Artikeldatenbank
Autor(en) | Titel | Zeitschrift | Ausgabe | Seite | Rubrik |
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Radinger, Alexander; Hofmann, Thomas; Holzer, Robert; Fasching, Florian; Kusnirak, David | Highly specialized geophysical methods for undergroud construction works - Semmering Base Tunnel, a practice report | Geomechanics and Tunnelling | 5/2021 | 654-660 | Topics |
KurzfassungThe use of geophysical methods for the planning of complex underground structures such as deep tunnels has made significant progress in the last two decades. The realization of large underground construction projects in complex geological environments has led to an increase of geophysical exploration during excavation activities, drilling, and geological documentation. The aim is to continuously update and improve the geological model in order to identify and mitigate potential risks. Flexible planning of geophysical measurements and their fast and efficient implementation are required to minimize the impact on ongoing construction works. x | |||||
Hartl, Irene; Schlögel, Ingrid; Behm, Michael; Wenighofer, Robert; Galler, Robert | Alternative seismic sources for exploration in conventional tunnelling / Alternative seismische Quellen für die Vorauserkundung im konventionellen Tunnelbau | Geomechanics and Tunnelling | 5/2021 | 662-670 | Topics |
KurzfassungFor seismic ahead-of-the-face prediction in tunnelling, sources with known properties are usually used, which, however, are not compatible with NATM. In order to integrate geophysical exploration into conventional tunnelling, the feasibility of construction machinery for generating seismic source signals was investigated. Passive monitoring during conventional tunnelling was used to analyse the seismic signals. Different radiation characteristics of drilling, blasting and bouldering could be identified and their characteristics regarding range and spectrum of the signal could be determined. In subsequent system tests, various machines used in NATM tunnelling were examined for their suitability as sources. The sensor positioning for source signal pickup was evaluated by stroke tests and during ongoing tunnelling operations. For the registration of the waves in the rock mass, different receivers with different geometries were used to characterize the wave field emitted to the front or side of the sources. In addition, the necessary processing steps were determined in order to make these signals usable for an ahead-of-the-face exploration. The results and data form a basis for further development into a practical technical solution for conventional tunnel construction. x | |||||
Thomas, Alun; Bernard, Erik Stefan | Developments in fibre reinforced concrete in tunnelling | Geomechanics and Tunnelling | 4/2021 | 333-339 | Topics |
KurzfassungThis paper will provide an overview of the state of the art of the use of fibre reinforced concrete in tunnelling. The major applications for fibres are for the reinforcement of sprayed concrete and pre-cast concrete segmental linings, but fibre reinforcement is also increasingly used for other applications such as trackbed/trackslab and minor precast concrete elements such as cable ducts, drip shields, and drainage elements. As the technology has matured, a wide variety of fibre types, made from different materials, has emerged. Standards have been developed for the manufacture, testing and application of all these fibre types. Moreover, design guidelines and codes have been published and new design methods are still being developed. The International Tunnelling Association has published several guidance documents in this field. Last but not least, FRC has an important role to play in reducing the carbon footprint of tunnelling projects. x | |||||
Thomas, Alun | The design of the Crossrail tunnels in UK | Geomechanics and Tunnelling | 4/2021 | 340-346 | Topics |
KurzfassungThis paper will focus on the use of fibre reinforced concrete on the Crossrail project in the UK. Crossrail (now named The Elizabeth Line) is a new railway running from West to East under the centre of London. This railway runs for approximately 14 km underground and five of the new stations were constructed with permanent sprayed concrete linings. Fibre reinforced concrete played a prominent role in all of the tunnelling - both for the segmental linings and the sprayed concrete tunnel (SCL) linings. Having reviewed the context of the project and the state-of-the-art in tunnel design at the time of the design, this paper will describe the design approach for both the TBM and mined tunnels and their fibre reinforced linings. While the segmental lining design followed a conventional approach, the SCL tunnels adopted an innovative design with the first major application of permanent sprayed concrete in the UK and featured the first use of a spray applied waterproofing membrane (SAWM) on a major project in Europe. Performance during construction will be reviewed and conclusions will be drawn on what can be learnt from the mega project. x | |||||
