Tunnel Engineering

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					Tunnel Engineering
                                                                                                                                                 Photo: Morten Larsen

COWI A/S is a leading international con-         Transportation
sultancy firm, founded in 1930. COWI is a         COWI has more than 70 years experience              Fields of Consulting Services by COWI
privately owned professional firm entirely        in transportation consultancy covering all
independent of any manufacturer, supplier        phases of infrastructure projects from initial      • Natural resources management
or contractor.                                   planning and feasibility studies over design,       • Environmental policy and regulation
   The COWI Foundation is the majority           construction and commissioning to mainte-           • Environmental protection
                                                                                                     • Coastal Engineering
shareholder. The foundation supports             nance management and rehabilitation.
research and development in various fields           More than 8000 km of roads and railway           Society
                                                                                                     • Welfare economics and services
of consultancy activities.                       lines with belonging bridges and tunnels of
                                                                                                     • Public administration
   The head office is located in Kongens          all types and sizes have been constructed in        • Social development and HRD
Lyngby, a suburb about 12 km north of            accordance with COWI’s designs.                     • Urban and regional development
Denmark’s capital Copenhagen.                                                                        • Development assistance
                                                                                                     • Cadastre and land administration
   COWI is a highly versatile and multidisci-    Tunnel Consultancy                                  • Geographical information systems and IT
plinary firm providing services of highest        COWI has provided cost-effective designs of           Mapping
quality in the fields of engineering, environ-    tunnels for more than 50 years for clients all      Transport
mental science and social economics.             over the world.                                     • Transport planning and management
   COWI employs around 3,300 staff, of             COWI is currently involved in some 20-30          • Roads
                                                                                                     • Airports
which 1,400 are based outside Denmark in         tunnel projects worldwide and the consul-           • Railways and metros
subsidiaries, branch offices or project offices.   tancy activities occupy almost 100 engineers        • Tunnels
2,100 employees are professionals holding        and other professionals generating an annual        • Bridges
                                                                                                     • Ports and marine structures
Ph.D., M.Sc. or B.Sc. degrees in civil,          turnover in the order of 10 million Euro.
structural, geotechnical, mechanical or                                                              Buildings
                                                                                                     • Residential buildings
electrical engineering and other academic                                                            • Educational buildings
areas such as geology, hydrology, chemistry,                                                         • Hospitals and health buildings
biology, agronomy, sociology, economics                                                              • Cultural and sports buildings
                                                                                                     • Commercial buildings
and planning.
   The annual turnover is at present (2004)                                                          Industry
                                                                                                     • Industrial buildings
350 million Euro. More than half of the
                                                                                                     • Production and processing plants
turnover of the company is generated                                                                 • Oil and gas
outside Denmark in more than 100 coun-                                                               • Health, safety and environment
tries around the world.                                                                              • Environmental and social due diligence
                                                    Anton Petersen         Torsten Mølgaard          Utilities
                                                    Vice President,        Head of Department,       • Municipal and hazardous waste
                                                    Bridge, Tunnel and     Tunnels and Underground   • Water and wastewater
                                                    Marine Structures      Structures                • Energy planning and systems
                                                    +45 4597 2888          +45 4597 2889             • Telecommunication
                                                    ape@cowi.com           tm@cowi.com
                                                                                                                                    Consultancy services and expertises
                                                                                                                                    covering all project phases:
                                                                                                                                    Feasibility phase
                                                                                                                                    • Ideas generation and evaluation
Tunnel Consultancy                                                                                                                  • Feasibility studies
                                                                                                                                    • Studies of infrastructure needs
                                                                                                                                    • Alignment studies
                                                                                                                                    • Cost estimation (considering uncertainties)
                                   Working with Tunnels                             knowledge for which we are internationally
                                                                                                                                    • Construction and procurement scheduling
  Main types of tunnels            COWI’s longstanding experience with all          renowned. TBM-tunnelling under high water       • Environmental impact assessment
  and areas of use
                                   phases of tunnel design and construction         pressure and in soft ground, long-term
                                                                                                                                    Design phase
  TBM bored tunnels                ensures the development of individual and        durability of structures, tunnel ventilation    • Design management
  • Tunnels in congested cities
    for road, rail or utilities.
                                   optimal tunnel solutions with a long and ef-     and safety systems can be mentioned.            • Establishment of design basis
                                   ficient service life.                                                                             • Fire safety and evacuation analyses
  • Sub-aqueous tunnels
                                                                                                                                    • Natural hazard analyses (storm water,
    for crossing of deep             Our experience includes a number of world      Clients                                           flooding, seismic action etc.)
                                   class tunnel projects such as the TBM bored      COWI work for tunnel owners as well as for      • Durability design
  • Long tunnels under
                                   8 km long railway tunnel for the Great Belt      contractors. We advocate for a close dialogue   • Civil and structural design
                                                                                                                                    • M&E installations
                                   Fixed Link in Denmark with the rails 75 m        with the contractor (BOT and design-build       • Operational risk assessment
  Immersed tunnels
  • Tunnels for crossing of        below sea level and the 4 km long immersed       projects) in order to optimize the design and   • Relocation of utilities from construction
    waters of limited depth        tunnel for a 4-lane motorway for the Busan-      construction. This knowledge is then reused,      area
    such as rivers, channels       Geoje Fixed Link in Korea with the road 50       when we design for tunnel owners.               Authority and public phase
    and harbour basins
                                   m below sea level.                                                                               • Authority approval management
  • Alternative to bridge
                                                                                                                                    • Property consultancy
    crossing to ensure                                                              Quality Management
                                                                                                                                    • Land acquisition management
    unobstructed navigation        Tunnel Projects                                  COWI have established an internal Quality       • Archaeological consultancy
  Cut and cover tunnels            COWI have been involved in tunnel projects       Assurance system, which is ISO 9001 certi-      • Public consultation
  • Shallow tunnels in urban       all over the world. Our experience covers        fied. All design activities are carried out in   Tender phase
    areas with moderate
    surface constraints            all types of tunnels, including bored tunnels,   accordance with individual project quality      • Development of tender design and dossiers
                                                                                                                                    • Management of tender procedures
  • Approaches to bored or         immersed tunnels, cut & cover tunnels, rock      plans tailored to meet the specific require-
                                                                                                                                    • Bid design
    immersed tunnels               and NATM tunnels.                                ments of each project.                          • Value engineering
  Rock and NATM tunnels                                                                                                             • Preparation of contract for construction
  • Tunnels with irregular or      Services and Expertises                                                                          Construction phase
    varying cross section shape
  • Short tunnels under
                                   COWI’s services cover the whole life cycle of                                                    • Construction management
                                   a project from the early ideas to the opera-                                                     • Quality, environmental and safety
    mountains or deep waters
    where the cost of a TBM        tion phase and rehabilitation or decommis-                                                       • Construction risk assessment
    makes TBM construction
                                   sioning.                                                                                         • Building damage survey and monitoring
                                   Our services range from professional advice                                                      • Interface coordination
                                                                                                                                    • Programme and budget control
                                   on a specific problem to comprehensive                                                            • Site supervision
                                   planning and total engineering design and                                                        • Contract and claims management
                                   implementation of large scale projects.                                                          Operation and maintenance (O&M)
                                      Our involvement in complex and demand-            Michael Bindseil      Søren Degn Eskesen    • O&M management system
                                   ing tunnel projects over the years has led to        Chief Project         Research and          • Inspection of structures and installations
                                                                                        Manager               Development Manager   • Ranking of maintenance and reinvestment
                                   the development of particular in-house               +45 4597 2947         +45 4597 2554           needs
                                                                                        mhb@cowi.com          sde@cowi.com          • Repair and strengthening design
4   Sub-aqueous Tunnels

