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  • 1.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Kartering av skredbenägenhet medartificiell intelligens2018In: Bygg & teknik, ISSN 0281-658X, no 1Article in journal (Other academic)
  • 2.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Landslide susceptibility hazard map in southwest Sweden using artificial neural network2019In: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 183, article id UNSP 104225Article in journal (Refereed)
    Abstract [en]

    Landslides as major geo-hazards in Sweden adversely impact on nearby environments and socio-economics. In this paper, a landslide susceptibility map using a proposed subdivision approach for a large area in southwest Sweden has been produced. The map has been generated by means of an artificial neural network (ANN) model developed using fourteen causative factors extracted from topographic and geomorphologic, geological, land use, hydrology and hydrogeology characteristics. The landslide inventory map includes 242 events identified from different validated resources and interpreted aerial photographs. The weights of the causative factors employed were analyzed and verified using accepted mathematical criteria, sensitivity analysis, previous studies, and actual landslides. The high accuracy achieved using the ANN model demonstrates a consistent criterion for future landslide susceptibility zonation. Comparisons with earlier susceptibility assessments in the area show the model to be a cost-effective and potentially vital tool for urban planners in developing cities and municipalities.

  • 3.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Storskalig kartering av skredbenägenhet i västra Götaland med artificiell intelligens2018Conference paper (Other academic)
  • 4.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Sjölander, Andreas
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Probability distributions of shotcrete parameters for reliability-based analyses of rock tunnel support2019In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 87, p. 15-26Article in journal (Refereed)
    Abstract [en]

    A common support measure for underground excavations in jointed rock masses to support loose blocks is to apply a thin shotcrete layer to the periphery of the excavation and systematically install rockbolts into the surrounding rock mass. In this support system, large blocks are carried by the rockbolts and small blocks are carried by the thin shotcrete layer. To verify the shotcrete layer's load-bearing capacity and to stringently account for the large uncertainties incorporated in the variables involved in determining its capacity, analytical calculations in combination with reliability-based methods can be used. However, a lack of knowledge exists regarding the magnitude and uncertainty of shotcrete characteristics (thickness, adhesion, flexural tensile strength, residual flexural tensile strength, and compressive strength), making it difficult to apply reliability-based methods. A statistical quantification of these characteristics is therefore important to facilitate reliability-based methods in design and verification of shotcrete support. In this paper, we illustrate how shotcrete support against small loose blocks can be viewed as a correlated conditional structural system and how this system can be analyzed using reliability-based methods. In addition, we present a unique amount of data for the aforementioned variables, which are all incorporated in the design and verification of a shotcrete layer's ability to sustain loads from small loose blocks. Based on the presented data, we statistically quantify and propose suitable probability distributions for each variable. Lastly, we illustrate how the proposed probability distributions can be used in the design process to calculate the probability of exceeding the shotcrete's load-bearing capacity. Both the probabilistic quantification and the defined correlated conditional structural system along with the illustrative calculation example are followed by a discussion of their implications.

  • 5.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spatial Variability of Shotcrete Thickness in Design of Rock Tunnel SupportManuscript (preprint) (Other academic)
  • 6.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Influence from spatially varying thickness on shotcrete’s load-bearing capacityManuscript (preprint) (Other academic)
  • 7.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics. KTH Royal Inst Technol, Dept Civil & Architectural Engn, SE-10044 Stockholm, Sweden..
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Influence of spatially varying thickness on load-bearing capacity of shotcrete2020In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 98, article id 103336Article in journal (Refereed)
    Abstract [en]

    A common approach to verify a shotcrete layer's ability to secure blocks that can exist between rockbolts in a tunnel is to use analytical calculations. For this situation, an attractive approach to account for variability in the shotcrete parameters is to use reliability-based methods. Variability can then be accounted for by assigning suitable probability distributions to all relevant input parameters. Structural safety can be ensured by verifying that the probability of limit exceedance is smaller than an acceptable target probability of failure. However, even though analytical calculations and reliability-based methods can be used to design shotcrete support, one of the commonly made basic assumptions is that the load-bearing capacity of the shotcrete is governed by the spatial average of the input parameters. Thus, the spatial variability of the parameters are neglected. As a result, if the capacity is governed by the lowest value of a certain parameter, this assumption is non-conservative. In this paper, we present a novel approach in which the minimum of either the spatial average of a shotcrete slab of varying thickness, or the spatial average along the periphery of a loose block of that same slab, is used to estimate the load-bearing capacity of the shotcrete in a tunnel. The approach is based on results from numerical simulations of a shotcrete slab that we perform to investigate the effect that a spatially varying thickness has on the flexural load-bearing capacity of the slab. The results from the simulations show that the shotcrete's flexural load-bearing capacity might be overestimated when using the spatial average of shotcrete thickness between four rockbolts in design. Using the presented approach, the spatial variability of shotcrete thickness can be accounted for in practical design of tunnels without complex and time-consuming numerical simulations.

  • 8.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Reliability-based design principles of shotcrete support for tunnels in hard rockManuscript (preprint) (Other academic)
  • 9.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Prästings, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Challenges in applying fixed partial factors to rock engineering design2017In: Geotechnical Special Publication, ISSN 0895-0563, no 283, p. 384-393Article in journal (Refereed)
    Abstract [en]

    The Swedish national guidelines for design of the main structural support system in road and railway rock tunnels have been adjusted to cohere with Eurocode 7. In the design guidelines, the limit states that the designer should consider are specified. The main method to account for uncertainties in the Swedish guidelines is similar to the method preferred in Eurocode 7: the partial factor method. For each limit state, fixed partial factors retrieved from different sections of the Eurocodes are specified. However, fixed partial factors may not correspond to the same structural reliability for all design situations. In this paper, we show for a common design situation in rock engineering design how partial factors in theory should vary with design geometries and uncertainties. The derived partial factors are compared to the Eurocodes’ fixed values. We find that using fixed partial factors to ensure structural safety in these limit states might not be suitable. The implications are discussed along with suggestions of other more suitable methods to account for uncertainties in rock engineering design.

