Artikeldatenbank
Autor(en) | Titel | Zeitschrift | Ausgabe | Seite | Rubrik |
---|---|---|---|---|---|
Sönser, Sabrina; Treichl, Hanspeter; Leitner, Andreas | Anchored retaining walls from the early 1980s in the Salzburg area / Geankerte Stützkonstruktionen aus den frühen 1980er-Jahren im Raum Salzburg | Geomechanics and Tunnelling | 5/2019 | 540-547 | Topics |
KurzfassungAll retaining walls along highways have to be controlled and checked regularly. In the course of these checks, defects and a wide variety of failure mechanisms to anchors have been found throughout Austria over the past ten years. The following article discusses retaining walls with anchors of the type Permaflex in the area around Salzburg. Due to their construction, these have an increased susceptibility to corrosion. The two examples, a retaining wall at Egger and slope stabilisation of the Donnergraben bridge are in each case anchored, coupled plate elements made of reinforced concrete. In particular, the importance of both the installation of permanent monitoring as well as the availability of inventory documents in remediation planning is emphasized. x | |||||
Stadlbauer, Jakob; Antony, Christoph | Case study on the maintenance of various anchored retaining walls in the Austrian high-speed road network / Erfahrungsbericht über die Erhaltung diverser geankerter Stützkonstruktionen im hochrangigen Straßennetz | Geomechanics and Tunnelling | 5/2019 | 548-554 | Topics |
KurzfassungAnchored retaining structures demand detailed preliminary investigations for appropriate and economic repair and upgrading. However, due to the complex constraints and insufficient data basis, it is often necessary to investigate the basis for the design of repair works in advance. The article described two anchored constructions. The first is a bored pile wall to dowel a slope. In addition to the repair of corrosion damage to the strand anchors, repair of the uphill drainage system is an essential part of the refurbishment concept. The second example is a retaining structure about 40 years old, in which several rod anchors show corrosion to their heads. Since there is a lack of information about the ground conditions for the assessment of structural safety and design of repair works, additional investigation boreholes were drilled. x | |||||
Bergmeister, Konrad | The Brenner Base Tunnel - geological, construction and logistical challenges and innovations at half time / Der Brenner Basistunnel - geologische, bautechnische, logistische Herausforderungen und Innovationen zur Halbzeit | Geomechanics and Tunnelling | 5/2019 | 555-563 | Topics |
KurzfassungThe Brenner Base Tunnel with a total of 230 km of tunnels is a geological, structural and logistical challenge. The transnational project is an additional challenge, considering different planning, approval and construction rules and cultures. From the start of construction in 2007 to the present, today halftime is reached with 100 excavated tunnel kilometers. An overview of selected topics is given in this contribution, such as project optimizations of the emergency areas, geological/geotechnical knowledge transfer from the already driven exploratory tunnel to the following construction lots of the parallel main tunnels, reprocessing and use of Schists as aggregates for the inner lining and shotcrete production, logistics experience with wheel-bound transport vehicles, measurements during construction with laser tunnel scanners and the service life of the tunnel of 200 years with an increased safety concept defined in the guide conceptual design. Preparations and planning are already at an advanced state for the second half of the project, concerning the next excavation lots, secondary linings as well as interior work with the installation of the technical equipment. The construction work is expected to be completed in 2025 and the end of construction is expected at the end of 2028 (2030 in case of risk occurrence). x | |||||
Reinhold, Chris; Cordes, Tobias; Bergmeister, Konrad | Geotechnical rock mass characterisation and classification at the Brenner Base Tunnel project - Methodology and solutions / Geotechnische Klassifizierung und Charakterisierung des Gebirges beim Brenner Basistunnel - Methodik und Lösungsansätze | Geomechanics and Tunnelling | 5/2019 | 564-574 | Topics |
