Since the flood hazard in the yellow and red zones in the municipal area of Sibratsgfäll if definitely lower than the landslide hazard in the brown zone, a revision of the hazard zone map is proposed, which homogenizes the brown zone to the red (building ban) and the yellow ones (construction possible under certain conditions). An evaluation scheme is outlined that allows the measurement of the risk of mass movements. To obtain a classification in terms of “buildable”, “buildable under certain conditions” and “not buildable” with the resolution of a parcel of land, a profound experience is necessary in the natural hazards occurring in the domain of study. Since different data and information exist in the relevant domain of study, an attempt was made to infer the remaining information for the area under consideration, on the basis of two well-studied reference situations. On the Sibratsgfäll map, every geological body is subdivided in either a red, orange or yellow hazard zone. Areas with no geogenic risks are shown in white. Gray striped areas require further soil testing in order to improve the quality of the hazard zoning. The most potentially harmful hazard is shown for areas that are affected by different geogenic hazards. The results of the risk assessment have been incorporated into the Forest Engineering Service in Flood torrents and Avalanche Control hazard zone map of the municipality of Sibratsgfäll. This is the first issued and negotiated hazard zone map in Austria in which, in addition to the danger of flood torrents and avalanches, the potential danger of slope movements is presented in detail and with clear delimitations in the entire domain of study.
Da im Gemeindegebiet von Sibratsgfäll flächenmäßig die gelben und roten Wildbachgefahrenbereiche weit hinter den braunen Hinweisflächen für Rutschungen zurücktreten, sollte für die Revision des Gefahrenzonenplanes ein Vorschlag erarbeitet werden, der diese braunen Hinweisbereiche in Anlehnung an die Wildbachgefahrenzonen rot (“Bauverbot”) und gelb (“bebaubar mit Auflagen”) konkretisiert. Dazu wurde ein Bewertungsschema entworfen, das die parzellenscharfe Beurteilung der von Massenbewegungen bedrohten Flächen ermöglicht. Um auf der Detailebene “Grundparzelle” eine Einstufung in “bebaubar”, “bebaubar mit Auflagen” oder “nicht bebaubar” treffen zu können, ist ein hohes Detailwissen über die Naturgefahren-Prozesse im Untersuchungsgebiet erforderlich. Da im gesamten raumrelevanten Bereich ein unterschiedlicher Wissens- und Datenbestand vorliegt, wurde versucht, anhand von zwei gut untersuchten Referenzgebieten. Auf der erstellten Gefahrenkarte für Sibratsgfäll wurde flächig für jeden geologischen Körper eine Einteilung in einen Gefahrenbereich rot, oder einen Gefahrenbereich orange oder einen Gefahrenbereich gelb vorgenommen. Flächen, die keine geogenen Gefahren aufweisen, wurden weiß dargestellt. Grau gestreifte Flächen sind Bereiche, die eine verbesserte Untergrunderkundung erfordern, um eine exaktere Grenzziehung vornehmen zu können. Bei Flächen, die von mehreren geogen bedingten Gefahren betroffen sind, wurde jene Gefahr dargestellt, die ein höheres Schadenspotenzial beinhaltet.