  • 10.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Prästings, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Reliability aspects of rock tunnel design with the observational methodManuscript (preprint) (Other academic)
  • 11.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Prästings, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Reliability aspects of rock tunnel design with the observational method2017In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 98, p. 102-110Article in journal (Refereed)
    Abstract [en]

    According to Eurocode 7, two accepted approaches for managing uncertainty in tunnel design are reliability based methods and the observational method. Reliability-based methods account for uncertainty by acknowledging the random variation of the input parameters; the observational method does this by verifying the expected behavior from an initial design during the course of construction. However, in the framework of the observational method, as defined in Eurocode 7, no guidance is given on the selection of suitable parameters for observation and how they can be linked to the limits of acceptable behavior and, at a sufficiently early stage, the decision for implementing contingency actions. Furthermore, no guidance is given on how to verify that the structure fulfills society's required safety level. In this paper, we present a design procedure for shotcrete-supported rock tunnels that combines reliability-based methods with the observational method. The design procedure applies a deformation-based limit state function for the shotcrete support that is based on the convergence confinement method. We suggest how the requirements in the observational method, as defined in Eurocode 7, may be satisfied for this application. In particular, we focus on the structural reliability aspects. The structural reliability of the preliminary design is assessed with Monte Carlo simulations by calculating the expected deformations of the tunnel. The appropriateness of the preliminary design is then verified by observing the actual deformations during the course of construction. The observed deformations are used to predict the future behavior of the tunnel and to update the assessed probability of unsatisfactory behavior. If the defined deformation-based alarm limit regarding the structural reliability is exceeded, predefined contingency actions are put into operation. The procedure is illustrated with a shotcrete-lined circular rock tunnel and practical aspects in satisfying the reliability requirements with the observational method are discussed.

  • 12.
    Bjureland, William
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE).
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Some aspect of reliability-based design for tunnels using observational method (EC7)2015In: EUROCK 2015 & 64th Geomechanics Colloquium, Salzburg, 2015Conference paper (Refereed)
    Abstract [en]

    According to Eurocode 7, the observational method is an accepted design method, where a preliminary design may be updated as the construction progresses. However, Eurocode 7 does not give any advice on how to relate the observations to the acceptable level of safety of the structure. In this paper, we outline a methodology for how to use deformation measurements to predict the final deformation of a circular rock tunnel to calculate the probability of failure. Consequently, the measurements can be used to verify that the design does not violate the specified safety level. The paper shows the potential of combining the observational method with reliability-based design in tunneling

  • 13.
    Damasceno, Davi Rodrigues
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Jan
    Naturgasteknik.
    Efficiency of subset simulation in the design of lined rock caverns for storage of hydrogen gas2019In: Proceedings of the 13th International Conference on Applications of Statistics and Probability in Civil Engineering, Seoul, South Korea, 2019, article id 124Conference paper (Refereed)
    Abstract [en]

    Efforts to substitute the use of fossil fuels in industry by hydrogen gas requires the storage of large volumes of gas with a reliable pressure vessel design. The Hydrogen Breakthrough Ironmaking Technology (HYBRIT) initiative aims to make the whole steel making process in Sweden fossil-free with the storage of industrial scale quantities of hydrogen in underground Lined Rock Cavers (LRCs). The LRC concept is a relatively new design methodology that can be further developed with respect to safety and economic efficiency and reliability-based design methods provide one option to comply with codes and regulations. High reliability is required for the storage of hydrogen gas and the computational time becomes unpractical for the evaluation of a complex system such as the LRC. In this paper, the efficiency of Subset Simulation (SuS) regarding accuracy, precision and required number of samples is studied for the calculation of probability of failure against fatigue of the steel lining. It can be observed that by increasing the number of samples per level and increasing the conditional probability of failure the precision increases as well as the total number of samples. The accuracy of the SuS is checked with respect to Monte Carlo simulation (MCS) showing good agreement and with greater precision for fewer number of samples. A case study is performed for the geologic conditions of Sweden showing that the considered failure mode is unlikely for high stresses and good rock mass quality.

  • 14.
    Johansson, Fredrik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Bjureland, William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Application of Reliability-based Design Methods to Underground Excavation in Rock2016Report (Other academic)
  • 15.
    Johansson, Fredrik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Damasceno, Davi
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Jan
    Naturgasteknik AB.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Investigation of research needs regarding the storage of hydrogen gas in lined rock caverns: Prestudy for Work Package 2.3 in HYBRIT Research Program 12018Report (Other academic)
    Abstract [en]

    The objective of HYBRIT RP1 is to explore and assess pathways to fossil-free energy-mining-iron-steel value chains and thereby provide a basis for industrial development activities and the necessary future transformative change in this field. A large-scale storage capacity for hydrogen gas is an important component of the proposed HYBRIT concept. Underground storage in lined rock caverns provides a reasonable option: a large-scale demonstration plant for storage of natural gas was constructed in Sweden in 2002 and has operated safely since then. Considering that this lined rock cavern facility was constructed for natural gas, the present report investigates the current research needs to allow for underground storage of hydrogen gas in such a facility. This will serve as a basis for the research in Work Package 2.3 of HYBRIT RP1.

    Studying the experiences from decades of Swedish and international research and practice on the construction of underground gas storage facilities, the conclusion is that the lined rock cavern concept seems a reasonable way forward. In terms of rock engineering research, there are currently no critical research issues; however, a development of a previously proposed risk-based design framework for lined rock caverns may further strengthen the ability to manage risks related to underground gas storage facilities. The report identifies several potential research questions on this topic to be further studied: development of a risk-based design approach using subset simulation, the optimization potential of the concrete thickness in the lining, and the effect of spatial variation of rock mass properties on a location’s suitability for the storage facility.