KurzfassungFor the construction of the Brenner Base Tunnel with a total length of the whole tunnel system of 230 km, the geotechnical characterisation of the rock and the rock mass based on the geological mapping, the exploration and the geological models is of essential importance. The reliability of the ground prediction and consequently the effectiveness of the construction and support measures are mainly influenced by the methodology for the evaluation of the characteristic material parameters of the ground. This mainly influences the project process and the construction as well as the maintenance costs of a tunnelling project. In this paper, the applied methodology with its approaches of resolution for the improvement of the reliability of the ground prediction at the Brenner Base Tunnel project are explained in detail. Furthermore the improvements to this methodology during different project stages are shown. The paper concentrates on the implementation of the results gained from the exploratory tunnel and the influence of these results on the methodology for the improvement of ground prediction and the reduction of ground risks. In addition problems and approaches for solving these problems are explained in detail. For instance the avoidance of the double consideration of the influence of schistosity by using a rock mass classification system for rock mass parameter identification. x | |||||
Flora, Matthias; Grüllich, Sebastian; Töchterle, Andreas; Schierl, Heimo | Brenner Base Tunnel exploratory tunnel Ahrental-Pfons - interaction between tunnel boring machine and rock mass as well as measures to manage fault zones / Brenner Basistunnel Erkundungsstollen Ahrental-Pfons - Interaktion zwischen Tunnelbohrmaschine und Gebirge sowie Maßnahmen zur Ereignisbewältigung in den Störzonen | Geomechanics and Tunnelling | 5/2019 | 575-585 | Topics |
KurzfassungApprox. 42 km of tunnel were excavated on the contract Tulfes-Pfons H33, including a 15 km long section of the exploratory tunnel, which has been excavated since October 2015 with a gripper TBM from the Ahrental access tunnel southward into the district of Steinach. The interaction of the tunnel boring machine with the rock mass is discussed here as a back analysis of the mechanized tunnelling drive. This article does compare the forecast with the actual geological/geotechnical conditions, but only considers the conditions actually encountered. The back analysis takes place analogously to the principle of geotechnical planning according to the ÖGG (Austrian Society of Geomechanics) guideline, in which, starting from the rock mass structure and the rock mass types, the encountered tunnel face and intrados behaviour are observed and an estimation of the system behaviour is carried out. A description of the tunnelling technology concept completes this paper together with two case studies and the lessons learned. x | |||||
Cordes, Tobias; Reinhold, Chris; Schneider-Muntau, Barbara; Grüllich, Sebastian; Himmelsbach, Christian; Wehrmeyer, Gerhard | Analyses of TBM disc cutter forces - application possibilities / Analyse der TBM-Diskenkräfte - Anwendungsmöglichkeiten | Geomechanics and Tunnelling | 5/2019 | 586-594 | Topics |
KurzfassungForecasts made during tunnelling of the daily advance, to control the machine, specify the lining and verify system behaviour are of great importance for safety and for the success of the whole project. In practice, such forecasts are obtained in deep tunnels by probe drilling, leading to downtime periods and by analog/digital face documentation with shorter downtime periods. Measurement and evaluation of rock mass cutting at the cutterhead of the TBM enables continuous monitoring without downtime. From the spatial distribution of the disc forces, basic geological/geotechnical information about the tunnel face can be derived. In addition, this data is valuable for load monitoring and monitoring the condition of the discs to determine the optimal changing time. This contribution deals with a geological-geotechnical interpretation of the disc forces of the open TBM on contract H33 Tulfes-Pfons of the Brenner Base Tunnel. The spatially distributed disc forces are evaluated and compared with the geological documentation. x | |||||
Lussu, Andrea; Grüllich, Sebastian; Kaiser, Christian; Fontana, Adrian | 15 km TBM exploratory tunnel excavation in the construction Lot H33 of the Brenner Base Tunnel / 15 km TBM Vortrieb im Los Tulfes Pfons - Erfahrungen und Erkenntnistransfer auf das Hauptbaulos | Geomechanics and Tunnelling | 5/2019 | 595-603 | Topics |
