Research Interests:
Research Interests:
Research Interests:
Two fundamental fracturing mechanisms act as the primary drivers for burden removal in rock blasting: the propagation of radial cracks from the borehole due to the internal detonation pressure and the tensile failure relatively close to a... more
Two fundamental fracturing mechanisms act as the primary drivers for burden removal in rock blasting: the propagation of radial cracks from the borehole due to the internal detonation pressure and the tensile failure relatively close to a free surface associated with spalling. A third mechanism may also influence cratering when the emitted compressive pulse is compounded by the reflected tensile waves to generate localized zones of high deviatoric stresses. This paper describes the conditions under which this additional mechanism can play an important role in burden removal by blasting, based on recent work performed on low porosity soft rock (i.e. rock salt) with relatively small wave impedance and weak mechanical strength. The process is described conceptually and expressed analytically and then illustrated using numerical modelling results that simulate the development fracture stages. The effect of key parameters, including pulse width, tangential stress magnitude, and damping, are also assessed with simulations performed with the FEM model LS DYNA. The numerical results obtained for rock salt are compared with those of hard rock to evaluate the impact of this third mechanism in low porosity soft rock. The analysis outcomes are also compared with actual observations from a single blast hole test in the field.
Research Interests:
Abstract This results presented in this paper follow the basic principles and methodology developed for horizontal Single Hole Blast (SHB) testing using terrestrial laser scanning (TLS), introduced in Part 1, and shows specific SHB test... more
Abstract This results presented in this paper follow the basic principles and methodology developed for horizontal Single Hole Blast (SHB) testing using terrestrial laser scanning (TLS), introduced in Part 1, and shows specific SHB test applications as a mean to investigate rock blasting behavior. Part 1 introduced a detailed procedure for consistent and systematic SHB testing to provide the means for reproducible and comparable data collection and characterization. The concept of crater breakout angle was expanded to account for the observed non linear shape, based on measurements made at small increments along the blasthole to capture variability of the overall geometry. This paper describes SHB testing campaigns conducted at two underground salt mines. Traditional reporting parameters (e.g. breakout angle, crater area) are presented in an enhanced approach by capturing their variation along the blasthole, and with respect to measured burden dimensions. A new crater model is proposed to better capture and represent the observed crater shape, and avoid the simplification of best-fitting triangular crater shapes. Results from the field campaigns are presented in details using LiDAR point clouds and SHB characteristic plots of the crater geometry. The crater model is calibrated from the test results to obtain site-specific burden-dependent trends of the crater shape. Two methods are then proposed for implementing SHB test results into blast pattern designs using the proposed crater model.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Based on recent advances in modelling the post‐yield behaviour of brittle rock, the authors have developed a calibrated inelastic model of the 7,910 level (2.4 km depth) at the Creighton Mine in Sudbury, Ontario, Canada using data... more
Based on recent advances in modelling the post‐yield behaviour of brittle rock, the authors have developed a calibrated inelastic model of the 7,910 level (2.4 km depth) at the Creighton Mine in Sudbury, Ontario, Canada using data collected from the monitoring of pillar dilatancy. While this calibrated model represents a state‐of‐the‐art continuum approach for capturing the progressive development of yield and stresses in mine pillars, alternative state‐of‐practice approaches (elastic and perfectly plastic material models, for example) represent potentially acceptable options for practical application.
Research Interests:
The crack damage progression in crystalline rocks is approximated in laboratory by means of rigorous strain measurement and/or monitoring of Acoustic Emission (AE) activity. When both means are used, they are treated independently for... more
The crack damage progression in crystalline rocks is approximated in laboratory by means of rigorous strain measurement and/or monitoring of Acoustic Emission (AE) activity. When both means are used, they are treated independently for quantification of damage in the rock. This paper is investigating a new method to combine the AE and strain data in a unified function to calculate the balance of stored and released energy in the rock due to loading (strain energy) and micro-cracking respectively. This method introduces a new solution for measurement and quantification of crack damage in rock and also provides a tool to investigate the brittleness of different rock types. Unconfined Compressive Strength (UCS) testing of six different rock types with strain measurement and AE monitoring was performed for this study. The application of the new method to the data collected from the UCS tests indicates the difference between the behaviour of the various rock types in terms of sudden energ...
Research Interests:
This paper provides a review of engineering geological contributions to the design and construction of deep Alpine tunnels during the last 150 years. The progress and current status in engineering geological approaches and theoretical... more
This paper provides a review of engineering geological contributions to the design and construction of deep Alpine tunnels during the last 150 years. The progress and current status in engineering geological approaches and theoretical understanding of observed phenomena and geological hazards is discussed and documented with a large number of examples from traffic tunnels constructed in the European Alps. Major engineering geological, rock mechanical, and hydraulic lessons learnt from the recently completed Lötschberg and Gotthard Base Tunnels are highlighted. Hazards discussed in detail include strongly squeezing ground, spalling and rock bursting, and water inflows. The role of brittle fracturing and faulting in controlling these hazards is critically reviewed. State-of-the-art methods on how to cope with these hazards in design and construction are summarized. The paper is closing with an outlook into unresolved key issues that should be addressed in future interdisciplinary rese...