                                                                                         General                                                   signed to cope with these conditions as failure
                                                                                         The construction of tunnels under wide and                of TBM performance can lead to serious cost
                                                                                         deep waterways requires special consideration             escalation and extensive construction delay.
                                                                                         to the design as well as the execution. COWI
                                                                                         has many years of experience in designing                 Immersed Tunnel Construction
                                                                                         sub-aqueous tunnels. Some of the technical and            An immersed tunnel consists of prefabricated
                                                                                         practical challenges related to the planning,             elements which are towed out and immersed
                                                                                         design and construction are mentioned in the              into a dredged canal in the sea- or riverbed.
                                                                                         following.                                                The dredging and the towing out and immer-
                                                                                                                                                   sion operations in waterways with heavy cur-
                                                                                         Offshore Geotechnical Survey                              rents and vessel traffic are critical and failure
                                                                                         Offshore geotechnical surveys in waterways                can lead to serious cost escalation and exten-
                                                                                         with strong currents, wave action, ice action             sive construction delay.
                                                                                         and vessel traffic is a demanding task. COWI’s
                                                                                         in-house experienced geotechnical specialists             Durability of Tunnel Structures
                                                                                         are conversant with such conditions.                      Sub-aqueous tunnels are subject to extraordi-
                                                                                                                                                   nary conditions with regard to outside pressure
                                                                                         Bored Tunnel Construction                                 and chemical aggressivity. Therefore, special
                                                                                         Tunnel Boring Machines (TBMs) for construc-               measures with regard to avoiding or delaying
                                                                                         tion of sub-aqueous bored tunnels exposed to              the development of concrete deterioration and
                                                                                         the extreme conditions with regard to water               reinforcement corrosion needs to be consid-
                                                                                         pressure and difficult grounds have to be de-              ered.

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    Longitudinal Profile,
    Great Belt Tunnel Denmark

Tunnel Ventilation
The ventilation shall ensure the comfort in the
tunnel during daily operation as well as con-
trolling smoke and providing fresh air to the
tunnel during an emergency situation. The long
distances in a sub-sea tunnel between ventila-
tion intakes and outlets place special require-
ments on the design of the ventilation system.

Safety Measures
As surface access is not feasible at long
distances, special measures are required for
sub-aqueous tunnels in order to meet the safety
requirements from the authorities. COWI has
experience in design and optimization of all
parts of the safety system including ventilation
system, emergency lighting, fire fighting system,
telecommunication system, SCADA system etc.

                                                   Photo: Steen Brogaard
6   Large Diameter and Soft Soil Tunnels

                                           General                                           greater cross section than e.g. rail tunnels, but
                                           Tunnels in soft soil are often constructed as     also bi-directional rail tunnels are now possible
                                           bored tunnels, when the use of cut & cover        to construct. The larger diameter tunnels
                                           tunnel techniques is not possible or too costly   involve larger challenges during construction in
                                           an option. Bored tunnelling techniques cover      terms of TBM operation, risk of settlements
                                           both tunnels constructed by the use of a          etc., due to the larger volumes of ground being
                                           Tunnel Boring Machine (TBM) and tunnels           excavated, but also ring building, with the very
                                           constructed by hand tools and machines, using     large concrete lining segments, is an extra
                                           an observational approach with temporary          challenge.
                                           support of the excavation. The latter is often
                                           called NATM tunnels (New Austrian Tunnel-         TBM Bored Tunnels
                                           ling Method).                                     Tunnels constructed by a TBM are typically
                                                                                             circular and used in soft ground for longer tun-
                                           Tunnel Boring Machines                            nels. TBM tunnels are used both in urban and
                                           Two typical TBM types are the Earth Pressure      non-urban areas in a soft soil and sub-aqueous
                                           Balance (EPB) machine and the Slurry machine.     environment. Compared to NATM tunnels,
                                           The former is during construction able to         TBM bored tunnels can be constructed in less
                                           counterbalance the ground and water pressures     competent ground and where water pressures
                                           in front of the TBM by the use of one or two      are high or impossible to drain.
                                           screws between the cutter head and the con-         TBM bored tunnels are typically lined with a
                                           veyer belt. The latter uses a technique where     prefabricated segmental concrete lining.
                                           bentonite slurry is pumped into the cutterhead
                                           and mixed with the excavated material. The        NATM Bored Tunnels
                                           mixed slurry is then pumped out of the tunnel     NATM bored tunnels are often used for con-
                                           where the bentonite and the excavated material    struction of non-circular tunnels, or shorter
                                           are separated again. This system also provides    tunnels in relative competent ground condi-
                                           stability in front of the TBM during tunnel       tions where the ground can be drained during
                                           construction.                                     construction.
                                             During recent years is has become possible to      The NATM cross-section can be excavated in
                                           built larger diameter TBM bored tunnels,          sections to suit the actual conditions, and
                                           mainly due to improved technology and the         excavations are temporarily lined with a
                                           development of larger diameter TBMs. This         primary lining consisting of shotcrete. The
                                           has opened the market for bored road tunnels      permanent secondary internal lining is built as
                                           significantly, as road tunnels often require a     an in-situ cast concrete lining.
Photo: Ørestadsselskabet / Rene Strandbygaard

