Proven Methods and state-of-the-art technology. Tunnelling & Underground Structures

Transcription

1 Proven Methods and state-of-the-art technology Tunnelling & Underground Structures

2 Longstanding underground expertise Hills and mountains, rivers and lakes dominate Switzerland s topography. Already at an early point in time the wish grew to drill through the natural barrier of the Alps, and to connect in particular the north and south of the country. The first Swiss traffic tunnel, the Urnerloch, was built from 1707 to The tunnel was 64 m long and made it easier to cross the Gotthard pass. In 1858, the first Swiss railway tunnel was opened on the Hauenstein route between Basel and Olten. More than 100 years later, in 1964, the first long road tunnel followed the Grand Saint Bernard tunnel. Pöyry, at that time under the name Elektro- Watt, worked on underground projects already in the early years of the company. The first big tunnelling projects were awarded in the years after World War II. In 1960, Elektro-Watt received also first orders in the Zurich area: the planning of the Käferberg railway tunnel and the Milchbuck road tunnel. These projects were then followed by the national road tunnels through the San Bernardino, the Gotthard and the Seelisberg. knowledge gained in numerous projects over many decades, which we combine effectively with the latest technologies. Everything from a single source Our services are not limited to the details of a single project stage or construction method. We offer you holistic, sustainable solutions, tailored to your needs. Our employees work in a great variety of fields. Geologists, specialists in rock and soil mechanics, and engineers from all areas of tunnelling belong to our core team. Experts from other company departments such as traffic planning, railway systems, operations and safety are consulted for specific topics. By exchanging our knowledge beyond the different specialist fields, we create synergies that guarantee smart solutions. Experienced professionals behind your success A company is just as good as its staff. Only a qualified and motivated team develops innovative and convincing solutions. We have always put great emphasis on the promotion of our employees. We offer them numerous training opportunities to allow them to extend their technical knowledge and gain international experience. This investment pays off in every respect: our employees can develop individually, and our clients can count on being supported by highly qualified experts. Active around the world Our tunnelling experience is in demand outside of Switzerland as well. We plan and design projects around the world and assist local clients and companies with our know-how and a global network of specialists. We are present in many countries and are therefore familiar with the local circumstances. You benefit from our global experience but have always a local contact person. At present Pöyry is involved in the realisation of the Gotthard base tunnel and the Zurich cross city link projects, two of the most important Swiss infrastructure projects. To this day, Pöyry has designed tunnels of more than 1,900 kilometres length in Switzerland and abroad. 2 The key to implement your projects successfully In our understanding, a tunnel is part of a whole infrastructure system. Urban rail tunnels are part of the public transport network. Railway and road tunnels relieve the city centres or make it easier to cross the Alps. Water galleries are key elements for the production of sustainable hydropower energy. We assist our clients during the entire life cycle of a structure. They benefit from our extensive experience and multidisciplinary technical Table of contents Your competent partner from A to Z 4 We always find a way 6 Railway tunnels 8 Road tunnels 10 Hydropower schemes 12 Know-how on demand 14 3

3 Your competent partner from A to Z Strategic planning Definition of needs Solution strategies Optimisation Preliminary studies Project definition Feasibility study Selection procedures Project Tender Implementation Preliminary design Detailed design Approval procedures Tender design Invitation to bid Bid evaluation Contract award Final design Implementation Commissioning Completion Operation & maintenance Operation Maintenance Refurbishment Sustainability We offer qualified services throughout the lifecycle of a structure. Our goal is to assist our clients in their projects under the motto everything from a single source. Studies and concepts Alignment studies Assessment of construction methods Feasibility studies Cost-benefit studies Risk assessment Visualisations Environmental studies Geotechnics and rock mechanics Geological and hydrogeological analyses Definition of geotechnical design parameters Soil and rock classification Deformation and settlement predictions 2D and 3D modelling Geotechnical monitoring programmes Tunnel ventilation and safety Risk and safety assessment Planning and design of operational and safety equipment Thermodynamic studies Aerodynamic modelling Monitoring and maintenance Tunnel inspection and structural assessment Material testing Refurbishment concepts Maintenance work planning Surveying Heading survey 3D deformation monitoring Tunnel profile recording Laser scanning Surface roughness measurements Planning and design of tunnels and underground structures Dimensioning and stability checks Excavation methods and specifications Installation concepts Materials procurement and disposal planning Project optimisation in terms of costs and risks Final design Construction programme and cost estimate Environmental impact assessment Construction management and support during implementation Tendering, bid evaluation, contracting Construction management and supervision Quality inspection Data management Cost and progress control Contract management Environmental monitoring Management support to clients 4 5

