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  • 1.
    Al-Ajmi, Adel M.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics. Department of Petroleum and Chemical Engineering, Oman .
    Zimmerman, Robert W.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    A new 3D stability model for the design of non-vertical wellbores2006Conference paper (Refereed)
    Abstract [en]

    The Mohr-Coulomb failure criterion is known to be too conservative in estimating the critical mud pressure required to maintain wellbore stability, due to ignoring the strengthening effect of the intermediate principal stress. To eliminate this deficiency, we have developed a new analytical model to estimate the mud pressure required to avoid shear failure at the wall of non-vertical boreholes (i.e., the collapse pressure). This has been achieved by using a linear elastic and isotropic constitutive model for the stresses, and the Mogi-Coulomb criterion to predict failure. For comparison, the stability analysis has been also carried out using Mohr-Coulomb, the modified Lade criterion, and the Drucker-Prager criterion. We have found that implementing the Mogi-Coulomb law instead of Mohr-Coulomb does indeed lessen the conservative nature of the wellbore stability analysis. In general, the Mogi-Coulomb criterion gives an estimate of the collapse pressure that is similar to that given by the modified Lade criterion in polyaxial stress states, and similar to Mohr-Coulomb in triaxial stress states. By comparison, the Drucker-Prager criterion always underestimates the required mud weight. The developed 3D stability model has been applied in a field case study.

  • 2.
    Al-Ajmi, Adel M.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Zimmerman, Robert W.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Stability analysis of vertical boreholes using the Mogi-Coulomb failure criterion2006In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 43, no 8, 1200-1211 p.Article in journal (Refereed)
    Abstract [en]

    A main aspect of wellbore stability analysis is the selection of an appropriate rock failure criterion. The most commonly used criterion for brittle failure of rocks is the Mohr-Coulomb criterion. This criterion involves only the maximum and minimum principal stresses, a, and sigma(3), and therefore assumes that the intermediate stress 92 has no influence on rock strength. As the Mohr-Coulomb criterion ignores the strengthening effect of the intermediate stress, it is expected to be too conservative in estimating the critical mud weight required to maintain wellbore stability. Recently, Al-Ajmi and Zimmerman [Relationship between the parameters of the Mogi and Coulomb failure criterion. Int J Rock Mech Min Sci 2005;42(3):431-39.] developed the Mogi-Coulomb failure criterion, and showed that it is reasonably accurate in modelling polyaxial failure data from a variety of rocks. We then develop a model for the stability of vertical boreholes, using linear elasticity theory to calculate the stresses, and the fully-polyaxial Mogi-Coulomb criterion to predict failure. Our model leads to easily computed expressions for the critical mud weight required to maintain wellbore stability.

  • 3.
    Arvidsson, Mimmi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Dahlin, T.
    Fernlund, Joanne
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Geoelectrical imaging for aggregate quality investigations2008In: Near Surface 2008 - 14th European Meeting of Environmental and Engineering Geophysics, European Association of Geoscientists and Engineers, 2008Conference paper (Refereed)
    Abstract [en]

    In the aggregate industry the use of geophysical measuring is rare. The aim of this project is to investigate how geophysical instruments can be a tool in prospecting for rock quarries, and also how they can be a help in which direction they should expand in. To have control over the quality of the aggregates is important and therefore to know when the rock mass is changing is of interest for the production. Three quarries, with different properties, were investigated with different geophysical methods, of which only the result from the resistivity and IP measurement is presented here. The fracture frequency was measured as well for comparison. The depth to the bedrock is visible in the inverted resistivity sections for the three sites, and an estimation of the quantity of the till is possible to make from the 3D-inversions. It is also shown that the fracture frequency affects the resistivity of the bulk mass. The results also show that the resistivity imaging is well suited for detecting anomalies in the rock mass, which might affect the production. This is especially clear in one of the quarries where a dolerite dyke is clearly visible in the combined resistivity and IP results.

  • 4.
    Ask, Daniel
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Measurement-related uncertainties in overcoring data at the Aspo HRL, Sweden. Part 2: Biaxial tests of CSIRO HI overcore samples2006In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 43, no 1, 127-138 p.Article in journal (Refereed)
    Abstract [en]

    This paper is the second dealing with measurement-related uncertainties of overcoring data undertaken at the Aspo Hard Rock Laboratory and focuses on the biaxial test data from CSIRO HI overcore samples. The first paper dealt with measurement-related uncertainties in connection with the overcoring phase [1]. The uncertainties identified in connection to biaxial tests of CSIRO HI overcore samples include too large applied pressures and poor sampling frequency. At the Aspo HRL, the results yield that most overcore samples fractured during biaxial testing, meaning that a significant part, 56%, of available strain gauge combinations were removed from calculations of the elastic parameters. Remaining strain gauge combinations indicate average values of 62 +/- 5 GPa for Young's modulus and 0.25 +/- 0.01 for Poisson's ratio, which are considerably lower than previously published values [2-5], and are in good agreement with results from biaxial tests on Borre Probe overcore samples [6-10]. The stress calculations were obtained from re-analyzed elastic parameters and strains, and show primarily a reduction in stress magnitudes. Overall, the stress field obtained with different stress measurement methods and its variation with depth is now quite well resolved. The overcoring data suggest that the principal stresses are inclined with a vertical component dipping about 65 degrees from the horizontal over the investigated rock volume (140-420 m depth). This is interpreted as a result of influence from the sub-vertical NE-2 Fracture Zone that divides the stress data into two stress domains [11], although it may also be an artefact because the sigma(2)- and sigma(3)-magnitudes are of the same order of magnitude.