Spideranchor Netting is a modified slope stabilization method after Körner for slopes in a limit equilibrium state. On the one hand, a surface protection e.g. a high-tensile strength geosynthetic or net, is pushed against a slope surface to increase the shear resistance on a sliding plane. And on the other hand Spideranchors are stabilizing the slope and are used for pushing the surface protection against the slope surface. A Spideranchor consists basically of a set of threaded rods and an associated top plate. The threaded rods are screwed fan shaped into the subsoil. Therefore an automated screwing machine is used. At the beginning of this paper results of slope failure experiments are discussed. An embankment (b · h · l ≈ 3.5 · 3.0 · 27.0 m) built between rigid plates was constructed for the full scale experiments and forced to fail by applying additional loads on the embankment crest, with the help of a horizontal beam. The experiments were conducted with and without applying Spideranchors and Spideranchor Netting. Afterwards a new prototype of the Spideranchor Netting and the application of this prototype in a real case study are presented. The prototype has been further developed as a result of the full scale experiments. Finally a discussion for slope stability calculations for slopes with applied Spideranchor Netting is presented.
Spinnanker Netting ist ein nach Körner modifiziertes Stabilisationsverfahren für Böschungen im Grenzgleichgewicht. Bei diesem Verfahren wird einerseits durch das Anpressen einer bedingt flexiblen Frontalausbildung an die Böschungsoberfläche, z. B. mit einem hochzugfesten Geogitter oder Viereckgeflecht aus hochfesten Stahldrähten, eine Erhöhung der Normalspannung auf einer möglichen Gleitfläche erzwungen und folglich ein zusätzlicher Scherwiderstand aktiviert. Andererseits findet eine Stabilisierung der Böschung durch den Einbau von Spinnankern statt, welche auch für das Anpressen der Frontalausbildung zur Anwendung kommen. Spinnanker bestehen im Wesentlichen aus Gewindestäben, welche fächerförmig, durch vorgegebene Gewindebohrungen einer Platte, in den Untergrund eingeschraubt werden. In diesem Beitrag werden zu Beginn die Ergebnisse aus experimentellen Untersuchungen an großmaßstäblichen Böschungen diskutiert. Für die Untersuchungen wurde ein Versuchsdamm (b · h · l ≈ 3,5 · 3,0 · 27,0 m) zwischen starren Wandelementen errichtet, und mithilfe einer Zusatzlast, welche über eine Traverse auf die Dammkrone aufgebracht wurde, wurden Böschungsbrüche erzwungen. Die Böschungsbrüche fanden mit und ohne Sicherungsmaßnahmen statt. Anschließend wird ein neuer Prototyp des Spinnanker-Netting-Systems sowie dessen Anwendung im Rahmen eines Projektes vorgestellt. Dieser Prototyp wurde auf Basis der Ergebnisse des Großversuches weiterentwickelt. Abschließend wird in diesem Beitrag eine grundlegende Diskussion zur Standsicherheitsberechnung von mit Spinnanker Netting gesicherten Böschungen durchgeführt.

This contribution deals with the construction of a snow retention basin (for manufacturing snow) in the ski region Shuttleberg Flachauwinkl-Kleinarl/Salzburg in a sagging mass movement. In the design stage it was not known whether deformations of the mass movement have to be expected and if so to what amount. Therefore probable scenarios of deformation rates of the mass movement were considered in the design and measurement equipment have been installed in order to observe the behaviour of the construction. First results of the observational system will be presented and discussed after a life time of about two years of the construction.
Im vorliegenden Beitrag wird über die Errichtung eines Beschneiungsteiches im Skigebiet Shuttleberg Flachauwinkl-Kleinarl im Bundesland Salzburg berichtet, der in einer großräumigen aktiven Sackungsmasse errichtet wurde. Da im Zuge der Planung/Bauausführung noch nicht bekannt war, ob und in welcher Größenordnung die Sackungsmasse tatsächlich noch Bewegungen aufweist, wurde die Projektierung auf Basis realitätsnaher Szenarien hinsichtlich möglicher Hangbewegungen durchgeführt und entsprechende (messtechnische) Überwachungsmaßnahmen vorgesehen. Nach einer mittlerweile ca. zweijährigen Beobachtungszeit werden erste Ergebnisse der messtechnischen Beobachtung präsentiert und diskutiert.

In preparation for the construction of the new Semmering Base Tunnel, which will reach a length of 27.3 km, comprehensive preliminary measures had to be completed. As a part of Contract Section SBT2.3, several slope stabilization measures, as well as earth retaining structures and ramps using the reinforced earth method, were constructed. This contribution will give an overview of the construction measures, as well as of the systematic geotechnical monitoring that was implemented as part of the geotechnical safety management program.
Für den 27,3 km langen Semmering-Basistunnel neu wurden umfangreiche vorbereitende Maßnahmen ausgeführt. Im Baulos SBT2.3 wurden neben einer Vielzahl an Böschungs- und Hangsicherungsmaßnahmen auch Stützkonstruktionen und Rampen in Bewehrte-Erde-Bauweise errichtet. Der vorliegende Beitrag bietet einen Überblick über die Baumaßnahmen und das systematische geotechnische Monitoring, das im Rahmen des geotechnischen Sicherheitsmanagement ausgeführt wurde.