Horny, Ulrich; Bayer, Lars; Schiesser, Karl; Kliem, Olaf | Metro Doha Green Line: Fibre reinforced tunnel linings - Design and construction experience | Geomechanics and Tunnelling | 4/2021 | 347-355 | Topics |
KurzfassungThe Design and Build project “Metro Doha Green Line Underground” has been awarded to a joint venture composed of Porr, the Saudi Bin Ladin Group and HBK in summer 2013. It contains the “ready to use” construction of the underground part of the Green Line with 2 × 17 km tunnels, six stations, switching areas as well as cross passages and emergency exit shafts. The 34 km of tunnelling, realized with six EPB machines simultaneously, have been completed in only 18 months. The main impact on the determination of the design and build specification in terms of the segmental ring design is based on the extraordinary geological environment properties of the project area of Doha City. The geology is characterized by a dominating 3-rocklayers system comprising massive upper and lower limestone deposits, which are commonly separated by a thin shale layer. Additionally, and in regard to the nearby located sea-side the type of identified aggressive exposure conditions relevant to the concrete segment lining in terms of significant sulphate and chloride impact requires a durable reinforcement solution fit for required 120-year service life. Especially due to chloride attack an ordinary steel bar reinforcement system including a projected 90 mm nominal concrete cover at lining's intrados and extrados turns out statically difficult and constructionally non-practicable. Therefore, steel fibres are chosen to meet the strict design constraints. x | |||||
Zeuli, Vincenzo; Maier, Christof; Diaz, José Manuel Suarez; Saeed, Fahed Ahmed; Tharamapalan, Jayapregasham; Germani, Carlo; Bayer, Lars; Atzl, Georg | Structural design of precast segmental lining reinforced by steel fibres | Geomechanics and Tunnelling | 4/2021 | 356-366 | Topics |
KurzfassungDubai Municipality awarded to Porr Besix JV the Project for the Main Tunnel component of the Deep Storm Water System. The tunnel will collect both rainwater and groundwater from approximately 500 sq. km and transfer the captured flow to the sea. The Design Builder JV selected COWI as Designer of the entire Project and IC Consultant as Design Checker for the Tunnels. The Project includes approximately 10.3 km of 10-meter-inside diameter tunnel in rock, three construction shafts and one drop shaft. The main tunnel will convey stormwater and groundwater flows from the EXPO 2020 area near the intersection of Sheikh Mohammed Bin Zayed Road and Jebal Ali Lehbab Road to the sea close to the EGA facility. The tunnel will follow beneath the road easement along Jebal Ali Lehbab Road and along Sheikh Zayed Road and continue to the pumping station. The tunnel traversed through the Barzaman and Fars formation with an overburden of 33 m with maximum water pressure of 4.4 bar and was excavated by EPB TBMs. This project is characterized by its dimensions with an internal diameter of 10 m and 350 mm of segment thickness, and by the use of steel fibre reinforced concrete in the precast segmental lining. The use of fibres aims to reduce the CO2 footprint obtaining an optimized design from the environmental point of view. These facts are associated to a complex design of precast segments, in order to ensure their structural competence and their integrity according to the durability requirements, under large thrust forces (temporary loads) and permanent load. Hence, considering such complexities, the structural design has been carried out producing a 3D structural model by means of a sophisticated FEM structural software. Results of the model allow to identify areas of the segment where spalling and bursting stresses are generated along circumferential joints and maximum value of those stresses in the temporary load cases. Moreover, a structural design verification of the segment has been undertaken considering the contribution of steel fibres class 4c, as it is set up in the FIB model code, aiming to ensure that the precast segments are structurally competent and fulfil the durability requirements of the Project. The article details the design approach and the independent checker design verification approach. The experience gained during construction is also reported, describing challenging aspects of the Tunnel execution and an analysis of the lining damages. x | |||||
Laubbichler, Jürgen; Schwind, Thomas; Gakis, Angelos; Sanz, Alejandro; Soto, Francisco | Advanced design of large cavern intersections in soft ground without conventional bar reinforcement | Geomechanics and Tunnelling | 4/2021 | 367-376 | Topics |