8   Ventilation Systems for Long Tunnels

    Ventilation of tunnels is one of the most impor-   Tunnel Ventilation Methods                         sometimes combined with exhaust from larger
    tant features to provide a functional, comfort-    The methods for providing the required venti-      caverns as e.g. cross-overs or bifurcations.
    able and safe tunnel environment for road          lation during normal operation or emergency        During normal and congested traffic the tunnel
    tunnels as well as railway tunnels.                operation depend on the actual conditions          ventilation will be operated to control the
                                                       (tunnel length, alignment, cross-section, inter-   temperature in the tunnels.
                                                       mediate ventilation shafts etc.).                    In tropical regions additional tunnel cooling
                                                         Normally for road tunnels longer than            will often be required e.g. to provide acceptable
                                                       approx. 4 km the longitudinal ventilation          operation conditions for train air-condition
                                                       method is not feasible and transverse or semi-     units to secure the comfort of the passengers.
                                                       transverse ventilation systems could be
                                                       introduced. The capability of the various          Ventilation Systems
                                                       systems and the choice of system depend on the     Longitudinal ventilation can be achieved using
                                                       fresh air requirement calculations, which are      jet fans in the tunnel profile or axial fans in
                                                       based on the estimated traffic conditions,          either shafts along the tunnel or in plant rooms
                                                       emission from vehicle, local standards and         at the tunnel portals.
                                                       requirements for pollution level in the exhaust       For longer tunnels a fully- or semi-transverse
                                                       air to protect the neighbouring environment.       ventilation concept could be introduced
                                                       The road traffic itself will provide a full or      creating fresh air supply and extraction of
                                                       partly ventilation of the tunnel depending on      polluted air at certain points. This requires
                                                       the travel speed, so normally mechanical           ventilation ducts along the tunnel.
                                                       ventilation is only required for diluting the
                                                       pollutants during lower traffic speed operation     Ventilation Design
                                                       and during fire situations.                         Ventilation calculations such as aerodynamics,
                                                         For railway systems the ventilation method is    thermodynamics and fire simulations will be
                                                       normally determined by the emergency               carried out during the various design phases.
                                                       scenarios to control the smoke during a fire.          The optimal tunnel ventilation concept
                                                       This leads to longitudinal ventilation provided    should be chosen considering safety, function-
                                                       by a push-pull concept using ventilation plants    ality, protection of the environment, construc-
                                                       at adjacent stations or intermediate shafts        tion and operation costs.
10   Tunnel Design Tools

     Advanced and reliable design tools are a pre-
     requisite for carrying out an optimised tunnel
       COWI use a number of computerised tools
     in our structural designs, including the following.
     FLAC                                                                                                                        IBDAS is an integrated design
                                                                                                                                 and analysis software tool devel-
                                                                                                                                 oped at COWI, which allows for
                                                                                                                                 geometrical modelling, structural
                                                           PLAXIS                                                                analysis and verification of engi-
                                                           PLAXIS is a finite element program                                     neering structures and generation
                                                           specifically developed for numerical                                   of construction drawings.
                                                           analysis of geotechnical and under-
                                                           ground structures.                         SES
                                                                                                      Subway Environmental
                                                                                                      Simulation software
                                                                                                      tool for estimation of
                                                                                                      airflows, temperatures
     FLAC is a finite difference program                                                               humidity and air-condi-     ABAQUS
     widely used for modelling in geo-                                                                tioning requirements for    ABAQUS is one of the lead-
     technical and tunnelling design.                                                                 subway systems.             ing multi-purpose finite element
                                                                                                                                  programs for a wide spectrum of
                                                                       ROBOT                                                      numerical analysis in engineering
                                                                       ROBOT is a finite element                                   and natural science.
                                                                       program for analysis and
     CFD                                                               design of beam, truss, slab,
     Computional Fluid                                                 shell and 3D structures.
     Dynamics software
     tool for modelling of
     physical phenomena
     in flow and heat
     transfer and fires in
     confined spaces.
Service Life Design of Tunnels                                                                                                                                                   11

COWI is spearheading the international              Sustainability achieved through reliability
development of service life design of               based service life design
tunnels                                             Internationally COWI provide the only avail-
The modern, reliability based service life          able reliability based service life design meth-
design is implemented in most new designs, in       odology against chloride and carbonation
re-design of existing tunnels, and in strategic     induced reinforcement corrosion. This contrib-
planning of maintenance and repairs.                utes optimally to the societal demands for a
  Tunnels are usually now to be designed for        sustainable built environment.
100, 120 or even 200 years service life. This         All uncertainties of the environmental
surpasses by far the assumed design life            exposure, the material properties, and the
following most codes and standards.                 deterioration modelling are taken into account.
                                                      Thus, service life design, based on functional
Internationally recognised expertise and            requirements, can be carried out by following
experience                                          the same load-and-resistance factor design
COWI’s recognised leading position within           concept as known for structural design.
durability design and concrete technology
is based on more than 40 years worldwide            Implementation in actual projects                    ��

experience within the design, operation and         This new methodology has been adopted by             ��
maintenance of exposed reinforced concrete          national authorities and individual clients in                                                             ���������

structures.                                         countries such as Norway, Sweden, The Neth-          ��
                                                                                                                                                    �� �

   COWI has been spearheading the interna-          erlands, Germany, Spain, UK, North America,
                                                                                                          ��                                        ��

tional research and technical development of        as well as in several former Eastern European

the rational service life design of concrete        countries, the Middle East and Gulf countries,                   �    �     ��   ��   ��        ��       ���   �����
structures. Selected positions have been the        and in the Far Eastern Countries.                          ��������������    ����������� �����������
initiation and management of the European                                                                                        ����������� �����������

research projects DuraCrete, DuraNet and
DARTS, and chairing all durability related
                                                          Carola Edvardsen
activities within the international organisations         Senior Specialist
of CEB (Comité Euro-international du Béton)               +45 4597 2813
and now fib (Fédération Internationale du                  cle@cowi.com

12   Risk Management of Tunnels

     Risk management is essential in tunnel             Safety Concept
     design and construction                            The safety concept is a description of the main
     In tunnels there is a potential for major ac-      features of tunnel design and operation, which
     cidents, both during construction and during       shall be implemented to ensure adequate safety
     operation of the completed tunnel. This fact is    during operation of the completed tunnel. The
     evident from the major accidents, which have       concept should be developed early in the design
     occurred in recent years. It is therefore impor-   process to serve as basis for initial project ap-
     tant that systematic risk management is imple-     proval and for the detailed design.
     mented in tunnel projects in order to ensure an
     adequate level of safety in a cost-efficient way.   Risk Assessment, Operational Risk
        COWI has many years of experience in Risk       An overall risk assessment should be carried
     Management. COWI has also led a workgroup          out in order to identify all types of risk during
     within the International Tunnelling Associa-       operation of the tunnel. For significant hazards
     tion, ITA, which has established a risk guide-     detailed risk assessment should be carried out
     line for design of tunnels.                        as basis for the design decisions. This may
                                                        include simulations of fire development and
     Safety Policy                                      smoke spread as well as simulation of evacua-
     The safety policy describes the overall safety     tion scenarios.
     goals for the tunnel owner or tunnel project.
     This policy should be established as the start-    Risk Assessment, Construction Risk
     ing point for the risk management activities.      An overall risk assessment should be carried
                                                        out in order to identify all types of risk during
     Safety Plan                                        construction of the tunnel. For significant
     The safety plan describes the framework of         hazards design and construction methods
     the risk management process including project      should be re-evaluated and risk mitigations
     organisation, safety responsibilities and the      should be considered in order to reduce risks
     activities required to document that the safety    to an acceptable level.
     goals have been met.
14   Great Belt Tunnel, Denmark

     The railway tunnel is one out of the three          Cross Passages
     major components of the Great Belt Link. The        The 4.5 m internal diameter cross passages,
     project includes two 7,410 m long main tunnel       are constructed of spheroid graphite cast iron
     bores with cross passages each 250 m, cut &         rings each 0.6 m wide consisting of 18 seg-
     cover tunnel sections at each end terminated        ments. The cross passages serve as emergency
     by portals and permanently drained ramps. At        routes between the two main tunnels. They are
     the deepest point, the rails are 75 m below sea     equipped with safety doors and stores electrical
     level. The maximum gradient is 1.56 percent.        and mechanical equipment required for opera-
                                                         tion of the railway.
     Alignment and Geology                                                                                   Services by COWI - MHAI JV
     Along the tunnel alignment, the water depths        Tunnel Ventilation and E&M                          • Tender design
     increase gradually from each side to about 20       Longitudinal tunnel ventilation is provided by
                                                                                                             • Tender evaluation
     m, and then in the central glacial erosion chan-    80 nos. of jet fans in each tunnel tube. Special
                                                                                                             • Detailed design of structures and mechanical
     nel more steeply to a maximum of about 55 m.        emergency double swing doors are developed
        The tunnels are situated in layered strata of    and comprehensively tested.
                                                                                                             • Design follow-up during construction
     tills and marls. The till incorporates melt water
     deposits containing water at pressures up to 4      Seabed Dewatering                                   • Site supervision
     bar and granite boulders. The marl is fissured       A revolutionary use of large scale dewatering
                                                                                                             Project Period
     with hydraulic pressures of up to 8 bar.            of the soil strata below the sea bottom contrib-
                                                                                                             1987 - 1997
                                                         uted significantly to the safety and the progress
     Bored Tunnels                                       of the tunnelling works. It allowed the tun-        Client
     The two parallel 7.7 m internal diameter main       nel boring to be carried out at reduced water
                                                                                                             A/S Storebæltsforbindelsen
     tunnels were constructed from both sides by         pressure and it allowed cross passages to be        (Great Belt A.S.)
     four Tunnel Boring Machines (TBMs) with             constructed safely using minor additional local
     an outer diameter of 8.75 m. The tunnels            dewatering.                                         Construction Cost
     are lined with 1.65 m wide and 0.40 m thick                                                             USD 1 billion
     bolted rings of seven precast reinforced con-       Portals and Ramps
     crete segments. High ground water chloride          The two, three-storey portal buildings contain
     and sulphate levels combined with a hydro-          facilities for operating the mechanical and elec-
     static pressure of up to 8 bar have required        trical installations in the tunnels. The ramps
     provision of several barriers against corrosion,    are constructed as permanently drained open
     including epoxy coating of the fully welded         ramps to level - 14 m at the portal building.
     reinforcement cages.
16   Busan - Geoje Immersed Tunnel, Korea

     The Busan - Geoje Fixed Link involves the
     construction of an 8.2 km motorway connect-
     ing Busan, Korea’s southernmost and second
     largest city, to the island of Geoje. The connec-
     tion includes a 4 km tunnel of which 3,400 m
     is an immersed tunnel – one of the longest in
     the world – and two cable-stayed bridges each
     2 km in length.