This paper presents the validation of a novel constitutive model for shotcrete in a tunnelling project. The shotcrete model is based on elastoplastic strain hardening/softening plasticity and can account for time dependent strength and stiffness, creep and shrinkage. The validation of the model considers the deformation behaviour of both the primary lining and the surface as well as the time dependent stress strain behaviour of the shotcrete. The calibrated model has been used to simulate the behaviour of the tunnel structure during the excavation process numerically. Furthermore different approaches to model the shotcrete lining for design are applied and briefly discussed.
Dieser Artikel befasst sich mit der Validierung eines neuen Stoffgesetzes für Spritzbeton mithilfe von Daten aus einem ausgeführten Tunnelprojekt. Das Stoffgesetz basiert auf elastoplastischer Ver- und Entfestigung und berücksichtigt zeitabhängige Festigkeit, Steifigkeit sowie Kriechen und Schwinden. Das kalibrierte Modell wurde verwendet, um das Verhalten des Tunnels während des Ausbruchvorgangs numerisch zu simulieren. Zudem werden verschiedene Ansätze für die Bemessung von Spritzbetonschalen angewandt und diskutiert.

The consistent application of the observation method on shield tunnel drives can make a considerable contribution to preventative dispute avoidance and conflict reduction when issues occur. The observation method should include not only the monitoring and analysis of mechanical process data such as machine data, control parameters and data from the geotechnical instrumentation but also process control as the tunnel advances, which is documented in the following quality assurance documents: explanatory report, machine concept, incident analysis, specification, tunnelling machine handbook and the tunnelling plan before tunnelling and report after completion. This should be interpreted as a unit and is defined as the holistic observation method.
Eine konsequente Umsetzung der Beobachtungsmethode kann bei Schildvortrieben einen wesentlichen Beitrag zur präventiven Streitvermeidung und Konfliktreduzierung bei Störsituationen leisten. Dabei soll die Beobachtungsmethode nicht nur die Überwachung und Analyse der maschinentechnischen Prozessdaten wie Maschinendaten, Steuerungsparameter und Daten aus dem geotechnischen Messprogramm einschließen, sondern auch die Kontrolle des vortriebsbedingten Prozessablaufs beinhalten, der durch die Qualitätssicherungselemente Erläuterungsbericht, Maschinenkonzept, Störfallanalyse, Pflichtenheft, Schildhandbuch und Vortriebsvor- und -nachschau dokumentiert ist. Dies ist als Einheit zu interpretieren und wird als ganzheitliche Beobachtungsmethode definiert.

As in most of the large European cities, the attractiveness of public transport is also an important matter for the inhabitants of Vienna. For this reason, the Vienna underground railway network has been continuously extended since its inception in 1978. At the moment, the extension of the Line U1 to the south is under construction, with about 50 % running underground and the rest either elevated or at ground level. Construction started in 2012 and the section should open in 2017. Part of this section is contract U1/10 Troststrasse, which runs underground. The tunnels mainly pass through loess and loess-loam soils, and are favourably above the free groundwater table so that only perched groundwater had to be pumped out of wells in the area of the tunnels. The running tunnels are being constructed according to the principles of the New Austrian Tunnelling Method (NATM). The station tunnels for track 2 are also being tunnelled according to the NATM although measures to reduce settlement were essential to comply with the requirement for the permissible tangential inclination of buildings. After various methods had been evaluated, a combination of a horizontal jet grout canopy supported on vertical jet grout columns was chosen. The shafts and the tunnel for track 1 were constructed in cut-and-cover with contiguous bored piles to support the excavation.
Wie in den meisten Großstädten Europas ist auch in Wien die Attraktivität des öffentlichen Verkehrs ein wichtiges Anliegen der Bürger. In diesem Sinn wird in Wien das U-Bahnnetz seit seinem Start im Jahr 1978 kontinuierlich erweitert. Derzeit ist die Verlängerung der Linie U1 in Richtung Süden in Bau. Davon verläuft ca. 50 % unterirdisch, der Rest wird in Hochlage bzw. niveaugleich errichtet. Baubeginn war 2012 und 2017 soll diese Strecke in Betrieb gehen. Einer dieser Abschnitte ist das Baulos U1/10 Troststraße, das in Tieflage geplant ist. Die Tunnel kommen dabei zum größten Teil in Lössen bzw. Lösslehmen zu liegen, günstigerweise oberhalb des freien Grundwasserspiegels, sodass nur Schichtwasser durch Brunnen im Vortriebsbereich abgepumpt werden musste. Die Herstellung der Streckenröhren erfolgt in der Neuen Österreichischen Tunnelbaumethode (NÖT). Der Vortrieb der Stationsröhre Gleis 2 erfolgte ebenfalls in der NÖT, jedoch waren setzungsmindernde Maßnahmen zur Einhaltung der zulässigen Tangentenneigung an den Gebäuden unumgänglich. Nach Evaluierung verschiedener Methoden wurde eine Kombination aus horizontalem DSV-Schirm aufgelagert auf vertikalen DSV-Säulen gewählt. Die Schächte und die Stationsröhre Gleis 1 wurden in offener Bauweise mit aufgelösten Bohrpfahlwänden als Baugrubensicherung hergestellt.