  • 5.
    Ask, Daniel
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    New developments in the Integrated Stress Determination Method and their application to rock stress data at the Aspo HRL, Sweden2006In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 43, no 1, 107-126 p.Article in journal (Refereed)
    Abstract [en]

    The Integrated Stress Determination Method (ISDM) is a powerful tool for estimating the regional stress tensor from in-situ measurements of local stress tensors using a wide variety of stress measuring techniques. This study presents new developments of the ISDM: The stress field may be described with up to 12 model parameters; and is applicable to data from CSIR- and CSIRO HI-type of overcoring devices, hydraulic fracturing, hydraulic tests of pre-existing fractures (HTPF), as well as to combined data sets. Furthermore, in combined data sets, the hydraulic fracturing and/or HTPF data may be used to constrain the average elastic parameters, Young's modulus and Poisson's ratio. The new ISDM developments were applied to the extensive and recently re-analysed rock stress data at the Aspo Hard Rock Laboratory. The results reveal a good fit of the re-analysed data. Overall, the re-analysis indicates that the stress field at Aspo HRL is relatively well constrained and consistent with depth. The NE-2 Fracture Zone influences the stresses, and dividing the regional stress field into a NW and a SE stress domain. When the hydraulic fracturing data were used to constrain the average elastic parameters, Young's modulus, E, and Poisson's ratio, v, quite similar results were obtained (E = 50.8 GPa and v = 0.33) compared with results from biaxial tests of overcore samples (E = 61.6 MPa and v = 0.26).

  • 6.
    Baghbanan, Alireza
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Scale and Stress Effects on Hydro-Mechanical Properties of Fractured Rock Masses2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In this thesis, the effects of size and stress on permeability, deformability and strength of fractured rock masses are investigated. A comparison study was carried out to examine the effects of considering, or not considering, the correlation between distributions of fracture apertures and fracture trace lengths on the hydro-mechanical behavior of fractured rocks. The basic concepts used are the fundamental principles of the general theory of elasticity, Representative Elementary Volume (REV), the tensor of equivalent permeability, and the strength criteria of the fractured rocks.

    Due to the size and stress dependence of the hydro-mechanical properties of rock fractures, the overall effective (or equivalent) hydro-mechanical properties of the fractured rocks are also size and stress-dependent. However, such dependence cannot be readily investigated in laboratory using small samples, and so numerical modeling becomes a necessary tool for estimating their impacts. In this study, a closed-form relation is established for representing the correlation between a truncated lognormal distribution of fracture apertures and a truncated power law distribution of trace lengths, as obtained from field mapping. Furthermore, a new nonlinear algorithm is developed for predicting the relationship between normal stress and normal displacement of fractures, based on the Bandis model and the correlation between aperture and length.

    A large number of stochastic Discrete Fracture Network (DFN) models of varying sizes were extracted from some generated large-sized parent realizations based on a realistic fracture system description from a site investigation programme at Sellafield, UK, for calculating the REV of hydro-mechanical properties of fractured rocks. Rotated DFN models were also generated and used for evaluation of the distributions of directional permeabilities, such that tensors of equivalent permeability could be established based on stochastically established REVs. The stress-dependence of the permeability and the stress-displacement behaviour were then investigated using models of REV sizes. The Discrete Element Method (DEM) was used for numerical simulation of the fluid flow, deformability properties and mechanical strength behavior of fractured rocks.

    The results show significant scale-dependency of rock permeability, deformability and strength, and its variation when the correlation between aperture and trace length of fractures are concerned, with the overall permeability and deformability more controlled by dominating fractures with larger apertures and higher transmissivity and deformability, compared with fracture network models having uniform aperture. As the second moment of aperture distribution increases, a fractured rock mass shows more discrete behavior and an REV is established in smaller value of second moment with much larger model size, compared with the models with uniform fracture aperture. When the fracture aperture pattern is more scattered, the overall permeability, Young’s modulus and mechanical strength change significantly.

    The effect of stress on permeability and fluid flow patterns in fractured rock is significant and can lead to the existence or non-existence of a permeability tensor. Stress changes the fluid flow patterns and can cause significant channeling and the permeability tensor, and REV may be destroyed or re-established at different applied stress conditions. With an increase in the confining stress on the DEM models, the strength is increased. Compared with the Hoek-Brown criterion, the Mohr-Coulomb strength envelope provides a better fit to the results of numerical biaxial compression tests, with significant changes of the strength characteristic parameters occurring when the second moment of the aperture distribution is increased.

  • 7.
    Baghbanan, Alireza
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Effects of size and stress on deformability and strength of fractured rocks with correlated fracture aperture and length2008In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545Article in journal (Other academic)
  • 8.
    Baghbanan, Alireza
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Hydraulic properties of fractured rock masses with correlated fracture length and aperture2007In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 44, no 5, 704-719 p.Article in journal (Refereed)
    Abstract [en]

    Permeability of fractured rocks is investigated considering the correlation between distributed fracture aperture and trace length, based on a newly developed correlation equation. The influence of the second moment of the lognormal distribution of apertures on the existence of representative elementary volume (REV), and the possibility of equivalent permeability tensor of the fractured rock mass, is examined by simulating flow through a large number of stochastic discrete fracture network (DFN) models of varying sizes and varying fracture properties.