                                                         Immersed Tunnel                                     Installations
         Services by COWI - DEC JV
                                                         The cross-section of the immersed tunnel is         The tunnel ventilation concept is chosen as
         • Basic design                                  designed for two-lane traffic with emergency         longitudinal ventilation including approx.
         • Detailed design for tunnels                   and climbing lane where appropriate due to the      90 nos. of jet fans in each tunnel tube as well
         • Detailed design for mechanical and            5% gradient. The centre section of the tunnel,      as an additional smoke extraction system.
           electrical works                              between the motorway lanes, will contain the          The escape gallery will be pressurized by
         • Follow-up during construction                 E&M services, the smoke extraction duct and         axial fans in the ventilation buildings in order
                                                         the emergency escape route.                         to secure safe evacuation routes and avoid
         Project Period                                     The tunnel consists of 18 pre-cast tunnel        smoke spread to the non-incident tunnel.
         2003 - 2010                                     elements placed in a dredged trench at a              A state of the art traffic control system
                                                         maximum water depth of 50 metres – the first         (Intelligent Transport System - ITS) is devel-
         Client                                          time in the world that an immersed tunnel is        oped covering the whole link.
         Daewoo Engineering & Construction               constructed at such depth. Furthermore, the
         Co. Ltd.                                        tunnel is founded on very week ground which
         Construction Costs
                                                         is a challenge to the foundation design.

         Approx. USD 1 billion
                                                                  Geoje                                                                                         Gaduk
                                                                           2.0 km       0.3 km      1.9 km           0.3 km                    3.7 km

                                                                                        Jeo                          Jungjuk
                                                         120 m
                                                          80 m                                                                 Daejuk
                                                          40 m
                                                         - 40 m
Malmö Citytunnel, Sweden                                                                                                                                17

A railway tunnel under the central part of          230 m long cut & cover bifurcation tunnel
Malmö linking the present central station with      passes under a harbour bridge and connect to      Services by SWECO-COWI JV
the Øresund link between Sweden and Den-            the bored main tunnels.                           • Conceptual studies of structures and E&M
mark is being constructed.                             The proximity of the harbour, the existing       systems
                                                    station, other existing buildings and utilities   • Support to environmental hearing
Tunnels                                             and the groundwater requirements create a
                                                                                                      • Client’s tender design of tunnels and station
The two parallel 4.6 km long bored tunnels are      complex groundwater situation, which requires       structures
7.9 m internal diameter tunnels with pre-cast       special works and provisions during construc-
                                                                                                      • Detailed design of station internals and
concrete segmental lining. The bored tun-           tion.                                               finishes
nels will be excavated by two Earth Pressure
                                                                                                      • Design follow-up during construction
Balance TBMs, which will have to be pulled          Triangeln Station
through the Trianglen station, approximately        Triangeln station is a two-track station with a   Project Period
half way on the bored tunnel section.               central 14.5 m wide platform. The platform is     1999 - 2011
  At the southern end, a 360 m long twin tube       250 m long and located 25 m below ground
cut & cover tunnel and a 390 m permanently          surface. The station will connect to the town     Client
drained open ramp bring the alignment to the        square via escalators at both ends of the plat-   Banverket (Swedish National Rail
surface.                                            form.                                             Administration)
  13 cross passages connect the two main              The station platform will be situated in a
                                                                                                      Construction Cost
tunnels every 300-400 metres. Two of the cross      large NATM cavern constructed from two 30
passages will be combined with emergency            metres diameter shafts. The cross-sectional       USD 1.25 billion

access shafts situated approximately at the         area of the cavern is approximately 320 m².
quarter points of the tunnels.                      The cavern will be supported by a central row
                                                    of columns.

Malmö Central Station                               Monitoring and Control
The central station is a four-track double box      The tunnels and underground stations are
cut and cover structure with a 325 m long           monitored and controlled by SCADA, CCTV
platform located 10 m below ground. West of         and fire alarm systems in order to ensure safety
the station the railway is brought to the surface   during railway operation.
via a 340 m long ramp. East of the station a
18   Limerick Immersed Tunnel, Ireland

     The Limerick Southern Ring Road will provide      Installations
     an east-west bypass of the Limerick City for      Safe egress has been in focus and a forceful
     both regional and local traffic. The ring road     tunnel ventilation system will be provided.
     shall pass the Shannon River and allow unre-      E&M systems as well as a state of the art
     stricted shipping traffic to the Ted Russel Dock   traffic control system (Intelligent Transport
     in Limerick.                                      System - ITS) is developed covering the
       The project is being tendered as a PPP-         whole ring road.
     project with award of contract for construction
     and operation & maintenance expected in
     early 2006.
       A number of crossing options (low level
     opening bridge, high level fixed bridge and            Services by MCOS – COWI JV

     immersed tunnel) have been considered with            • Constraints study, route selection and
     due consideration of environmental and                  conceptual design

     aesthetic constraints and the soil conditions.        • Conceptual design for immersed tunnels,
                                                             cut and cover tunnels and ramp sections

     Immersed Tunnel                                       • Design basis for tunnel works
     The preferred option is a tunnel comprising           • Proposals for temporary structures,
     a dual tube immersed concrete tunnel with a             casting basins and sedimentation ponds
     length of about 600 m. A temporarily drained          • Tender design
     open ramp of approximately 150 m will be              • Tender evaluation
     used as a construction dock for the tunnel ele-
                                                           • Design follow-up
     ments on the northern bank. On the southern
     bank a ramp of 150 m combined with an                 Project period
     embankment through Bunlicky Clayfield Pond             1999 - 2010
     is anticipated.
        The works entail major excavations/dredging        Client
     and foundation of structures in very soft,            Limerick County Council, Limerick
     organic clays and very hard limestone. A large        Corporation, Clare Council, National
     sedimentation basin is envisaged for dredged          Roads Authority

     material on the northern bank.
Hallandsås TBM Tunnel, Sweden                                                                    19

