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Spross, J. & Stille, H. (2023). Geotekniska bedömningsgrunder (GBR): Ett verktyg för tydligare riskdelning i kontrakt. In: : . Paper presented at Bergteknikdagen 2023. Stockholm: Svenska bergteknikföreningen
Open this publication in new window or tab >>Geotekniska bedömningsgrunder (GBR): Ett verktyg för tydligare riskdelning i kontrakt
2023 (Swedish)Conference paper, Published paper (Other (popular science, discussion, etc.))
Abstract [sv]

Undermarksprojekt är ofta tekniskt komplicerade, samtidigt som de kännetecknas av stora geologiska och geotekniska risker. Riskerna har sitt ursprung i att det för bergbyggande är svårt att i förväg fastställa vilka tekniska egenskaper som berget har. Denna osäkerhet ger inte bara tekniska, utan även juridiska och ekonomiska utmaningar. Ofta hamnar man i frågan vem som ska stå för den ekonomiska risken om kostnaderna blir högre än väntat. Om riskfördelningen mellan parterna inte är tydligt reglerad i kontraktet, kan det uppstå en både arbetsam och kostsam tvist. Ett relaterat problem är hur riskerna presenteras i förfrågningsunderlaget. Ett otydligt förfrågningsunderlag försvårar för entreprenadbolagen att komma fram till en rimlig prissättning. Internationellt finns ett kontraktsdokument som kallas Geotechnical Baseline Report (rapport för geotekniska bedömningsgrunder), som tagits fram för att tydliggöra parternas ansvar för geologiska och geotekniska risker i geotekniska byggprojekt. I en ny BeFo-rapport har vi introducerat principerna för hur detta kontraktsdokument kan förstås, tolkas och tillämpas i upphandling och utförande av svenska undermarksprojekt. Denna artikel och tillhörande presentation på Bergdagarna ger ett sammandrag av rapporten. Särskild vikt läggs vid definitionen av geoteknisk bedömningsgrund och hur sådana kan användas för att uppnå en tydlig riskdelning i förfrågningsunderlag och kontrakt i praktiken.

Abstract [en]

Underground excavation is often technically complex, as well as associated with large geological and geotechnical risk. The risks originate from the rock engineer’s challenge to determine in advance the technical properties of the rock mass. This uncertainty gives not only technical, but also legal and economic challenges. It is often unclear which party shall own the economic risk, if there is a cost increase. If the risk ownership is not clear from the contract, a time-consuming and costly dispute may occur. A related issue concerns how risks are presented in the tender documents. Vague tender documents make the bidder’s task to find a reasonable price more challenging. Interna-tionally, a concept known as Geotechnical Baseline Report (GBR) is often used to clar-ify the risk allocation in geotechnical engineering projects. In a new research report published by BeFo (Rock Engineering Research Foundation), the authors have intro-duced the principles of GBR in a Swedish context, focusing on Swedish underground excavation projects in rock. This article and accompanying presentation at the Rock Engineering Days provide the main points from the research report, focusing on the defi-nition of a geotechnical baseline and its potential use to achieve a fair risk allocation in tender documents and contracts.

Place, publisher, year, edition, pages
Stockholm: Svenska bergteknikföreningen, 2023
Keywords
Tunnel, GBR, Geoteknisk Bedömningsgrund
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-327861 (URN)
Conference
Bergteknikdagen 2023
Funder
Rock Engineering Research Foundation (BeFo), 400
Note

QC 20230615

Available from: 2023-06-01 Created: 2023-06-01 Last updated: 2025-02-07Bibliographically approved
Mohammadi, M., Spross, J. & Stille, H. (2023). Probabilistic Time Estimation of Tunneling Projects: The Uri Headrace Tunnel. Rock Mechanics and Rock Engineering, 56(1), 703-717
Open this publication in new window or tab >>Probabilistic Time Estimation of Tunneling Projects: The Uri Headrace Tunnel
2023 (English)In: Rock Mechanics and Rock Engineering, ISSN 0723-2632, E-ISSN 1434-453X, Vol. 56, no 1, p. 703-717Article in journal (Refereed) Published
Abstract [en]

Probabilistic time estimation is an essential part of proper risk management in tunneling projects. In recent decades, several models have been developed for this purpose, one of which was developed by Isaksson and Stille (Rock Mech Rock Eng 38:373–398, 2005). In this paper, Isaksson and Stille’s probabilistic time and cost estimation model was improved and then applied to estimate the total tunneling time of the headrace tunnel in the Uri hydropower project in India. The improvements allow the user to more accurately account for different types of geological features and disruptive events. The result of the estimation is a distribution of tunneling time. The outcome illustrates how a proper understanding of the geological setting of the project and its effect on construction performance can contribute to effective risk management. 