Research Interests:
LiDAR technology has been proven to be a real asset in many geological and geotechnical applications but it can also be a powerful tool for modelling. Discontinuity data, such as joint orientation, density and length, can be extracted... more
LiDAR technology has been proven to be a real asset in many geological and geotechnical applications but it can also be a powerful tool for modelling. Discontinuity data, such as joint orientation, density and length, can be extracted from LiDAR scanning data using manual and automated techniques. Such data can be further processed and used in DFN modeling and generation. However, the sampling method applied in the LiDAR data and the reconstruction method of the DFN, including deterministic and statistical approaches, may result to realistic or unrealistic DFN models. Different methodologies and techniques are discussed and compared based on two specific case studies, including data sets obtained from the Shawinigan, Quebec, Canada and Brockville, Ontario, Canada railway tunnels.
The generation of geologically realistic and locally accurate Discrete Fracture Networks (DFNs) for mechanical analysis is gaining ground over conventional equivalent material techniques based on heuristic structural classification... more
The generation of geologically realistic and locally accurate Discrete Fracture Networks (DFNs) for mechanical analysis is gaining ground over conventional equivalent material techniques based on heuristic structural classification systems. The success of DFN creation and application is based on two significant factors: input parameter selection and model reconstruction methodology. Input parameter selection (mean orientation, persistence and spacing specified along with variability descriptors) for each discontinuity set involved in an analysis has to be reasonable and correspond to the in-situ, field conditions. Therefore, data management and the necessary geological interpretation are required when used in the DFN generation process. Additionally, the options for model reconstruction, after the initial discontinuity data has been synthesized, include a deterministic approach matching observed conditions at a local site, or a more statistical approach, blending discrete observatio...
During the construction process, of an underground excavation, the rock-mass is damaged and beyond the damaged area the stresses are modified. These zones are collectively this is known as the excavation damages zones (EDZs). The lab... more
During the construction process, of an underground excavation, the rock-mass is damaged and beyond the damaged area the stresses are modified. These zones are collectively this is known as the excavation damages zones (EDZs). The lab re-sults, including UCS and T as well as crack thresholds CI and CD can be used to de-termine numerical model input properties. With a large data set it is possible to test the best, mean, and worst case scenarios and to evaluate the results statistically. Using two rock data sets, a limestone and a granite, and two nominal stress re-gimes the influence of the best, mean and worst cases (with hi and lo outliers filtered) were computed to determine the sensitivity of EDZ dimensions. It was demonstrated that both an inner and outer excavation damage zone (EDZ i and EDZ o) could be diffe-rentiated using the model results by the reversal point in the volumetric strain (con-traction to extension). This indicates the transition between a confined micro-damage...
Research Interests: Geology and Excavation
The Beauregard Landslide is a deep-seated gravitational slope deformation located in the Aosta Valley (Dora di Valgrisenche river) in northwestern Italy. Numerical simulations of the Beauregard Landslide use three-dimensional mixed... more
The Beauregard Landslide is a deep-seated gravitational slope deformation located in the Aosta Valley (Dora di Valgrisenche river) in northwestern Italy. Numerical simulations of the Beauregard Landslide use three-dimensional mixed continuum-discontinuum methods to explore the role and importance of sophisticated geometric interpretations in analyzing landslide mechanics and to test model sensitivity to shear zone strength parameters. 3DEC (3-Dimensional Distinct Element Code) has been used to generate complex three-dimensional landslide geometries. The landslide and surrounding, undisturbed, rockmass are defined as distinct continuum blocks which interact along discrete discontinuities representing landslide shear surfaces. The full three-dimensional geometries of these shear surfaces are interpreted from geological and morphological data using a rigorous statistical interpolation approach. This study aims to improve landslide hazard management by recreating observed slope deformat...
Research Interests:
Research Interests:
The Canadian National Memorial Site, Vimy Ridge, France, commemorates the efforts and loss of life of Canadian troops in the First World War (WWI). The site comprises the monument, a Visitors Centre, the Grange Tunnels and restored... more
The Canadian National Memorial Site, Vimy Ridge, France, commemorates the efforts and loss of life of Canadian troops in the First World War (WWI). The site comprises the monument, a Visitors Centre, the Grange Tunnels and restored trenches and several ...
