Artikeldatenbank
Autor(en) | Titel | Zeitschrift | Ausgabe | Seite | Rubrik |
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Potten, Martin; Bohnsack, Daniel; Käsling, Heiko; Thuro, Kurosch | Geomechanical reservoir characterisation in Bavaria within the framework of the Geothermal-Alliance Bavaria / Geomechanische Reservoircharakterisierung in Bayern im Rahmen der Geothermie-Allianz Bayern | Geomechanics and Tunnelling | 1/2022 | 27-36 | Topics |
KurzfassungTo increase the use of geothermal energy in Bavaria, the subsurface, which serves as a reservoir, must be explored as precisely as possible. In the projects of the Geothermal-Alliance Bavaria, the most promising areas for geothermal exploration in Bavaria were characterised based on an extensive geomechanical laboratory testing program which was carried out on both drill cores and analogue samples from quarries. In the North Alpine Foreland Basin (SE Germany), the geomechanical test results on Upper Jurassic carbonate rocks show a high heterogeneity. On the contrary, in the Franconian Basin (NE Bavaria) the geomechanical properties of granite analogues are rather homogenous. For the numerical simulation of the borehole stability, the determined parameters from ultrasonic- and compression tests serve as input parameters for different scenarios. For both locations, the determination of the failure depth around the borehole and the stress distribution in the near-field of the borehole were accomplished. In the North Alpine Foreland Basin, the borehole stability decreases with increasing depth. For all scenarios in NE Bavaria, the borehole stability is very low. In the future, the determined parameter ranges will allow to validate already existing models and to develop new ones. This will enable a better knowledge of the sedimentary and crystalline reservoirs and a more effective use of geothermal energy in Bavaria. x | |||||
Stockinger, Georg; Thuro, Kurosch; Moeck, Inga; Straubinger, Robert | The rock mass as the governing factor for successfully developing deep geothermal systems in Southern Germany | Geomechanics and Tunnelling | 1/2022 | 37-47 | Topics |
KurzfassungIn Southern Germany, geothermal wells target Upper Jurassic carbonates, formerly referred to as Malm, below the Northern Alpine Foreland Basin (NAFB). In the northern, shallower carbonates (3000 m depth), e.g., in the Munich area, hydrothermal systems prevail, and wells yield proper flow rates. Deeper carbonates (> 4000 m) towards the south indicate a petrothermal system due to a decline in porosity and permeability. Inexplicably, fractures only contribute poorly to larger flow rates. This sets the goal for the project Dolomitkluft to analyse the rock mass for options countering low flow rates in two geothermal wells at Geretsried, Bavaria. Therefore, 20 m drill cores from 4600 to 4715 m total vertical depth (TVD) depict the initial structure of the rock mass: the rock parameters, the discontinuity network, and the in situ stresses. Alternating homogeneous, micritic, strong, to inhomogeneous, porous, weak limestones and massive, crystalline dolostones define the stratigraphy. Five joint sets from the cores can be distinguished into the bedding, two paleo anti- and synthetic normal faults and two recent strike-slip faults. The latter, in combination with core disking, allows exclusively a strike-slip (SS) stress regime and delimits the ratio to at least SH : Sv : Sh = 1.7 : 1.0 : 0.7. According to the results, including dilatation- and slip-tendencies, drill trajectories of prosperous geothermal wells should head ESE/WNW, perpendicular to SS-faults, and avoid the presence of normal faults. x | |||||
Rioseco, Ernesto Meneses; Dussel, Michael; Moeck, Inga S. | 3D thermo-hydro-mechanical simulation of the behaviour of a naturally fractured petrothermal reservoir in deep Upper Jurassic carbonates of the Bavarian Molasse Basin - Case study Geretsried | Geomechanics and Tunnelling | 1/2022 | 48-57 | Topics |
KurzfassungBased on multi-scale and multi-disciplinary measured data, gathered at the Geretsried geothermal site, a 3D reservoir model of the deep and fracture-controlled Upper Jurassic carbonates in the North Alpine Foreland Basin is generated in this work. An efficient methodology is developed to numerically simulate the coupled reservoir processes of fluid flow, heat transport and thermoporoelastic stresses resulting from possible geothermal doublet operating schemes with cold fluid injection and production profiles in an enhanced naturally fractured reservoir. A variety of numerical experiments is conducted to study the reactivation potential and dilation tendency of the fracture and fault system. Simulation results show the spatiotemporal evolution of the thermoporoelastic stresses and the zone affected after 50 years of geothermal doublet operation. From these simulations, the thermoelastic response of a geothermal doublet operating with 60 °C fluid injection temperature and 20 l/s flow rate translates into a maximum induced thermal stress of around 49.4 MPa near the injection well. In terms of a long-term reservoir performance and fault and fracture reactivation potential, the findings reveal a negligible risk to a sustainable geothermal doublet operation. x | |||||