    Additionally, the report identifies the potential effect of hydrogen embrittlement on the steel lining as a critical research issue to ensure safe storage of hydrogen gas in lined rock caverns. However, as this issue is not related to rock engineering, but a material issue, it will not be covered further in Work Package 2.3.

    Download full text (pdf)
    fulltext
  • 16.
    Johansson, Fredrik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Fransson, Lennart
    Dammsäkerhet - Islast mot dammkonstruktioner: Sammanställning av kunskapsläget samt förslag till forskning och utveckling2013Report (Refereed)
    Download full text (pdf)
    13_56_rapport_final_2.pdf
  • 17.
    Johansson, Fredrik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Westberg Wilde, Marie
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Krounis, Alexandra
    KTH, School of Architecture and the Built Environment (ABE).
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Ríos Bayona, Francisco
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Some recent developments in reliability based slidingstability assessments for concrete dams2018In: 26th International Congress on Large Dams, 2018, CRC Press/Balkema , 2018, p. 1277-1294Conference paper (Refereed)
    Abstract [en]

    In this paper, a reliability based framework for the assessment of sliding stability for concrete dams was presented. The framework consists of several parts based on the Probabilistic model code for concrete dams developed by Westberg-Wilde and Johansson and includes guidelines on how reliability based sliding stability assessment should be performed, together with recent work by Krounis et al. how to account for partially bonded interfaces. In the proposed framework, the assessments start with performing preliminary calculations using a priori assumptions on parameters included in the analysis. If cost-benefit analyses show that further analyses could be beneficial, investigations are undertaken on relevant parameters in the failure modes. The results from the investigations are used to update the calculations in the assessment and decisions on stability enhancing measures are undertaken if necessary. In the presented example the preliminary sliding stability analysis of the interface, before testing was performed, showed a reliability index of 4.91, indicating an unacceptable failure probability of the dam without any testing. Taking into account the information obtained from testing the basic friction angle of the interface increased the reliability index from 4.91 to 7.24, clearly showing the gain of including test results in the assessment. When the influence of cohesion was accounted for a reliability index of 6.49 was obtained, which shows that cohesion can give a potential gain to the stability, even though it in this case still is lower than the gain from updating the basic friction angle. When both limit states of the interface were considered as a system the reliability index increased to 8.1.

  • 18.
    Krounis, Alexandra
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Influence of cohesive strength in probabilstic sliding stability re-assessment of concrete dams2016In: Journal of Geotechnical and Geoenvironmental Engineering, ISSN 1090-0241, E-ISSN 1943-5606, Vol. 143, no 2, article id 04016094Article in journal (Refereed)
    Abstract [en]

    For concrete dams, cohesive strength often constitutes a significant share of the overall shear strength of partially bonded concrete-rock interfaces. However, cohesive strength is also associated with great uncertainties that may have a significant impact on the assessed stability of the analyzed structure. In this paper, the merits of including cohesion are evaluated using a probability-based approach to analyze the sliding stability of an existing concrete gravity dam. The shear strength properties of the interface are inferred from a limited number of site-specific tests and previous knowledge from similar structures using Bayesian updating. The study shows that the potential gain from cohesive strength is strongly related to the involved uncertainties and identifies the bonding percentage and basic friction angle as the most influential parameters. The importance of testing, both with regard to the specific project and for future projects, is also highlighted.

  • 19.
    Larsson, Stefan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Wersäll, Carl
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Geotekniker och bergmekaniker ska lära för livet: men hur ska det gå till?2014In: Bygg & teknik, ISSN 0281-658X, no 1, p. 70-72Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Geoteknikeroch bergmekaniker ska ha förmågan att projektera, bygga och underhålla geokonstruktionerför det moderna samhället. Konstruktionerna måste vara både ekonomiska, säkra,estetiska och miljövänliga. Ingenjören får sin kompetens genom utbildning,träning och erfarenheter från skolan, annan fortbildning och arbete iprojekten. Kraven på en bred kunskapsbas ökar alltmer, samtidigt som det krävsen betydande fördjupning inom det specifika ämnesområdet. Både högskolorna ochnäringslivet genomgår nu ett påtagligt generationsskifte och det är därförlämpligt att inom de närmaste åren utföra en omfattande didaktisk analysavseende: Vad ska läras ut? Varför ska det läras ut? Hur ska det läras ut? Förvem ska det läras ut? Vi anser att geoteknik­ och bergmekanikundervisningen börinriktas på att ge ingenjören förmågor som ska utgöra en bas för ett livslångtlärande.

  • 20.
    Larsson, Stefan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Bjureland, William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Obefintlig tillsyn utarmar geoteknisk kompetens hos husbyggare2017In: Bygg & teknik, ISSN 0281-658X, no 1, p. 61-63Article in journal (Other (popular science, discussion, etc.))
  • 21.
    Larsson, Stefan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Bjureland, William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Ignat, Razvan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Tar byggherrar geotekniska risker på allvar?2017Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    During the fall of 2015, the state owned property company Akademiska hus started the construction of a new education building on KTH:s Campus. Due to the astounding and poor management of geotechnical risks during construction, we have in two previous papers discussed our observations and the built in system error that we consider exists. In this paper, we go deeper into more technical questions and present the process that we ran parallel to the construction with responsible authorities and Akademiska hus. As can be seen in the paper, property developers, such as Akademiska hus, flaws symptomatically in their management of geotechnical risks simultaneously as responsible authorities acts neglectfully. The paper brings a serious lack of competence in light which must be scrutinized and treated with urgency.