    The REV size of the DFN models increases with the increase of the second moment of the lognormal distribution, for both the correlated and uncorrelated cases. The variation of overall permeability between different stochastic realizations is an order of magnitude larger when the aperture and length are correlated than when they are uncorrelated. The mean square error of the directional permeability increases with increasing value of the second moment of the lognormal distribution function, and good fitting to an ellipsis of permeability tensor can only be reached with very large sizes of DFN models, compared with the case of constant fracture aperture, regardless of fracture trace length.

  • 9.
    Baghbanan, Alireza
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Scale and stress effects on permeability tensor of fractured rocks with correlated fracture length and aperture2008In: Thermo-Hydromechanical and chemical coupling in geomaterials and applications: Proceedings of the 3rd International Symposium GeoProc’2008 / [ed] Nicolas Burlion, Jian-Fu Shao, 2008, 439-446 p.Conference paper (Refereed)
    Abstract [en]

    The effect of stress on permeability tensor and Representative Elementary Voliume (REV) of fractured rock masses is studied using a Discrete Element Approach (DEM). A new nonlinear model of rock fractures is developed for prediction of normal stress-normal displacement behavior of fractures based on the correlation between fracture aperture and length distributions. The results show that at small differential stress ratios K (=horizontal/vertical stresses) the overall permeability of fracture networks is generally decreased. However contribution from a few large fractures of higher hydraulic conductivity prevents drastic reduction of the overall permeability, compare with DFN models of constant fracture apertures regardless of fracture trace length. With large values of differential stress ratios, the overall permeability of the DFN models is controlled by a combination of highly conductive larger fractures and fractures with shear slipping and dilation. With increasing differential stress ratios (K=1,3,4 and 5) the REV of a fractured rock may exist at much larger model sizes comparing with the model without stress (K=0).

  • 10.
    Baghbanan, Alireza
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Stress effects on permeability in fractured rock mass with correlated fracture length and aperture2008In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 45, no 8, 1320-1334 p.Article in journal (Refereed)
    Abstract [en]

    The effect of stress on permeability and fluid flow patterns in fractured rock masses is studied when distributed fracture aperture is correlated with fracture trace length, using a discrete element method (DEM). The basic assumptions are that the rock matrix is impermeable and linearly elastic, and that the fluid flows only in fractures. A new nonlinear algorithm is developed for prediction of normal stress-normal displacement behavior of fractures based on the Bandis model and the correlation between aperture and length. The results show that when small stress ratios (K = horizontal/vertical stress) are applied at the model boundaries, the overall permeability of the fracture network is generally decreased. However, contribution from a few large fractures of higher hydraulic conductivity prevents drastic reduction of the overall permeability, compared with models that assume uniform fracture apertures. With large values of the stress ratio, both the overall permeability and flow patterns are controlled by a combination of highly conductive larger fractures and fractures with shear slipping and dilation, with much increased overall permeability and shear-induced flow channeling. With increasing stress ratios, it becomes more and more difficult to establish an equivalent permeability tensor and representative elementary volume (REV) of a fractured rock, compared with the unstressed model. These results show significant difference between correlated and non-correlated aperture and fracture length distributions, and highlight more significant scale and stress dependence of hydro-mechanical behavior of fractures rocks when geometric parameters of rock fractures are correlated.

  • 11. Bäckström, A.
    et al.
    Antikainen, Janne
    Backers, Tobias
    Feng, X.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Kobayashi, A.
    Koyama, Tomofumi
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Pan, P.
    Rinne, M.
    Shen, B.
    Hudson, J.A.
    Numerical modelling of unaxial compressive failure of granite with and without saline porewater2008In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 45, no 7, 1126-1142 p.Article in journal (Refereed)
  • 12.
    Bäckström, Ann
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Rock damage caused by underground excavation and meteorite impacts2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The intent of this thesis is to contribute to the understanding of the origin of fractures in rock. The man-made fracturing from engineering activities in crystalline rock as well as the fracturing induced by the natural process of meteorite impacts is studied by means of various characterization methods. In contrast to engineering induced rock fracturing, where the goal usually is to minimize rock damage, meteorite impacts cause abundant fracturing in the surrounding bedrock. In a rock mass the interactions of fractures on the microscopic scale (mm-cm scale) influence fractures on the mesoscopic scale (dm-m scale) as well as the interaction of the mesocopic fractures influencing fractures on the macroscopic scale (m-km scale). Thus, among several methods used on different scales, two characterization tools have been developed further. This investigation ranges from the investigation of micro-fracturing in ultra-brittle rock on laboratory scale to the remote sensing of fractures in large scale structures, such as meteorite impacts. On the microscopic scale, the role of fractures pre-existing to the laboratory testing is observed to affect the development of new fractures. On the mesoscopic scale, the evaluation of the geometric information from 3D-laser scanning has been further developed for the characterisation of fractures from tunnelling and to evaluate the efficiency of the tunnel blasting technique in crystalline rock. By combining information on: i) the overbreak and underbreak; ii) the orientation and visibility of blasting drillholes and; iii) the natural and blasting fractures in three dimensions; a analysis of the rock mass can be made. This analysis of the rock mass is much deeper than usually obtained in rock engineering for site characterization in relation to the blasting technique can be obtained based on the new data acquisition. Finally, the estimation of fracturing in and around two meteorite impact structures has been used to reach a deeper understanding of the relation between fracture, their water content and the electric properties of the rock mass. A correlation between electric resistivity and fracture frequency in highly fractured crystalline rock has been developed and applied to potential impact crater structures. The results presented in this thesis enables more accurate modelling of rock fractures, both supporting rock engineering design and interpretation of meteorite impact phenomena.