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Overrun, Probabilistic approaches, Risk management, Time and cost estimation, Tunneling, Cost benefit analysis, Cost estimating, Geology, Project management, Risk perception, Uncertainty analysis, Cost estimations, Headrace tunnel, Probabilistics, Probabilistics approach, Risks management, Time estimation, Tunneling project, Tunneling time, hydroelectric power plant, numerical model, parameter estimation, probability, risk assessment, India
National Category
Geotechnical Engineering and Engineering Geology
Identifiers
urn:nbn:se:kth:diva-326790 (URN)10.1007/s00603-022-03022-3 (DOI)000839440300001 ()2-s2.0-85135806373 (Scopus ID)
Note

QC 20230515

Available from: 2023-05-15 Created: 2023-05-15 Last updated: 2025-02-07Bibliographically approved
Walter, H., Labiouse, V., Lamas, L., Nuijten, G., Spross, J. & Stille, H. (2023). Rock engineering design in tomorrow's geotechnical toolbox: Eurocode 7 – General Rules (EN 1997-1:2024). Geomechanics and Tunneling, 16(5), 491-509
Open this publication in new window or tab >>Rock engineering design in tomorrow's geotechnical toolbox: Eurocode 7 – General Rules (EN 1997-1:2024)
Show others...
2023 (English)In: Geomechanics and Tunneling, ISSN 1865-7362, E-ISSN 1865-7389, Vol. 16, no 5, p. 491-509Article in journal (Refereed) Published
Abstract [en]

The second generation of Eurocode 7 aims at covering ground, including both soil and rock. Current practice of ground engineering forms the basis, and the aim is to include rock engineering, improving ease of use, harmonization of regulations, and covering new developments. This paper deals with EN 1997 part 1 addressing the general rules of geotechnical design, connected to EN 1990, the basis of structural and geotechnical design, and parts 2 and 3 of EN 1997. The design process from ground investigation to the verification of limit states is illustrated with a focus on rock engineering. The following topics are dealt with in more detail: Geotechnical Categories: They are now based on Consequence Classes and newly introduced Geotechnical Complexity Classes. A limit state design to be sufficient has to be combined with other checks depending on these classes.Replacement of the Design Approaches of the current Eurocode 7: Ultimate limit states will be verified by a combination of Verification Cases with partial factors on actions and action effects, and sets of partial factors on ground properties and resistances, respectively.Application of numerical methods, where a ULS-verification with two sets of partial factors is defined.Use of probabilistic methods in design by calculation, especially appropriate in cases where properties of discontinuities govern the design.Practice of the Observational Method, including design variants and regulations about their choice.

Abstract [de]