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  • 22.
    Larsson, Stefan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Bjureland, William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Ignat, Razvan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Tar husbyggare geoteknisk säkerhet på allvar?2016In: Samhällsbyggaren, ISSN 2000-2408, no 3, p. 30-31Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Sedan 1 januari 2011 ska standarden Eurokod 7 användas för att garantera geotekniska konstruktioners säkerhet. Efter att på nära håll ha följt ett pågående husprojekt ifrågasätter vi nu hur väl uppföljningen av pågående grundläggnings- arbeten för byggnader fungerar. Hur lätt ska det vara att strunta i säkerheten — och komma undan med det utan konsekvenser?

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    Geoteknisk säkerhet
  • 23.
    Müller, Rasmus
    et al.
    Tyréns AB.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Extended multivariate approach for uncertainty reduction in the assessment of undrained shear strength in clays2014In: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 51, no 3, p. 231-245Article in journal (Refereed)
    Abstract [en]

    Important features of the multivariate approach are discussed, and an extension to this approach is proposed whereby the total uncertainty in site investigation methods due to spatial averaging is assessed prior to its adoption. Results from a site investigation of spatially averaged values of undrained shear strength (S-u) and the corresponding coefficient of variation (COVSu) in Veda sulphide clay were used as a practical illustration of the extended multivariate approach and provide a basis for discussion. The inherent variability and scales of fluctuation for different methods are presented. The study shows the usefulness of the extended multivariate approach for the evaluation of representative values of S-u and COVSu based on results from different methods. It is also a way of implicitly reducing the transformation errors that arise when a property is derived from measurement results. Nevertheless, considerable care must be taken as a much lower COV for one method will have a significant impact on the results.

  • 24.
    Müller, Rasmus
    et al.
    Tyréns AB.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Multivariate stability assessment during staged construction2016In: Canadian geotechnical journal (Print), ISSN 0008-3674, E-ISSN 1208-6010, Vol. 53, no 4, p. 603-618Article in journal (Refereed)
    Abstract [en]

    For staging the construction of embankments on soft clay, an important aspect in deterministic or probabilistic stability analyses is the assessment of the representative average values and associated uncertainties for the undrained shear strength as the height of the embankment is sequentially increased. Assessments made prior to construction can be verified by performing observations during the construction phase. All relevant available information should be incorporated into an analysis to increase the level of confidence and the objectivity of the assessment. To this end, we apply an extended multivariate approach to assess the undrained shear strength using different indirect measurement methods during the staged construction of the Veda embankment (Sweden). This multivariate approach implies that uncertainties associated with the assessments are reduced, and objectively weighted averages are obtained. The resulting implications on the calculated deterministic safety factors and the probabilistically retrieved reliability indices of the embankment are thoroughly discussed in this work.

  • 25.
    Olsson, Lars
    et al.
    Geostatistik AB.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Hintze, Staffan
    NCC.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Båtelsson, Olle
    Trafikverket.
    Framtidens riskhantering – nu med systemförståelse2019Conference paper (Other (popular science, discussion, etc.))
    Abstract [sv]

    Geoteknikern hanterar i sin vardag många och ofta stora risker. Men trots att kostnaden för negativa utfall av geotekniska risker årligen bedöms ligga på flera miljarder kronor, används tillgängliga verktyg för strukturerad riskhantering sparsamt. I ett SBUF-projekt har vi tagit fram en vägledning för hur sådana verktyg kan användas i praktiken. Vi har i denna vägledning särskilt fokuserat på den för riskhanteringen så viktiga systemförståelsen av det geotekniska sammanhanget som man verkar i. Denna artikel är en sammanfattande kortversion av den slutrapport som författarna skrivit inom ramen för SBUF-projektet.

  • 26.
    Prästings, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Characteristic values of geotechnical parameters in Eurocode 72019In: Proceedings of the Institution of Civil Engeneers: Geotechnical Engineering, ISSN 1353-2618, E-ISSN 1751-8563, Vol. 172, no 4, p. 301-311Article in journal (Refereed)
    Abstract [en]

    Lack of harmonisation between reliability-based design and the partial factor method in Eurocode 7 (EN 1997-1:2004) is preventing the widespread introduction of a risk-based concept in geotechnical design. This paper discusses how uncertainties are managed according to EN 1997-1:2004 and possible implications of not harmonising the current safety format with reliability-based design. One of several challenges highlighted is how EN 1997-1:2004 defines the characteristic value and design value. The characteristic value is therein defined based on a classical frequentist approach through a confidence interval. From a Bayesian point of view, the current definition does not treat the characteristic value as an uncertain variable. Consequently, the definitions of the characteristic value and design value in EN 1997-1:2004 feature weak connections between uncertainties in the geotechnical properties and the consequences of failure, as regulated by the target reliability index.

  • 27.
    Prästings, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Müller, Rasmus
    Tyréns AB.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Bjureland, William
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Implementing the Extended Multivariate Approach in Design with Partial Factors for a Retaining Wall in Clay2017In: ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering, ISSN 2376-7642, Vol. 3, no 4, article id 04017015Article in journal (Refereed)
    Abstract [en]

    Limitations with the current design using partial factors in Eurocode 7 have been identified. Uncertainties in the material properties are incorporated in both the cautious estimate of the characteristic value and the partial factor. Furthermore, the partial factor is fixed, which limits the opportunities to update the design when additional information is available. A more rational procedure of managing uncertainties in design with partial factors is proposed based on the Bayesian methodology referred to as the extended multivariate approach. The benefits of the approach are illustrated with a case study in which uncertainties of undrained shear strength are characterized for a Swedish clay. The characteristic value and design value is calculated in accordance with the Swedish national annex to Eurocode 7 by adjusting the otherwise fixed partial factor with a conversion factor allowable through EN 1990. The study highlights major benefits in managing uncertainties in a quantifiable and rational way.