  • 13.
    Bäckström, Ann
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Cosgrove, John W.
    Department of Earth Science and Engineering, Imperial College, London.
    Hudson, John A.
    Department of Earth Science and Engineering, Imperial College, London.
    Interpretation of the development of induced cracks within a pre-cracked rock microstructure and the similarities with the geometry of larger-scale geological fracturesIn: Journal of Structural Geology, ISSN 0191-8141, E-ISSN 1873-1201Article in journal (Other academic)
  • 14.
    Bäckström, Ann
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Feng, Quanhong
    Berg Bygg Konsult AB.
    Lanaro, Flavio
    Berg Bygg Konsult AB.
    Excavation Damage Zone (EDZ) at the TASQ tunnel (Äspö, Sweden): Quantification of blasting effects on the geological settings by 3D-laser-scanningIn: Engineering Geology, ISSN 0013-7952, E-ISSN 1872-6917Article in journal (Other academic)
  • 15.
    Bäckström, Ann
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Feng, Quanhong
    Berg Bygg Konsult AB.
    Lanaro, Flavio
    Berg Bygg Konsult AB.
    Christiansson, Rolf
    Swedish Nuclear Fuel and Waste Management Co.
    Evaluation of the Excavation Damage Zone (EDZ) by using 3-D laser scanning technique2006In: The 4th Asian Rock Mechanics Symposium, Singapore, 8 - 10 November 2006, 2006Conference paper (Other academic)
  • 16.
    Bäckström, Ann
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Koyama, Tomofumi
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    et al.,
    Numerical modelling of uniaxial compressive failure of granite with and without saline porewater2008In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 45, no 7, 1126-1142 p.Article in journal (Refereed)
    Abstract [en]

    It is important for rock engineering design to be able to validate numerical simulations, i.e. to check that they adequately represent the rock reality. In this paper, the capability and validity of four numerical models is assessed through the simulation of an apparently simple case: the complete process of microstructural breakdown during the uniaxial compressive failure of intact crystalline rock. In addition to comparing the capabilities of the four models, the results generated by each model were compared with the experimentally determined complete stress-strain curves for the Swedish Avro granite for different porewater conditions. In this way, it has been possible to audit the models' adequacy for this particular simulation task. It was found that although the models had common features, they were each idiosyncratically different and required considerable expertise to match the actual stress-strain curves (which did not monotonically increase in axial strain)-indicating that, for more complex simulations, both adequate modelling and appropriate validation are not going to be an easy task. The work was conducted within the framework of the international 2004-2007 DEmonstration of COupled models and their VALidation against EXperiments with emphasis on Thermo Hydro Mechanic and Chemical aspects (DECOVALEX-THMC) phase on coupled modelling extended to include chemical effects and with application to the excavation damaged zone (EDZ) in crystalline rock.

  • 17. Chen, Y.F
    et al.
    Zhou, C.B
    Mao, X.Y
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Numerical simulation of coupled thermal elastic behaviors for hard rock pillar in Äspö Pillar Stability Experiment, Sweden2010In: Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering, ISSN 1000-4548, Vol. 32, no 8, 1200-1206 p.Article in journal (Refereed)
    Abstract [en]

    The goal of the Äspö Pillar Stability Experiment performed in Äspö Hard Rock Laboratory, Sweden is to investigate the mechanical response and progressive failure process of ahard rock pillar during excavation and heating. Numerical simulation of the thermalelastic behaviors for the pillar is one of the three tasks of the DECOVALEX-2011 project. The evolutions of stress, deformation and temperature of the pillar are modeled by using a coupled thermal elasticity model. The research results demonstrate that the thermalelasticity model is suitable for describing the coupled thermal mechanical behaviors of the pillar during excavation and heating. The stress redistribution and temperature evolution processes of the pillar are largely modeled, and the failure process and its propagation are qualitatively analyzed. The major limitations of the thermal elasticity model are its absence of the multiphase flow and progressive failure processes. The model developed and the modeling experiences accumulated in this study may be helpful for the stability and safety assessment of the hard granite host rock in China's Beishan preselected area for high-level radioactive waste disposal.

  • 18. Chen, Yifeng
    et al.
    Zhou, Chuangbing
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Modeling coupled THM processes of geological porous media with multiphase flow: Theory and validation against laboratory and field scale experiments2009In: Computers and geotechnics, ISSN 0266-352X, E-ISSN 1873-7633, Vol. 36, no 8, 1308-1329 p.Article in journal (Refereed)
    Abstract [en]

    A FEM model for analysis of fully coupled multiphase flow, thermal transport and stress/deformation in geological porous media was developed based on the momentum, mass and energy conservation laws of the continuum mechanics and the averaging approach of the mixture theory over a three phase (solid-liquid-gas) system. Six processes (i.e. stress-strain, water flow, gas flow, vapor flow, heat transport and porosity evolution processes) and their coupling effects are considered, which not only makes the problem well-defined, but renders the governing PDEs closed, complete. compact and compatible. Displacements, pore water pressure, pore gas pressure, pore vapor pressure, temperature and porosity are selected as basic unknowns. The physical phenomena such as phase transition, gas solubility in liquid, thermo-osmosis, moisture transfer and moisture swelling are modeled. As a result, the relative humidity and other related variables in porous media can be evaluated on a sounder physical basis. A three dimensional computer code, THYME3D, was developed, with eight degrees of freedom at each node. The laboratory CEA Mock-up test and the field scale FEBEX benchmark test on bentonite performance assessment for underground nuclear waste repositories were used to validate the numerical model and the software. The coupled THM behaviors of the bentonite barriers were satisfactorily simulated, and the effects and impacts of the governing equations, constitutive relations and property parameters on the coupled THM processes were understood in terms of more straightforward interpretation of physical processes at microscopic scale of the porous media. The work developed enables further in-depth research on fully coupled THM or THMC processes in porous media.