KurzfassungThe design of three mined stations in Toronto as part of the Eglinton Crosstown Light Rail Project involved several intersections of large tunnels situated in the heterogenous, water-bearing glacial till deposits. The most challenging openings, 220 m2 each, were formed in the two sides of the 18 m high cross-cut tunnels to allow the excavation of the 18 m wide platform caverns. A key objective for the design was the optimization of the tunnel shapes and the advanced simulation of the fibre reinforced shotcrete properties, to allow these openings in the initial tunnel linings to be achieved without conventional bar reinforcement or thickenings, thus simplifying and accelerating the construction, whilst reducing health and safety risks. x | |||||
Perner, Reinhard; Schorn, Roland; Atzl, Georg | New construction of Albula Tunnel II - Experience with steel fibre shotcrete / Neubau Albulatunnel II - Erfahrungen mit Stahlfaserspritzbeton | Geomechanics and Tunnelling | 4/2021 | 377-389 | Topics |
KurzfassungThe new construction of the 5860 m long Albula Tunnel was mainly carried out by blasting from the Preda and Spinas portals. Due to the exposed location in the high mountains, mixing plants were installed on both portal sides for the concrete supply; the concrete aggregate was largely produced from the excavated material, with a gravel plant being built in Preda for this purpose. The planned tunnel lining provides for a single-shell shotcrete construction for the most part. In the course of the excavation work, the excavation support was optimised so that the reinforcement mesh in the main support class in the single-shell area were replaced by steel fibre shotcrete. x | |||||
Proksch-Weilguni, Clemens; Wolfger, Hannes; Kollegger, Johann | Optimized reinforcement in longitudinal joints of segmental tunnel linings | Geomechanics and Tunnelling | 4/2021 | 390-399 | Topics |
KurzfassungWhen building tunnels using segmental lining, the segmental lining takes over the supporting role of the excavated soil. With the workspace in tunnel construction being very constricted the circular, segmental linings are divided into small segments called tubbings which are assembled by a tunnel boring machine. This kind of construction results in numerous longitudinal and circumferential joints. The loading situation for the longitudinal joints is typically dominated by the compressive normal forces combined with relatively small bending moments. The thickness of the tubbings usually depends on the longitudinal joints of the individual segments. The cross-sectional area of the tubbings has to be reduced at the joints in order to avoid spalling of the concrete leading to higher compression in the joints themselves. The Institute of Structural Engineering of TU Wien developed a new reinforcement design for tubbings with strengthened longitudinal joints. With a patent application pending, the newly designed joints were manufactured and tested demonstrating that the TU Wien proposal significantly increases the load-bearing capacity of the tubbings in comparison to conventional tubbing solutions. The very satisfying results, obtained from the large-scale tests of the newly developed joint design, show great potential for the construction of tunnels with thinner tubbings in the near future. x | |||||
Voit, Klaus; Depiné, Manuel; Hofmann, Matthias; Orsi, Georg; Murr, Roland; Zangerl, Christian; Bergmeister, Konrad | Material characteristics and compactability of phyllitic tunnel excavation material / Verdichtungseigenschaften von schiefrig-phyllitischem Tunnelausbruchmaterial - Examination of non-recyclable spoil at the Brenner Base tunnel / Betrachtung von nicht verwertbarem Ausbruch beim Brenner Basistunnel | Geomechanics and Tunnelling | 4/2021 | 400-415 | Topics |
KurzfassungLarge quantities of excavated rocks are generated during tunnel driving. Recycling possibilities and total percentage of recycling are depending on the rock conditions (rock type and rock properties), as well as the applied driving method. If recycling of the excavated rock mass is not possible or reasonable from a technical or economical point of view, the excavated material needs to be deposited in landfills. Thereby, the consumed landfill volume depends on the material volume of non-recyclable rock and its compactability as a function of the loosening of the rock by excavation and landfill installation. Both, material volume and compactability of the excavated material, are difficult to evaluate in advance. Apart from unpredictable lithological changes and variation of the driving parameters (e.g. depth of advance in conventional driving, contact pressure of tunnel boring machine), external influences - like afflux of water or weather conditions during installation of the material - significantly affect the compactability of the excavated aggregates. In this study, the actual example of phyllitic rock material excavated by conventional drilling and blasting from the main tunnel tubes of the Brenner Base Tunnel has been chosen to take a closer look at the research question concerning the compactability of phyllitic rock material. Since excavation material is increasingly used in construction industry, detailed knowledge on this matter is necessary for a successful application. x | |||||