The Cityringen (The City Circle) project is the latest phase of the metro system in Copenhagen, Denmark. The phase comprises the construction of 17 new stations, three shafts, a control and maintenance centre and 16.5 km of twin-tube tunnel excavated by four Earth Pressure Balance TBMs. The design and build contract was awarded in January 2011 and inauguration is planned for late 2018.
The geology in the project area includes 10 to 30 m of Quaternary sand, gravel and clay tills underlain by limestone, often containing benches of flint or other hard horizons. The stations and shafts are constructed with secant pile walls or diaphragm walls. Permeation grouting is undertaken for one cavern and grouting for the break-in and break-out of the TBMs.
Groundwater control is carried out by pumping from abstraction wells at the bottom of the deep excavation, treating the abstracted groundwater and recharging between 95 and 100 % of the groundwater.
A monitoring system consisting of a comprehensive database system has been adopted, where real time information from the TBMs and from buildings and structures adjacent to the works is collected. Movement is monitored by an extensive 3D monitoring system together with extensometers, inclinometers and piezometers.

The Prague Metro is an inseparable economic and cultural part of city development in Prague, with its transport capacity and architectural styles. A look into the Metro history reveals the evolution of the early construction methods into today's modern tunnelling technologies. The description of the latest Metro Line A extension construction is concluded with an outline of future plans for Prague Metro expansion.

The Metro Network in São Paulo has five lines in service with a total length of 107 km in one of the most booming cities in South America with a population of over 11 million inhabitants. The network can still be considered to be in its early stages; the first line was only constructed in 1968 and is now being extended. Whilst the settlement-prone Tertiary soils under São Paulo and also the crystalline basement, with its different grades of weathering and fracturing and high abrasiveness, pose challenges for shield tunnelling, they actually represent optimum conditions for high performance shield tunnelling. The paper deals with the experience gained by operator Companhia do Metropolitano de São Paulo- Metrô, contractor Construtora Norberto Odebrecht and consultant Maidl Tunnelconsultants in the construction of the metro lines with mechanised shield tunnelling technology.

The central section of the Warsaw 2nd Metro Line required preventive measures to protect buildings located in the Praga district above the tunnel alignment. The sections passing below buildings with EPB machines were certainly one of the most critical points. It was decided to carry out ground treatment in order to consolidate the subsoil around the tunnels. For this purpose grouting holes up to 261 m long were drilled by HDD following the tunnel path. Tunnelling did not affect the structures located above the ground, which always remained under close supervision with the use of specialist and multithreaded monitoring.

In 2008, Indian Strategic Petroleum Reserve Limited started construction of an underground unlined rock cavern complex for storage of imported crude oil at Visakhapatnam for 1.3 MMT (million metric tons) of crude oil. The excavation of the works was finally completed in February 2014. During the construction stage, after 95 % of the total excavation volume had already been excavated, an extreme wedge sliding event occurred in one of the cavern walls in April 2011, which caused a major delay to completion of the project. This wedge slide and other rock mass behaviour encountered during the excavation of the underground storage facility are described and discussed in this paper.

Ever since being built in the middle ages, the Gerlos Strasse has been affected by slope sides and wild torrents, resulting in an almost continuous history of rebuilding and repairs with correspondingly high costs. The route is in the immediate vicinity of the Salzach Fault, one of the most significant fault zones on the eastern Alps, and the enormous forces that formed the mountains can be seen in action, together with the destructive erosion processes with their natural tendency to reduce the angle of the slope. Three individual events are described in order to illustrate the heterogeneous geological conditions, and the selected repair and protection measures for the infrastructure are briefly described. It appears that even with the geotechnical measures available today, an end to the permanent cycle of repair is still barely conceivable.
Seit ihrer Entstehung im späten Mittelalter ist die Gerlos Straße von Rutschungen und Murenabgängen betroffen, die einen nahezu ununterbrochenen Wiederherstellungs- und Sanierungsbedarf mit entsprechend hohem finanziellen Aufwand nach sich ziehen. Ihr Verlauf im unmittelbaren Nahebereich der Salzachstörung als einer der bedeutendsten Störungszonen der Ostalpen lässt die enormen gebirgsbildenden Kräfte wie auch die zerstörerischen Erosionsprozesse mit ihrer natürlichen Tendenz zur Verringerung der Hangneigungen eindrucksvoll vor Augen treten. Anhand dreier Einzelereignisse werden die heterogenen Untergrundverhältnisse dargestellt und die gewählten Sanierungs- und Sicherungsmaßnahmen für die Infrastruktureinrichtungen skizziert. Es zeigt sich, dass auch mit den heute zur Verfügung stehenden geotechnischen Mitteln ein Ende der Dauersanierungsmaßnahmen nur schwer absehbar ist.

