Artikeldatenbank
Autor(en) | Titel | Zeitschrift | Ausgabe | Seite | Rubrik |
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TBM DiGs 2022 | Geomechanics and Tunnelling | 1/2023 | Cover Pictures | ||
KurzfassungThe 27 km long second track between Divaca and Koper is one of Slovenia's most important infrastructure projects and includes seven tunnels with a total length of approx. 20.5 km. For tunnel T7 - Mlinarji above the Ospska valley in rni Kal, DSI Underground supplies all ground support equipment. (photo: DSI Underground) x | |||||
Content: Geomechanics and Tunnelling 1/2023 | Geomechanics and Tunnelling | 1/2023 | Contents | ||
Geomechanics and Tunnelling: Table of contents Volume 15 (2022) | Geomechanics and Tunnelling | 1/2023 | Annual table of contents | ||
Galler, Robert | International tunneller meeting in Leoben / Internationales Tunnelbauer-Treffen in Leoben | Geomechanics and Tunnelling | 1/2023 | 2 | Editorials |
News: Geomechanics and Tunnelling 1/2023 | Geomechanics and Tunnelling | 1/2023 | 3-12 | News | |
KurzfassungFinal major tunnelling contract awarded for Sydney Metro West - Letzter großer Tunnelbauauftrag für Sydney Metro West vergeben x | |||||
Lehmann, Gabriel; Käsling, Heiko; Praetorius, Steffen; Seng, Frederic; Thuro, Kurosch | Small-diameter tunneling in difficult ground - Analysis of TBM performance in hard rock | Geomechanics and Tunnelling | 1/2023 | 15-21 | Topics |
KurzfassungSmall-diameter tunneling in hard rock is increasingly widespread due to the need for new and longer utility tunnels comprising sewer, stormwater, freshwater, or hydropower as well as cable tunnels and casings for pipelines transporting gas or hydrogen. Utility tunnels have to deal with a wide range of geological settings, like small overburden, weathered rock, rock-soil transitions, as well as fractured or intact hard rock with high strength and abrasivity. A database has been created including 35 hard rock projects with diameters between 1 and 5 m as well as more than 70,000 m of tunnel alignments, with a median drive length of less than 500 m. Challenges in creating it and some early interpretations based on the contents of the database are presented. Details about an exemplary pipe jacking project in basement rocks in Brittany, France, are given. The large variety in this small-diameter range in hard rock includes different TBM types, cutterhead designs, cutter types, and geotechnical conditions. Potential pitfalls in small-diameter TBM data analysis are shown and general drive parameter trends and penetration prediction approaches are presented and set in relation to the geotechnical conditions. Our analysis shows that difficult ground conditions do not only incorporate rocks with very high strength, but also generally weak rocks like schist or limestone could be responsible for low penetration rates and high thrust forces. x | |||||
Bisenberger, Tobias | Innovative contract and compensation model in mechanised tunnelling - Calculation of the deviating construction time based on digital excavation and process data | Geomechanics and Tunnelling | 1/2023 | 22-27 | Topics |
KurzfassungThe handling of a tunnel construction project poses great challenges for all those involved. Variables that cannot be clearly quantified can arise during the entire process of the project. The subsoil in tunnelling is one of these parameters which is difficult to forecast. The geological and hydrogeological conditions must be assessed during the planning phase with the help of exploratory measures and from the experience from projects that have already been built. x | |||||
Hassanpour, Jafar; Goodarzi, Saeed; Yagiz, Saffet; Rostami, Jamal; Sarem, Milad Davari | Soft sedimentary rocks and their boreability characteristics in mechanised tunnelling projects | Geomechanics and Tunnelling | 1/2023 | 28-37 | Topics |