The Hallandsås Tunnel is part of the expan-       construction will now be carried out with
sion of the railway network in the western        TBMs instead of the first attempted drill and
part of Sweden. This expansion, which is          blast techniques. COWI was awarded the key
planned by Banverket (Swedish National            positions in the supervision of the Tunnel
Railway Administration), involves the increase    Boring Machines (TBMs) and the tunnel lining
of capacity from one to two tracks along the      concrete production.
western coastline of Sweden and preparing the       The two single-track tunnels will each be
railway network for high-speed trains. Part       8,600 m long with connecting tunnels at 500
of the preparation for high-speed trains is the   m intervals.
construction of two single-track tunnels trough     The TBMs are going to be 210 m long
the Hallandsås ridge.                             including the service module, have an outer
  The work commenced in the early 1990’s but      diameter of 10.5 m and weight 1,350 tons.
was stopped in 1997 due to severe water           41,000 tunnel segments will have to be
inflows and environmental problems. The            installed. Each ring consists of 8 segments.
work re-commenced in 2002, and the tunnel

    Services by COWI
    • Supervision tunnel boring
    • Supervision Segmental Lining
    Project Period
    2002 - 2011

    Banverket (Swedish National
    Railway Administration)
20   Tunnels for Copenhagen Metro, Denmark

     Copenhagen Metro is the first underground          of TBM launch chambers, cross passages and
     mass rapid transport system to be in opera-       for deeper parts of the emergency shafts which      Services by COWI
     tion in Denmark. The project was constructed      were excavated in limestone.                        • Tender design for: TBM tunnelling, NATM
     under design and construct contracts.               Cut & cover tunnelling was used to connect          tunnelling and Cut & Cover tunnels
        The Metro runs underground for a length of     the bored tunnels to ramps where the ground         • Segmental linings, in-situ
     9 km under the central part of Copenhagen,        cover for bored tunnelling was insufficient.           linings, shotcrete linings,
     where several buildings of national and                                                                 steel linings and waterproofing systems

     cultural heritage are located. Underground        Installations                                       • Conceptual design
     stations are located approximately per 1 km.      Tunnel ventilation facilities are provided in the   • Preparation of tender documents including a
     Emergency shafts are located at half point        underground stations and in some of the inter-        reference project
     between stations, providing emergency exits       mediate shafts as well as dedicated extraction      • Tender evaluation and contract negotiation,
     per maximum 300 m. In addition to the             from the cross-over cavern.                         • Design follow-up and site supervision
     underground sections the Metro includes             At the stations platform screen doors create
                                                                                                           • Construction management
     elevated and at grade sections and stations as    a partition between the tracks and the platform
     well as a control and maintenance centre.         for safety and comfort reasons as well as for       • Feasibily study for a new circle line

                                                       improving the tunnel ventilation in case of fire
                                                                                                           Project Period:
     Tunnels                                           emergencies.
                                                                                                           1994 - 2007
     Most of the tunnels are constructed in lime-
     stone containing layers of hard flint. In the      New Circle Line in Copenhagen                       Client
     outer sections where the alignment raises the     In the period from 2002-2005, for the Danish
                                                                                                           Ørestadsselskabet I/S
     tunnels are located in mixed faces of limestone   Ministry of Transport and Energy COWI has
     and a clayed sandy till.                          carried out a feasibility study for a new 15 km     Construction Cost
        The 4.9 m internal diameter running tunnels    long Circle Line in Copenhagen, all under-          USD 1 billion
     were constructed by using two Earth Pressure      ground with 16-17 deep stations and five trans-
     Balance TBMs to ensure ground stability and       fers to existing railway lines and the Metro.
     that the groundwater level would stay essen-      It is expected that planning and design of the
     tially unchanged during tunnelling.               Circle Line will continue from 2006 and it is
        NATM tunnelling was used at few locations      anticipated that the new line can be opened for
     where non-circular cross-sections were re-        operation in 2017.

                                                                                                                                                           Photo: Ørestadsselskabet / Thomas Ibsen
     quired, i.e. for excavating an underground
     cross-over cavern and two bifurcation cham-
     bers. NATM was also used for the construction
Photo: Ørestadsselskabet / Jens Dige

22   Preveza - Aktio Crossing, Greece

                                          The project consists of a 152 m cut & cover       Before excavation of the trench, 0.6 m diameter
       Services by COWI                   tunnel on the Aktio side, a 909 m immersed        stone columns were constructed, in order to
       • Tender design                    tunnel under the strait and a 509 m cut &         prevent liquefaction under possible earthquake
                                          cover tunnel on the Preveza side.                 loadings.
       • Detailed design
                                            The immersed tunnel is designed for two           Flexible joints are provided between the tunnel
       • Construction follow-up           lanes of traffic within a box cross-sectional      elements. The water-tightness of the joints is
       Project Period                     profile of 10.6 m internal width. The outer        ensured by rubber gaskets. The tunnel elements
       1993 - 2002                        dimensions of the immersed tunnel are 12.6 m      are further encased within a watertight mem-
                                          wide by 8.75 m high.                              brane in order to avoid potential leakage.
       Client and Contractor                The eight prefabricated tunnel elements of        The tunnels have been designed to withstand
       Joint Venture between Christiani   59.2 m to 134.5 m length were constructed in      severe seismic loadings. In comparison to normal
       & Nielsen Ltd. (UK) and            a casting basin connected to the strait by an     immersed tunnels, the shear keys at the joints
       Technical Company of General
       Constructions SA (Greece).         approximately 150 m long channel. From the        between the tunnel elements have been strengt-
                                          casting basin the elements were floated to their   hened. Furthermore, prestressing cables have
                                          final position. The elements were then installed   been placed across the joints in order to limit
                                          in a pre-dredged trench.                          differential movements during seismic events.
                                                                                                          Photo: JW Luftfoto
24   Fehmarn Belt. Tunnel Feasibility Study, Denmark - Germany