KurzfassungThe Tulfes Pfons H33 construction contract of the Brenner Base Tunnel includes a 15 km long exploratory tunnel. The tunnel is being driven by an open gripper TBM, permitting a view of the surface of the rock mass, to achieve the best possible geological and geotechnical exploration for the deep tunnel system. Geologists and geotechnical engineers follow the TBM excavation on a daily basis and guarantee ongoing mapping and interpretation of the rock mass classification and of the TBM data. All data from the exploratory tunnel advance, the TBM data, the measured deformations and the seismic explorations as well as the findings of geological mapping are incorporated into the geotechnical longitudinal section, which serves as the basis for the tenders of the main construction contracts. In particular, discussions take place with the designer of the following contract, how the encountered fault zones and overbreaks can be passed successfully in the main tunnels. Both the improvement of the rock mass from the exploratory tunnel and ramps are considered in order to excavate the most difficult fault zones from the exploratory tunnel. x | |||||
Marchetti, Diego; Fabris, Carla; Schweiger, Helmut F. | The Flat Dilatometer and Seismic Dilatometer for in situ testing / In-situ-Versuche mit Flat Dilatometer und seismischem Dilatometer | Geomechanics and Tunnelling | 4/2019 | 306-317 | Topics |
KurzfassungIn the last decades there has been a massive migration from laboratory testing to in situ testing, to the point that, today, in situ testing is often the major part of a geotechnical investigation. In particular direct-push in situ tests, such as Cone Penetration Test (CPT) and the Flat Dilatometer Test (DMT), are fast and convenient in situ tests for routine site investigation. The scope of this paper is to describe the DMT and its recent updates, in particular the Seismic Dilatometer Test (SDMT) for measuring shear and compression wave velocities and the automated dilatometer probe (Medusa DMT). An Example of SDMT test results and its application to derive soil stiffness parameters are shown, as well as the result of a class-A prediction of an anchor pull-out test, which was calibrated with the SDMT profile. x | |||||
Macek, Matej; Logar, Janko; Pulko, Bo tjan | Comparative evaluation of soil properties using CPT and DMT in-situ tests / Vergleichende Bewertung der Bodeneigenschaften durch CPT und DMT | Geomechanics and Tunnelling | 4/2019 | 318-327 | Topics |
KurzfassungThe piezocone penetration test (CPT) and flat dilatometer test (DMT) are routinely used in geotechnical practice and are often considered adequate for detailing of soil profile and determination of soil properties. This paper presents comparison of results of ground characterization and evaluation of soil properties based on the combined use of CPT and DMT at four different locations, each with different ground composition. Evaluation of both tests in terms of soil type, undrained shear strength, constrained modulus and friction angle is presented and results are compared. In some cases the results are also compared with laboratory data. The main objective is to show that companion sets of CPT and DMT at a given site could be used to better define the geotechnical ground model and to increase confidence in the evaluation of soil properties. x | |||||
Ausweger, Georg M.; Havinga, Michael; Lüftenegger, Roland; Marte, Roman; Oberhollenzer, Simon | Stiffness of Salzburger Seeton - Comparison of results from cone penetration tests and laboratory tests / Steifigkeit des Salzburger Seetons - Vergleich von Ergebnissen aus Drucksondierungen und Laborversuchen | Geomechanics and Tunnelling | 4/2019 | 328-339 | Topics |
KurzfassungCone penetration tests are a good option for in situ tests in case of soft, fine-grained soils. Thus, they are often used for subsoil investigations in the Salzburger Becken, which mainly consists of silty, fine-sandy sediments. Unfortunately, empirical correlations for the determination of soil parameters from cone penetration tests in case of silty, fine-sandy soils are very rare in literature. This contribution should help to evaluate the known correlations and correlation factors for the determination of soil stiffness based on cone penetration tests regarding their applicability for the Salzburger Seeton. This is done by the comparison of cone penetration test results with results from laboratory tests. x | |||||
Oberhollenzer, Simon; Marte, Roman; Gasser, Daniel; Premstaller, Michael; Leitich, Alexander | Microstructure of the Salzburger Seeton - Characterization based on cone penetration tests / Mikrostruktur des Salzburger Seetons - Charakterisierung basierend auf Drucksondierungen | Geomechanics and Tunnelling | 4/2019 | 340-351 | Topics |