Morocutti, Alex; Lussu, Andrea; Leitner, Edgar; Kaiser, Christian; Ertl, Anton; Grüllich, Sebastian | Innovative TBM transport logistics in construction section H33 of Brenner Base Tunnel / Innovative Transportlogistik zur TBM-Versorgung im Baulos H33 des Brenner Basistunnels | Geomechanics and Tunnelling | 3/2021 | 233-244 | Topics |
KurzfassungThe Tulfes-Pfons construction section of the Brenner Base Tunnel includes a 16.6 km long tunnel section excavated with an open gripper TBM. Due to the very difficult logistic conditions (steep access tunnel with 10 % gradient and a 90° bend at the transition to the exploratory tunnel as well as a limited clearance profile with 8 m diameter), the contractor and client decided on an alternative supply of the TBM - the 'multi-service vehicle' (MSV). This laser-controlled train on rubber wheels without rails is able to handle both the steep access and the 90° bend. After 16 km of excavated tunnel with a top performance of 61 m/d and top monthly performance of up to 800 m in hard rock conditions with 1000 m overburden, the decision to use the MSV has proved to be a complete success. In addition to the logistics and safety advantages, a cost reduction has also been achieved compared to the planned conventional system. MSV are a cost-effective and technically proven alternative to conventional track-bound TBM supply equipment. x | |||||
Goliasch, Robert; Gschnitzer, Ernst | Rail-bound logistics in tunnelling - Challenging logistics for a 30 km long TBM drive / Gleislogistik im Tunnelbau - Logistische Herausforderungen bei einem 30 km langen TBM-Vortrieb | Geomechanics and Tunnelling | 3/2021 | 247-257 | Topics |
KurzfassungDuring the early years of the 19th century, narrow-gauge railways found their way into mines and tunnel projects. Due to economic reasons, these rail-bound transport systems were successfully used for the transport of personnel, supplies and muck operations. While the worldwide transport logistics developed and changed continuously over the following century, there was limited demand within the tunnelling industry on innovation and improvement for these robust, durable and simple railways. Moreover, rubber-tired transport systems were introduced to the market and replaced traditional rail equipment on many tunnelling projects. The MTS tunnel Drive 1, originally planned to be 13 km in length and now extended to 30 km, will become the longest single tunnel drive in the world, demonstrating the flexibility of a rail-bound system. Since the start of the project, various suppliers and manufacturers for rail-bound equipment and rail track systems have been involved in the development of innovative drive systems, under-carriages and rail tracks. This article provides an overview of the design, implementation and lessons learned so far. x | |||||
Dankl, Wolfgang; Reith, Marco | Logistics of deep tunnel construction sites without portal access - SBT2.1 Semmering Base Tunnel / Logistik von tiefliegenden Tunnelbaustellen ohne Portalzugang - Baulos SBT2.1 Semmering Basistunnel | Geomechanics and Tunnelling | 3/2021 | 258-269 | Topics |
KurzfassungThe 27.3 km long Semmering Base Tunnel is a major component of the Baltic-Adriatic Corridor trans-European rail link. The SBT2.1 Fröschnitzgraben Tunnel section involves more construction work than any other contract section of the Semmering Base Tunnel project. First, two shafts over 400 m deep had to be sunk down to tunnel level in order to create the emergency station. From here, the tunnels are being driven towards Gloggnitz and Mürzzuschlag. The falling drives towards Gloggnitz, each approx. 8.5 km long, are being excavated with two tunnel boring machines (TBM), while conventional tunnelling methods (drill and blast) are being used to drive the 4.3 km long rising section towards Mürzzuschlag. Another major component of the contract is the creation and management of the Longsgraben landfill site. x | |||||
Entfellner, Manuel; Hauer, Hannes; Bauer, Johann | Logistic challenges at contract SBT 1.1 - Intermediate construction access Göstritz / Logistische Herausforderungen beim Baulos SBT 1.1 - Zwischenangriff Göstritz | Geomechanics and Tunnelling | 3/2021 | 270-285 | Topics |
KurzfassungBase tunnels usually require temporary intermediate construction accesses in order to be able to carry out the tunnelling work in a timely, economical and logistical reasonable scope. Intermediate construction accesses in the form of shafts lead to particular logistical challenges in supplying the tunnel headings. At contract SBT 1.1-Tunnel Gloggnitz as the eastern section of the Semmering Base Tunnel, the shafts of the intermediate construction access Göstritz cannot be sunk from the surface for topographical reasons but are instead developed by an access tunnel. This fact requires the construction of complex underground structures and logistical interfaces to supply the four tunnel headings, beginning from the building site facilities, via the access tunnel, through the shafts to the tunnel face. In addition to the ongoing supply of all kinds of support measures, the excavated material is mucked by means of fully automatic belt and shaft conveyor systems. To ensure the permanent safety of the crew on-site, the highest demands and resilience are placed on the transport systems through the two 250 m deep shafts, the ventilation and the mountain water drainage systems of up to 500 l/s. The article describes the experience and ongoing optimization of the logistics concept as well as innovative new developments that are applied in this special tunnel project. x | |||||