  • 19. Chijimatsu, M.
    et al.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Millard, A.
    Nguyen, T. S.
    Rejeb, A.
    Rutqvist, Jonny
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Souley, M.
    Sugita, Y.
    Building Confidence in the Mathematical Models by Calibration With A T-H-M Field Experiment2004In: Coupled Thermo-Hydro-Mechanical-Chemical Processes in Geo-Systems — Fundamentals, Modelling, Experiments and Applications, Elsevier, 2004, no C, 193-198 p.Chapter in book (Refereed)
    Abstract [en]

    Geological disposal of nuclear fuel wastes relies on the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX project. These models in general consider the full coupling of thermal (T), hydrological (H) and mechanical (M) processes that would prevail in the geological media around the repository. This paper shows the process of building confidence in the mathematical models by calibration with a reference T-H-M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables.

  • 20. Chijimatsu, M.
    et al.
    Nguyen, T. S.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    De Jonge, J.
    Kohlmeier, M.
    Millard, A.
    Rejeb, A.
    Rutqvist, J.
    Souley, M.
    Sugita, Y.
    Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository - BMT1 of the DECOVALEX III project. Part 1: Conceptualization and characterization of the problems and summary of results2005In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 42, no 5-6, 720-730 p.Article in journal (Refereed)
    Abstract [en]

    Geological disposal of the spent nuclear fuel often uses the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX III project. These models in general consider the full coupling of thermal (T), hydraulic (H) and mechanical (M) processes that would prevail in the geological media around the repository. For Bench Mark Test no. 1 (BMTI) of the DECOVALEX III project, seven multinational research teams studied the implications of coupled THM processes on the safety of a hypothetical nuclear waste repository at the near-field and are presented in three accompanying papers in this issue. This paper is the first of the three companion papers, which provides the conceptualization and characterization of the BMT1 as well as some general conclusions based on the findings of the numerical studies. It also shows the process of building confidence in the mathematical models by calibration with a reference T-H-M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables.

  • 21. Chijimatsu, Masakazu
    et al.
    Borgesson, Lenart
    Fujita, Tomoo
    Jussila, Petri
    Nguyen, Son
    Rutqvist, Jonny
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Model development and calibration for the coupled thermal, hydraulic and mechanical phenomena of the bentonite2009In: Environmental Geology, ISSN 0943-0105, E-ISSN 1432-0495, Vol. 57, no 6, 1255-1261 p.Article in journal (Refereed)
    Abstract [en]

    In the international DECOVALEX-THMC project, five research teams study the influence of thermal-hydro-mechanical (THM) coupling on the safety of a hypothetical geological repository for spent fuel. In order to improve the analyses, the teams calibrated their bentonite models with results from laboratory experiments, including swelling pressure tests, water uptake tests, thermally gradient tests, and the CEA mock-up THM experiment. This paper describes the mathematical models used by the teams, and compares the results of their calibrations with the experimental data.

  • 22. Chuang, T.C
    et al.
    Henkel, Herbert
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    GIS Visualization of Complex Geoscientific Data from the Björkö Structure2006In: GeoCongress 2006: Geotechnical Engineering in the Information Technology Age, Atlanta: American Society of Civil Engineers (ASCE), 2006, 2, , 204-209 p.204-209 p.Conference paper (Refereed)
    Abstract [en]

    Based on the idea of Scientific Visualization, this research is aimed to visualize the complex geoscientific data to support the mapping work of the Björkö Energy Project, which has an ultimate goal to place a heat exchanging mechanism at the most suitable location in the subsurface. The production from this impact crater structure is expecting to supply the heating use for the great Stockholm area. The various point data types were compiled to diverse maps according to their characteristics. Several GIS and numerical tools are introduced integratedly to accomplish the work. The research in addition helps to streamline the data and maps processing activities carried out by the varied working groups

  • 23. David, E.
    et al.
    Zimmerman, Robert W.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Sliding crack model for the uniaxial compression of rock2007In: Proceedings of the 1st Canada-US Rock Mechanics Symposium - Rock Mechanics Meeting Society's Challenges and Demands, Taylor & Francis, 2007, 575-580 p.Conference paper (Refereed)
    Abstract [en]

    Uniaxial compression tests on rocks, if conducted at stresses below failure, typically show non-linearity in the stress-strain curve, and hysteresis. Walsh (J. Geophys. Res., 1965) explained this behavior in terms of frictional sliding along the faces of closed cracks. Although well known and widely cited, Walsh's model has not previously been developed in sufficient detail to be used for quantitative predictions. We revisit and extend his model, by including the effect of the stress required to close an initially open crack, and we examine the unloading process in detail. Our analysis leads to closed-form expressions for the loading and unloading portions of the stress-strain curve, as functions of elastic modulus of the uncracked rock, the crack density, the characteristic aspect ratio, and the crack friction coefficient. The model provides a good fit to the loading and unloading portions of the stress-strain curves, for experimental data on sandstones taken from the literature.