Research Interests: Mining Engineering, Civil Engineering, Archaeology, Geology, Rock Mechanics, and 15 moreSoil Mechanics, Slope Stability, First World War, Subsidence, Risk assessment, Finite Element, Stability, Risk Analysis, Numerical Simulation, Historical, Excavation, Landslide, Excavations, Risk Assessment, and TUNEL
... Pete Quinn, D. Jean Hutchinson, Mark S. Diederichs, R. Kerry Rowe, Robin Harrap and Jackie Alvarez GeoEngineering Centre at ... Hodgson (1927) presented the earliest inventory of historic landslides in Quebec, documenting nine events... more
... Pete Quinn, D. Jean Hutchinson, Mark S. Diederichs, R. Kerry Rowe, Robin Harrap and Jackie Alvarez GeoEngineering Centre at ... Hodgson (1927) presented the earliest inventory of historic landslides in Quebec, documenting nine events that occurred between 1840 and 1925. ...
Research Interests:
A critical component of a nuclear waste repository is the cut-off seal, which will mitigate flow and gas migration along the excavation surface and damage zone. This paper examines a thin to wide slot cut-off geometry under fixed stress... more
A critical component of a nuclear waste repository is the cut-off seal, which will mitigate flow and gas migration along the excavation surface and damage zone. This paper examines a thin to wide slot cut-off geometry under fixed stress (an upper bound) and sedimentary rock properties. Volumetric extensile strain was used as an indicator of the extent of excavation damage prior to and after the construction of the cut-off. Using the volumetric extensile strain to plastic yield zone area ratio the cut-off performance for thickness to depth ratios between 0.05 and 0.7 were examined. It was found that for a cut-off with a thickness to depth ratio of less than 0.13 a complete disconnect could be established across the cut-off slot, indicating that a slender slot is optimum under the conditions modelled. Further modelling with different stresses and properties will establish if these results are applicable for a wider range of possible repository settings.
Research Interests:
During deep tunnelling or mining infrastructure development, the assumed stress state has significant implications on geomechanical design. Remote measurement of the three-dimensional stress state at depth has proven to be a significant... more
During deep tunnelling or mining infrastructure development, the assumed stress state has significant implications on geomechanical design. Remote measurement of the three-dimensional stress state at depth has proven to be a significant challenge and is often assumed from historic tests or the regional tectonic setting. To date, borehole breakout analysis has only provided some assistance for orientation of the principal stresses in the plane perpendicular to the borehole axis. This paper presents a stress estimation methodology using numerical modelling, which allows for the back analysis of breakout profiles from a shaft pilot hole at KGHM’s Victoria project in Sudbury, Canada. By iteratively changing the horizontal principal stress ratio and maximum tangential wall stress, a set of generalised curves relating breakout characteristics (breakout depth and opening angle) and borehole strength along the 2 km borehole were made. By recording the change in breakout geometry along the l...
Research Interests:
Despite operational constraints, rock tunnel construction projects require a solid understanding of rockmass conditions in order to effectively design excavation and support methods. Where tunnel instability is governed by structural... more
Despite operational constraints, rock tunnel construction projects require a solid understanding of rockmass conditions in order to effectively design excavation and support methods. Where tunnel instability is governed by structural discontinuities, LiDAR or 3D laser scanning technology shows great potential to complement current assessment techniques. LiDAR scans of the rock face offer digital documentation of rockmass conditions from which an interpreter can extract a large quantity of structural data. The authors propose a workflow for applying LiDAR scan data to 3D discontinuum modelling for practical design outputs. RÉSUMÉ La construction de tunnel en roche demande des précises informations géotechniques pour prévoire les conditions futures. À présent, la méthode de rassembler des informations geo-structurelles est beaucoup limitée par accès aux sections de roche non-soutenuees. LiDAR, une technologie seulement récemment appliquée à la géotechnique, montre beaucoup de potentie...
Lidar is a range based imaging technique with diverse applications, including but not limited to detailed hazard mapping, urban development, and mining. Due to recent advancements in the rate of data collection there is now great... more
Lidar is a range based imaging technique with diverse applications, including but not limited to detailed hazard mapping, urban development, and mining. Due to recent advancements in the rate of data collection there is now great potential for the use of lidar in an operational tunnel environment. The practical employment of a static lidar scanner for geotechnical assessment in a drill and blast tunnel operation has been demonstrated in the Sandvika tunnel near Oslo, Norway. A tripod setup at the rock face allows for remote, rapid geotechnical evaluation without costly delays and disruption of the construction workflow. Active tunnel construction sites are nontraditional environments for lidar scanning and required unique and adaptable solutions, these are discussed. With correct data interpretation techniques, lidar technology provides a precise 3dimensional tool for geomechanical assessment of exposed rock in the face and walls. Discontinuity orientation and spacing can be assesse...