Fentzloff, Wolfgang; Rothe, Stefanie; Stahn, Christian; Papantonakis, Dimitrios | BIM meets Lean - Logistics study of a long tunnel using BIM and Lean methods / BIM und Lean im Doppelpack - Logistikuntersuchung eines langen Tunnels mit Methoden von BIM und Lean | Geomechanics and Tunnelling | 3/2021 | 285-297 | Topics |
KurzfassungInfrastructure projects in inner-city areas are gaining in importance on the one hand and are subject to increasingly restrictive requirements due to the space available on the other. This affects not only the site installations, but also to a large extent the access to and the material handling on the construction sites. Implenia has been using the digital capabilities of BIM to improve project execution for several years. Visualisations, data management and collaboration create a transparency that is necessary to face the difficult boundary conditions. Lean Construction method of optimizing and stabilizing material flows, which is new to the infrastructure sector, can ideally use BIM digital tools to map its processes. It was obvious to use this symbiosis of the two methods. x | |||||
Phillips, Mina; Fadhel, Haider; Raafat, Ibrahim; El-Kelesh, Adel | Use of artificial ground freezing in construction of cross passages under Suez Canal / Bodenvereisung für den Bau von Querschlägen unter dem Suezkanal | Geomechanics and Tunnelling | 3/2021 | 298-307 | Topics |
KurzfassungThe Artificial Ground Freezing (AGF) has demonstrated its versatility as an effective approach for both temporary ground stabilization and ground water control in almost all types of saturated soils. This paper describes the use of a closed circuit freezing system in the construction of four cross passages. The passages connect 4.8 km long twin road tunnels that have recently been constructed at depths of up to 60 m under Suez Canal in Ismailia, Egypt. The paper starts by describing the ground conditions at the locations of the cross passages and by presenting the results of laboratory tests conducted on unfrozen, frozen and thawed soil specimens. The main design criteria considered in designing the freezing works are discussed and the freezing and cross passages construction works are described. The frozen body was carefully monitored during the freezing process and construction of passages. Records of the adopted monitoring program are presented and discussed. Significant observations that contribute to effective planning of future freezing works are also presented. x | |||||
Dietler, Thomas | Characterisation of rock as foundation for dams and hydropower plants - Experience from a field geologist's perspective / Beschreibung von Fels als Baugrund für Talsperren und Wasserkraftanlagen - Erfahrungen aus Sicht des Feldgeologen | Geomechanics and Tunnelling | 2/2021 | 129-141 | Topics |
KurzfassungThe characterisation of rock as a foundation for hydropower plants in general and dams in particular is highly complex and requires a great deal of experience on the part of the geologists involved. Geology cannot be studied remotely; it requires geological field surveys and investigations. This paper describes the aspects to be considered, the planning of the investigations and the degree of detail needed at the various planning phases from the field geologist's perspective. It also highlights the internationally recognised methods of investigation used for large-scale projects and describes how the results are documented and recorded. It concludes by briefly outlining the soft factors which constitute an integral part of successful geological feasibility studies. Geology is an “inexact” science that requires extensive experience in order to generate the most realistic ground model possible. For this reason, a clear distinction must be made between facts (basic data) and their interpretation (experience). Furthermore, it is important to consider what other conclusions can be drawn from surveying the subsoil. x | |||||
Kogler, Kurt; Hechenbichler, Johann | Exceptional problems for grouting in power station construction in exposed locations / Außergewöhnliche Aufgabenstellungen an die Injektionstechnik im Kraftwerksbau in exponierten Lagen | Geomechanics and Tunnelling | 2/2021 | 142-157 | Topics |
