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By P Christen

The Ernest Henry Copper gold mine situated in North West Queensland, Australia, is owned and operated by Xstrata Copper. Currently the open pit produces 11 Mtpa of ore. With open pit mining ceasing in mid 2011 development has begun on an underground sublevel cave mine to extend the life of the operation by another 12 years. When completed the open pit will be 530 m deep and 1.5 km in diameter. The orebody dips at approximately 45° and has been outlined a further 450 m below the base of the pit. This provides some challenges for the Ernest Henry underground mine which is designed to initially truck development and production ore from the end of the pit until a hoisting shaft is commissioned in 2013. Production will then increase to 5.0 Mtpa on its way to an ultimate rate of 6.0 Mtpa in 2016.This paper will focus on the capital development and infrastructure requirements for the underground mine. Areas covered include mine accesses, ore handling system, accommodations for the dip of the orebody, primary ventilation design, dewatering systems and selection of an underground workshop over surface only maintenance.Discussions include the complications arising due to the mine being located directly below a large open pit and the combination of first principle cost analysis and risk assessment which has been used to safely optimise the feasibility study designs.

Mar 21, 2011

By P Marlow

Raiseboring is an attractive method of constructing shafts, being safe, fast and comparatively cheap. But this means back-reaming through weathered ground. However in the gravels and weathered near-surface rocks typical of the Western Australian goldfields, back reaming large diameter shafts through to the surface is risky and conventional sinking from surface has normally been required.An alternative construction approach has recently been used to stabilise the weak surficial materials and allow raiseboring through to the surface. The method is based on first installing rings of non-contiguous reinforced bored piles around the shaft perimeter, for temporary support, then back reaming shafts at full diameter through to the surface. Immediately after the reaming head is removed, the weak exposed materials are supported using remotely sprayed fibrecrete.The method has been successfully applied to four shafts since July 2007; 3 m and 4 m diameter shafts at Trident Mine, a 3 m diameter shaft at Wattle Dam and a 4.5 m diameter shaft at Athena Mine.Bored pile layout designs have varied from eight to 24 piles, of diameters 120 to 270 mm, in one or two rings. In one case, the top 10 m of the proposed shaft was pregrouted. Subsequent surveys have confirmed that fallout occurred in some shafts, out to the ring of piles, implying that the piles inhibited collapse.The practical implementation of the method was not always easy and many valuable lessons have been learnt. This paper documents key aspects of the method and the critical elements for its application.

Mar 21, 2011

By W A. Peck

Raise boring is the preferred option for constructing ventilation shafts in Australia. The trend has been towards larger diameters and longer single-pass shafts, and if at all possible, reaming through to the surface. The risk of raise failures, due to missed, unforseen or latent ground conditions has therefore been increasing, along with the need for better, more confident stability assessments.While the stability of specific weak zones and structures must be assessed individually, empirical rock mass classification schemes have been successfully used for about the last 20 years to assess general raise stability; eg the McCracken and Stacey method (M&S).Unfortunately M&S, as originally documented in McCracken and Stacey (1989), did not include a database of raise diameter and rock mass conditions versus actual performance. Nor was there a procedure for assessing the risk of failure due to adverse ground conditions. Peck and Lee (2008) published an Australian database of raise bore performance. Raise diameter and ground conditions, in terms of a lower bound Qr value, were presented for 50 cases versus raise performance. This paper updates the 2008 raise performance plot with more and SRF-corrected data. McCracken and Stacey (1989) had previously recommended that additional geotechnical data should be acquired and analysed when the proposed raise plotted on the unstable side of raisebore stability ratio (RSR) = 1.3, but the Australian data used in this study also suggests that all sites with Qr Contributions and sensitivities of various rock mass parameters (RQD, Jn, Ja, Jr, Jw, SRF, time-dependent weathering/deterioration) to raise stability and risk of failure are discussed. Numerous case studies are used to illustrate issues with stability assessments.As raises can now be remotely supported using sprayed fibrecrete, questions of time-dependency are also discussed. In recent times, contiguous piles, ‘mini-piles’ and grouting have also been successfully used to presupport or otherwise improve the stability of near-surface sections of weathered, or poor quality rock masses.