Backers, Tobias; Kahnt, René; Stockinger, Georg | Structural dominated geothermal reservoir reaction during proppant emplacement in Geretsried, Bavaria / Strukturdominierte Reaktion des geothermischen Reservoirs während Stützmitteleintrag in Geretsried, Bayern | Geomechanics and Tunnelling | 1/2022 | 58-64 | Topics |
KurzfassungAs a source of sustainable, renewable, and clean energy, deep geothermal systems increasingly gain importance for the energy transition. In Germany, the North Alpine Foreland Basin is the success story for hydrothermal systems. Besides successful projects in the Munich area, recent attempts to establish successfully operating geothermal wells southwards, e.g., in Geretsried, failed due to a lack of permeability of the rock mass. Subsequent research in Geretsried found that all existing discontinuities are low to non-productive. The current project ZoKrateS, rethinking the Geretsried reservoir being a petrothermal play, bypasses these limitations by stimulating the existing fractures, and trying to keep them conductive by embedding proppants that prevent full closure. Four detached sections of the well GEN-1ST-A1 were subject to individual stages of stimulation. These four sections have been stimulated by placing proppants at injection pressures below the in-situ least principal stress at no microseismic activity. After injection the communication between well and formation appeared to be increased. Although data processing is still ongoing, linear correlations between cumulative injected volume and quasi-static pressure may be interpreted as channel flow within highly disturbed rock masses at intersections of faults. The high elasticity of these sections enables even low pressure to cause discontinuity opening below the least principal stress. x | |||||
Stoxreiter, Thomas; Galler, Robert | Results of the EU H2020 project ThermoDrill - Contribution of rock mechanics to the utilization of geothermal energy / Ergebnisse aus dem EU-H2020-Projekt ThermoDrill - Ein Beitrag der Felsmechanik zur effizienteren Gewinnung geothermischer Energie | Geomechanics and Tunnelling | 1/2022 | 65-73 | Topics |
KurzfassungThe urgent need to speed up the process of reducing CO2 emissions, as well as to stimulate the production and use of renewable energy demands sophisticated technologies to reach these goals. By developing an advanced drilling technology, the EU H2020 project ThermoDrill set itself the target to make the utilization of geothermal energy more economical. The new drilling technology is based on the combination of rotary drilling and high-pressure fluid jetting. Rock mechanics largely contributes to the achievement of the common purpose of the project. Especially the investigation of the rock destruction process due to the combined hydraulic and mechanical impact plays a major role. The results are based on extensive experimental research concerning rock fracture under varying conditions. Additionally, various methods of crack detection are applied to identify the underlying mechanisms of the drilling technology. As a result, the specifications of the developed prototypes are to a considerable amount based on the rock mechanical findings. The huge potential of the advanced drilling technology is supported by the results of laboratory tests and field tests. x | |||||
Hahn, Simon; Polat, Berker; Jamali, Shahin; Wittig, Volker; Bracke, Rolf | Water jet drilling technology for application in geothermal environments / Erschließung geothermischer Lagerstätten mittels Hochdruck-Wasserstrahl Bohrtechnik | Geomechanics and Tunnelling | 1/2022 | 74-81 | Topics |
KurzfassungHigh-pressure water jet drilling technologies are widely used in the drilling industry. Especially in geothermal and hard rock applications, jet drilling is, however, confronted with several limitations like lateral length, hole size, steerability and jetability of the reservoir rock. The application of jet drilling technologies in the field can only be estimated based on the experience of the operator and surface experiments imitating downhole conditions. To predict a successful jetting operation in the field, a modelling framework has been developed, which considers operational and technical parameters as well as reservoir rock specifications. The framework consists of calibrated models describing downhole hydraulics and mechanics during the jetting operation and estimates the required technical equipment to successfully penetrate the reservoir rock and the maximum achievable lateral length for various hole configurations. The modelling framework is applied on a theoretical case study. x | |||||