Die zweite Generation des Eurocodes 7 zielt darauf ab, den Baugrund, einschließlich Boden und Fels, abzudecken. Die derzeitige Praxis der geotechnischen Planung bildet die Grundlage; das Ziel ist es, den Felsbau einzubeziehen, die Benutzerfreundlichkeit zu verbessern, die Vorschriften zu harmonisieren und neue Entwicklungen zu berücksichtigen. Dieser Beitrag behandelt EN 1997 Teil 1, der sich mit den allgemeinen Regeln der geotechnischen Planung befasst, in Verbindung mit EN 1990, den Grundlagen der Planung von Tragwerken und geotechnischen Bauwerken, und den Teilen 2 und 3 von EN 1997. Der Entwurfsprozess von der Baugrunderkundung bis zum Nachweis der Grenzzustände wird mit einem Schwerpunkt auf dem Felsbau dargestellt. Die folgenden Themen werden ausführlicher behandelt: Geotechnische Kategorien: Das Konzept wurde beibehalten, basiert nun aber auf Versagensfolgeklassen (definiert in EN 1990) und neu eingeführten Klassen der geotechnischen Komplexität. Um ein ausreichendes Maß an Zuverlässigkeit eines geotechnischen Bauwerks zu gewährleisten, ist nicht nur eine ausreichende Bemessung für Grenzzustände erforderlich, sondern es müssen auch andere Anforderungen in Abhängigkeit von diesen Klassen erfüllt werden.Ersatz der Nachweisverfahren des aktuellen Eurocodes 7: Die Grenzzustände der Tragfähigkeit werden in Abhängigkeit von der Art des geotechnischen Bauwerks durch eine Kombination aus den in EN 1990 definierten Nachweisfällen (Verification Cases), in denen die Teilsicherheitsbeiwerte für Einwirkungen und Auswirkungen der Einwirkungen definiert sind, und den in EN 1997 definierten Sätzen von Teilsicherheitsbeiwerten für Bodeneigenschaften bzw. Widerstände nachgewiesen.Anwendung numerischer Methoden, wobei ein ULS-Nachweis mit zwei Sätzen von Teilsicherheitsbeiwerten vorgesehen ist, und mögliche Vorgangsweisen für eine Abfolge von Bauzuständen definiert werden.Anwendung probabilistischer Methoden bei der Bemessung, insbesondere in Fällen, in denen die Eigenschaften von Trennflächen (z. B. Trennflächen) die Bemessung bestimmen.Praxis der Beobachtungsmethode, einschließlich des Konzepts von Bemessungsvarianten und von Vorschriften für deren Auswahl

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
Eurocode, design, verification, rock engineering, probabilistic methods
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-337730 (URN)10.1002/geot.202300019 (DOI)2-s2.0-85169448232 (Scopus ID)
Note

The article has both an English and a German version.

Germna title: Felsbauplanung mit dem geotechnischen Werkzeugkasten von morgen: Eurocode 7 – Allgemeine Regeln (EN 1997-1:2024)

QC 20231009

Available from: 2023-10-06 Created: 2023-10-06 Last updated: 2025-02-07Bibliographically approved
Maca, N., Dietz, K., Stille, H. & Virely, D. (2023). Rock engineering design in tomorrow's geotechnical toolbox: Eurocode 7 – Geotechnical structures: Anchors, rock bolts soil nails, and groundwater control (EN 1997-3:2024). Geomechanics and Tunneling, 16(5), 536-558
Open this publication in new window or tab >>Rock engineering design in tomorrow's geotechnical toolbox: Eurocode 7 – Geotechnical structures: Anchors, rock bolts soil nails, and groundwater control (EN 1997-3:2024)
2023 (English)In: Geomechanics and Tunneling, ISSN 1865-7362, E-ISSN 1865-7389, Vol. 16, no 5, p. 536-558Article in journal (Refereed) Published
Abstract [en]

In 2025 the new generation of the Eurocode 7 will be introduced and set a framework for geotechnical design for the next 20 years. As Eurocode 7 is an essential design code, the changes will affect numerous practising geotechnical Engineers. The paper provides an overview of significant changes in rock engineering design introduced in the new EN 1997 part 3, considering limit state design, durability, reliability, testing and other crucial design aspects. It focuses on the anchor clause revision and first introduced design rules for rock bolts and soil-nailed structures. The improvements described include distinguishing between different tension supporting elements that have often been confused. Furthermore, the provisions for groundwater control measures influencing the working condition and limit states for all other geotechnical systems that have not yet been comprehensively addressed in the current Eurocode 7 are also clarified. Finally, the design of the described geotechnical structure will also be strongly affected by changes in the overall philosophy of the Eurocodes, which is also explained.

Abstract [de]