  • 28.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    A Critical Review of the Observational Method2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Building a sustainable structure in soil or rock that satisfies all predefined technical requirements implies choosing a rational and effective construction method. An important aspect is how the performance of the structure is verified. For cases when the geotechnical behaviour is hard to predict, the existing design code for geotechnical structures, Eurocode 7, suggests the so-called “observational method” to verify that the performance is acceptable. The basic principle of the method is to accept predefined changes in the design during construction, in order to accommodate the actual ground conditions, if the current design is found unsuitable. Even though this in theory should ensure an effective design solution, formal application of the observational method is rare. It is therefore not clear which prerequisites and circumstances that must be present for the observational method to be applicable and be the more suitable method.

    This licentiate thesis gives a critical review of the observational method, based on, and therefore limited by, the outcome of the performed case studies. The aim is to identify and highlight the crucial aspects that make the observational method difficult to apply, thereby providing a basis for research towards a more applicable definition of the method. The main topics of discussion are (1) the apparent contradiction between the preference for advanced probabilistic calculation methods to solve complex design problems and sound, qualitative engineering judgement, (2) the limitations of measurement data in assessing the safety of a structure, (3) the fact that currently, no safety margin is required for the completed structure when the observational method is applied, and (4) the rigidity of the current definition of the observational method and the implications of deviations from its principles.

    Based on the review, it is argued that the observational method can be improved by linking it to a probabilistic framework. To be applicable, the method should be supported by guidelines that explain and exemplify how to make the best use of it. The engineering judgement is however not lost; no matter how elaborate probabilistic methods are used, sound judgement is still needed to define the problem correctly. How to define such a probabilistic framework is an urgent topic for future research, because this also addresses the concerns regarding safety that is raised in the other topics of discussion.

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    spross_lic_kappa
  • 29.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Toward a reliability framework for the observational method2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Constructing sustainable structures in rock that satisfy all predefined technical specifications requires rational and effective construction methods. When the geotechnical behaviour is hard to predict, the Euro­pean design code, Eurocode 7, suggests application of the observational method to verify that the performance is acceptable. The basic principle of the method is to accept predefined changes in the design during con­struction to comply with the actual ground conditions, if the current de­sign is found unsuitable. Even though this in theory should ensure an effective design solution, formal application of the observational method is rare.

    Investigating the applicability of the observational method in rock en­gineering, the aim of this thesis is to identify, highlight, and solve the aspects of the method that limit its wider application. Furthermore, the thesis aims to improve the conceptual understanding of how design deci­sions should be made when large uncertainties are present.

    The main research contribution is a probabilistic framework for the observational method. The suggested methodology allows comparison of the merits of the observational method with that of conventional design. Among other things, the thesis also discusses (1) the apparent contradiction between the preference for advanced probabilistic calculation methods and sound, qualitative engineering judgement, (2) how the establishment of limit states and alarm limits must be carefully considered to ensure structural safety, and (3) the applicability of the Eurocode defini­tion of the observational method and the implications of deviations from its principles.

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    fulltext
  • 30.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Vilken roll har observationsmetoden i framtidens bergbyggande?2017Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    In 2016, BeFo’s research project Observational method and reliability analysis wascompleted. The aim of this PhD project was to investigate how the observationalmethod can be linked to reliability-based design and when that is applicable. The resultshowed that reliability-based design methods are well adapted to apply together withthe observational method, in particular when such methods are combined with decisionanalysis. The main reason is that reliability-based methods straightforwardly canaccount for the effect of increased knowledge gained from measurements and observations.The decision analysis allows comparison of design options and design methods,so the most favourable method can be chosen. In this paper, I briefly present the mainresearch contributions of the project and discuss the future prospects of the observationalmethod.

  • 31.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Damasceno, Davi
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Jan
    Naturgasteknik AB.
    Stojanovic, Bojan
    Vattenfall.
    Simonsson, Nicklas
    Vattenfall.
    Storskalig lagring av vätgas i bergrum2019In: Bygg och Teknik, ISSN 0281-658X, no 1, p. 41-44Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Sveriges stålproduktion släpper idag ut stora mängder växthusgaser. Med initiativet HYBRIT hoppas SSAB, LKAB och Vattenfall göra stålproduktionen fossilfri genom att använda vätgas i processen. I HYBRIT:s forskningsprogram RP1 bidrar KTH Jord- och bergmekanik med att utveckla och förfina storskalig teknik för lagring av vätgas i bergrum. Artikeln beskriver de viktigaste frågeställningarna i forskningsprojektet.

  • 32.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Gasch, Tobias
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Reliability-based alarm thresholds for structures analysed with the finite element method2019In: Structural Safety, ISSN 0167-4730, E-ISSN 1879-3355, Vol. 76, p. 174-183Article in journal (Refereed)
    Abstract [en]

    Civil engineering structures are commonly monitored to assess their structural behaviour, using alarm thresholds to indicate when contingency actions are needed to improve safety. However, there is a need for guidelines on how to establish thresholds that ensure sufficient safety. This paper therefore proposes a general computational algorithm for establishment of reliability-based alarm thresholds for civil engineering structures. The algorithm is based on Subset simulation with independent-component Markov chain Monte Carlo simulation and applicable with both analytical structural models and finite element models. The reliability-based alarm thresholds can straightforwardly be used in the monitoring plans that are developed in the design phase of a construction project, in particular for sequentially loaded structures such as staged construction of embankments. With the reliability-based alarm thresholds, contingency actions will only be implemented when they are needed to satisfy the target probability of failure.

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  • 33.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    When is the observational method in geotechnical engineering favourable?2017In: Structural Safety, ISSN 0167-4730, E-ISSN 1879-3355, Vol. 66, p. 17-26Article in journal (Refereed)
    Abstract [en]

    The observational method in geotechnical engineering is an acceptable verification method for limit states in Eurocode 7, but the method is rarely used despite its potential savings. Some reasons may be its unclear safety definition and the lack of guidelines on how to establish whether the observational method is more favourable than conventional design. In this paper, we challenge these issues by introducing a reliability con­straint on the observational method and propose a probabilistic optimi­sation methodology that aids the decision-making engineer in choosing between the observational method and conventional design. The method­ology suggests an optimal design after comparing the expected utilities of the considered design options. The methodology is illustrated with a practical example, in which a geotechnical engineer evaluates whether the observational method may be favourable in the design of a rock pillar. We conclude that the methodology may prove to be a valuable tool for deci­sion-making engineers’ everyday work with managing risks in geotech­nical projects.