Mar 21, 2011

By J Ross

The foundation of effective leadership is communication. You can have all the leadership theories, models and training you want, but in the end it is all about leaders talking to, listening to and understanding the point of view of those below and above them.The foundation of effective safety is peoples’ behaviours. Every incident, every near miss and every safe act comes down to what one person does and how that affects themselves and others. We tend to focus these behavioural considerations on the people at the ‘coal face’, those most in harm’s way. But it is the individual behaviours of everyone in the organisation, particularly those at the top, which are just as (if not more) important. The foundation of effective safety leadership in the mining industry is that it starts at the top, with the individual behaviours of leaders. The behaviours of each and every leader will be reflected in their teams. And where their teams are made up of leaders, these leaders will pass these behaviours on to their teams and so on. It’s the sum total of what people see their leaders do and what they do as a result, that creates the ‘culture’ of the business – and it’s this culture that makes or breaks how safely people work.

Mar 21, 2011

By S Mitchell

Jetcrete Australia Pty Ltd, shotcrete contractor took the initiative in 2008 to discontinue the use of ‘road registerable’ concrete trucks for all underground works in Australia and internationally.The rationale for this decision was basic, safety. Historically these vehicles have been and still are involved in far too many accidents; this obvious trend needs to be addressed by engineering out the root cause of the problem which in this case is suitability for purpose.Road registerable concrete trucks have been widely used for the delivery of concrete in Australian mines for many years prior to and after the inception of wet shotcrete as ‘in cycle’ ground support in underground excavations around 1992. With this inception came a wide interest in the shotcrete process and an influx of new shotcrete contractors, all using road registerable concrete trucks to deliver the large volumes of Shotcrete required for these services and in turn largely increasing the use of these vehicles underground. The road registerable concrete trucks were difficult to control and each trip underground required the operators to maintain good management of the inherent risks. We virtually had no reasonable alternative for the industry and could only encourage the operators to drive with soft controls such as, reducing overall speed to a maximum of 15 km per hour when declining, regardless of the road conditions, coming to a complete halt prior to turning into any sharp corners, remaining in the same gear both inclining and declining.

Mar 21, 2011

By D Beck

Open access to forecasts of mine geotechnical performance in the form of open databases of model results has been considered risky in the past, with a concern that the results will not be understood or will be misused. However, some modelling techniques allow very high similitude modelling of mine deformation and the results can be presented as deformation, damage and other parameters which are unambiguous and which all engineers can be more easily trained to understand. With some effort, sufficient reliability and quantifications of error are possible to overcome many of the issues.Allowing more members of the planning team to have direct access to forecasts of mine deformation will promote awareness of geotechnical issues and will act as a mechanism for improving mine designs. The models will also be more easily integrated into quality assurance programs, by providing a framework for understanding measurement results.The sufficiency requirements for undertaking simulation aided mining engineering will be presented, included some conclusions about requirements for training, quality standards and software development.

Mar 21, 2011

By Y Potvin

Underground mines in Australia are progressively operating at greater depth, sometimes in conditions where mine induced stresses are very high. In such conditions, the seismic activity often becomes intense and violent and in response, mines must develop and implement a sound rock burst risk management strategy to continue operating safely.This paper discusses the latest techniques successfully used in Australian mines to mitigate the risk of rock bursts. In particular, the paper describes how the analysis of data collected from seismic monitoring systems can provide an understanding of the seismicity and be used for quantifying seismic hazards in the mine. Once an adequate understanding and assessment of seismic hazard has been achieved, the associated risk can be mitigated using different layers of protection.Strategically, modifying the mining method, the extraction sequence and/or the mining layout can alleviate the seismic hazard, but these solutions generally cannot be implemented rapidly. In the short-term, seismic risk can be mitigated tactically using an energy absorbing support system or to remove personnel from being exposed to rock burst damage by implementing exclusion zones.