Im Jahr 2025 wird die neue Generation des Eurocodes 7 eingeführt, die den Rahmen für die geotechnische Bemessung in den nächsten 20 Jahren vorgibt. Da der Eurocode 7 eine wesentliche Bemessungsvorschrift ist, werden die Änderungen zahlreiche praktizierende Geotechniker betreffen. Der Beitrag gibt einen Überblick über einige wesentliche Änderungen in der Felsplanung, die in der neuen EN 1997 Teil 3 eingeführt wurden, und berücksichtigt dabei die Grenzzustandsbemessung, die Dauerhaftigkeit, die Zuverlässigkeit, die Prüfung und andere wichtige Bemessungsaspekten. Der Schwerpunkt liegt auf der Überarbeitung des Abschnitts Anker und den erstmals eingeführten Bemessungsregeln für Felsnägel und bodenvernagelte Strukturen. Zu den beschriebenen Verbesserungen gehört die Unterscheidung zwischen verschiedenen Sicherungselementen, die oft verwechselt wurden. Die Bestimmungen für Grundwasserschutzmaßnahmen, die den Betriebszustand und die Grenzzustände für alle anderen geotechnischen Systeme beeinflussen, die im aktuellen Eurocode 7 noch nicht umfassend behandelt wurden, werden ebenfalls klargestellt. Darüber hinaus wird die Bemessung des beschriebenen geotechnischen Bauwerks auch stark von Änderungen in der Gesamtphilosophie der Eurocodes beeinflusst, was ebenfalls erläutert wird.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
Eurocode, rock engineering, anchors, rock bolts, rock support, soil nailed structures, groundwater control
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-337733 (URN)10.1002/geot.202300026 (DOI)2-s2.0-85172985626 (Scopus ID)
Note

The article has both an English and a German version.

German title: Felsbauplanung im geotechnischen Werkzeugkasten von morgen: Eurocode 7 – Geotechnische Bauwerke: Anker, Felsnägel, Bodennägel und Grundwasserkontrolle (EN 1997‐3:2024)

QC 20231009

Available from: 2023-10-06 Created: 2023-10-06 Last updated: 2025-02-07Bibliographically approved
Stille, H., Ashcroft, B., Boley, C., Labiouse, V. & Pinto, P. (2023). Rock engineering design in tomorrow's geotechnical toolbox: Eurocode 7 – Geotechnical structures: slopes, spread foundations and retaining structures (EN 1997-3:2024). Geomechanics and Tunneling, 16(5), 524-535
Open this publication in new window or tab >>Rock engineering design in tomorrow's geotechnical toolbox: Eurocode 7 – Geotechnical structures: slopes, spread foundations and retaining structures (EN 1997-3:2024)
Show others...
2023 (English)In: Geomechanics and Tunneling, ISSN 1865-7362, E-ISSN 1865-7389, Vol. 16, no 5, p. 524-535Article in journal (Refereed) Published
Abstract [en]

The second generation of Eurocode 7 includes both soil and rock. In addition to the current practice of ground engineering, this document aims at incorporating rock engineering, improving the ease of use, the harmonization of regulations and covering new developments. This paper provides an overview of some of the significant changes to Eurocode 7 in rock engineering design, taking into consideration limit state design, robustness, durability, and reliability. It focuses on the design of slopes, spread foundations, and retaining structures.

The clauses focus on soil mechanics, but also include special rock mechanical issues such as the influence of discontinuities and strength anisotropy on the limit states. Many matters associated to verification of rock mechanical design are linked to the use of prescriptive rules and shall be given in National Annexes. For geotechnical structures in rock, it is mentioned that geotechnical mapping and documentation is important to verify the limit states. However, the basic issues with partial factor methods for verification of the ground-structure interaction of reinforced slopes and retaining structures are not fully resolved. This has caused some difficulties in setting up partial factors and obtaining a sufficient overview of the application of partial factor method, especially in rock engineering.

The design of slopes, spread foundations and retaining structures must likewise consider other clauses in the Eurocode. Rock support for slopes and retaining structures is described in Clause 13 ”Rock Bolts and Surface Support“. Groundwater-related issues are described in clause 12 ”Ground water control“ which influence the design and limit states for the actual geotechnical structure. Dams and levees are featured in Clause 4 ”Slopes, Cuttings and Embankments“.

Abstract [de]

Die zweite Generation des Eurocodes 7 umfasst sowohl Boden als auch Fels. Wesentliche Grundlage ist die Berücksichtigung der aktuellen Praxis im geotechnischen Ingenieurwesen. Der Felsbau wird einbezogen, weitere Ziele sind die Verbesserung der Anwenderfreundlichkeit, die Harmonisierung von Regelwerken und die Erfassung neuer Entwicklungen. Der Beitrag gibt einen Überblick über einige wesentliche Änderungen des Eurocodes 7 in der Bemessung im Felsbau, hinsichtlich der Bemessung im Grenzzustand, der Robustheit, Dauerhaftigkeit und Zuverlässigkeit. Der Beitrag behandelt die Bemessung von Böschungen, Flachgründungen und Stützbauwerken.