KurzfassungSoft sedimentary rocks are frequently found in many mountainous regions of the world like Zagros Mountains located in the south and west of Iran, where most of Iran's water conveyance projects have been constructed or are under construction. These rocks usually contain considerable amounts of different types of clay minerals. The clay mineral-rich rocks cause many problems in the deep and long mechanised tunnelling projects. In particular, the boreability of these rocks is very different from other rocks, and due to their plastic behaviour and the lack of complete formation of chips during the cutting process by disc cutters, the prediction of cutterhead penetration in these rocks, with existing models, is often inaccurate. In this paper, a new model for estimating the disc cutter penetration in these rocks is introduced, which is based on data obtained from the main tunnelling projects completed in sedimentary rocks of Zagros Mountains. Then, the validity of the developed model is checked using actual data obtained from a tunnel recently constructed in the area. The new model can offer a more accurate estimate of machine performance in similar rocks. x | |||||
Poisel, Alexander; Meier, Alexander; Bach, Dietmar | The application of the guideline for the geotechnical design of underground structures with TBM excavation in Austria | Geomechanics and Tunnelling | 1/2023 | 38-46 | Topics |
KurzfassungIn 2013, the Austrian Society for Geomechanics published the Guideline for the Geotechnical Design of Underground Structures with TBM Excavation. The Guideline contains general procedures for the geotechnical design and construction. In the design phase, the first steps are evaluating different ground conditions by classifying different ground types, different ground behaviours, their categorization into ground behaviour types, and the determination of construction measures derived from the ground behaviour. On this basis the expected system behaviour in each system sector of the tunnel boring machine (TBM) is predicted and described in detail to enable comparison in the construction phase. In the construction phase, geotechnical relevant ground parameters as well as observations regarding the actual system behaviour are recorded and compared with the assumptions of the design. The geotechnical design is updated continuously based on the encountered ground conditions and geotechnical observations. The improved quality of the geotechnical model allows an optimization of the construction while meeting all safety and environmental requirements. In the first part of the article, the general procedures of the guideline are described and parameters to describe the system behaviour in each system sector adequately are listed. In the second part of the article, the implementation of the guideline during design and construction at the Semmering Basetunnel in Austria is described. x | |||||
Bianchi, Gianpino Walter | Analysis of TBM parameters during tunnelling in adverse conditions - The case study of the Frejus Safety Tunnel, Western Alps | Geomechanics and Tunnelling | 1/2023 | 47-52 | Topics |
KurzfassungOne of the main hazards during tunnel boring machine (TBM) excavation in hard rock is related to the occurrence of unforeseen adverse conditions, leading to unfavourable rock mass behaviour during tunnel boring. In this respect, the continuous analyses of TBM excavation parameters may represent an interesting tool for a continuous monitoring of geotechnical conditions at the tunnel face and for early detection of changing ground conditions in the rock mass. This work provides a back-analysis of TBM data recorded during the excavation of the Frejus Safety Tunnel, bored across the French-Italian border in the Western Alps. It is a 13 km-long tunnel excavated by a 9.4 m diameter, single-shield TBM through strongly anisotropic calcareous schist, with cover up to 1800 m. Main problems faced during TBM excavation were related to the local occurrence of buckling-related convergence and consequent asymmetrical loading on the precast segment rings. Correlating TBM performance parameters to the encountered geological and geomechanical conditions provides the possibility to identify which parameters are most affected by geomechanical properties of the rock mass at the tunnel face and by rock mass behaviour. Conversely, the analysis indicates which parameters can be adopted as monitoring tool of ground conditions during TBM advance. In addition, this work highlights how buckling phenomena can be distinguished, in terms of TBM operation and performance, from other adverse conditions as, e.g., blocky ground or squeezing. x | |||||