The 9 km long Chenani-Nashri Tunnel, currently under construction, is the longest road tunnel in India and is part of the planned four-lane widening of the NH-1A between Udhampur and Banihal in the state of Jammu and Kashmir. Bypassing the existing NH-1A from km 89 to km 130, the tunnel crosses a sub-Himalayan formation with a maximum overburden of 1,050 m. With an escape tunnel running parallel to the main tunnel, excavation is performed by Leighton-Welspun Contractors using the drill and blast method. Geodata Engineering (GDE) is providing consultancy services for detailed design and construction supervision including 3D-geotechnical monitoring. Back-analyses of already-excavated sections are performed to better understand the behaviour of the heterogeneous rock mass in which the tunnels are excavated. The numerical models are fed with the actual geological and geomechanical conditions encountered during excavation and the monitoring results. The 3D-monitoring system, specially implemented by GDE for this project, has played a key role in understanding the real rock mass behaviour, allowing the highlighting of potential risks, selecting the correct tunnel support class, checking of the effectiveness of countermeasures, identification of the tunnel stretches in which the final lining needs to be reinforced and providing cost-effective solutions to speed-up the construction process.

The Rohtang Tunnel has been advancing into the Himalaya Mountains in the northern state of Himachal Pradesh since autumn 2010. After the completion of almost 50 % of the alignment, it is time for an intermediate report. The article will intentionally not only describe technical matters but also describe the local aspects of tunnelling in India.
Im Himalaja-Gebirge im nordindischen Bundesstaat Himachal Pradesh wird seit Herbst 2010 der Rohtang-Tunnel in den Berg getrieben. Nach fast 50 % der Strecke ist es Zeit für eine Zwischenbilanz. Der Beitrag will dabei bewusst nicht nur auf die Technik eingehen, sondern gemäß dem Thema Indien auch die lokalen Aspekte beleuchten.

The Pir Panjal Railway Tunnel was the first tunnel in India to be constructed in accordance with the principles of the New Austrian Tunnelling Method. Despite very heterogeneous rock conditions with frequent changes of solid and completely fractured rock, with high water inflow in places, the work progressed without prolonged excavation-related interruption and delays. This was possible because of the design and construction method, which permits prompt reaction to changing geology and installation of initial support measures, but also rapid adaptation of support measures to cope with the conditions of a young rock mass like the Himalayas. An important tool in regard to control and manage the ground deformations in the different geological conditions was the 3D monitoring of the lining displacements and its interpretation.
The tunnel was driven from numerous faces by conventional mined tunnelling methods using drill and blast as well as roadheader, with immediate installation of the primary support. The excavation and lining works were completed in late 2012, mechanical and electrical works in early 2013. Considering the difficult geology, extreme weather situation in winter and the hostile conditions of the area, the overall performance was satisfactory, although the initially scheduled target was not achieved. The tunnel has now been in operation since summer 2013.

The consultant Bernard Ingenieure has two decades of design, site supervision and technical assistance experience working with Indian contractors on hydropower and infrastructure projects on the Indian subcontinent. This article presents the lessons learnt by the consultant from these projects, in particular the 126 MW Dagachhu Hydropower Project, which is due to be completed in 2014. The article subsequently describes how the consultant has applied regulatory measures in tender documents for its ongoing projects, as well as ideas for further measures to be applied in future contract models.
The regulatory measures intrude on what is traditionally considered to be the contractor's sphere of influence, such as selection of plant and equipment, personnel and works sequencing. Since the proposed measures are only as useful as the provisions to enforce their implementation, the fulfilment of contract conditions is linked to payment deductions, which have the aim of encouraging contractors to improve their performance and therefore project outcomes rather than to save cost.
Projects in India would benefit from replacing awards based on the lowest price with Quality and Cost-Based Selection (QCBS), as this would promote improved Technical Proposals, hence an improved quality of construction. The marking schemes for Technical Proposals must be clearly defined and give traceable results to prevent subjective decision-making.