Die Abschnitte haben ihren Schwerpunkt auf der Bodenmechanik, beinhalten jedoch darüber hinaus spezielle gebirgsmechanische Fragestellungen wie den Einfluss von Diskontinuitäten und der Festigkeitsanisotropie auf die Grenzzustände. Viele Punkte im Zuge der Bemessung im Felsbau betreffen die Anwendung von Vorschriften und sind in den Nationalen Anhängen zu behandeln. Für geotechnische Bauwerke im Fels wird darauf hingewiesen, dass die geotechnische Kartierung und Dokumentation wichtig sind im Zuge der Betrachtung der Grenzzustände. Die grundlegenden Fragestellungen bei der Bemessung nach dem Teilsicherheitskonzept beim Nachweis der Boden-Bauwerk-Interaktion von befestigten Böschungen und Stützbauwerken sind nicht vollständig gelöst. Dies hat an einigen Stellen Schwierigkeiten bei der Erarbeitung der Teilsicherheitsbeiwerte und der generellen Umsetzung des Teilsicherheitskonzepts insbesondere im Felsbau geführt.

Bei der Bemessung von Böschungen, Flächengründungen und Stützkonstruktionen sind darüber hinaus weitere Abschnitte des Eurocodes zu berücksichtigen. Felssicherungen für Böschungen und Stützbauwerke sind in Abschnitt 13 „Felsanker und Oberflächensicherung” beschrieben. Grundwasserbezogene Fragestellungen werden in einem Sonderabschnitt 12 „Grundwasserschutz” beschrieben und haben ebenso Einfluss auf die Bemessungs- und Grenzzustände des eigentlichen geotechnischen Bauwerks. Deiche und Dämme werden ein Teil von Abschnitt 4 „Böschungen, Einschnitte und Dämme”.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
Eurocode, rock engineering, slopes, spread foundations, retaining structures
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-337732 (URN)10.1002/geot.202300025 (DOI)2-s2.0-85173018994 (Scopus ID)
Note

The article has both an English and a German version.

German title: Felsmechanische Planung in der geotechnischen Werkzeugkiste von morgen: Eurocode 7 – Geotechnische Bauwerke: Böschungen, Flachgründungen und Stützkonstruktionen (EN 1997‐3:2024)

QC 20231009

Available from: 2023-10-06 Created: 2023-10-06 Last updated: 2025-02-07Bibliographically approved
Harrison, J. P., Burbaum, U., Lamas, L., Spross, J. & Stille, H. (2023). Rock engineering design in tomorrow's geotechnical toolbox: Perspectives on the evolution to the 2035 third generation of Eurocode. Geomechanics and Tunneling, 16(5), 560-572
Open this publication in new window or tab >>Rock engineering design in tomorrow's geotechnical toolbox: Perspectives on the evolution to the 2035 third generation of Eurocode
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2023 (German)In: Geomechanics and Tunneling, ISSN 1865-7362, E-ISSN 1865-7389, Vol. 16, no 5, p. 560-572Article in journal (Refereed) Published
Abstract [en]

The current Eurocode revision process is sought to improve Eurocode 7 for application to rock engineering, while including only techniques and procedures that are in widespread customary use. The revision process has exposed much about the application of the Eurocodes to rock engineering, thereby offering hints as to what material should be included in the next revision – tentatively suggested for publication in 2035. Crucially, ideas have developed about how rock engineering practice may need to develop to embrace the principles on which the Eurocodes are based. In particular, aspects of determining the properties of rock masses, and design verification by observational methods, partial factors, numerical modelling, and prescriptive rules are all thought to require significant improvement or dramatic modification. This paper highlights challenges identified regarding the application of the Eurocodes to rock engineering, and which will need to be addressed in the future. Ideas are presented about how these challenges may be overcome, but these are given in the spirit of stimulating ongoing conversation within the rock mechanics and rock engineering community rather than presenting definite proposals.