KurzfassungPiezocone penetration tests (CPTu tests) allow continuous measurements of the tip resistance, the sleeve friction and the pore water pressure over depth. Furthermore, they minimize the required time as well as costs for a soil characterization. Due to the difficulty related to undisturbed sample recovery of soils (i.e. of weak silty fine-grained sediments) for laboratory testing, in situ investigations are becoming increasingly popular in geotechnical engineering. The article illustrates results of cone penetration tests, executed at three test sites in the city of Salzburg. It is shown that CPT-based soil behaviour type charts according to Robertson lead to a realistic characterization of the underground conditions. The grain size distribution of the Salzburger Seeton varies between fine sand-silt mixtures, which are found in the upper parts, to clayey silts in greater depths. According to CPT-based soil behaviour type charts of Robertson clayey silts behave clay-like contractive and are characterized by homogeneous properties with increasing depth. Qtn-IG diagrams underline that the Salzburger Seeton with a high clay content presents a weak microstructure. On the other hand, the upper Seeton layers, which can be classified as silt-sand mixtures and silty sands respectively, show a stronger bounding between the particles. x | |||||
Mahler, András; Móczár, Balázs | Strength and deformation characteristics of tertiary soils / Scherfestigkeits- und Verformungsverhalten von tertiären Böden | Geomechanics and Tunnelling | 4/2019 | 352-361 | Topics |
KurzfassungThis article presents the results of in-situ and triaxial testing of tertiary soils (Pannonian sand and Oligocene clay) performed for two major Hungarian projects. The shear strength of these formations varies greatly. Just interpreting the shear strength of tertiary soils poses a number of questions, which definitely exceeds the scope of existing standards. Since extracting multiple samples from the overconsolidated, high-density samples was not possible, the necessary parameters had to be determined from one larger specimen. Through short examples, it is demonstrated how the test results can be described using soil models and transferred into geotechnical design, highlighting the limits of numerical modelling (in case of these soils). x | |||||
Spagnoli, Giovanni; Feinendegen, Martin; Ziegler, Martin | Assessing the clogging potential of clay/additive / mixtures by cone pull-out tests | Geomechanics and Tunnelling | 4/2019 | 362-371 | Topics |
KurzfassungClogging can be a massive problem during the mechanized excavation of tunnels. Soil conditioning with foams and/or polymers is normally used in these cases to decrease the adverse effect of clogging. In a research project the cone pull-out test was used to assess the variation of adherence for four sticky clays with four commercial additives. Results show that the additives have also an impact on the basic mechanical properties of the clays such as liquid limit, plasticity index and shrinkage limit. The tests were performed on the one hand by spraying the additives on the metal surface of the cone and on the other hand by directly mixing them to the clays to reach the critical consistency index (i.e. where the maximum adherence with water was observed). Sprayed cone tests show for two clays a decrease in adherence. However, by directly mixing the additives to the clay, adherence considerably decreases, except for one kaolinitic clay. The results can be useful to select suitable additives or to develop new ones considering the geotechnical and mineralogical properties of the excavated clays. x | |||||
de Oliveira, Daniela Garroux G.; Thewes, Markus; Diederichs, Mark S. | EPB machine excavation of mixed soils - Laboratory characterisation | Geomechanics and Tunnelling | 4/2019 | 373-385 | Topics |