4 We always find a way noise and smoke included - drilling and blasting The typical work sequence of the drill-andblast method remains always the same, no matter if applied to tunnels of any shape, or caverns with the size of multilevel buildings: drilling, loading, blasting, support and mucking. To this day, this conventional excavation method in hard rock provides unparalleled versatility and flexibility. Based on the structure s type of use we define also the finishing ranging from a simple shotcrete blinding to a fully sealed cast-in-situ concrete lining. Open-air tunnelling the cut-andcover method Where little overburden and suitable ground conditions occur, the cut-and-cover method often proves to be the most economic tunnelling option. The structure is erected in an open pit or cut similar to a conventional building, and then backfilled. This method is frequently applied close to the portals of mined tunnels, sometimes in connection with the facilities for tunnel ventilation and operation. Support is essential - the shotcrete method in unstable ground Tunnels can be excavated in soft rock or soil conditions even without the use of tunnel boring machines. In these cases the ground needs to be sufficiently stabilised before creating the excavation. Advance support ahead of the actual working front is often achieved by means of a so-called canopy, consisting of steel rods, steel tubes, or jet-grouting columns. Ground freezing or pressurising the tunnel are alternative techniques to secure the excavation front, in particular where groundwater ingress is a critical issue. Once excavated, shotcrete and steel arcs are used for primary support of the cavity, usually followed by the installation of a permanent lining. An all-round thing - mechanical excavation in hard rock Long tunnels in solid rock that s the race track for tunnel boring machines (TBM). Once put in motion, this drill can hardly be stopped. Technological developments have continuously widened the range of applications and the efficiency of these machines. For example, disc cutters are today able to break up even the hardest rock into small chips. With this method as well, the lining of the tunnel largely depends on its eventual use. The tunnel factory - mechanical excavation in unstable ground Tunnel boring machines are also used in unstable rock and soil. A closed front compartment, filled with plasticised muck (EBP TBM) or a suspension (hydro-shield TBM), supports the excavation face. The tunnel lining is assembled from pre-fabricated segments, socalled tubbings, under the protection of the machine s shield. This method helps to avoid large settlements and allows for an industrialised production of the tunnel lining ideal requirements for tunnels in urban areas or in difficult ground conditions. The intelligent solution - special construction methods Complex challenges require our engineers to be creative. A typical example is the new Zurich cross city link of the Swiss Federal Railways. The historical main station could only be underpassed thanks to a unique combination of galleries, diaphragm walls and pre-stressed crossbars. All this was executed while the passenger flows and services at Switzerland s most busy railway hub were maintained to their full extent. Vertical tunnelling construction of shafts What is done horizontally is also possible vertically: excavating, supporting and lining of shafts is our business as an access to underground schemes, for ventilation, or in the waterway for a hydropower plant. In addition to conventional tunnelling methods, we are familiar with special techniques such as raise boring, where a pilot hole is extended from bottom to top with a rotating cutting tool. Nothing is constructed for eternity - tunnel maintenance Tunnels built in the early days of the railway system are now more than 100 years old. Their walls and arches were often built by using blocks of natural stone. Structural damages and new operational requirements, for example with regard to the clearance, lead to an increasing demand for modernisation. Even concrete structures, many of them built as part of the national road programme, have to be renovated or adapted to new requirements. During recent years a great number of tunnel rehabilitations were the consequence of stricter fire safety policies. To implement such a modernisation program during normal tunnel operation imposes particular challenges on all partners within a project. 6 7