  • 24.
    Ekneligoda, Thushan C.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Zimmerman, Robert W.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Boundary perturbation solution for nearly circular holes and rigid inclusions in an infinite elastic medium2008In: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 75, no 1, 011015- p.Article in journal (Refereed)
    Abstract [en]

    The boundary perturbation method is used to solve the problem of a nearly circular rigid inclusion in a two-dimensional elastic medium subjected to hydrostatic stress at infinity. The solution is taken to the fourth order in the small parameter epsilon that quantifies the magnitude of the variation of the radius of the inclusion. This result is then used to find the effective bulk modulus of a body that contains a dilute concentration of such inclusions. The corresponding results for a cavity are obtained by setting the Muskhelishvili coefficient K equal to -1, as specified by the Dundurs correspondence principle. The results for nearly circular pores can be expressed in terms of the pore compressibility. The pore compressibilities given by the perturbation solution are tested against numerical values obtained using the boundary element method, and are shown to have good accuracy over a substantial range of roughness values.

  • 25.
    Ekneligoda, Thushan C.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Zimmerman, Robert W.
    Shear compliance of two-dimensional pores possessing N-fold axis of rotational symmetry2008In: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences, ISSN 1364-5021, E-ISSN 1471-2946, Vol. 464, no 2091, 759-775 p.Article in journal (Refereed)
    Abstract [en]

    We use the complex variable method and conformal mapping to derive a closed-form expression for the shear compliance parameters of some two-dimensional pores in an elastic material. The pores have an N-fold axis of rotational symmetry and can be represented by at most three terms in the mapping function that conformally maps the exterior of the pore into the interior of the unit circle. We validate our results against the solutions of some special cases available in the literature, and against boundary-element calculations. By extrapolation of the results for pores obtained from two and three terms of the Schwarz-Christoffel mapping function for regular polygons, we find the shear compliance of a triangle, square, pentagon and hexagon. We explicitly verify the fact that the shear compliance of a symmetric pore is independent of the orientation of the pore relative to the applied shear, for all cases except pores of fourfold symmetry. We also show that pores having fourfold symmetry, or no symmetry, will have shear compliances that vary with cos 4 theta. An approximate scaling law for the shear compliance parameter, in terms of the ratio of perimeter squared to area, is proposed and tested.

  • 26.
    Ekneligoda, Thushan Chandrasiri
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Zimmerman, Robert W.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Compressibility of two-dimensional pores having n-fold axes of symmetry2006In: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences, ISSN 1364-5021, E-ISSN 1471-2946, Vol. 462, no 2071, 1933-1947 p.Article in journal (Refereed)
    Abstract [en]

    The complex variable method and conformal mapping are used to derive a closed-form expression for the compressibility of an isolated pore in an infinite two-dimensional, isotropic elastic body. The pore is assumed to have an n-fold axis of symmetry, and be represented by at most four terms in the mapping function that conformally maps the exterior of the pore into the interior of the unit circle. The results are validated against some special cases available in the literature, and against boundary-element calculations. By extrapolation of the results for pores obtained from three and four terms of the Schwarz-Christoffel mapping function for regular polygons, the compressibilities of a triangle, square, pentagon and hexagon are found (to at least three digits). Specific results for some other pore shapes, more general than the quasi-polygons obtained from the Schwarz-Christoffel mapping, are also presented. An approximate scaling law for the compressibility, in terms of the ratio of perimeter-squared to area, is also tested. This' expression gives a reasonable approximation to the pore compressibility, but may overestimate it by as much as 20%.

  • 27. Feng, X. -T
    et al.
    Liu, J.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Research and application on coupled t-h-m-c processes of geological media in china - a review2004In: Coupled Thermo-Hydro-Mechanical-Chemical Processes in Geo-Systems — Fundamentals, Modelling, Experiments and Applications, Elsevier, 2004, no C, 37-48 p.Chapter in book (Refereed)
    Abstract [en]

    Theoretical models of coupled T-H-M-C processes of geological media and the associated numerical solutions have become an attractive research focus in geomechanics and related fields in China. This paper provides a systematic overview of the past progress in the fundamental studies of the coupled THM models and numerical methods, and their applications in the fields of oil/gas reservoir, coal mining, and water resources engineering works. The key areas of weakness in research in this field are also outlined and possible directions for the future development are discussed.

  • 28.
    Fernlund, Joanne M. Robison
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Tafesse, Solomon
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Magnusson, Mimmi K.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Total analysis of till using resistivity and 3D image analysisArticle in journal (Other academic)
  • 29.
    Fernlund, Joanne
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Tafesse, Solomon
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Magnusson, Mimmi
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Lithological analysis of multiple size fractions of tillArticle in journal (Other academic)
  • 30. Guha, D. K.
    et al.
    Henkel, Herbert
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Abandoned on-shore deep wells: a potential for geothermal energy resource for rural Bangladesh2005In: Proceedings of the World Geothermal Congress 2005: paper 2214, 2005Conference paper (Other academic)
  • 31.
    Henkel, Herbert
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Bäckström, Ann
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Bergman, Börje
    Stephansson, Ove
    Lindström, Maurits
    Geothermal energy from impact craters?: The Björkö study2005In: Proceedings of the World Geothermal Congress 2005: paper 0667, 2005Conference paper (Other academic)
  • 32.
    Henkel, Herbert
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Ekneligoda, Thushan Chandrasiri
    Aaro, Sven
    The extent of impact induced fracturing from gravity modeling of the Granby and Tvaren simple craters2010In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 485, no 1-4, 290-305 p.Article in journal (Refereed)
    Abstract [en]