     A fixed link is being investigated between Putt-    competitive. For the other immersed tunnel
     garden in Germany and Rødby in Denmark.            alternatives with widths ranging from 27 m to
     This link will provide a direct connection         43 m, concrete tunnels are the most favourable
     between Scandinavia and Central Europe.            solutions.
       A feasibility study has been carried out for       During operation the railway tunnels will be
     bridge and tunnel alternatives by the joint        ventilated by the piston effect, with fans
     venture COWI-Lahmeyer and the first phase is        intended for emergency use. For the road
     now concluded.                                     tunnels semi-transverse ventilation is required
       Bored tunnels as well as immersed tunnels in     with a ventilation shaft, protected by an
     steel and concrete have been investigated.         artificial island in the middle of the Belt.
       At the location of the link the width of the
     Belt is about 19 km and the water depth up to
     30 m.
       The diameters for the bored tunnels range
     from 8.0 m for the railway tunnels to 14.2 m
     for the three-lane roadway tunnel. The
                                                                       Services by COWI-Lahmeyer
     thickness of the concrete lining ranges from 0.5                  JV:
     m to 0.7 m.
                                                                       • Pre-feasibility study
       The boring is proposed to be carried out
     with earth pressure balance machines in the                       • Technical and environmental
                                                                         feasibility study
     clay strata, and slurry/mixshield machines in
     deposits with sand, silt, gravel and boulders.                    Project Period:
       The immersed tunnels are expected to be                         1993 - 2002
     fabricated in 150 m long elements which will
     be fully embedded into the seabed for environ-                    Client
     mental reasons.                                                   The Danish and German
       For the railway and shuttle tunnel with a                       Ministries of Transport
     width of 19 m a steel immersed tunnel may be
Selected References                                                                                                                                                                                                                                                                                                                                                        25

                                                                                                                                                                                                         Green Heart Tunnel,
                                                                                                                                                                                                         The Netherlands
                                                                                                                                                                                                         Description: Single tube 14.5 diameter
Tunnels for Taiwan High-Speed                                                                                                                                                                            and 8 km long high-speed railway tunnel
Rail Project                                                                                                                                                                                             under the Green Heart of Holland.
Description: Sections C240 and C250                                                                                                                                                                      Completed: 2004
including 3 km long Miaoli tunnel and                                                                                                                                                                    Client: Dutch Ministry of Transport and
13 small tunnels with a total length of                                                                                                                                                                  Public Works
3.5 km, 3 km cut & cover tunnels and
9 km cuts and embankments.                                                                                                                                                                               Services by COWI: Review of tunnel
                                                                                                                                                                                                         durability design, TBM operating
Expected Completion: 2006                                                                                                                                                                                procedures, pre-cast concrete lining
Client: Hyundai Cheng Lin JV, Hochtief-                                                                                                                                                                  production, erection and repair and
Ballast Nedam-Pan Asia JV                                                                                                                                                                                independent tunnel/TBM inspection.
Services by COWI: Independent Design

                                                                                                                                                                                                                                                           ��������                                                                     �����������

                                                                                                                                                                                                         Helsingør - Helsingborg Tunnel,                           ������ ��� � �����                      ����� ������                 ��� � �����
District Heating Tunnel in                                                                                                                                                                               Denmark - Sweden
Copenhagen, Denmark                                                                                                                                                                                                                                  ���
                                                                                                                                                                                                         Description: 5 km subsea railway                                     �������                                                             �������

Description: 4 km 5 m ext. diameter EPB                                                                                                                                                                  tunnel between Denmark and Sweden
                                                                                                                                                                                                                                                       �      ��
TBM bored tunnel for district heating,                                                                                                                                                                   performed as a twin bored tunnel, as an     ���

between 3 shafts. Lower parts of shafts                                                                                                                                                                  immersed tunnel or as a combined bored      ���
                                                                                                                                                                                                                                                                               ��� �
and tunnel ends are constructed using the                                                                                                                                                                and immersed tunnel.                        ���
                                                                                                                                                                                                                                                                                             �                              ��

NATM technique.
                                                                                                                                                                                                         Client: Municipalities of Helsingør and
Expected Completion: 2008                                                                                                                                                                                Helsingborg                                                               �             �   �            �         �       �             �

Client: Copenhagen Energy (KE)                                                                                                                                                                           Services by COWI: Feasibility study in               ���������                                  ����������� ����          ���� ����� ��������

Services by COWI: Feasibility study,                                                                                                                                                                     joint venture with SCC.                              ����� ��� ������ ��������
                                                                                                                                                                                                                                                              ����� ��������
                                                                                                                                                                                                                                                                                                         ����������� ����
                                                                                                                                                                                                                                                                                                         ������� ��������
conceptual and preliminary design, tender
documents and contract negotiation,
detailed design and supervision.