5 Railway tunnels references Gotthard base tunnel, Sedrun, Faido and Bodio sections, Switzerland AlpTransit Gotthard AG Zurich cross city link, sections no. 2 and 3, Switzerland SBB AG, project management for the Zurich hub Tasna Tunnel, Switzerland Rhaetian Railway Ho Chi Minh City Metro, Vietnam Management Authority for Urban Railways (MAUR) For environmental reasons, the public and politicians push for an extension of the rail transport capacities in many countries both for the transport of people between and within metropolitan areas, and for pan-european freight transport. And everything should of course be as fast and comfortable as possible contribution. And we are proud to be an essential part of the team implementing the Zurich cross city link, the centrepiece of which will be a new underground station below the existing main station. Tunnels are often the only solution to accelerate the transalpine traffic, and to avoid long climbs and narrow curves. The so-called flat railway links in the centre of Europe move the metropolises in the north and south closer together and make rail transport an attractive alternative to its competitors on the road and in the air. Constant investments are made within the cities as well. A particular challenge not only in Switzerland is the construction of underground through stations, intended to partially replace the terminus system with its operational disadvantages stemming from the early years of railway transport. At the same time, local public transport is constantly extended in order to keep up with the population growth, and to relieve the city centres from private transport. Pöyry has contributed to such projects for decades. The design and implementation of the Zimmerberg tunnel near Zurich and the Gotthard base tunnel currently the world s longest railway tunnel are part of the NRLA programme, the Swiss contribution to the European high-speed rail network. The Zurich commuter system has been an outstanding success from its beginnings more than twenty years ago. Many underground subschemes have been designed and built with Pöyry s From a tunnelling point of view some of these projects are an extreme challenge as well: big overburden, intense rock deformation and high rock temperatures on the one hand, minimum distances to the surface and existing structures on the other hand. In both situations our engineers, based on their experience and expertise, contribute to innovative and safe solutions. Yet we are not only tunnelling experts thanks to the seamless involvement of our specialists in the areas of railway technology, route construction, operations and safety, we can provide our clients with schemes tailored to all aspects of railway transport. We do not leave you alone after commissioning either Pöyry has monitored the structural condition and inspected tunnels of the Swiss Federal Railways for years. At Zurich-Stadelhofen station, a railway hub with an extraordinary architectural design and the third biggest passenger frequency in Switzerland, Pöyry performs regular measurements for long-term monitoring. If rehabilitation works are required, they often have to be executed during night closures or short traffic interruptions. All measures thus have to be carefully planned and adjusted to the operational conditions. The safety aspect always takes the highest priority in our work. 8 9

6 Road tunnels references N Birmensdorf bypass (Zurich Western bypass), Switzerland Aescher, Hafnerberg and Eggrain tunnels Canton of Zurich, Department of Civil Engineering N4 Schaffhausen Süd Herblingen, Switzerland Federal roads office (FEDRO), Winterthur N01/40 Milchbuck safety tunnel, Switzerland Federal roads office (FEDRO), Winterthur N02 EP Schänzli, Switzerland Federal roads office (FEDRO), Zofingen A well developed infrastructure and flexible and reliable transport systems are important conditions for a thriving economy. Individual mobility also rates high in our society. tion systems depends to a lesser degree on the needs of normal operation, but is mostly governed by strict requirements for the case of fire. The installation of remotely controlled dampers, powerful ventilators, and structural modifications in the operational facilities of an existing tunnel require often to follow a complex sequence of small working steps, in order to guarantee the safety of the tunnel users at all times. Examples are the recent renovations of the ventilation systems in the Gubrist and Milchbuck tunnels. Despite continuous investments, road traffic is often faced with capacity constraints. Efficient, safe and above all environmentally sustainable solutions are required for the extension of our road network. Road tunnels play an important role in this respect. They contribute to relieving metropolitan areas from transit traffic and connecting areas separated by topographic barriers. As the Swiss network of national roads has been completed with the exception of some small gaps, priority is now given to the elimination of bottlenecks. Examples of such projects of the Federal roads office (FEDRO) are the improvement of the eastern motorway ring around Basel, and a second tube for the Fäsenstaub tunnel between Schaffhausen Süd and Herblingen. Both projects are located in urban settings and very demanding as a result of local constraints and numerous particular interests. Our tunnelling engineers work closely with specialists from other disciplines such as routing, traffic planning, operational and safety equipment and environment. The overall project manager provides the coordination between the different specialist divisions and the client in regard to technical issues and scheduling. New bypass roads are intended to relieve the population in towns and metropolitan areas from transit traffic. Once built, they are not only very significant for long-distance traffic but allow also for new developments in our urban environment. One key project of the last decade was inaugurated in 2009 the western bypass around Zurich, completing the scheme of motorways around this booming region. Large parts of the new section run through tunnels, and the variety of geological conditions placed high demands on the design and the implementation of the scheme. Central logistic hubs were established to handle materials in an environmentally friendly way, relying to a large extent on railway transport The operational and safety equipment of the Western bypass was implemented as an overall system and integrated into the centralised traffic monitoring and control system of the Zurich metropolitan area. The fire disasters in the Mont Blanc, Tauern and Gotthard road tunnels have led to a comprehensive revision of the applicable standards and policies. Regular safety checks of existing tunnels by the European automobile associations increased also the pressure of the public. Priority is given to the selfrescue of persons in case of an incident. At present many existing structures are therefore upgraded with safety tunnels. Excavating these tunnels immediately next to the main tunnel under operation, and then connecting the structures via cross-passages, places high demands on the planning and execution of works. An additional challenge during the current construction of the Milchbuck safety gallery derived from the fact that the entire tunnel runs under built-up areas in the city of Zurich. The introduction of catalytic converters and particle filters has generally improved the air quality in our road tunnels. Today, the dimensioning and layout of tunnel ventila- Structural checks and inspections in terms of the integrity of materials form the basis of maintenance concepts. For economic reasons, the individual remaining life spans of tunnel components are increasingly taken into account and fully utilised. One of the biggest challenges is the design and implementation of rehabilitation works during normal operations, in accordance with the applicable safety requirements, and with minimum impact on the traffic flow. Working hours dictated by predetermined interruption intervals and limited space conditions make the logistics and coordination of such programs extremely challenging, and have a big influence on the construction methods and processes