    The Granby and Tvaren impact structures are two of the 5 recognized early Paleozoic impact structures in Scandinavia. They have a similar diameter of ca 2 km and contain a substantial post impact fill with Paleozoic sedimentary rocks. The Granby structure represents an almost completely preserved impact crater within a Paleozoic sedimentary rock sequence - only the uppermost part of the raised crater rim might be eroded and was subsequently covered by Quaternary sediments. The Tvaren structure is eroded below the surrounding pre-impact Paleozoic cover rocks into the underlying crystalline basement and has Quaternary sediment fill. Gravity measurements have been made on land, and in the case of the Tvaren structure also on sea ice, as a basis for modeling of the extent of impact induced fracturing below and around the craters, expressed as porosity. In the models, the contributions to the gravity field from the crater fill materials seawater, Quaternary sediments and Paleozoic sedimentary rocks are accounted for. The remaining negative gravity anomaly is related to the volume of impact fractured crystalline rock indicating an outward decreasing intensity of fracturing extending beyond the morphologic crater edge to ca 1.5 km radial distance from the explosion center. The remaining porosity in the central part of this sub-crater damage zone approaches 15%. A model is suggested for the gradual change of density and the equivalent porosity with radial distance within the damage zone around simple craters. (C) 2010 Elsevier B.V. All rights reserved.

  • 33.
    Henkel, Herbert
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Piazolo, Sandra
    Wörman, Anders
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Hydraulic Engineering.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    A deep rock laboratory in the Dellen impact crater2010In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 132, no 1, 45-54 p.Article in journal (Refereed)
    Abstract [en]

    The Deep Rock Lab is a platform to establish a comprehensive subsurface bedrock characterization approach, by integrating site characterization techniques applied from different disciplines of geo-mechanics, geochemistry, hydrogeology, structural geology, lithology and geophysics, with consideration of the effects of coupled geological processes of importance for the understanding of groundwater renewal, continental shield deformations, engineering issues related to geological disposal of nuclear waste and CO2, and geothermal energy retrieval in crystalline rocks. The approach will focus on the physics and chemistry of crystalline rocks and groundwater with down-the-hole measurements of relevant variables, using and developing more efficient geo-scientific site investigation techniques for deep boreholes at a chosen site, and develop more advanced down-the-hole measurements and numerical modelling methods with more advanced inversion algorithms to help integrate data interpretations and object representations. The goal is to develop this platform into a long-term research facility that can be readily used by the scientific community for both subsurface fundamental and engineering-oriented research. Such a platform will be especially important for the education of PhD students for generations to come. The integrated drilling and research facility is suggested to be located at the Dellen site. This site has an impact crater with a large range of expected physical property changes with depth, complex and multiple thermal processes that have affected the bedrock, a favorable infrastructure and local supporting activities, and a large body of existing geo-scientific data.

  • 34.
    Horta, Andre
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Impacts of Using Crushed Rocks in Concrete.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Concrete in Sweden has traditionally been manufactured with natural aggregate from glaciofluvial eskers. There is a need to preserve the remaining eskers because of their cultural value and importance for water filtration, thus natural aggregate has to be replaced. The most realistic alternative is to use crushed rocks. The major problem with crushed rocks in concrete production is the workability. This is because crushed rocks have less favorable properties. The fragments are flakier and have a rougher surface than natural aggregates that have been rounded in water. Without any amelioration of the crushed rock, to reach a certain workability and strength, the amount of cement in the mix has to be increased. Cement production requires large amounts of energy and the decarbonation of limestone releases large amounts of CO2. Combined, the release of CO2, due to burning and decarbonation of limestone, accounts for about 5% of the global CO2 emissions. An increase in cement consumptions is less desirable. Thus to replace natural aggregates, the use of crushed rocks has to be optimized as regard cement consumption.

    Several crushed aggregates, most from granitic rocks, from all over Sweden were analysed in this study. These crushed rocks were characterized according to their grading, specific surface, shape and petrography and compared to natural sand.

    Rheological tests that reveals the workability in detail was performed on mortars. The tests showed that as regard workability the 0-2 mm fraction is the most important factor. Further, the maximum aggregate size was gradually increased up to 16 mm, to have a more realistic approach to the concrete produced by the building industry.

    The results showed that with grading optimization and superplasticizer, some crushed rocks can be used for concrete production without increasing, and even decreasing, the cement consumption. This research also contemplated the use of filler. As a mineral admixture it can improve the compressive strength. It can also be used to replace cement; a replacement up to 20 kg/m3 of cement by filler can be done without significant effect on compressive strength.