Bücken, Daniel; Meier, Tobias; Backers, Tobias | Geomechanical effects of seasonal heat storage in abandoned mines / Geomechanische Auswirkungen saisonaler Wärmespeicherung in stillgelegten Bergwerken | Geomechanics and Tunnelling | 1/2022 | 82-90 | Topics |
KurzfassungFor the transition to sustainable heat sources, storage infrastructure is required to provide heat evenly throughout the year. Solar heat is typically produced in the summer and can be stored in underground heat reservoirs for the winter. Flooded coal mines, e.g., are potential heat reservoirs. To assess whether the geomechanical integrity of a colliery and the surrounding rock mass are affected by seasonally stored heat, a numerical case study was performed at “Zeche Dannenbaum” in the Ruhr valley, Germany. During summer, hot water was injected into level 8 of the colliery while cold water was produced from level 4. This process was reversed in winter. Detailed subsurface models of the colliery, rock mass and tectonic faults were used to numerically simulate the cyclical changes in pore pressure and temperature and the resulting stress changes. The displacement of the land surface, and geomechanically critical regions in the rock mass were derived. Moreover, the reactivation potential of the fault zones and the risk of induced seismicity were evaluated. The high injection temperatures induce strong thermoelastic effects, which could potentially lead to fault reactivation and induced seismicity. Surface displacements, however, are negligeable. x | |||||
Burger, Ulrich; Geisler, Thomas; Lehner, Florian; Cordes, Tobias; Marcher, Thomas | Sectional discharges as geothermal potentials of deep tunnels / Teilströme als geothermisches Potential bei tiefliegenden Tunneln | Geomechanics and Tunnelling | 1/2022 | 92-103 | Topics |
KurzfassungDeep tunnels are long tunnel systems which cross different hydrogeological environments as a drainage. Thus, their water inflows have very different characteristics. The tunnel water discharges formed from these water inflows, which drain individual sections of the tunnel system, also have different properties. These discharges from individual tunnel sections - so-called sectional discharges - are important for determining the geothermal potential of deep tunnels. Knowledge of the origins of sectional discharges and their properties allows optimising the usage of the geothermal potential of the water by provision of adequate tunnel water management. By monitoring sectional discharges, the most effective “mixing scenarios” can be calculated and thus an optimization of the geothermal output can be achieved. The concept of sectional discharges for the geothermal evaluation of deep tunnels is presented based on data from the Brenner Base Tunnel (BBT). x | |||||
Stemmle, Ruben; Menberg, Kathrin; Rybach, Ladislaus; Blum, Philipp | Tunnel geothermics - A review / Tunnelgeothermie - Ein Ãœberblick | Geomechanics and Tunnelling | 1/2022 | 104-111 | Topics |
KurzfassungTunnel geothermal systems hold the potential to promote decarbonization of the building heating and cooling sector. They can be integrated into existing infrastructure, resulting in low additional costs. In addition, these systems have large contact areas with the ground leading to larger heat fluxes. However, tunnel geothermics is relatively unknown and rarely used. Thus, the objective of this study is to provide an overview of the two primary tunnel geothermal system types as well as their application and potential. Open hydrothermal systems use the tunnel drainage water as a heat source, whereas closed absorber systems harness the heat flux from the subsoil and the warm tunnel interior via heat exchangers. The evaluation of the global application of existing and planned tunnel geothermal systems shows that all open systems are currently located in mountainous regions with a thick rock overburden. In contrast, closed absorber systems are mostly installed in urban tunnel infrastructures. The spatial distribution of geothermal tunnel systems has a focus in central Europe with Switzerland, Germany and Austria being the countries with the highest number of installed systems. Finally, this study also presents a brief summary of existing methods to determine the geothermal potential of tunnels. x | |||||
Carstens, Volker; Ilg, Ludwig; Pospisil, Petr | Rock heat input of ventilated tunnel structures / Felswärmeeintrag belüfteter Tunnelbauwerke | Geomechanics and Tunnelling | 1/2022 | 112-120 | Topics |