                                                                                                                                                                                                         Jacked Tunnel under Odense Å,
                                                                                            Yenýkapi TCDD transfer station

                                                                                                 Yenýkapi tube tunnel station                           Assumed existing ground profile
                                                                                                                                                                                                         Description: New rain water discharge
Bosphorus Crossing, Turkey
                                                      Highway overpass

                                                          Yedýkule tube tunnel station                                                                                                                   system in Odense, including app. 10 pipe
Description: 13.3 km new underground
                                                                                                                                Sýrkecý station
                                                                                                                                                         Üsküdar station
                                                                                                                                                                                                         jacking sections of 25 m to 250 m length,
railway line with 4 stations, consisting of                                                                                                                                                              lined with 2.5 m int. diameter concrete
8.2 km bored tunnel, 1.8 km cut & cover                                                                                                                                                                  lining.
                                              +10 m

                                                                                                                                                                                                                                                                                                                                                       Photo: Tao Lytzen
sections and 1.8 km immersed tunnel.           0m                                                                                                                                                        Expected Completion: 2006
Client: HPYG JV: Hazama (J) Penta-            -10 m

                                              -20 m
                                                                                                                                                                                                         Client: Odense Water Supply
Ocean (J) Yüksel (TÜR) and Güris (TÜR)        -30 m                                                                                                                                                      Services by COWI: Detailed design,
Services by COWI: Tender design               -40 m
                                                                                                                                                                                                         construction management, site
programme management.                         -50 m

                                                                                         Bored tunnel                                             IMT                                     Bored tunnel
26   Selected References
     The Øresund Link, Immersed
     Tunnel, Sweden / Denmark
     Desciption: 18 km combined road and        Guldborgsund Road Tunnel,
     railway link across the sound between      Denmark
     Denmark and Sweden, including a 4 km       Description: 460 m 2-lane immersed
     immersed tunnel section in fissured         road tunnel under the Guldborgsund
     limestone to cross the main navigation     with drained ramps.
                                                Completed: 1988
     Client: Skanska (SE), MT Højgaard (DK)
     and Hochtief (D)                           Client: Danish Ministry of Public Roads,
                                                Road Directorate
     Completed: 2000
                                                Services by COWI: Conceptual design,
     Services by COWI: Conceptual design.       tender design, detailed design and

     Conwy Estuary Tunnel, Wales
     Description: Dual two-lane highway
     tunnel with 710 m long immersed            Fourth Victoria Harbour Immersed
     section under the 5-12 m deep Conwy        Tunnel, Hong Kong
     Estuary, 320 m long in-situ section and    Description: 1.7 km double metro
     610 m long ramps in alluvial sands and     tunnel for the new Shatin - Central Link
     clays.                                     under Victoria Harbour in Hong Kong,
     Completed: 1991                            including a 1.35 km immersed tunnel.
     Client: The Welsh Office, Transportation    Client: KCRC Kowloon - Canton
     and Highways Group                         Railway Corporation
     Services by COWI: Tender design,           Services by COWI as sub to Scott
     detailed design and supervision in joint   Wilson: Initial design, scheme design and
     venture with Travers Morgan.               tender design.

     Bjørvika Immersed Tunnel, Oslo,
     Norway                                     Thessaloniki Immersed Tunnel,
     Description: Dual tube highway             Greece
     connection under Bjørvika and Bispevika    Description: 4 km 6 lane road toll-
     in Oslo Harbour. The design includes       tunnel. 1.5 km immersed tunnel and
     approximately 600 m immersed tunnel        2.5 km cut & cover tunnel.
     and 250 m cut & cover tunnels.
                                                Client: FCC (ES), Pantechniki (GR),
     Expected completion: 2010                  Attikat (GR), Pihl & Søn (DK)
     Client: Statens Vegvesen, Oslo Vegkontor   Services by COWI: Tender design
     (The Norwegian National Road               management, tender design of immersed
     Administration)                            tunnel and mechanical installations in
     Services by COWI: Design review.           tunnels.
Selected References                                                                     27

                                           Lötschberg Base Tunnel,
Road, Railway and Subway Tunnels           Description: 34.6 km long twin tunnel
by the Reichstag,                          as part of the Swiss-Cross-Alpine Rail
Berlin, Germany                            Tunnels from Frutigen to Raron. Rock
Description: 530 m long and total 90 m     temperatures of up to 45 o C are expected.
wide tunnelled traffic corridor below the   Expected completion: 2007
river Spree in Berlin. The cut & cover     Client: Bundesamt für Verkehr,
tunnels comprise dual road, - railway      Switzerland
and - metro tunnels placed in 20 m deep
excavations below groundwater with         Services by COWI: Review of tunnel
anchored diaphragm walls and jetgrouted    ventilation strategy and concept design
or anchored bottoms.                       report for emergency ventilation.
                                           Suggestions on alternative design and
Completed: 2001                            ventilation methods.
Client: Spie - Batignolles SA
Services by COWI: Detailed design.

                                           Lærdal Tunnel, Norway
Copenhagen Airport Railway                 Description: A 24.5 km long road tunnel
Station, Denmark                           - the world’s longest. The tunnel is
                                           bi-directional and is provided with 15
Description: The Copenhagen Airport
                                           turning points and 48 breakdown lay-
Railway Station comprises a 600 m
railway station for a double-tracked
railway. The consulting services are       Completed: 2000
performed in a joint venture with COWI     Client: Norwegian Road Directorate
as lead partner.
                                           Services by COWI: Detailed design of
Completed: 1999                            electrical installations (electrical power
Client: Øresund A/S                        systems, control systems and emergency
                                           phone system and electrical design of the
Services by COWI: Detailed design,
                                           tunnel ventilation system).
construction management and site

Copenhagen Airport and
Sydhavnsgadetunnel, Denmark                Nam Wan Tunnel for Route 9 -
                                           Hong Kong
Description: 600 m long cut & cover
station and app. 4 km cut & cover          Description: The Nam Wan tunnel is a
tunnels in total on the Øresund Link       1.25 km long 3-lane highway tunnel.
railway line between Copenhagen Central    It has two separate tubes, 12 cross
Station and Copenhagen Airport.            passages, and a portal building at each
Completed: 2001
                                           Expected completion: 2007
Client: Øresund A/S
                                           Client: Ove Arup & Partners Hong Kong
Services by COWI: For various parts of
the works: Tender documents, detailed
design, design check, construction         Services by COWI: Basic design of
management, technical support and site     electrical and mechanical systems as well
supervision.                               as review of client’s detailed design.

                                                                                                                                                                                                                Photo: Ørestadsselskabet / Ole Ziegler

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