Mar 21, 2011

By D Laurence

Mining cycles have come and gone and with them there have been dramatic swings in the levels of interest and student entry into minerals-related education programs, hence graduate supply to the industry. So what is the problem? These trends will keep happening and the industry will keep on keeping on – or will it?This paper discusses recent trends in Australian minerals education programs and some international examples, together with some of the more recent initiatives taken by both the minerals education sector and the industry, such as the Minerals Tertiary Education Council (MTEC) and MEA. The real problem is that things will not just keep going the way they have over recent decades – there will come a time when there is no longer a supply of minerals academics available to provide the educational programs; and universities will simply shut down subcritical mass mining programs and invest in the much more lucrative programs such as commerce, law, medicine, etc. By the time this starts to happen it will be at least ten years too late for any last-minute reactive response by industry, if they were to try and avert such a consequence. International experience with mining programs bears out this scenario quite clearly.It is therefore timely for industry individual mines and mine management to take a much more strategic look at their role in the education sector. Sustainable mining also means sustainable minerals education – without one, the other will not function over the long-term. There is a pressing need for long-term strategic buy-in by industry into the education sector – not just for the good times, but also through the tough times. This means much more than a scholarship here or there, but includes such commitments as major industry-university research partnerships; collaborative recruitment initiatives and much more. The paper will discuss a range of such issues, problems and opportunities to address these important issues through strategic, comprehensive, long-term commitments by industry and equally significant and appropriate responses by the education sector. We care – do you?

Mar 21, 2011

By A Reschke

The Thiess John Holland Group is undertaking the design and construction of Brisbane’s Airport Link Project, the largest single investment in transportation infrastructure in Australian history. Twin Herrenknecht TBMs are being used to bore parallel road tunnels from Kalinga Part in Toombul through to Lutwyche, a distance of 2.45 km. At 12.48 m, these tunnel boring machines (TBM) are the largest diameter machines, outside of Japan, to incorporate annular two-component type grouting through the tailskins.Grout design, preparation and injection have been given particular attention in this project in order to push the boundaries of achievement. Laboratory testing was conducted on various mix designs to ensure the contract specifi cations for grout strength could be met. To study the mechanics of the grout injection process, Herrenknecht supplied a test rig which duplicates the grout injection systems on the TBMs. Multiple recipes were tested, carefully selected to balance the requirements of rapid strength development with high mobility (to completely fill the void between the segmental lining and the ground) and minimal bleed.Team Mixing Technologies, Canada, was selected as the grout plant provider based on the technical performance of their high shear colloidal mill mixers. Field results have shown that the colloidal mixer prepared grout gives almost double the strength of an identical grout prepared by a paddle mixer.

Mar 8, 2011

By H Asche

The Melbourne Metro project has evolved from the Victorian Transport Plan. MM1 is the second major phase of the proposed separation of Melbourne’s radial railway system, creating a line that will operate independently across the metropolitan region. The central section will run beneath the inner suburbs and the central city. The initial project comprises nearly 8 km of twin bore tunnels, three cavern stations and two cut and cover stations, as well as a dive structure and connections with the existing rail system. This paper describes the development of the geological model, a modification of the rock mass classification system derived during the EastLink project and the influence of the geology on the design of the tunnels and stations for the Department of Transport’s business case.The majority of the tunnelling will be in the siltstone and sandstone bedrock. This material has been extensively folded, sheared and intersected by igneous intrusions. A revised rock mass classification system has been developed for the Melbourne Formation to assist in identifying the important engineering properties of the rock and to rationalise the support types required.The Metro’s tunnel alignment crosses the Yarra Delta deposits in the lower reaches of the Moonee Ponds Creek and again at the Yarra itself near Princes Bridge. These deposits vary in extent and thickness over very short distances. The investigation of these materials has been carried out using conventional drilling techniques in conjunction with sonic drilling methods.Over the central section of the Metro, the positions of the new station are determined largely by transport planning requirements and urban development opportunities. However, the stations, and the tunnels, have been the subject of studies, optimising exercises, and selection processes to arrive at the concept design. This paper describes the influence of the varied geology on the development of the design, and the identification and management of the risks in tunnelling under the centre of Melbourne.