Abstract [de]

Bei der derzeitigen Überarbeitung des Eurocodes wird angestrebt, den Eurocode 7 für die Anwendung im Felsbau zu verbessern, wobei allgemein übliche und anerkannte Techniken und Verfahren aufgenommen wurden. Der Überarbeitungsprozess hat viel über die Anwendung der Eurocodes im Felsbau in den Mitgliedsländern des CEN zutage gefördert und damit Ideen gegeben, welche Inhalte in die nächste, dritte Überarbeitung bis 2035 aufgenommen werden sollten. Entscheidend ist, dass Vorstellungen entwickelt werden, wie sich die Felsbaupraxis weiterentwickeln soll, um die Grundsätze, auf denen die Eurocodes basieren, zu berücksichtigen. Insbesondere die Aspekte der Bestimmung der Eigenschaften von Gestein und Gebirge sowie der Überprüfung der Planung durch Beobachtungsmethode, Entwicklung von Teilsicherheitsbeiwerten, numerische Modellierung und festgelegten Bemessungsregeln bedürfen einer erheblichen Verbesserung oder drastischen Änderung. In diesem Beitrag werden die Herausforderungen dargestellt, die bei der Anwendung der Eurocodes im Felsbau festgestellt wurden und die in der Zukunft angegangen werden müssen. Es werden Ideen vorgestellt, wie diese Herausforderungen gemeistert werden können. Diese werden jedoch nicht als konkrete Vorschläge präsentiert, sondern als Anregung für laufende Diskussionen innerhalb der Felsmechanik und des Felsbaus.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
Eurocode, design, verification, development, research
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-337731 (URN)10.1002/geot.202300027 (DOI)2-s2.0-85169680420 (Scopus ID)
Note

The article has both an English and a German version.

German title: Felsbauplanung mit dem geotechnischen Werkzeugkasten von morgen: Perspektiven der Entwicklung der dritten Generation des Eurocodes 2035

QC 20231009

Available from: 2023-10-06 Created: 2023-10-06 Last updated: 2025-02-07Bibliographically approved
Zhang, S., Johansson, F. & Stille, H. (2022). Design Methodology for Grout Curtains Under Dams Founded on Rock. Geotechnical and Geological Engineering, 40(4), 2167-2186
Open this publication in new window or tab >>Design Methodology for Grout Curtains Under Dams Founded on Rock
2022 (English)In: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529, Vol. 40, no 4, p. 2167-2186Article in journal (Refereed) Published
Abstract [en]

Grout curtains are commonly constructed under dams to reduce the seepage through the rock foundation. In the design of grout curtains, empirical methods have mainly been used since the introduction of dam foundation grouting. Although empirical methods have been used with success in several projects, they have their limitations, such as poor control of the grout spread, only an indirect consideration of the threat of internal erosion of fracture infillings in the grouted zones, and the risk of hydraulic jacking. This paper presents a theory-based design methodology for grout curtains under dams founded on rock. In the design methodology, the grout curtain is designed as a structural component of the dam. The risk of erosion of fracture infilling material is explicitly accounted for along with the reduction of the hydraulic conductivity of the rock mass, and an optimization of the total uplift force. By applying the proposed design methodology, engineers can create a design better adapted to the prevailing geological and hydrogeological conditions in the rock mass, resulting in more durable grout curtains. The proposed methodology also enables cost and time estimates to be calculated for the grout curtain’s construction. Applying the principles of the observational method during the grouting execution also allows the design to be modified via predefined measures if the initial design is found to be unsuitable.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Dam, Grout curtain, Internal erosion, Rock mass, Stop criteria, Concrete construction, Dams, Design, Erosion, Grouting, Hydrogeology, Mortar, Rock mechanics, Dam foundation, Design Methodology, Empirical method, Fracture infilling, Grout curtains, Hydraulic jacking, Rock foundation, Rock-mass, Rocks
National Category
Geotechnical Engineering and Engineering Geology
Identifiers
urn:nbn:se:kth:diva-313253 (URN)10.1007/s10706-021-02019-z (DOI)000720206900001 ()2-s2.0-85119249948 (Scopus ID)
Note

QC 20220603

Available from: 2022-06-03 Created: 2022-06-03 Last updated: 2025-02-07Bibliographically approved
Spross, J. & Stille, H. (2022). Hantering av ekonomiska risker i undermarksprojekt: Geotekniska bedömningsgrunder för riskdelning. Stockholm: Stiftelsen Bergteknisk forskning
Open this publication in new window or tab >>Hantering av ekonomiska risker i undermarksprojekt: Geotekniska bedömningsgrunder för riskdelning
2022 (Swedish)Report (Other academic)
Alternative title[en]
Management of economic risks in underground excavation : Geotechnical baselines for risk sharing
Abstract [sv]