Strategic storage of crude oil in unlined underground rock caverns below the groundwater table is being constructed for the first time in India. The projects are being implemented by Indian Strategic Petroleum Reserves Ltd., (ISPRL) a Special Purpose Vehicle (SPV) created by the Government of India. The article deals with Indian experience of working on underground civil works contracts with design consultants as well as contractors.
Apart from discussing the basic principles of storage, salient design and construction aspects, it describes the implementation philosophy of the projects including a description of the awarding of contracts through a relatively new online method of procuring services called Reverse Auction.
A unique combination of government agencies, private foreign and Indian consultants, private foreign and Indian contractors are collaborating on the projects and therefore an analysis has been made of the interactive experience. It is recommended that foreign agencies and Indian agencies including government agencies should learn from the feedback and improve their professional potential.

Underground storage schemes are gaining importance in India, as all over the world. Such storage schemes involve the excavation of large underground caverns, connecting tunnels and various types of shafts. This example provides storage for more than 1.3 mill. metric tons of crude oil stored in unlined caverns 20 m wide, 30 m high and up to 820 m long. The scheme also includes three 110 m deep product intake shafts, two 90 m deep product extraction shafts and about 2,600 m of tunnels. The total volume, excavated by drill and blast method, is about 2 mill. m3 and rock support is provided by post-grouted rock bolts and steel fibre reinforced shotcrete. The product is confined on the principle of a groundwater curtain system, essentially employing ground water pressure gradients to contain the crude oil within the unlined rock cavern complex. Excavation works on the project commenced in the middle of 2008 and, after some delays, were finally completed in February 2014. This paper focuses on the risk management practices employed for this project. The paper “Rock mass behaviour of weathered, jointed and faulted Khondalite - Examples from the underground crude oil storage caverns, Visakhapatnam, India” by Sigl, Millen and Höfer-Öllinger that refers to the actual situation will be published in issue 3-2014 of Geomechanics and Tunnelling.

The planned tunnel alignment of the Brenner Base Tunnel crosses the aquifer of the Hochstegen marble between the Valsertal and Pfitschtal valleys. Due to the great importance of this aquifer for the water balance of the affected gullies, a 2D model was produced of the groundwater flow system. The intention of the 2D model was on one hand to gain information about the effects of the lowering of the groundwater table by the draining effect of the tunnel holes. Another intention of the model was to investigate whether the lowering of the groundwater table could be kept to a small and acceptable extent through a suitable grouting campaign and thus keep the influence on the groundwater balance in the model area small.
Starting with the experience gained with grouting during the construction of the Lötschberg and the Gotthard Base Tunnels, which had been able to considerably reduce the permeability in the area around the tunnel bores, calculations were performed with the finite difference program Modflow, in which the effect of a grouted ring around the tunnel holes was investigated in detail. With the calculations, it was possible to demonstrate that the lowering of the groundwater table in the vicinity of the aquifer of the Hochstegen marble can be reduced to a small, acceptable extent. The article deals with the model, the hydraulic parameters, the values from experience for grouting measures or their effects on the modelling parameters and describes in detail the knowledge gained.
Die geplante Tunneltrasse des Brenner Basistunnels quert zwischen dem Valser- und Pfitschtal den Aquifer des Hochstegenmarmors. Aufgrund der hohen Bedeutung dieses Aquifers für den Wasserhaushalt der betroffenen Gerinne wurde ein 2D-Modell des Grundwasserfließsystems angefertigt. Ziel des 2D-Modells war es einerseits, Erkenntnisse über die Auswirkungen einer Grundwasserabsenkung durch die Dränagewirkung der Tunnelröhren zu gewinnen. Eine weitere Zielsetzung der Modellierung bestand darin, zu untersuchen, ob durch geeignete Injektionsmaßnahmen rund um die Tunnelröhren die Absenkung des Grundwasserspiegels auf ein geringes, vertretbares Maß reduziert und somit die Beeinflussung des Grundwasserhaushalts im Modellgebiet gering gehalten werden kann.
Aufbauend auf den Erfahrungen bei Injektionen beim Bau des Lötschberg bzw. des Gotthard Basistunnels, mit denen die Durchlässigkeit im Bereich rund um die Tunnelröhren erheblich herabgesetzt werden konnte, wurden Berechnungen mit dem Finite Differenzen Programm Modflow durchgeführt, in denen die Wirkung eines Injektionsrings rund um die Tunnelröhren eingehend untersucht wurde. Mit den Berechnungen konnte gezeigt werden, dass die Absenkung des Bergwasserspiegels im Bereich des Aquifers des Hochstegenmarmors auf ein geringes, vertretbares Maß reduziert werden kann. Der Beitrag behandelt das Modell, die hydraulischen Parameter, die Erfahrungswerte der Injektionsmaßnahmen bzw. deren Auswirkungen auf die Modellierungsparameter und beschreibt die gewonnenen Erkenntnisse im Detail.