KurzfassungPower station construction has always posed very complex problems for engineers. The dimensions of such construction works, their geographical location and the effects on people and nature reflect not only the great public interest but also show how extensive and challenging the design and construction of such construction works can be. Grouting technology is a reliable partner for waterproofing, consolidation and prestressing measures in power station construction and in such exposed locations, provides special solutions for the particular local conditions. The following article describes through selected examples grouting solutions for the refurbishment and new construction of hydropower facilities, concentrating on the implementation of specialised civil engineering measures on international power station projects. x | |||||
Marte, Roman; Ausweger, Georg; Schweiger, Helmut F.; Seiwald, Stephan; Kainz, Florian; Breymann, Helfried | Safety aspects of a water reservoir influenced by a creep like landslide / Sicherheitsbetrachtungen für einen durch eine Massenbewegung beeinträchtigten Speicher | Geomechanics and Tunnelling | 2/2021 | 158-172 | Topics |
KurzfassungOn the basis of a case history of a pumping storage which is endangered by a slow moving landslide, the interaction of the reservoir operation and the deformation behaviour of the landslide will be discussed in this paper. Comprehensive measurements as well as theoretical investigations, which had been performed to understand the determining factors for the deformation behaviour of the landslide, will be discussed. Based on these investigation results a warn and alarm plan as part of the safety concept for the storage had been developed. x | |||||
Hautz, Werner; Neuner, Johann | Expansion of Kirchbichl Power Plant in Tyrol - Challenges of foundation engineering / Erweiterung Kraftwerk Kirchbichl in Tirol - Herausforderungen an den Spezialtiefbau | Geomechanics and Tunnelling | 2/2021 | 175-183 | Topics |
KurzfassungTiwag - Tiroler Wasserkraft AG sees itself as a driving force in the energy transition, pursuing the goals of the Tyrolean and Austrian energy strategies with a moderate, environment friendly expansion of hydropower. The projects are essentially aimed at expanding existing power plants so that they can be used more effectively, and additional hydropower potential can be developed. The Kirchbichl Power Plant is a good case in point. From 2017 to 2020, the power plant was made fit for the next decades as part of an extensive refurbishment and expansion project. The main project components are to improve flood security through the construction of an additional weir field, to adapt to enhanced environmental standards through the construction of a fish passage and a power plant for residual flow, and to increase the discharge of the power plant by installing an additional turbine. One of the challenges was the construction pits in the immediate vicinity of the existing system. The pit design with bored pile retaining wall and base seal with a jet grout slab has proven to be very effective. x | |||||
Innerhofer, Guntram; Bickel, Lukas | Rodundwerk I, new headrace system - Concept and realization / Rodundwerk I, neuer Kraftabstieg - Konzeption und Ausführung | Geomechanics and Tunnelling | 2/2021 | 185-195 | Topics |
KurzfassungAs a result of several feasibility studies from which sound economic and technical arguments emerged, the decision was made to construct a new headrace system for the Rodundwerk I consisting of a low pressure tunnel, a shallow pressure shaft parallel to the surface slope and a subsequent high-pressure penstock gallery. The new distribution pipeline was designed as a concrete-encased gravity abutment. Construction started at the beginning of May 2020 and since then excavation work has progressed according to plan. Particular attention had to be addressed to the impact of construction operations on the existing power plant structures. Hence, a detailed monitoring concept was established concerning the vibration transmission in the rock mass. Excavation works are carried out partly by tunnel boring machine, partly by drilling and blasting and, once the critical threshold of vibration has been reached, by alternative methods. By continuously adjusting the blasting parameters (charge amount, ignition timing), it was possible to minimise the detonation-related effects in the vicinity of the existing structures. x | |||||
Smesnik, Mathias; Nowotny, Hans; Nowotny, Hans; Krstic, Sanja; Sever, Özgür | Lower Kaleköy Dam - A tailor made composite dam structure | Geomechanics and Tunnelling | 2/2021 | 197-206 | Topics |