KurzfassungPredicting the heat input from rock is particularly important for climatic conditions in long tunnels during the construction phase because, although other heat sources are present, this often has the greatest impact on the amount of heat transferred to the air in tunnels with a high rock overburden. Correctly predicting the time-dependent rate at which the excavated tunnel tube cools is of fundamental importance, as this determines the amount of cooling power required to maintain the working climate. Two different rock heat calculation methods will be presented here: an analytical method based on a series development and a method based on solving the heat conduction equation using a numerical method. x | |||||
Todaro, Carmine; Martinelli, Daniele; Boscaro, Alessandro; Carigi, Andrea; Saltarin, Simone; Peila, Daniele | Characteristics and testing of two-component grout in tunnelling applications | Geomechanics and Tunnelling | 1/2022 | 121-131 | Topics |
KurzfassungTwo-component grout is nowadays the most popular backfilling technique, used widely in rock or soil thanks to its versatility and the undoubted advantages for operatives compared to other backfilling technologies. Despite its intensive adoption in shielded tunnelling projects, very poor and often fragmented information is available, especially on the engineering properties used for the mix design calibration (design phase) and secondly on construction sites as the acceptance protocol (operative phase). In this work, starting from real construction sites data, an analysis has been performed in order to determine the intrinsic characteristics of the two-component grout technology. Moreover, the most frequently used engineering parameters have been identified to characterise both component A and the hardened grout, correlated with their usage frequency. The outcomes illustrate that although at the current time different choices are made at different construction sites, a pattern of tests has been recognised, that can be considered as a significant cornerstone for the characterisation of two-component grout. x | |||||
Gasser, Oliver; Haidenthaller, Christoph; Magnusson, Robert; Laubreiter, Felix | The Stockholm bypass project / Förbifart, Umfahrung Stockholm | Geomechanics and Tunnelling | 6/2021 | 697-707 | Topics |
KurzfassungThe Stockholm bypass (E4 Förbifart Stockholm) is being built by the Swedish Transport Administration (Trafikverket) - the office responsible for transport infrastructure in Sweden. The project aims to improve connections between the regional town centres and reduce congestion on the main urban roads. The route, which runs mainly underground, employs numerous contractors and has a planned construction period of 14 years, preceded by a 10-year planning phase. This article looks at three projects: the FSE 61 Akalla Interchange, the FSE 309 Lovön Interchange and in particular, the FSE 613 Akalla Tunnel. The Akalla Tunnel is driven as a conventional full-face excavation with pre-grouting and supported with rock bolts and steel-fibre-reinforced shotcrete. The tunnel excavation is followed by the interior work comprising precast concrete walls, a suspended membrane reinforced with shotcrete, ceiling foundations and the carriageway structure. x | |||||
Göbl, Arthur | Swinoujscie Tunnel - Using a slurry shield under the Baltic Sea / Tunnel Swinemünde - Hydroschildeinsatz unter der Ostsee | Geomechanics and Tunnelling | 6/2021 | 708-717 | Topics |
KurzfassungThis paper discusses the concept and the practical experiences of excavating an under-river crossing with a slurry shield (D = 13.45 m) to construct a single-tube road tunnel. Unstable sand and gravel as well as harder chalk zones in the invert area combined with high groundwater pressure require the tunnel face to be actively supported at all times. Over long stretches the overburden to the river bed is only around 0.5 D, which means that a delicate balance has to be struck between achieving the minimum support pressure required to stabilise the tunnel face while at the same time preventing blow-out. An innovative segment sealing system with integrated expanding insert combined with a push-fit dowel system achieves a high degree of protection from moisture and voids. The evacuation and rescue concept for the single-tube road tunnel is based on a refuge running under the carriageway. This evacuation channel is accessed via staircases in recesses at the side. Ground freezing is used to stabilise the sand during excavation of the recesses at around 4 bar water pressure. x | |||||
Sinkovec, Christoph; Wippersberger, Markus; Tschofen, Josef | Site optimization of the ÖBB power plant Spullersee - Building between a natural gem and alpine extremes / Standortoptimierung ÖBB Kraftwerk Spullersee - Bauen zwischen Naturjuwel und alpinen Extremen | Geomechanics and Tunnelling | 6/2021 | 718-729 | Topics |