The Garner and Coffman method was developed to design a proposed underground facility based on an allowable settlement profile; the method may also be used to characterize an unknown underground facility based on an observed surface settlement profile. The method uses both static methods and 2-D finite element analyses to relate the characteristics of the ground surface settlement profile to the underground facility (depth, diameter, and number of tunnels). The calibration and validation of the Garner and Coffman method, as obtained by using tunnel segment data from historical tunneling projects (Bangkok, London, Taipei, Singapore, and Heinenoord), are presented. Specifically, the method was calibrated using settlement profiles and facility characteristics from 15 tunnel segments and validated using settlement profiles from 16 additional tunnel segments. A numerical relationship (developed during this research project) was then used during the validation of the model to predict facility characteristics for the “unknown” underground structures. The predicted depth and diameter for each of the “unknown” underground structures were within ten percent of the actual diameter and actual depth of the underground structure, as obtained from the literature. For all 16 validation tunnel segments, the tunnel location was predicted within one tunnel diameter of the actual facility centerline.

Classic tunnelling shields can reach their technical, but also their economic limits, when they have to drive through highly varied geologies along the tunnel route. A tunnel route may pass through extended sections of stable rock faces which alternate with soft, water-bearing loose soils. Such tunnelling routes are among the most demanding challenges in tunnel construction and they have to be mastered more and more often, because important infrastructures nowadays are being built in such formations. Herrenknecht has developed so-called Multi-mode tunnel boring machines especially for ground conditions of this kind. These are hybrid tunnel boring machines which offer optimum safety and flexibility when choosing the support and excavation method. They allow for an optimum tunnelling strategy that is adaptable to the conditions along the tunnel alignment. And they also have a positive influence on the desired efficiency. Multi-mode machines have different concepts in terms of how rapidly or how easily they can be adapted. The following chapters describe the functionalities of the Multi-mode TBM and the corresponding reference projects. In addition, this paper deals with the innovative concept of the Herrenknecht Variable Density TBM, a first universal tunnel boring machine for mixed ground conditions.
Klassische Vortriebsschilde können bei geologisch variantenreich aufgebauten Tunneltrassen an technische, aber auch wirtschaftliche Grenzen stoßen. So kann eine Tunneltrasse längere Passagen standfestes Gebirge enthalten, das in weiche, wasserführende Lockerböden wechselt sowie umgekehrt. Derartige Streckenverläufe gehören zu den anspruchsvollsten Anforderungen im Tunnelbau. Sie stellen immer öfter eine Herausforderung dar, da wichtige Infrastrukturen in solchen Formationen gebaut werden. Herrenknecht hat speziell für solche Baugründe und Projekthintergründe sogenannte Multi-Mode-Tunnelbohrmaschinen entwickelt. Es handelt sich hier um hybrid aufgebaute Vortriebsmaschinen, die höchstmögliche Sicherheit und Flexibilität bei der Wahl des Stütz- und Abbauverfahrens bieten, also eine in Hinsicht auf den Streckenverlauf anpassungsfähige und möglichst optimale Vortriebsstrategie ermöglichen. Dies hat auch positive Effekte auf die gebotene Wirtschaftlichkeit. Multi-Mode-Maschinen sind hinsichtlich der Anpassungsschnelligkeit und des Anpassungsaufwands unterschiedlich angelegt. Die folgenden Kapitel beschreiben die Funktionsweisen der Multi-Mode-TBM und entsprechende Referenzprojekte. Zudem geht der Beitrag auf das neuartige Konzept der Herrenknecht “Variable Density TBM” ein, einer ersten universellen Vortriebsmaschine für Lockergestein.

