliveira and M Thewes and MS Diederichs},

url = {https://www.sciencedirect.com/science/article/pii/S0886779818307879},

doi = {https://doi.org/10.1016/j.tust.2019.103110},

issn = {0886-7798},

year  = {2019},

date = {2019-12-01},

journal = {Tunnelling and Underground Space Technology},

volume = {94},

pages = {103-110},

abstract = {For earth pressure balance (EPB) machines, it is fundamental to characterise the excavated ground in its natural and conditioned states. The characteristics of the excavated material have a direct influence on machine operation, impacting the functions as a support medium maintaining the support pressure ahead of the tunnel face, besides its transportation and disposal. The current available methods to assess the clogging potential focus mainly on sedimentary pure clayey soils, not including mixed soils. Mixed soils exist widely in nature, including a wide variety of residual soils, which are by-products of intense tropical weathering. This paper presents a combined laboratory routine to characterise and evaluate the clogging and fluidity of soils, including mixed soils by considering different clay fractions. This routine still requires tests conducted directly on-site, where the results should be compared with machine operation parameters, such as torque of cutterhead and screw conveyor, temperature, pressure, as well as occurrence of clogging. This testing procedure provides on-site assessment that can also be conducted prior the excavation using borehole material. The intention of this routine is to provide a geological-geotechnical qualitative characterisation of the material to be excavated, and of the effectiveness of the additives that could be added, as a general guidance for EPB soil conditioning, especially of cohesive soils. The advantage of this routine is its simplicity and low cost to be reproducible in different laboratories and jobsites, making feasible the comparison between different soils by different operators, before and during excavation.},

keywords = {Clogging, EPB Machine, Flow behaviour, Fluidity, Mixed soils, Soil conditioning},

pubstate = {published},

tppubtype = {article}

}

@article{Bonneau2019b,

title = {Surface reconstruction for three-dimensional rockfall volumetric analysis},

author = {D Bonneau and PM DiFrancesco and DJ Hutchinson},

doi = {10.3390/ijgi8120548},

year  = {2019},

date = {2019-11-30},

journal = {International Journal of Geo-Information},

volume = {8},

number = {12},

pages = {548},

abstract = {Laser scanning is routinely being used for the characterization and management of rockfall hazards. A key component of many studies is the ability to use the high-resolution topographic datasets for detailed volume estimates. 2.5-Dimensional (2.5D) approaches exist to estimate the volume of rockfall events; however these approaches require rasterization of the point cloud. These 2.5D volume estimates are therefore sensitive to picking an appropriate cell size to preserve resolution while minimizing interpolation, especially for lower volume rockfall events. To overcome the limitations of working with 2.5D raster datasets, surface reconstruction methods originating from the field of computational geometry can be implemented to assess the volume of rockfalls in 3D. In this technical note, the authors address the methods and implications of how the surface of 3D rockfall objects, derived from sequential terrestrial laser scans (TLS), are reconstructed for volumetric analysis. The Power Crust, Convex Hull and Alpha-shape algorithms are implemented to reconstruct a synthetic rockfall object generated in Houdini, a procedural modeling and animation software package. The reconstruction algorithms are also implemented for a selection of three rockfall cases studies which occurred in the White Canyon, British Columbia, Canada. The authors find that there is a trade-off between accurate surface topology reconstruction and ensuring the mesh is watertight manifold; which is required for accurate volumetric estimates. Power Crust is shown to be the most robust algorithm, however, the iterative Alpha-shape approach introduced in the study is also shown to find a balance between hole-filling and loss of detail.},

keywords = {Alpha-shape, Convex Hull, LiDAR, point cloud, Power Crust, rockfall, surface reconstruction, volume estimate},

pubstate = {published},

tppubtype = {article}

}