KurzfassungThe construction site is located close to the Spullersee, one of the most impressive mountainsides in the Alps, and is part of the ÖBB Spullersee power station, which is used to generate green 16.7 Hz traction current. The Spullersee, a formerly natural mountain lake, is located over 1800 m a.s.l.in the municipality of Dalaas in Vorarlberg. After almost a century of generating electricity, essential parts of the plant have reached the end of service life, resulted in essential facility renewals as well as numerous operational optimizations in the last two years. In a first construction phase, a new access tunnel to the existing apparatus chamber had to be excavated before seasonal winter closure of the access road. For the winter construction phase, thousands of tons of building materials were stored on the construction site in order to replace the old system parts in the area of the lake-side apparatus chamber after the Spullersee had been completely emptied. Due to high-alpine location of the site in one of the snowiest regions in Austria, not just working in winter was challenging, but also access. In winter the site was achieved only by using a small cable car and a narrow footpath through the almost two-kilometer-long pipe tunnel. This was not everyone's cup of tea. x | |||||
Holzer, Wolfgang; Wagner, Oliver Kai; Leitner, Wolfgang | Revision of the Austrian standard ÖNorm B 2203-2 for work contracts in continuous drives / Überarbeitung der österreichischen Werkvertragsnorm ÖNorm B 2203-2 für den kontinuierlichen Vortrieb | Geomechanics and Tunnelling | 6/2021 | 730-739 | Topics |
KurzfassungWorking Group 169.02 has been working on the revision of Austrian standard ÖNorm B 2203-2 “Underground Works - Works Contract - Part 2: Continuous Driving” since mid-2016. For tunnelling classes, the common goal was to develop a classification methodology with balanced risk allocation which would improve calculability and make billing more transparent. A further focus was to minimise the potential for disputes during project management. To achieve these goals, tunnelling classes are to be classified on the basis of machine operating data. x | |||||
Lauffer-Neumann, Dagmar | RVS 09.01.53 Quartz, asbestos, chromium VI - Handling the unavoidable in a tunnel - a guideline / RVS 09.01.53 Quarz, Asbest, Chrom VI - Zum Umgang mit dem Unvermeidbaren im Tunnel - ein Leitfaden | Geomechanics and Tunnelling | 6/2021 | 740-752 | Topics |
KurzfassungQuartz, asbestos and chromium (VI) compounds can be found again and again in tunnel construction, especially quartz dust is an everyday companion at tunnel construction sites in Austria. The dusts from quartz, asbestos and chromium (VI) compounds are clearly carcinogenic, so measures to avoid and minimize dust exposure for employees are accordingly important. In the 2021 limit value ordinance, the limit value for fine quartz dust was reduced to 0.05 mg / m3, i.e. to a third of the previous value. Reaching this limit value represents a new challenge for everyone involved in underground projects, and the new RVS 09.01.53 is meant to provide a guideline for the planning of appropriate protective measures. The RVS 09.01.53 is expected to be published in autumn 2021. x | |||||
Karasek, Georg | The tunnel construction contract - A review / Der Tunnelbauvertrag - Eine Bestandsaufnahme | Geomechanics and Tunnelling | 6/2021 | 755-761 | Topics |
KurzfassungIn tunnel construction there is a clear need for specific contractual regulations, as unforeseen events make it far more difficult to predict the construction measures required than is the case in above-ground construction. Tunnel construction contracts must make provision for all such events associated with changes in performance to ensure conflict-free invoicing wherever possible. Conflict avoidance begins at the tender phase. In addition to the two ÖNorm B 2203 standards, the Guideline for the Geotechnical Design of Underground Structures with Conventional Excavation is an important basis for tunnelling contracts. Austrian standard ÖNorm B 2118 also plays a major role in tunnel construction as the agreed contractual basis in most cases. It contains contractual provisions for building services based on the partnership model and is intended for large-scale projects and complex construction works. In future, other alternative contract models with a partnership approach could become an even greater focus of attention. For instance, the alliancing contract model is particularly suitable for complex, technically challenging projects requiring innovative solutions. The early involvement of all key project participants is intended to reduce design errors and encourage innovation. x | |||||