Wannenmacher, Helmut; Schlicke, Marcel | Analyses of Pre-Excavation Grouting for TBM Tunnelling | Geomechanics and Tunnelling | 1/2023 | 55-59 | Topics |
KurzfassungPre-excavation grouting (PEG) is essential for mitigating groundwater inflow to unlined tunnel structures. Prevention of initial water inflow proved best practice to balance groundwater conditions throughout the utilisation of a tunnel. The grouted rock mass acts as a circumferential sealing barrier instead of a secondary lining to minimise groundwater inflow to an acceptable level over the structure's lifetime. The construction of unlined tunnels relies on existing favourable in-situ rock mass conditions with an overall low hydraulic head, mainly to keep the effort of grouting inferior and avoid an unbalanced proportion of pre-excavation grouting during the tunnel construction works. x | |||||
Allahverdi, Navid; Bakhshi, Mehdi; Partovi, Maziar; Nasri, Verya | 3D-nonlinear finite element analysis of staged shield-driven tunnel excavation with a focus on response of segmental tunnel lining | Geomechanics and Tunnelling | 1/2023 | 60-67 | Topics |
KurzfassungThe complex and dynamic nature of shield-driven tunnel excavation, staged construction, segmental lining installation process, and tail-void grouting necessitate using detailed numerical modeling for predicting ground behavior and response of segmental lining. In this article, results of three-dimensional advanced finite element modeling are presented for one of the major ongoing construction projects in the North America. Different segment joint models, i.e., rigid joints, perfect hinge joints, Janssen joints, and rigid joints with reduced lining thickness, are used in the analysis. Critical responses such as ground deformation, settlement trough, crown deformation, and the internal forces in the linings considering different segment joint modeling are discussed. x | |||||
Steiner, Walter | Lessons from tunnelling through glacial open gravel deposits / Erfahrungen beim Tunnelbau in durchlässigem glazialen Lockergestein: offener Kies | Geomechanics and Tunnelling | 1/2023 | 68-80 | Topics |
KurzfassungGlacial soil deposits are present in Europe on both sides of the Alps, in Scandinavia, Northern Germany, Poland and in North America. There are typical names of the stages of the glaciation, however, the geotechnical characteristics of glacial deposits are similar in all regions; but are very heterogeneous locally. Glacial deposits extend from boulders to invisible silt particle (rock flour) and to clay particles, both of similar grain size. In this paper the focus will be on clean gravel without fines, so-called open gravel and the challenges and solutions for tunnelling. x | |||||
Fantini, Paolo; Miranda, Javier Calderon; Dell'Ava, Gabriele; Flor, Alberto | EPB tunnelling in long, highly sensitive sections - The experience of Grand Paris Line 14 underpassing the Orly Airport | Geomechanics and Tunnelling | 1/2023 | 81-87 | Topics |
KurzfassungThe correct definition and application of face confinement pressure is one of the main challenges for urban tunnels, where soil perturbation can affect the surrounding structures with undesirable or even severe consequences. The choice of this parameter needs to comply not only with minimal geotechnical performances, such as volume loss control, water pressure balance, and front stability, but also with optimization criteria (impact on production rate and Tunnel Boring Machine (TBM) components wear). The Grand Paris Line 14 South tunnel has emphasized this concept especially on the 1.5 km section below the Orly International Airport, with two constraints: the limitation of deformations on sensitive airport structures and the tight schedule due to the Olympic Games of 2024. The 8.83 m-diameter Earth Pressure Balance (EPB) TBM 'Koumba' successfully performed the excavation at 20 m depth. The design face pressure profile, varying between 0.8 and 2.6 bar, was studied. A complex monitoring system was also provided to validate design expectations and to update the TBM-soil interaction prediction model. This article focuses on the experience acquired on the EPB face confinement pressure management along this long, highly sensitive section. The first part presents the comparison between reference values and thresholds given by the designer and the real TBM drive oscillation. The second part is dedicated to the observed influence of the face pressure on the geotechnical aspect, machine mechanical parameters, and production rates. x | |||||