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    fulltext
  • 34.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Observationsmetoden – hur svårt kan det vara?2015Conference paper (Other academic)
  • 35.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    On the use of pore pressure measurements in safety reassessments of concrete dams founded on rock2013In: Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, ISSN 1749-9518, E-ISSN 1749-9526, Vol. 8, no 2, p. 117-128Article in journal (Refereed)
    Abstract [en]

    In probabilistic stability analyses of concrete dams founded on rock, the uplift pressure is often a parameter of major importance. In previous literature, it has been suggested that assessing uplift with pore pressure measurements, instead of using empirical assumptions, could improve the calculated dam safety. This paper presents a coherent methodology to investigate whether incorporating pore pressure measurements has any impact on the calculated dam safety, based on Bayesian linear regression of pore pressure data in combination with series-system and the first-order reliability method. The study concludes that the probability of sliding failure is closely related to the probability of an extreme increase in uplift. Hence, measured uplift should only be incorporated while this probability remains sufficiently small, which requires proper programs both for uplift monitoring and for maintenance of drains and grout curtains.

  • 36.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Reducing uplift pressure uncertainty with measurements under concrete dams2013In: Proceedings ICOLD 2013 International Symposium, Denver: US Society on Dams , 2013, p. 2551-2560Conference paper (Refereed)
    Abstract [en]

    In quantitative risk analyses of concrete dams founded on rock, it is necessary to consider the uplift pressure in the foundation with respect to both mean value and variation. With a more accurately predicted uplift pressure, the calculated probability of failure of the dam can be reduced. This paper proposes a methodology for predicting the current uplift pressure and related uncertainty, based both on pore pressure measurements and on expert judgment. An illustrative example is presented and the suggested methodology is compared with other conceivable approaches. The results are found to be reasonable in most conditions. However, it should be recognized that in risk analyses of dams, more extreme load cases not captured by the measurements also must be considered.

  • 37.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Tillståndsbedömning av betongdammar grundlagda på berg med observationsmetoden2013In: Bygg & teknik, ISSN 0281-658X, no 1, p. 83-87Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Observationsmetoden erbjuder ett alternativ till dagens mer etablerade dimensioneringsmetoder för geokonstruktioner. På Avdelningen för jord- och bergmekanik på Kungliga Tekniska högskolan (KTH) pågår för tillfället ett forskningsprojekt om när och i vilka typer av projekt som denna metod kan vara lämplig att använda, då man bygger i och på berg. Nu påbörjar vi ett delprojekt som syftar till att undersöka om och hur observationsmetoden kan tillämpas vid tillståndsbedömning av betongdammar grundlagda på berg, som ett led i att utveckla förvaltningen av Sveriges bestånd av dammar. Projektet finansieras av Svenskt Vattenkraftcentrum (SVC), Stiftelsen Bergteknisk forskning (BeFo) och Formas.

  • 38.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Towards an improved observational method2014In: Rock Engineering and Rock Mechanics: Structures in and on Rock Masses - Proceedings of EUROCK 2014, ISRM European Regional Symposium, Taylor & Francis Group, 2014, p. 1435-1440Conference paper (Refereed)
    Abstract [en]

    The observational method is today an accepted method in Eurocode 7 for design of geotechnical structures. However, case studies with formal application of its principles are still rare. One reason could be that the method to some extent is considered complex and associated with low safety margins. In fact, the Eurocode does not give any reference to how the safety of the completed structure can be assured. This paper strives to open up a discussion on how the observational method can be improved by including a requirement for a safety margin of the completed structure. A methodology is outlined and illustrated with a simple calculation example analysing the safety of a square rock pillar. Lastly, the compatibility with the observational method is discussed.

  • 39.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Uotinen, Lauri K.T.
    Department of Civil and Environmental Engineering, Aalto University.
    Rafi, Jalaleddin
    BGC engineering Inc.
    Using observational method to manage safety aspects of remedial grouting of concrete dam foundations2016In: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529, Vol. 34, no 5, p. 1613-1630Article in journal (Refereed)
    Abstract [en]

    As concrete dams age, the need for remedial grouting to reduce the seepage and uplift pressure in the rock foundations under them increases. Based on a case study of a Swedish dam with very low calculated safety against sliding, this paper discusses the application of the observational method (as defined in Eurocode 7) to manage safety aspects during remedial grouting. The studied case was complex in that grouting works posed the risk of causing increased uplift pressure, which could have induced sliding failure along a shallow, persistent, horizontal rock joint in the foundation. The approach applied in the studied case mainly followed the principles of the observational method, except in some highly significant safety aspects for which alternative procedures are suggested and discussed. Implementing these procedures along with the observational method offers a coherent framework to manage the safety aspects of the remedial grouting of concrete dam foundations that is in line with modern risk-informed dam safety policies.

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    Spross et al 2016
  • 40.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    On the observational method for groundwater control in the Northern Link tunnel project, Stockholm, Sweden2014In: Bulletin of Engineering Geology and the Environment, ISSN 1435-9529, E-ISSN 1435-9537, Vol. 73, no 2, p. 401-408Article in journal (Refereed)
    Abstract [en]

    For tunnelling in rock in Sweden, the public authorities usually set stringent requirements on low groundwater inflow to the tunnel, to minimise the risk of building settlement and the environmental impact. To improve this groundwater control, the potential application of the observational method in this matter was studied. A comparison was made between the actual implementation of groundwater control in the Northern Link road tunnel project in Stockholm and the definition of the observational method in Eurocode 7. The results showed that the groundwater control in the Northern Link project mainly agreed with the Eurocode. The significance of the deviations was discussed, and it was concluded that adopting the observational method for groundwater control so that it complied with Eurocode 7 would mostly entail simply a formalisation of today's procedures.