Att bygga undermarksanläggningar är ofta tekniskt komplicerat, samtidigt som dessa byggprojekt kännetecknas av stora geologiska och geotekniska risker. Riskerna har sitt ursprung i att det för bergbyggande är svårt att i förväg fastställa vilka tekniska egen­skaper som berget har. Men detta ger inte bara tekniska utmaningar utan även juridiska och ekonomiska: vem ska stå för den ekonomiska risken om kostnaderna blir högre än väntat? Denna fråga regleras i kontraktet mellan beställare och entreprenör. Om kon­traktet visar sig vara otydligt beskrivet när kostnader väl ska regleras, hamnar man ofta i en juridisk tvist. Ett relaterat problem är hur riskerna presenteras i förfrågnings­underlaget. Om detta är otydligt avseende riskerna försvårar det för entreprenadbolagen att göra sin kalkyl och komma fram till en rimlig prissättning.

Internationellt finns ett kontraktsdokument som kallas Geotechnical Baseline Report (rapport för geotekniska bedömningsgrunder) och som tagits fram för att tydliggöra parternas ansvar för geologiska och geotekniska risker i geotekniska byggprojekt. Syftet med denna förstudierapport är att introducera principerna för hur detta kontrakts­dokument kan förstås, tolkas och tillämpas i upphandling och utförande av svenska undermarksprojekt. Rapporten är tänkt att utgöra en teoretisk grund för fortsatt forsk­ning och utveckling kring dessa frågor i Sverige.

Rapporten ger dels en överblick över hur valet av affärsform (entreprenadform och kon­traktstyp och dyl.) kan förstås ur ett riskperspektiv, dels en teoretisk analys av begreppet geoteknisk bedömningsgrund och hur det fungerar som ett verktyg för riskdelning mel­lan byggprojektets parter. Ett praktiskt tillämpningsexempel presenteras och diskuteras också. Rapporten avslutas med en diskussion av det fortsatta forsknings- och utveck­lingsbehovet som kvarstår innan geotekniska bedömningsgrunder kan börja användas i praktiken i Sverige.

Abstract [en]

Constructing underground structures is often technically challenging and characterised by large geological and geotechnical risk. These risks originate from the fact that it is difficult to predict the properties of the rock mass before the construction has started. But this does not only give technical challenges, but also economic and legal: who shall own the economic risk if the final cost is larger than expected? This issue is regulated in the contract between the client and the contractor. If the contract is vague, claims and disputes often arise. A related issue concerns how risks are presented to the bidders in the tender documents. If the tender documents are vague regarding the risks, it becomes more difficult for the bidders to come up with a reasonable bid amount.

Internationally, there exist a contractual document called Geotechnical Baseline Report (GBR), which was created to clarify the contractual parties’ ownership of geological and geotechnical risks in geotechnical engineering projects. The purpose of this prestudy report is to introduce the principles of how this contractual document can be understood, interpreted and applied in procurement and execution of Swedish under­ground excavation projects. The report is intended to be a theoretical basis for future research and development in this field.

The report first gives an overview of how the client’s considerations of different contract types can be understood from a risk perspective, which is followed by a theoretical analysis of geotechnical baselines as a concept as well as how these baselines can serve as a tool for risk sharing between the project parties. An application example is also presented and discussed. The report ends with a discussion of the research and development need that remains before geotechnical baselines can be used in the Swedish practice.

Place, publisher, year, edition, pages
Stockholm: Stiftelsen Bergteknisk forskning, 2022
Series
BeFo rapport, ISSN 1104-1773 ; 227A
Keywords
Geotechnical baseline report, Economic Risk, Contract, Tunnel, GBR, Geoteknisk bedömningsgrund, Ekonomisk risk, Kontrakt, Tunnel, Entreprenadform
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-322829 (URN)BEFO-R-227A-SE (ISRN)
Funder
Rock Engineering Research Foundation (BeFo), 400
Note