Cordes, Tobias; Voit, Klaus | Structural optimization of shotcrete lining - load capacity comparison of optimized and non-optimized excavation sections / Strukturoptimierung von Spritzbetonschalen - Versagensanalysen von Spritzbetonschalen bei Betrachtung von Vortriebsoptimierungen | Geomechanics and Tunnelling | 1/2023 | 88-101 | Topics |
KurzfassungA framework with a robust design of the driving classes is fundamental for the tunnel design. During tunnel advance, the detailed design of the lining is depending on the documented geology and the observed system behaviour. To reduce costs, the excavation profile is optimized with the aim of reducing overbreaks and shotcrete masses. This achieved profile accuracy is beneficial for the load-bearing capacity of the rock and the shotcrete lining. For temporary and permanent tunnel shotcrete linings, the excavation profile accuracy influences the stress distribution, the crack pattern and the expected deformations. In the course of this study, the effect of the excavation geometry on the load-bearing capacity of the primary lining of drill and blast tunnels was examined. For this purpose, shotcrete linings, reinforced by steel meshes and fibre-reinforced linings, were compared in optimized and non-optimized scanned excavation cross-sections. In each case, an ultimate load and failure analysis was carried out to assess shells in the hardened state by means of numerical modelling (ATENA). The aim is to determine the load-bearing capacity of the shell structure in order to obtain a conclusion regarding its structural robustness. The interaction between the rock/soil soil and the structure as well as a time-dependent material behaviour were not considered. It could be shown how an irregular overbreak or an inconsistent shell thickness has a negative effect on the load-bearing capacity of the structure. x | |||||
Zahed, Mohammad Ali; Seidi, Fouad; Salehi, Samira; Pardakhti, Amirarsellon | Simultaneous assessment of health, safety, and environmental risks using William Fine and FMEA methods based on OHSAS 18001: 2007 standard in the Alborz tunnel, Iran | Geomechanics and Tunnelling | 1/2023 | 103-113 | Topics |
KurzfassungIn this study, the critical risks and their effects on each other for the Alborz tunnel construction project, which is known as the longest road tunnel in the Middle East, have been evaluated on a case-by-case basis. In addition to covering all safety hazards in important tunnel drilling operations using the failure modes and effect analysis (FMEA) method, which is one of the risk assessment methods for operations and has been widely used in manufacturing, drilling, and tunneling industries, health hazards that affect employees and can cause a variety of job diseases have been studied and in order to identify, evaluate, and quantify the results, the William Fine method has been implemented. Also, all the risks have been identified and evaluated within the framework of OHSAS 18001 standard which was presented in 1999 due to the lack of an international standard regarding occupational health and safety and its last revision was done in 2007. Based on the research results, according to FMEA method, a total of 46 critical risks, 26 very high risks, 22 high risks, 8 medium risks, 34 low risks, 29 very low risks, and 8 insignificant risks in the field of safety have been identified and evaluated. In the field of job health, 165 high-level risks, 28 medium-level risks, and 57 low-level risks were assessed and finally in the environmental field, 7 high-level risks and 1 risk for each of the intermediate and low level have been inferred. x | |||||
Site Reports: Geomechanics and Tunnelling 1/2023 | Geomechanics and Tunnelling | 1/2023 | 114-115 | Site Reports | |
KurzfassungSlovenia's largest rail project underway - Sloweniens größtes Eisenbahnprojekt in vollem Gange x | |||||
Diary of Events: Geomechanics and Tunnelling 1/2023 | Geomechanics and Tunnelling | 1/2023 | 116-117 | Diary of Events | |