KurzfassungEarth pressure balance (EPB) tunnel boring machines are shield machines that rely on their own excavated material as a support medium to maintain the support pressure at the face. This material also needs to have the necessary properties to be extracted, transported and, finally, disposed of. Whenever the natural material does not fulfil the necessary requirements, additives like water, foam, polymers, and fines, must be added, modifying the excavated ground to the desired conditions. The rheological properties of any excavated material, together with any additives, must be investigated and understood, as they will influence the flow behaviour of this conditioned material, directly affecting the machine operation and tunnel logistics. While studies assessing the flowability related to the EPB excavation of sand or clay soils are available, there is a lack of information on mixed soils. This paper presents the results from a testing campaign with mixed clay-sand samples, aiming to reproduce a simplified tropical weathered mixed soil, investigating its flow behaviour when changing certain controlled variables: clay-sand proportions, clay mineral, size of the clastic grain mixed with clay, water content, and additives (foam and polymers). Results from the tests conducted with a flow table, a slump test, and a rheometer device were compared, providing insights about the flow behaviour of the tested samples and its interaction with an EPB machine. x | |||||
Gerstner, Reinhold; Vigl, Alois; Jäger, Manfred; Wilfinger, Nicole | Suitability and selection of excavation methods for headrace tunnels of high head hydropower plants / Eignung und Auswahl von Vortriebsverfahren für Druckstollen von Hochdruck-Wasserkraftanlagen | Geomechanics and Tunnelling | 3/2019 | 199-211 | Topics |
KurzfassungIn the construction of high-pressure hydropower plants, the headrace is often the decisive cost component and determines the economic feasibility of the plant. For this reason, the selection and dimensioning of the most suitable tunnelling method is of fundamental importance. This starts with the determination of a suitable layout followed by a reliable geological prediction and covers the geotechnical interpretation and identification of geotechnical requirements. This is followed by the most accurate forecast of the performance of different excavation systems and risk assessments for each estimate. Finally, the development and comparison of different construction process scenarios is required to determine the most practical and safest combination of the most suitable excavation methods. Subsequently, these individual steps are explained and a comparison is drawn with experience gained in construction practice in the implementation of numerous headraces of high-pressure hydropower plants. x | |||||
Blauhut, Andreas; Steyrer, Peter; Eichiner, Hans; Fiegl, Marco; Gasser, Oliver; Riediger, Christian | Lower Tuxbach diversion - A high pressure diversion tunnel: Excavation and lining design for internal pressure greater than 20 bar / Untere Tuxbachüberleitung - Ein Überleitungsstollen als Hochdruckstollen: Vortrieb und Auskleidungskonzept für Innendrücke über 20 bar | Geomechanics and Tunnelling | 3/2019 | 212-227 | Topics |
KurzfassungThe “Lower Tuxbach diversion” project includes an 8.5 km headrace tunnel to the Stillupp reservoir. Nearly in the middle, the tunnel has to pass under the Zemm valley, which is more than 200 m deeper than the weir and the reservoir. With the shallow gradient of the TBM excavation, long sections of the tunnel will then have a high internal pressure during operation (pressure > 20 bar). The TBM excavation was carried out mainly in the Ahorn gneiss of the “Tauernfenster”, which strikes perpendicular to the tunnel axis. The stability of the rock mass was regular, but in the tunnel section to the weir, many joints and smaller fault zones with non-water-resistant infilling were encountered. Considering the high internal pressure, it was decided to retain most of the originally foreseen concrete lining. In the tunnel section to the reservoir, the decision about a possible optimisation of the lining design will be made after the completion of excavation. x | |||||
Gerstner, Reinhold; Dich, Christopher; Tschuchnigg, Franz; Bickel, Lukas | Geological basics, geotechnical design and lining of the new headrace system for the Rodundwerk I / Geologische Grundlagen, geotechnische Planung und Auskleidung des neuen Kraftabstiegs Rodundwerk I | Geomechanics and Tunnelling | 3/2019 | 228-237 | Topics |
KurzfassungIn Memoriam Reinhold Gerstner x | |||||
Wachter, Robert; Bonapace, Paul; Bilak, Andreas | Underground construction on the Prutz/Ried contract of the Gemeinschaftskraftwerk Inn (GKI) / Der Untertagebau im Baulos Prutz/Ried des Gemeinschaftskraftwerks Inn (GKI) | Geomechanics and Tunnelling | 3/2019 | 238-250 | Topics |