  • 35. Hudson, John A.
    et al.
    Bäckström, Ann
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Rutqvist, J.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Backers, T.
    Chijimatsu, M.
    Christiansson, R.
    Feng, X. T.
    Kobayashi, A.
    Koyama, Tomofumi
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Lee, H. S.
    Neretnieks, Ivars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Pan, P. Z.
    Rinne, M.
    Shen, B. T.
    Characterising and modelling the excavation damaged zone in crystalline rock in the context of radioactive waste disposal2009In: Environmental Geology, ISSN 0943-0105, E-ISSN 1432-0495, Vol. 57, no 6, 1275-1297 p.Article in journal (Refereed)
    Abstract [en]

    This paper describes current knowledge about the nature of and potential for thermo-hydro-mechanical-chemical modelling of the excavation damaged zone (EDZ) around the excavations for an underground radioactive waste repository. In the first part of the paper, the disturbances associated with excavation are explained, together with reviews of Workshops that have been held on the subject. In the second part of the paper, the results of a DECOVALEX [DEmonstration of COupled models and their VALidation against EXperiment: research funded by an international consortium of radioactive waste regulators and implementers (http://www.decovalex.com)] research programme on modelling the EDZ are presented. Four research teams used four different models to simulate the complete stress-strain curve for Avro granite from the Swedish A"spo Hard Rock Laboratory. Subsequent research extended the work to computer simulation of the evolution of the repository using a 'wall-block model' and a 'near-field model'. This included assessing the evolution of stress, failure and permeability and time-dependent effects during repository evolution. As discussed, all the computer models are well suited to sensitivity studies for evaluating the influence of their respective supporting parameters on the complete stress-strain curve for rock and for modelling the EDZ.

  • 36.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Baghbanan, Alireza
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Stress and scale effects of the hydraulic properties of fractured rocks2008In: Boundaries of rock mechanics: recent advances and challenges for the 21st century : proceedings of the International Young Scholars' Symposium on Rock Mechanics, 28 April-2 May, 2008, Beijing, China / [ed] Meifeng Cai, Jin'an Wang, 2008, 41-48 p.Conference paper (Refereed)
    Abstract [en]

    The paper investigates the stress and scale effects on the hydraulic permeability of fractured rocks considering the correlation between distributed fracture aperture and trace length, where the fracture aperture and trace length follow a truncated lognormal distribution and a power-law distribution, respectively This parameter correlation of fractures leads to larger REV size and permeability magnitudes of the DEM models compared with the case of using constant apertures, which vary with stress conditions, and with the overall permeability more controlled by large-sized fractures.

  • 37.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Min, Ki-Bok
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Baghbanan, Alireza
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Stress and scale-dependency of hydromechanical properties of fractured rocks2009In: Rock Mechanics: New Research / [ed] M. Abbie and J. S. Bedford, New York: Nova Science Publishers, Inc., 2009, 1, 109-165 p.Chapter in book (Refereed)
  • 38.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Case Studies of Discrete Element Method Applications in Geology, Geophysics and Rock Engineering2007In: Fundamentals Of Discrete Element Methods For Rock Engineering: Theory And Applications, Elsevier, 2007, 447-538 p.Chapter in book (Refereed)
  • 39.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Constitutive Models of Rock Fractures and Rock Masses - The Basics2007In: Fundamentals Of Discrete Element Methods For Rock Engineering:: Theory And Applications, Elsevier, 2007, 47-109 p.Chapter in book (Refereed)
  • 40.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Discrete Element Methods for Granular Materials2007In: Fundamentals Of Discrete Element Methods For Rock Engineering: Theory And Applications, Elsevier, 2007, 399-444 p.Chapter in book (Refereed)
  • 41.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Discrete Fracture Network (DFN) Method2007In: Fundamentals Of Discrete Element Methods For Rock Engineering: Theory And Applications, Elsevier, 2007, 365-398 p.Chapter in book (Refereed)
  • 42.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Explicit Discrete Element Method for Block Systems - the Distinct Element Method2007In: Developments in Geotechnical Engineering: Fundamentals of Discrete Element Methods for Rock Engineering — Theory and Applications, Elsevier, 2007, 235-316 p.Chapter in book (Refereed)
  • 43.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Fluid Flow and Coupled Hydro-Mechanical Behavior of Rock Fractures2007In: Fundamentals Of Discrete Element Methods For Rock Engineering: Theory And Applications, Elsevier, 2007, 111-144 p.Chapter in book (Refereed)
  • 44.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Governing Equations for Motion and Deformation of Block Systems and Heat Transfer2007In: Fundamentals Of Discrete Element Methods For Rock Engineering: Theory And Applications, Elsevier, 2007, 25-46 p.Chapter in book (Refereed)
  • 45.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Implicit Discrete Element Method For Block Systems - Discontinuous Deformation Analysis (DDA)2007In: Fundamentals of Discrete Element Methods for Rock Engineering — Theory and Applications, Elsevier, 2007, 317-364 p.Chapter in book (Refereed)
  • 46.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Introduction2007In: Fundamentals of Discrete Element Methods for Rock Engineering Theory and Applications, Elsevier, 2007, 1-21 p.Chapter in book (Other academic)
  • 47.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    Numerical Techniques for Block System Construction2007In: Developments in Geotechnical Engineering Fundamentals of Discrete Element Methods for Rock Engineering — Theory and Applications, Elsevier, 2007, 199-232 p.Chapter in book (Refereed)
  • 48.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    The Basics of Combinatorial Topology for Block System Representation2007In: Fundamentals of Discrete Element Methods for Rock Engineering: Theory and Applications, Elsevier, 2007, 179-197 p.Chapter in book (Refereed)
  • 49.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Stephansson, O.
    The Basics of Fracture System Characterization - Field Mapping and Stochastic Simulations2007In: Developments in Geotechnical Engineering Fundamentals of Discrete Element Methods for Rock Engineering — Theory and Applications, Elsevier, 2007, 147-177 p.Chapter in book (Refereed)
  • 50.
    Jing, Lanru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Stephansson, Ove
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Discrete methods for rock engineering-theory and application2007 (ed. 1)Book (Refereed)
123 1 - 50 of 109
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