  • 41.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Lizka, Hana
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Observationsmetodens tillämpning på inläckande grundvatten i bergtunnlar – Fallstudie: Norra länken i Stockholm2012In: Bergmekanikdag 2012 - Föredrag / [ed] Eva Friedman, 2012, p. 89-100Conference paper (Other academic)
  • 42.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Olsson, Lars
    Geostatistik AB.
    Hintze, Staffan
    NCC.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Geotekniska risker kan hanteras bättre2016In: Bygg och teknik, ISSN 0281-658X, Vol. 108, no 1, p. 63-66Article in journal (Other (popular science, discussion, etc.))
  • 43.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Olsson, Lars
    Geostatistik AB.
    Hintze, Staffan
    NCC.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Hantering av geotekniska risker i byggprojekt: Ett praktiskt tillämpningsexempel2015Report (Other academic)
    Abstract [sv]

    Skador till följd av utfall av negativa geotekniska risker kostar stora summor för svensk byggindustri. Det krävs därför en effektiv och transparent riskhantering som kan minska kostnaderna. I dagsläget används sällan de verktyg som finns tillgängliga för riskhantering fullt ut i byggprojekten.

    Denna rapport visar hur ett sådant verktyg, Svenska Geotekniska Föreningens metodbeskrivning för geoteknisk riskhantering (SGF Rapport 1:2014), kan användas i praktiken. Vi ger ett omfattande illustrativt exempel på hur riskhantering kan utföras i alla skeden av ett typiskt geotekniskt projekt från idéfas till driftskede. Exemplet är fingerat men baserar sig på schakt och grundläggning till utbyggnaden av Hästsportens hus vid Solvalla travbana från 1992.

    Det är vår uppfattning att metodiken i SGF Rapport 1:2014 är tillämpbar på alla skeden i byggprocessen, från idéfas till driftfas, i både stora och små projekt. Det är dock avgörande att riskhanteringen anpassas till varje nytt projekt eller projektskede. Det strukturerade arbetssättet som metodiken ger höjer kvalitén på riskhanteringen jämfört med ett ad hoc-betonat arbetssätt, som man ofta ser i dagens projektstyrning.

    Med tanke på denna höjda kvalitet menar vi att riskkostnaderna kan bli mindre. En absolut grund för detta är dock att man uppfyller de fyra baskraven. Dessa syftar dels till att skapa och upprätthålla en kultur där man är medveten om risker som finns hur de påverkar projektet, dels till att definiera och tydliggöra riskhanteringen inom organisationen så att inget faller mellan stolarna. Därför är det viktigaste kravet att den som bestämmer har en medveten risksyn.

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    SBUF13009
  • 44.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Olsson, Lars
    Geostatistik AB.
    Hintze, Staffan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway Engineering Laboratory.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Would risk management have helped? – A case study2015In: Geotechnical safety and risk V / [ed] T. Schweckendiek, A.F. van Tol, P. Pereboom, M.Th. van Staveren, P.M.C.B.M. Cools, Amsterdam: IOS Press, 2015Conference paper (Refereed)
    Abstract [en]

    To reduce the costs of unexpected geotechnical events in construction projects in Sweden, the Swedish Geotechnical Society has adopted a general methodology for risk management. In this paper, we exemplify how the proposed risk management philosophy could have been applied on a sheet-pile wall, which failed in 1992 in Stockholm because the design did not consider the complex site conditions. Focusing on the design phase, we discuss how geotechnical risks may be managed effectively as a natural part of the engineer’s everyday work.

    Download full text (pdf)
    Spross et al_ISGSR 2015
  • 45.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Olsson, Lars
    Geostatistik AB, Tumba, Sweden..
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    The Swedish Geotechnical Society's methodology for risk management: a tool for engineers in their everyday work2018In: Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, ISSN 1749-9518, E-ISSN 1749-9526, Vol. 12, no 3, p. 183-189Article in journal (Refereed)
    Abstract [en]

    The Swedish Geotechnical Society has adopted a general methodology for risk management in geotechnical engineering projects to reduce the costs related to negative outcomes of geotechnical risks. This technical note highlights the main features of the methodology and strives to inspire the international geotechnical community to apply sensible risk management methods. In the authors' opinion, a successful geotechnical risk management needs to be structured, be tailored to the project, and permeate the engineers' everyday work. Then, sufficient quality can be achieved in the project with larger probability.

  • 46.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Prästings, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Probabilistic evaluation of settlement monitoring with the observational method during construction of embankments on clay2019In: Proceedings of the 7th International Symposium on Geotechnical Safety and Risk (ISGSR 2019): State-of-the-Practice in Geotechnical Safety and Risk / [ed] Jianye Ching, Dian-Qing Li and Jie Zhang, 2019, article id IS3-3Conference paper (Refereed)
    Abstract [en]

    Preloading  is  commonly  used  to  accelerate  primary  consolidation  and  increase  strength  under  embankments founded on highly compressible clay. By installing prefabricated vertical drains, this process can be even further accelerated. Because of significant geotechnical uncertainties, primarily regarding the vertical and horizontal coefficients of consolidation, prediction of settlement development with time is difficult. This paper shows how Bayesian statistics can be used to update a prior prediction of  the  final  settlement  from  the design  stage, with observations of  settlement made during  the preloading. With  this  approach,  the  observations  during  construction  are  used  to  significantly  reduce  the  considerable  epistemic uncertainty present at the design stage. This allows the surcharge design to be adjusted to suit the actual ground conditions, which is done by increasing the surcharge height if the settlement develops too slowly.