QC 20230214

Available from: 2023-01-08 Created: 2023-01-08 Last updated: 2025-02-07Bibliographically approved
Spross, J., Olsson, L., Stille, H., Hintze, S. & Båtelsson, O. (2022). Risk management procedure to understand and interpret the geotechnical context. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 16(2), 235-250
Open this publication in new window or tab >>Risk management procedure to understand and interpret the geotechnical context
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2022 (English)In: Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, ISSN 1749-9518, E-ISSN 1749-9526, Vol. 16, no 2, p. 235-250Article in journal (Refereed) Published
Abstract [en]

Unexpected and unforeseen geotechnical events cause large cost increases in geotechnical engineering projects and threaten construction workers’ health and safety all around the world. Practical tools and guidelines for how to implement structured and effective risk management methods in geotechnical engineering projects are however few and rarely applied. The Swedish Geotechnical Society has therefore published a methodology for this issue. A key activity in this methodology is to create an understanding of and to interpret the geotechnical context in which the project is to be carried out. This paper presents a guide for how practising geotechnical engineers, hydrogeologists, and other related professionals can perform this activity in a structured way. The procedure is illustrated through the foundation design for a new office building in a geotechnically challenging environment.

Place, publisher, year, edition, pages
Informa UK Limited, 2022
Keywords
Risk management, risk analysis, risk communication, geotechnical design, ISO 31000
National Category
Geotechnical Engineering and Engineering Geology
Research subject
Civil and Architectural Engineering, Soil and Rock Mechanics
Identifiers
urn:nbn:se:kth:diva-316321 (URN)10.1080/17499518.2021.1884883 (DOI)000618009000001 ()2-s2.0-85101076191 (Scopus ID)
Funder
Swedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF), 13417
Note

QC 20220815

Available from: 2022-08-12 Created: 2022-08-12 Last updated: 2025-02-07Bibliographically approved
Rafi, J. & Stille, H. (2021). A method for determining grouting pressure and stop criteria to control grout spread distance and fracture dilation. Tunnelling and Underground Space Technology, 112, Article ID 103885.
Open this publication in new window or tab >>A method for determining grouting pressure and stop criteria to control grout spread distance and fracture dilation
2021 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 112, article id 103885Article in journal (Refereed) Published
Abstract [en]

Determining optimum pressure in a grouting procedure affects a project?s outcome as well as associated costs. Application of relatively low pressure may lead to insufficient grout spread around the borehole and prolongation of grouting time. On the other hand, a pressure higher than in-situ stresses can lead to jacking of the fractures and consequently increase of usage of grout, and in much higher pressures, ground heaving and uplifts. In a review of current practices, the ?apparent lugeon? method uses low pressure regardless of geology and function of the grouted zone. The theoretical approach of RTGC estimates the grout spread from grouting borehole in a fracture with constant size aperture, which obligates the usage of a pressure that avoids any deformations. On the other hand, the GIN method appreciates the usage of higher grouting pressures while the induced energy is controlled. However, the controlling Grout Intensity Number is determined based on experience and provides no information regarding the distance that grout mix is spreading and the state of fracture during grouting. The present study discusses an analytical approach that defines stop criteria that allow the spread of grout to a certain distance while controlling deformations to the extent that ensures fracture jacking remains beneficial. To elaborate this approach, first the concept of fracture jacking and approaches for detecting onset and duration of it are reviewed. This is followed by a discussion of the positive and negative effects of fracture jacking and the determination of thresholds for limiting these deformations. The paper goes on to explain the analytical solution for establishing the Deformation Limiting Curves as a stop criterion and estimation of the grout spread distance in a continuously dilating fracture. The significance and benefits of this solution are argued through case studies involving different functions and geological conditions. It is concluded that understanding the function of the grouted zone and geological conditions to define the grouting requirements, recognizing the risks associated with under or over spreading of grout and jacking of rock fractures, and using proper stop criteria to control these risks, would allow the use of an optimum grouting pressure.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
Grouting, Rock fracture jacking, Grout spread distance, Stop criteria, Analytical solution
National Category
Geotechnical Engineering and Engineering Geology
Identifiers
urn:nbn:se:kth:diva-295368 (URN)10.1016/j.tust.2021.103885 (DOI)000640899000007 ()2-s2.0-85102968021 (Scopus ID)
Note

QC 20210524

Available from: 2021-05-24 Created: 2021-05-24 Last updated: 2025-02-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5628-9673

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