7 Hydropower schemes references Nant de Drance pump-storage scheme, Switzerland Nant de Drance SA Taschinas hydropower plant, Switzerland REPOWER AG Kárahnjúkar hydropower plant, Iceland Landsvirkjun Uma Oya hydropower plant, Sri Lanka Ministry of Irrigation and Water Management Since 2010 Hydropower schemes in the alpine region are highly complex structures, combining a great variety of specialist fields. Underground engineering often plays a key role in the construction of hydropower projects. points, the engineer of an underground hydropower plant has to achieve an optimum efficiency under the given topographic and hydrological conditions. This leads often to widely spread systems of tunnels, shafts and caverns. Pressure tunnels of many kilometres length and pressure shafts of several hundred metres high are quite common. Two typical examples are the Kárahnjúkar hydropower plant and the Nant de Drance pump-storage scheme. A typical optimisation of waterways includes to determine the most economic tunnel cross sections, depending on the flow rate and the construction requirements. The rock support and lining concepts of the tunnels, caverns and shafts are carefully designed according to local hazard scenarios and the internal and external water pressures during operation. High durability and minimum maintenance are particularly essential for waterways, as any operational interruption will cause economic losses. For water galleries, the alternatives include completely unlined excavations, sealing with shotcrete, cast-in-situ concrete linings, or the installation of a steel armouring. We can proudly look back on some 100 years experience in the design of hydropower schemes in Switzerland and abroad. Our expertise covers all structural aspects of such projects. Clients profit in particular from our high skills in the design and dimensioning of waterways, having a big influence on the operational and construction costs. Each project is based on our practical experience with various excavation methods, like for example the excavation of water galleries with tunnel boring machines (TBM), the raise-drill method for shaft construction, or sequential drilling and blasting for the excavation of large caverns. Due to our often very exposed project areas, we are well acquainted with challenging access conditions, complex site logistics, and the recycling or careful disposal of materials in an alpine environment. Thanks to underground elements such as tunnels, shafts and power caverns, entire hydropower schemes from the intake to the outlet can be moved into the mountain. Power plants like the one recently realised in Taschinas (Grisons) can thus be built without affecting the landscape, and with a minimum loss of cultivated land. Low emissions during construction and operation relieve the environment and the construction works are largely independent of the season. While the design of traffic tunnels has to find the best solution to connect two defined 12 13