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... more
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.
Research Interests:
Research Interests:
Research Interests:
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... more
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 (FD...
Research Interests:
Research Interests:
Research Interests:
In order to assess the safety performance of a DGR, it is necessary to establish the extent of the different degrees of damage to the rockmass created by the excavation process. This must include shaft, adit, room and cut-off excavation... more
In order to assess the safety performance of a DGR, it is necessary to establish the extent of the different degrees of damage to the rockmass created by the excavation process. This must include shaft, adit, room and cut-off excavation processes, throughout the life of the DGR, such that migration of radionuclides through the damaged rockmass can be adequately predicted. Perfectly plastic, strain weakening and brittle models were used to demonstrate the importance of selecting the appropriate yield criteria when using volumetric strain as an EDZ indicator.
Research Interests:
Research is underway to develop a rigorous and geomechanically sound approach to analyzing risk potential associated with slow-moving, massive landslides. Multi-dimensional instability analyses of complex landslides integrate data from... more
Research is underway to develop a rigorous and geomechanically sound approach to analyzing risk potential associated with slow-moving, massive landslides. Multi-dimensional instability analyses of complex landslides integrate data from instrumented sensor networks with three-dimensional numerical modeling. Field monitoring data and numerical model output provide impressive volumes of information describing slope behaviour. Major challenges lie in managing the large quantities of data returned from simulated case histories, in visualizing both field and simulated data and in comparing simulated data with field data. The use of geographic information systems (GIS) tools is vital to overcoming this challenge.
Research Interests:
Research Interests:
Three-dimensional laser scanning (Lidar) techniques have been applied to a range of industries while their application to the geological environment still requires development. Lidar is a range-based imaging technique which collects a... more
Three-dimensional laser scanning (Lidar) techniques have been applied to a range of industries while their application to the geological environment still requires development. Lidar is a range-based imaging technique which collects a very accurate, high resolution 3-dimensional image of its surroundings. While the use of Lidar in underground environments has been primarily limited to as-built design verification in the past, there is great value in the scan data collected as the excavation advances. The advantages of employing a static Lidar system for geotechnical and operational applications have been demonstrated at a drill and blast tunnel operation at the Sandvika–Asker Railway Project near Oslo, Norway as well as in two other test tunnels in Oslo. The increased scanning rate of newer systems makes it possible to remotely obtain detailed rockmass and excavation information without costly delays or disruption of the construction workflow with a simple tripod setup. Tunnels are non-traditional environments for laser scanners and add limitations to the scanning process as well as the in-office interpretation process; these are discussed. Operational applications of the data include: calculation of shotcrete thickness, as-built bolt spacing, and regions of potential leakage. The authors find that Lidar data, when correctly interpreted, can also provide detailed 3-dimensional characterization of the rockmass. Geometrical characterization of discontinuity surfaces including location, orientation, frequency and large-scale roughness can be obtained. Discontinuity information may be synthesized for a much more representative geomechanical understanding of the rockmass than was previously impossible with traditional hand mapping limited by face accessibility. The alignment of Lidar scans from successive exposed faces offers additional interpretation and recording advantages, particularly where shotcrete is subsequently applied behind the face. In aligning scans, larger scale features can be readily identified and rockmass trends over several rounds may be identified. Discontinuity geometries and characteristics may be input into kinematic and numerical models for further analysis.
Research Interests: Engineering, Civil Engineering, Remote Sensing, LiDAR, Construction Safety, and 15 moreDesign verification, Classification, Laser Scanning, Geotechnics, Data Collection, Excavation, Application, Dimensional, High Resolution, Laser scanner, Numerical Model, Large Scale, Site Analysis, Rock Mass, and Drill
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Large landslides are common in the gently sloping clay plains of the Saint Lawrence Lowlands of eastern Canada. These tend to occur along rivers carved into the marine soils deposited in the former Champlain Sea, which occupied the area... more
Large landslides are common in the gently sloping clay plains of the Saint Lawrence Lowlands of eastern Canada. These tend to occur along rivers carved into the marine soils deposited in the former Champlain Sea, which occupied the area roughly 10 000 years ago. This paper presents a landslide susceptibility model, developed at the regional scale using a bivariate statistical method: the weights of evidence method. The analysis considers the association of existing large landslides in a portion of the study area with key terrain features, such as ground elevation, flow accumulation in adjacent streams, soil type, soil thickness, and land use. The resulting model identifies three different levels of susceptibility: low, low to moderate, and moderate to high. These descriptors are related statistically to the probability of encountering existing large landslides within 500 m, 1 or 2 km, respectively. The model is tested along primary railway corridors and isolates 8% of the total leng...