  • 47.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Palmström, Arild
    Rock Mass AS.
    Hur ska bergbyggande kunna inkluderas i Eurokod 7: How to include rock engineering in Eurocode 72019In: Proceedings Bergdagarna 2019, 2019Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Sweden, among other countries, has chosen not to apply Eurocode 7 to rock engineer­ing design. However, Eurocode 7 is currently under revision, with one purpose being to improve its applicability to rock engineering. Such a revision would however require that the code accommodates the current principles of rock engineering design and exe­cution, since rock engineering in many cases fundamentally differs from other types of construction. In this presentation, we give our view on how a design code for rock engineering needs to be organized, in order to ensure that new rock engineering struc­tures become both sufficiently safe and cost-effectively constructed. An important pre­requisite is having a decision-theoretical connection between design and risk manage­ment that always should permeate geotechnical design and construction. The presented research is based on the results from a research project funded by the Rock Engineering Research Foundation (BeFo) that was finalized in January 2019.

  • 48.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Palmström, Arild
    RockMass Consulting Co, Ovre Smestad Vei 35E, N-0378 Oslo, Norway..
    On the Need for a Risk-Based Framework in Eurocode 7 to Facilitate Design of Underground Openings in Rock2018In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 51, no 8, p. 2427-2431Article in journal (Refereed)
    Abstract [en]

    The European design code for geotechnical engineering, EN-1997 Eurocode 7, is currently under revision. As design of underground openings in rock fundamentally differs from design of most other types of structures, the revised Eurocode 7 must be carefully formulated to be applicable to underground openings. This paper presents the authors' view of how a design code for underground openings in rock needs to be organized to ensure that new structures are both sufficiently safe and constructed cost-effectively. The authors find that the revised version of Eurocode 7 carefully must acknowledge the fundamental decision-theoretical connection between design and risk management that should permeate all geotechnical design work. Otherwise, if the revised code is not given a risk-based framework, the authors fear that, as a consequence, the observational method will not be favorable to use in excavations of underground openings in rock. Then, cost-effective construction will be very difficult to achieve.

  • 49.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Palmstrøm, Arild
    Rock Mass Consulting Company.
    Principles of risk‑based rock engineering design2020In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 53, p. 1129-1143Article in journal (Refereed)
    Abstract [en]

    In comparison with other types of construction, the development of rock engineering design codes has been slow. Codesmust, however, be developed with relevant discipline-specific characteristics in mind. This paper, therefore, presents ageneric design framework for rock engineering. The framework is based on the presumption that rock engineering designmust be viewed as decision-making under uncertainty, which makes the design process subject to general risk managementprinciples, as risk is defined as “effect of uncertainties on objectives” (ISO 31000). Thus, rock engineering design codesultimately need to facilitate design processes that target the risk, to enable design of structures that not only are sufficientlysafe and durable and cost-effectively constructed, but also imply safe and healthy work conditions during construction andan acceptably low environmental impact. The presented framework satisfies this fundamental requirement and the authorsfind codification of its principles to be rather straightforward, as long as the level of detail in the code is governed by a strictapplication of ISO’s general risk management principles. Further details on methods and practical recommendations caninstead be supplemented in separate handbooks and application guidelines.

    Download full text (pdf)
    fulltext
  • 50.
    Spross, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Stille, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Palmstrøm, Arild
    Rock Mass Consultancy Company.
    Utredning av riskbaserade principer inom bergdimensionering: Så bör en standard vara uppbyggd2019Report (Other academic)
    Abstract [en]

    The design of a rock engineering structure generally needs to satisfy a number of requirementsthat may originate from clients, as well as laws, court verdicts, and design codes. Thedesigning rock engineer needs to account for all these requirements, while trying to optimizethe structure to maximize the utility of the invested funds. The Eurocodes have beenthe current design code in Sweden for almost all construction work, except for rock engineering.However, in the ongoing revision of Eurocode 7, one main purpose is to improvethe applicability with respect to rock engineering. A scientific basis for this work has howeverbeen missing. The purpose of this research project, which ends with this final report,has therefore been to support the revision work by publishing two scientific articles on rockengineering design principles.

    The research project has mainly focused on the general design principles and how these bynecessity needs to be viewed from a risk management perspective. As we see it, it is essentialthat the revised Eurocode 7 is structured in accordance to risk-based principles. Thisimplies that design needs to be understood as a part of the necessary structured risk managementwork that is carried out in construction projects. In the two appended articles, weshow how design may be interpreted within the general risk management principles establishedby the international standard ISO 31000. Such a risk-based view facilitates bothtransparent and structured design work. This also allows the design work to be integrated inthe general risk management process that regardless is carried out in the constructionproject.

    In Article I, we discuss synoptically the general principles for how a rock engineeringdesign code needs to be structured to facilitate both cost-effective construction and sufficientlysafe structures. In particular, we discuss the importance of integrating the observationalmethod into the design code, so that this limit state verification method is equallytreated as the others.

    In Article II, we take a more holistic approach to the fundamental meaning of risk-based rock engineering design. The article presents a generic framework for rock engineeringdesign, where it is presupposed that design by definition is decision-making under uncertainty. We discuss and structure the required decisions and considerations that are made in the design work and show how those decisions can be made from a risk perspective. Tosupport the revision work of Eurocode 7, we also discuss how the presented framework canbe implemented in a design code. An essential principle is that the code allows the designingrock engineer to manage the associated risks in a way that is suitable given the projectat hand. This implies that code writers should refrain from putting too detailed requirementsregarding for example the extent and quality of pre-investigations. Otherwise, we fear thatpotentially costly measures occasionally will need to be taken not because they are neededfrom a risk perspective, but only because the code requires them. This would in our opinionnot be in line with the overall striving toward a long-term sustainable societal development.

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