Müllneritsch, Brigitte; Wiesner, Wolfgang | Measuring cooperation - The COOP-Quickcheck of the Austrian Construction Technology Association (ÖBV) / Messen von Kooperation - Der KOOP-Quickcheck der Österreichischen Bautechnikvereinigung | Geomechanics and Tunnelling | 6/2021 | 762-770 | Topics |
KurzfassungCooperation on the construction site means less stress, a better atmosphere, working together to find solutions and fun at work. This gives the opportunity to focus more on the technical challenges, because much less time is needed to settle disputes. This also requires significantly less administrative cost and thus ensures greater efficiency, because any improvement in communication creates trust and openness, reduces controversial correspondence and the risk of misunderstandings. The working group “Cooperative Project Management” of the ÖBV, launched a pilot project in 2016 to measure the cooperation on construction sites. Ongoing anonymous surveys of key people in a construction project were intended to establish mutual cooperation and, in particular, to monitor its development over time. On the basis of these findings, it should be possible to detect and counteract any undesirable developments in cooperation on construction projects at an early stage. x | |||||
Hödl, Reinhold; Bach, Dietmar; Lehner, Wolfgang | Execution of tunnel construction projects - analysis of the current situation / Abwicklung von Tunnelbauvorhaben - Analyse der Ist-Situation | Geomechanics and Tunnelling | 6/2021 | 771-780 | Topics |
KurzfassungThe situation on the sites of large tunnel construction projects has become increasingly tense in recent years. On all sides, the implementation of these projects suffers from economic constraints, which inevitably lead to a decline in the culture of dialogue and a deterioration in personal relationships. A solution to this problem cannot be achieved by simple calculations or rules. It is much more a matter of working out new alternative paths and possibilities together, and then taking them. However, those responsible and, above all, those involved on the ground must be able to take this step, and be allowed to do so. x | |||||
Deutschmann, Daniel | Alliance Contracts - Without litigation through the crisis / Allianzverträge - Ohne Rechtsstreit durch die Krise | Geomechanics and Tunnelling | 6/2021 | 782-793 | Topics |
KurzfassungClaim- and anti-claim-management is becoming increasingly important on construction sites. More and more (human) resources from contractor and owner are being invested in projects for this purpose. This is clearly counterproductive for the success of the project, since claim and anti-claim-management do not create any added value in the project and the actual target of a construction project is pushed into the background. In this article, the differences between plannable and dynamic-complex systems are used to show, where classic construction contract models reach their limits and which projects are better implemented with alternative contracts. Based on the Alliance Contract for the successfully completed project “Triebwasserweg Maria Stein”, it is shown why Alliance Contracts are more suitable than classic contract models for dynamic-complex (risky) large-scale projects, such as large tunnel projects in difficult geology. By choosing the right contract model for the project, the best project results can be achieved, and legal disputes can be avoided even in crisis situations. x | |||||
Ertl, Hannes; Hechenblaickner, Kurt | The Emerald Book - A milestone on the road to the future / Das Emerald-Book - Ein Meilenstein auf dem Weg in die Zukunft | Geomechanics and Tunnelling | 6/2021 | 794-800 | Topics |
KurzfassungThe Emerald Book as a joint work of ITA and FIDIC is the first international standard for contracts in tunnelling and shows the necessity and the need for such regulations. The Geotechnical Baseline Report is the key element and can be combined with Austrian regulations such as ÖN B2203 and the guidelines of the Austrian Society for Geomechanics. Characterised by a balanced risk sharing and embedded in the FIDIC suite, the Emerald Book is an attractive alternative to Central European contracts. x | |||||
Klösges, Simon; Müller, Michael | Artificial ground freezing as a consolidation measure for tunnelling under Bern main station / Erstellung eines Gefrierkörpers als Bauhilfsmaßnahme für einen Tunnelvortrieb unter dem Hauptbahnhof Bern | Geomechanics and Tunnelling | 5/2021 | 441-447 | Topics |