KurzfassungWorldwide various type of dams are used to create reservoirs for multiple purposes. Particularly in usual cases, a single dam type is used to form a watertight barrier. Keeping safety and finance in mind, less challenging dam locations, that concerns with aspects like foundation conditions, seismicity at the dam sites, availability of construction materials, etc. are preferred. Ironically, where there is a demand for a reservoir, a suitable dam location is not always available. In those cases, these circumstances make advanced design of dam structures indispensable. An example of such a dam design is the Lower Kaleköy composite dam structure. The same consists of a roller compacted concrete gravity dam at the right bank, which is linked with one of the world's highest deformation joint to the very first asphalt core embankment dam in Turkey, situated on the left bank. The Lower Kaleköy Hydroelectric Power Plant (HEPP) constructed and operated by Kalehan Genç Enerji Üretim A.. with an installed capacity of 500 MW, as part of the Beyhan Kaleköy HEPP cascade is located on the Murat River, a tributary to the Euphrat River in Eastern Turkey. This paper summarizes the design methodology developed by the design consortium (AFRY/Temelsu), headed by AFRY, for the tailored composite dam. x | |||||
Grunicke, Urs H.; Lienhart, Werner; Vorwagner, Alois | Long-term monitoring of visually not inspectable tunnel linings using fibre optic sensing / Langzeitmonitoring von nicht visuell inspizierbaren Tunnelinnenschalen mittels Faseroptik | Geomechanics and Tunnelling | 1/2021 | 19-32 | Topics |
KurzfassungRegular structural assessments of tunnel linings are commonly performed by visual inspection. Crack phenomena and their development over time are essential indicators of changes of the stress regimen. These are the most prominent input data for the structural assessment of linings. Cladding for fire protection or noise control inhibit visual inspection and call for alternative methods of crack detection and monitoring. This paper presents the application of an alternative method which employs distributed fibre optic sensing (DFOS) which is installed on already existing linings. The objective is to obtain monitoring results with best reliability in comparison to conventional inspection. While the application of DFOS with fibres embedded in new linings has already been tested extensively, later installation on existing linings poses various challenges. Based on findings obtained from laboratory and field tests in an operational highway tunnel, we found that by means of later installed fibres with lengths of up to 70 m, strain measurements can achieve accuracies of about 1 &mgr;m/m over 10 mm. This allows the detection of both current and historical crack widths at 0.01 mm precision, conspicuous strain patterns and temperature abnormalities. The system can be mounted onto the inner lining surface which is covered by later claddings and are hence inaccessible to visual inspection. The structural performance can eventually be inferred from interpreted crack patterns. x | |||||
Moritz, Bernd; Heissenberger, Roman; Schachinger, Tobias; Lienhart, Werner | Long-term monitoring of railway tunnels / Langzeitüberwachung von Eisenbahntunneln | Geomechanics and Tunnelling | 1/2021 | 35-46 | Topics |
KurzfassungAt the large infrastructure projects of the Austrian Federal Railways in the Alpine region geotechnical structures with different characteristics are encountered. Especially heterogeneity and composition of fault zones associated with different stress conditions are a great challenge during tunnelling. Although the system behaviour resulting from ground-support interaction is measured by monitoring methods, after completion of tunnel works with installation of the inner lining usually the tunnel is no further monitored. The goal of ÖBB-Infrastructure AG is to apply robust, reliable and durable monitoring systems for the observation of geotechnical relevant structures during a service life of the tunnels of 150 years. Thereby unfavourable tendencies of system behaviour shall be detected early and measures in terms of predictive maintenance planned in due time to ensure high availability of the tunnels during operation. The paper presents the implementation of long-term monitoring at the projects Koralm Tunnel and Granitztal Tunnel and gives an outlook at the Semmering Base Tunnel. x | |||||
Keuschnig, Markus; Schober, Andreas; Delleske, Robert; Brandner, Katharina; Höfer-Öllinger, Giorgio | Scale-oriented landslide monitoring and early warning system for uranium legacy complexes in Mailuu Suu, Kyrgyzstan | Geomechanics and Tunnelling | 1/2021 | 47-53 | Topics |
KurzfassungRadioactive waste and the legacies of uranium mining combined with massive landslides pose tremendous risks to vast areas of Kyrgyzstan and their inhabitants. These risks comprise the potential destruction of radioactive legacies and thus, the mobilisation of radioactive material through streams and rivers into intensively cultivated agricultural areas. To tackle these challenges, a scale-oriented landslide monitoring and early warning system (LMEWS) was developed to increase the safety of Kyrgyz uranium legacy complexes in the Mailuu Suu region, southern Kyrgyzstan. The LMEWS utilizes cutting-edge technologies like satellite- and ground-based InSAR as well as Unmanned Aerial Systems (UAS) to ensure flexibility, transferability, and maximum protection against vandalism. x |