KurzfassungEven in the 1920s were already the plans for hydropower exploitation of the upper River Inn. Since the resumption of design work, the Gemeinschaftskraftwerk Inn (GKI) project has been optimised and adapted to the latest state of the technology as well as ecological requirements. After a collaborative process involving the authorities from both countries, the start of construction could be approved in 2014. The project will build a diversion hydropower station with an annual generation of about 414 GWh in the border area of Switzerland and Austria. x | |||||
Pikl, Franz Georg; Richter, Wolfgang; Zenz, Gerald | Large-scale, economic and efficient underground energy storage / Großtechnische, wirtschaftliche und effiziente untertägige Energiespeicher | Geomechanics and Tunnelling | 3/2019 | 251-269 | Topics |
KurzfassungThe conversion of the energy supply system towards renewable technologies is indispensable for climate and environmental protection. With the predominant use of inexhaustible but fluctuating renewable energy sources, energy storage capacities and physical networks are key infrastructure for sustainable functionality. Efficient pumped-storage hydropower can meet these demands. However, suitable sites for conventional surface reservoirs are facing natural limits, and new storage capacities in ecologically sensitive mountainous valleys are increasingly difficult to license. To gap these aspects this article reflects the construction of fully underground pumped-storage hydropower plants to cover multipurpose energy storage requirements. x | |||||
Innerhofer sen., Guntram; Greiner, Richard; Innerhofer jun., Guntram | Structural design concept for pressure shafts of hydro plants using the passive resistance of the rock mass / Bemessungskonzept für Druckschächte bei Nutzung des passiven Gebirgswiderstands | Geomechanics and Tunnelling | 3/2019 | 270-281 | Topics |
KurzfassungThe proposed method can be seen as an adaption of the “Seeber” concept considering developments in geomechanics, calculation methods and steel technology over the last decades. When exposed to inner pressure, the cracking condition is transgressed and steel linings will not protect the rock mass against cracking. Accordingly, the post-failure behaviour of the rock mass is an essential basis for structural design. The effects of crack water pressure on radial displacements and the width of gaps are considered. The resistant behaviour of the rock mass is determined by its minor primary principal stress. Under mountain ridges and slopes, there is no correlation between the minor stresses and the height of overburden. Obviously damage cases in concrete lined tunnels are the result of inappropriate assessment of principal stresses. A better approach is proposed based on fundamental considerations and FE calculations. Crack water pressure close to the level of the minimal principal stress will induce progressive hydraulic fracturing in the rock mass, which requires safe waterproofing sealing of the shaft. Grouting the coaxial gap in rock mass is a firm part of any design concept. In shafts sealed by membranes, the capability to bridge fissures must be proved by tests. In steel lined shafts, the usable passive resistance of rock mass is determined by the acceptable radial displacement. x | |||||
Kieffer, Scott; Dreese, Trent; Weil, Jonas; Kleberger, Johannes | Tools for optimizing rock mass grouting | Geomechanics and Tunnelling | 2/2019 | 121-128 | Topics |
KurzfassungOptimization of rock grouting procedures during construction is necessitated when sparse data sets and incomplete geologic understanding form the basis of initial design. Relying on geologic investigation findings that often have limited budgets, initial designs typically consider data from only a small volume of the entire rock mass to be grouted. During construction, thousands of production boreholes may be drilled and grouted, and each of these boreholes has the potential to provide valuable information for modifying the injection materials and construction means/methods. Implementation of procedural changes is greatly facilitated by the ability to efficiently assemble, query, visualize and interpret vast amounts of 3D data in near real-time. x | |||||
Kogler, Kurt; Hechenbichler, Johann; Gabriel, Patrick | Grouting measures in dam construction / Injektionsmaßnahmen im Talsperrenbau | Geomechanics and Tunnelling | 2/2019 | 129-140 | Topics |