8 Specialised services 14 Special know-how on demand Our experts find a solution to (almost) any challenge. The multidisciplinary approach of Pöyry Switzerland and our integration in the Pöyry group give us access to a wide variety of professional, human and technical resources. The following areas of expertise are examples of the special skills provided by our company. Geotechnics and numerical modelling The way ahead looks black even if this quote from the ancient times of mining is only partly true today, tunnelling can be still considered one of the most difficult disciplines in the area of construction. With comprehensive investigations, calculations and studies we strive to predict the behaviour of soil and rock as reliably as possible, and take the geotechnical conditions into consideration when planning our clients projects. This becomes even more important if structures push the boundaries of what is technically possible be it underground power stations with enormous dimensions, excavations and underpasses with minimum overburden, or the excavation of cavities in problematic ground conditions. Our underground engineering department has proven experts and modern hard- and software at their disposal to model stresses and deformations, dimension temporary and permanent support measures, carry out static and dynamic verifications, plan monitoring programmes and design ancillary construction measures. Surveying and monitoring Surveying is required for almost any stage of a project as a basis for the project planning, design and implementation, in the context of quality control, or to monitor structures and developments during different construction stages. Thanks to their solid practical experience and state-of-the-art technology our staff is used to perform precise measurements under the most extreme conditions. New areas of application are increasingly discovered besides the conventional tasks of geodetic surveying. Thanks to the threedimensional registration of a cavity profile with a laser scan, deviations from the target specifications may be detected and corrective measures taken rapidly and at an early stage. Such measurements can also be used as a basis for the bill of quantities and the construction accounts. A similar technology has been successfully applied in the micro range for measuring the roughness of the intrados after excavating a headrace gallery. Our measurements allowed to calculate the expected hydraulic losses, and based on our forecast it was possible to abandon an expensive concrete lining a significant optimisation to the benefit of our client. Methods rather known from geophysical exploration are also applied for the nondestructive inspection of a tunnel lining. The impact echo method and the georadar allow for an in-situ assessment of the thickness of structural concrete, and also for the detection of cavities behind the lining. In some countries, this kind of quality control is already standard and required by the clients. Data management In the early days of tunnelling, the options for geological explorations were very limited. Decisions on the actual excavation and support requirements were made by the excavation staff at the working face, based on its experience and intuition. The volume of records and technical information was therefore easily manageable. Given our modern needs to verify the stability of underground structures based on numerical calculations, to predict and monitor deformations and other effects of tunnelling as precise as possible, and due to the fact that tunnels are built in increasingly sensitive areas, today a great number of technical and structural data is collected during the preparation and implementation of a project. Managing this flood of information has thus become a big challenge. The aim is not only to monitor the construction works, detect critical developments in time, and establish a qualified basis for decision-making. Actual requirements on the extent and quality of project records have also increased considerably, not at least in connection with the collection of evidence for possible contractual and legal disputes. With the 2doc data management system, Pöyry provides an effective tool to register the entire technical information deriving from underground construction in a structured manner, make it available for technical analyses and reports, and archive it permanently. The capacity of experts working on the project is no longer blocked by time-consuming data processing. Instead, they have more time for their genuine tasks: to analyse and evaluate the situation, develop technical concepts, and advise their clients and partners. Structural maintenance and material technology Traffic tunnels are built for a typical operating life of years, and numerous tunnels from the early days of railway transport have already been in use for a significantly longer period. There is therefore an increasing need for the rehabilitation of the basic structure, often combined with the necessity to modernise the operational equipment and make the system compliant with actual requirements, standards and policies. The qualified analysis of the actual condition of the structure, possibly combined with analytical tests, is mandatory when a sustainable rehabilitation concept needs to be developed. Profound knowledge of the involved chemical and physical processes, possible damage mechanisms, and the interaction between existing and new construction materials during the remaining lifespan of the structure are also required. In new construction projects as well, the choice of appropriate building materials sets the course for long durability and low operational and maintenance costs. Whether old or new with the early involvement of our material experts in planning, tendering and implementation, we guarantee that our clients won t suffer nasty surprises after the (re)commissioning of a scheme. Depending on the requirements, we cooperate with scientific institutions and laboratories in order to provide our clients with an ideal and customised solution. 15

9 Pöyry Switzerland Ltd. Hardturmstrasse 161, P.O. Box 8037 Zurich / Switzerland phone fax Pöyry is an international consulting and engineering company. We serve clients globally across the energy and industrial sectors and locally in our core markets. We deliver strategic advisory and engineering services, underpinned by strong project implementation capability and expertise. Our focus sectors are power generation, transmission & distribution, forest industry, chemicals & biorefining, mining & metals, transportation, water and real estate sectors.