Titelbild: geotechnik 1/2023 | geotechnik | 1/2023 | Titelbild | ||
Kurzfassung
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geotechnik: Inhaltsverzeichnis des 45. Jahrgangs 2022 | geotechnik | 1/2023 | Jahresinhaltsverzeichnis | ||
Inhalt: geotechnik 1/2023 | geotechnik | 1/2023 | Inhalt | ||
Vrettos, Christos | Schwindender Vorsprung | geotechnik | 1/2023 | 1-2 | Editorials |
Wacker, Matthias | Baugrubensteifen aus Stahlrohren - Vereinfachte Bemessung für Querschnittsklasse 4 | geotechnik | 1/2023 | 3-11 | Aufsätze |
KurzfassungIn ausgesteiften Baugruben werden häufig Stahlrohre als Steifen eingesetzt. Bei langen Steifen ohne Zwischenauflagerung ist es besonders wirtschaftlich, große Durchmesser mit geringer Wanddicke zu wählen. Dabei kann Querschnittsklasse 4 erreicht und ein Beulsicherheitsnachweis nach EN 1993-1-6 erforderlich werden. Im vorliegenden Beitrag wird ein vereinfachtes Berechnungsverfahren mit profilbezogenen Beulspannungen auf Grundlage von EN 1993-1-6 Anhang D beschrieben. Es werden gebrauchsfertige profilbezogene Beulspannungen für häufig verwendete Rohre der Querschnittsklasse 4 angegeben. x | |||||
Döbber, Michelle; Glasenapp, Ralf; Arnold, Patrick; Rackwitz, Frank | Einfluss von Huminstoffen auf die Festigkeit bindemittelverbesserter organischer Böden | geotechnik | 1/2023 | 12-27 | Aufsätze |
KurzfassungOrganogene und organische Böden sind häufig als gering tragfähig einzustufen und erfüllen daher für übliche geotechnische Bauwerke nicht die Anforderungen an eine bautechnische Verwendung. Baugrundverbesserungsmaßnahmen ermöglichen es, die Festigkeit und Steifigkeit gering tragfähiger Böden z. B. durch das Einarbeiten von Bindemitteln in die örtlich anstehende Bodenmatrix zu erhöhen und darüber hinaus die gesellschaftlich wichtigen Ziele der Ressourcenschonung und Abfallvermeidung umzusetzen. Die Vorgänge bei der Zementhydratation bei Vorhandensein organischer Bestandteile sind jedoch sehr komplex und multivariat. Insbesondere der lösliche Anteil der Huminstoffe in der Organik kann dazu führen, dass die Zielfestigkeiten nicht erreicht werden. Um den Einfluss der Huminstoffe, insbesondere der Huminsäuren, auf die festigkeitsbestimmende Zementhydratation zu untersuchen, bestand das Ziel der vorliegenden Studie darin, die Huminstoff-Fraktionen verschiedener organischer Böden zu quantifizieren, um bei nachfolgend durchgeführten Festigkeitsuntersuchungen Rückschlüsse auf die Vorgänge beim Abbindeprozess zu ziehen. Zudem wurde zur qualitativen Bestimmung der Huminsäuren eine Farbskala entwickelt, die für die Anwendung in der Praxis vorgeschlagen wird. Die Analyse der Huminstoff-Fraktionen basiert auf deren Extraktion und anschließender Bestimmung mittels UV/VIS-Spektroskopie unter Einsatz von Kalibrierstandards. Die sich anschließenden Festigkeitsuntersuchungen stützen sich auf die Ermittlung der einaxialen Druckfestigkeit von Probekörpern, die aus bindemittelverbesserten Sandproben bestehen, denen verschiedene organische Böden in unterschiedlichen Anteilen beigemengt wurden. Es wird gezeigt, dass nicht nur die Wahl des Bindemittels oder der Anteil an organischen Beimengungen, sondern insbesondere die Zusammensetzung der Organik einen Einfluss auf das Verfestigungspotenzial organogener und organischer Böden hat. x | |||||
Tafili, Merita; Triantafyllidis, Theodoros; Wichtmann, Torsten | Validierung des anisotropen visko ISA Modells (AVISA) für bindige Böden | geotechnik | 1/2023 | 28-37 | Aufsätze |
KurzfassungDas Bauen auf bindigen Böden stellt trotz fortgeschrittener Ausführungstechnologien immer noch eine Herausforderung dar. Vor allem sind die Werkzeuge zur Prognostizierung der Langzeitverformungen des feinkörnigen Bodens beschränkt, wenn es um zyklische Belastungszustände in Verbindung mit dem zeitabhängigen Verhalten bindiger Böden geht. Solche Fragestellungen ergeben sich z. B. bei Offshore-Konstruktionen oder auch bei Staumauern oder Widerlagern von Brückenkonstruktionen. Aufgrund des komplexen Einflusses der Belastungsrate, der Vorbelastung und der Struktur des Bodens ist es notwendig, die Auswirkungen dieser Einflüsse auf bindige Materialien durch Laborversuche zu verstehen und durch akkurate und physikalisch basierte konstitutive Gleichungen numerisch zu beschreiben. x |