As a result of growing urbanisation, subsurface space is developed and has to be expanded. New and bigger tunnels are required to meet the infrastructural needs. The ground is the decisive factor regarding the type of tunnelling method and its efficiency. The bigger such projects the greater the chance to encounter inhomogeneous in situ ground conditions. This makes an adequate and economic choice of the process technology more difficult, especially in mechanised shield tunnelling. A clear differentiation based on the grain-size distribution between the field of application of an EPB shield and a hydro shield nowadays is hardly possible. An application of a hydro shield machine in fine soils is just as feasible as tunnelling with EPB shields in coarse soils. In this article, the authors explain selected geological conditions, which represent challenging situations for the application of EPB shields. Therefore, it is particularly focused on overconsolidated cohesive soils, highly permeable non-cohesive soils and sedimentary rock as well as areas of mixed face conditions (rock and soil). Moreover, test methods and tools for the planning and the construction phase are presented.
Im Zuge der fortschreitenden Urbanisierung wird der Bau neuer und größerer Tunnel erforderlich. Je größer solche Projekte angelegt sind, desto unwahrscheinlicher ist es, dass die In-situ-Bodenverhältnisse homogen und verfahrenstechnisch eindeutig sind. Beim maschinellen Tunnelbau im Schildvortrieb ist der Baugrund der entscheidende Faktor für die Auswahl und die Effizienz des Bauverfahrens. Eine eindeutige Differenzierung zwischen dem Einsatzbereich eines Erddruckschilds und eines Hydroschilds nur auf Grundlage der Kornverteilung des Baugrunds ist heute kaum noch möglich. Eine Verschiebung des Einsatzbereichs von Hydroschilden in den Feinkornbereich ist ebenso möglich wie die Erweiterung des Einsatzbereichs der Erddruckschilde in grobkörniges Lockergestein. In diesem Beitrag erläutern die Autoren ausgewählte geologische Situationen, die für den Einsatz von Erddruckschilden eine besondere Herausforderung darstellen können. Exemplarisch sind dies überkonsolidierte bindige Böden, stark durchlässige nichtbindige Böden sowie Sedimentfestgesteine bzw. Bereiche mit gemischter Ortsbrust aus Fest- und Lockergestein. Es werden Untersuchungsmethoden und Hilfsmittel für die Planung und Begleitung von Schildvortrieben vorgestellt.

Slurry TBM versus EPB TBM
The contract C310 comprises the construction of the Plumstead and North Woolwich Portals and the twin tube Thames Tunnel, which has a length of approximately 2.6 km between the two portals. The two TBMs used for the construction of the Thames Tunnel will drive through varying ground conditions (Thanet Sand, River Terrace Deposit (gravel), and chalk) below the water table. During the drive under the River Thames, the tunnels will only have an overburden of approximately 12 m. The effect of pressure variation due to the tidal River Thames has to be accounted for in the control of the tunnelling. The tunnel will pass underneath several grade II listed buildings, utilities, adjacent to operational railway tracks and close to existing subway tunnels. Previous experience of the handling and disposal of excavated chalk has been gained on several tunnelling projects in chalk, most notably the Dartford Road Tunnels, the Channel Tunnel, the Brighton Stormwater Tunnel, the Lille Metro Tunnel, the Socatop Road Tunnel near Paris and Channel Tunnel Rail Link CTRL 320. The Contract allowed for both Mixshield and EPB TBM Technology. The advantages and disadvantages of a TBM-S with Earth Pressure Balanced face support (EPB-TBM) and a TBM-S with Slurry Face support (Mix-Shield TBM) for the C310 Thames Tunnels were discussed after contract award and a comparative risk assessment was developed. A Mixshield TBM is more expensive but outperformed the EPB TBM in the overall scoring of risk assessment and therefore it has been decided to use this type at C310.

The Line 4 South being constructed in Rio de Janeiro crosses complex geology that includes a long stretch of sand bounded by two stretches of hard, highly abrasive rock. These geological conditions, combined with the fact that the project is located in a distinct urban area, creates a demanding project scenario where special care needs to be taken. After carrying out an evaluation to determine whether to use earth pressure balance or slurry technology, the design of a convertible EPB boring machine that can excavate both rock and soils was developed. This paper outlines the technical difficulties of the project and describes the decision-making process and the solutions adopted. A technical description of the different operation modes of this hybrid TBM and the conditioning process related to each of them is provided.