KurzfassungIn the course of the planned underground extension of the central station in Bern, an access tunnel had to be constructed from an existing shaft. The first 60 m of this tunnel cross through unstable, water-bearing and unconsolidated rock, and run under existing railway tracks. Thyssen Schachtbau GmbH has been commissioned the contract to carry out an artificial ground freezing measure to enhance the realization of the tunnel construction. The horizontal directional drilling work within the shaft as well as the construction and operation of the freezing plant were carried out in 2020 in a very confined space, and parallel to the ongoing operation of the train station. In order to ensure sufficient water saturation and thus the freezability of the unconsolidated rock, artificial ground irrigation procedure was operated. After completion of the predefined frost body, the tunnel was successfully and safely driven from the shaft into the bedrock. x | |||||
Höser, Sebastian; Bathaeian, Iman | Settlements in urban areas - Evaluation of building settlements as a result of complex underground constructions / Oberflächensetzung im urbanen Raum - Auswertung der Oberflächensetzungen an Gebäuden infolge komplexer unterirdischer Bauabläufe | Geomechanics and Tunnelling | 5/2021 | 448-456 | Topics |
KurzfassungTo relieve congestion on the S-Bahn main line in Munich (urban railway), a second main line is being built over a length of 10 km, with more than 7 km of tunnels and three new underground stations. These new stations at Hauptbahnhof, Marienhof and Ostbahnhof each have a length of about 250 m and are located at depths of up to 45 m. The stations mostly have a central staircase, which will be constructed using the top-down method with building pits enclosed by diaphragm walls. The platform tubes subsequently constructed using NATM, with a 40 m wide cross-section consisting of five tubes, have an overall excavation cross-section of approx. 450 m2. This paper presents the evaluation of the calculated building settlements due to a construction process comprising groundwater drawdown, building pit construction, platform tubes constructed using NATM, traffic tunnels constructed using TBM, and the exploration and rescue tunnel located between the two traffic tunnels, using the Marienhof West station as an example. To perform the evaluation it is necessary to superpose all settlements arising from the different construction stages for each structure, which in some case are calculated across planners and construction sections. From these superposed calculated settlements, the corresponding angular distortions are calculated according to the type of curvature, i.e. concave type or spandrel type of settlement, and compared with the permissible limit values. x | |||||
Sempelmann, Franz; Matt, Kajetan; Konrad, Frank | The A26 Linz Motorway - A new landmark for Linz / Die A26 Linzer Autobahn - Ein neues Wahrzeichen für Linz | Geomechanics and Tunnelling | 5/2021 | 459-467 | Topics |
KurzfassungThe A26 not only relieves the central part of the road network in Linz but also allows the river Danube to be crossed by means of a 300 m long bridge, anchored in the rock slopes which form the banks of the Danube.The elements of the 1st phase are the Danube bridge and two underground motorway junctions, Danube North and South, with excavation cross-sections of up to 375 m2 and the tight radii of the motorway on-ramps. In addition to the elevated location of the main portals, the river Danube, the infrastructure facilities and the built-up area take space in the valley cause unfavourable conditions. Besides these conditions, urban planning requirements have an effect on the realization of the construction project. The excavated material from the tunnel is transported off-site by ship. The project conditions such as the high number of portals, the noise-reflecting effect of the “Danube gorge” and the low overburden require substantial measures to limit and monitor the immissions. x | |||||
Radon i , Nedim; Vesely, Jan | Urban Swedish tunnelling practice - Middle European designer's perspective / Die schwedische innerstädtische Tunnelbaupraxis aus der Sicht eines mitteleuropäischen Planers | Geomechanics and Tunnelling | 5/2021 | 468-476 | Topics |
KurzfassungAmberg Engineering was involved in numerous subsurface infrastructure projects in Sweden, predominantly in the Stockholm metropolitan area. Our rock mechanical and engineering expertise represented and represents our key contribution to the projects, while we came in touch with valuable, and sometimes very different tunnelling approaches. While certain technical solutions still appear exotic, majority of them have to be valued as correct and consequent answers to the predominant geological conditions in Scandinavia. The present publication will show our experience based on one case study. Special attention is given to rock mass characterisation, design processes and tunnelling philosophy. The issues of support, water ingress control and vibration control are treated in detail, and a comparison with our local practice is presented. The paper attempts to deliver an objective treatise and honest presentation of our experience, and a summary of “lessons learned”. x |