KurzfassungGrouting measures in dam construction are of increasing importance in Europe, where many of the largest dams were constructed during the 1950s and 1970s. Nowadays, these dams often have to resist higher loads then they were originally designed for, and changes of reservoir management have increased loads on the structures in many cases. For this reason, many plant operators have decided to adapt dam structures for present-day use, to increase sustainability and guarantee serviceability. At the same time, the construction of new dams requires comprehensive planning as well as full cooperation between all areas of civil engineering and grouting technology. Grouting works are key elements of dam structures, which are usually not directly visible from the surface and therefore seldom perceived by the public. This paper gives an insight into the possibilities of grouting measures in dam construction and a brief overview of objectives of grouting measures and their assignment to components of dams as well as grouting measures for waterproofing curtains, pressure tunnels, pressure shafts, surge tanks and porous mass concrete. x | |||||
Hognestad, Hans-Olav; Kieffer, Scott | Pre-excavation grouting in rock tunneling - Dealing with high groundwater pressures | Geomechanics and Tunnelling | 2/2019 | 141-146 | Topics |
KurzfassungIn rock tunneling, pre-excavation grouting (or, pre-injection) refers to systematic treatment of the rock mass ahead of an advancing tunnel face via pressure grouting. The main purpose of pre-excavation grouting is to reduce water inflows, or to improve geomechanical properties of the rock mass. This paper summarizes approaches for treating competent rock masses with systematic pre-injection of cementitious grouts through boreholes drilled from the working tunnel face. The focus is on traditional cement based grouting technology and drill-and-blast tunneling under high static groundwater pressures (> 20 bar). Post-injection, where drilling and grouting is performed somewhere behind the tunnel face, provides an additional means for achieving a high degree of watertightness, but is beyond the scope of this paper. x | |||||
Creütz, Mikael; Osterman, Fredrik | The Stockholm Bypass - Design and execution of grouting works - Pre-excavation grouting by means of rock fissure grouting with cementitious grouts | Geomechanics and Tunnelling | 2/2019 | 147-157 | Topics |
KurzfassungThe E4 Stockholm Bypass is a new route for the European highway (E4) past the Swedish capital Stockholm. The bypass will connect the southern and northern parts of Stockholm. To reduce the impact on the surroundings, 18 km of the total of 21 km of the Stockholm Bypass are being constructed in tunnels. The Bypass will be one of the longest road tunnels in the world, with a construction cost of 3.1 billion Euro (2009 prices). x | |||||
Wannenmacher, Helmut; Entfellner, Manuel; Krenn, Harald | Considerations for rock mass grouting for tunnelling in faulted rock masses with tubes á manchette / Überlegungen zu Gebirgsinjektionen für den Tunnelbau im gestörten Gebirgsverband mittels Manschettenrohren | Geomechanics and Tunnelling | 2/2019 | 158-167 | Topics |
KurzfassungGrouting into an open borehole is a process that has been well described academically. Numerous grouting techniques and grouting criteria are available for various applications and combinations of rock mass/ground. Tube á manchette (TAM) or sleeve port grouting systems have until now mostly been used in specialized civil engineering work in soft ground. In order to be able to carry out grouting successfully in faulted rocks, cased drilling is necessary in order to maintain the stability of the borehole for the insertion of the sleeve pipe. Under these premises, fundamental considerations for successful TAM grouting in faulted rocks are presented. The rheological properties of the grout used, the form and size of the injection opening and the strength and thickness of the sheathing compound significantly influence the penetration into the surrounding rock mass. Increased effective pressure is necessary in order to break through the sheathing compound and also to overcome friction losses during the grouting process. The necessity of high effective pressure and the emergence of the grout at the sleeve ports can, in contrast to an open borehole, increase the risk of jacking the ground in the course of grouting and this has to be carefully taken into account and investigated in advance. The interaction of effective grouting pressures and friction losses of the grouting system and their effect on the grouting process in faulted rock are described through the formulation of a general grouting criteria for TAM grouting. x |