Mar 8, 2011

By E Claridge

There are a number of major infrastructure tunnelling projects currently underway or proposed in New Zealand, including construction of new road and rail facilities and the refurbishment of existing road tunnels. These new projects have triggered a rethink of traditional practices in underground fire and life safety and local regulation.While there is a current surge in activity, tunnels have been a signifi cant part of New Zealand’s transport infrastructure for over a century. Despite this background, the new projects commonly face challenges that are symptoms of a national regulatory environment that has aspects that are inappropriate for underground environments. There are inconsistencies in local regional regulation and an absence of national guidance and standards relating to tunnel design. Historically, New Zealand has looked across the Tasman for guidance. Although recent overseas tunnel designs present learning opportunities, the adoption of international best practice and standards may not necessarily address local expectations or needs.This paper explores a number of specific matters affecting the design of road and rail tunnels in the New Zealand context, namely; the Building Regulations and associated local consenting processes and parties, and the responsibilities and needs of the New Zealand Fire Service.The discussion highlights the importance of a collaborative approach involving the designer, asset owner, regulators, emergency services, and other parties, and ensuring up-front clarity in design responsibility and ownership of residual risk.

Mar 8, 2011

By M Habte

This paper presents a simplified method for the assessment of creep deformations in rock masses containing bands of low strength or soil strength rock. The main impetus for this work was the need to assess the impact of distinct bands of clay and/or low strength rock on the long term deformation behaviour of a rock pillar formed as part of a series of proposed tunnelling works. In particular, the authors were interested in being able to provide criterion which could be used by site personnel to assess the encountered rock conditions against design assumptions.Creep deformation versus time plots are presented for a range of material consistencies. These plots were produced using the hyperbolic creep equation proposed by Mesri et al (1981). This empirically based equation was chosen for its simplicity and practicality. Discussion is included regarding typical input parameter values and the sensitivity of the results to these values is explored. Finally, in the soil strength materials, the secondary consolidation equation is used to check the veracity of the results calculated using the hyperbolic creep equation.

Mar 8, 2011

By J Karlovšek

Civil engineering infrastructures are often subjected to different types of natural and mechanical activities. These influences may result in serviceability or even in stability of structures due to material deformations, increased water content within the materials used or the formation of internal or adjacent cavities that may threaten the infrastructure. Construction practices can lead to development of such defects in the form of cavities. In civil engineering it is crucial to detect these variations in material properties and to detect the presence of defects. However, as they are often hidden from view, these attributes may be difficult or impossible to target with traditional testing methods. For these reasons rapid geophysical methods, such as ground penetrating radar (GPR), are increasingly being used. At the University of Queensland (UQ) GPR is used for detection of voids and cavities which have been caused by an over excavation of the earth pressure balance machine (EPB) operating in a closed mode.A variety of numerical simulations using the finite-difference time-domain (FDTD) methods and preliminary experiments have been carried out in order to specify information about the nature, type, size, location and other characteristics of targets to be detected by GPR. In doing this the difficulty of interpreting GPR data, which is mainly due to the complexity of the factors involved in multiple possible solutions of the observed features, can be overcome.

Mar 8, 2011

By P Ridley

EnergyAustralia’s Sydney Central Business District (CBD) cable tunnel network will form a loop 6.2 km in length. The 3.2 km long, 3.5 m, diameter city east cable tunnel (CECT) currently in design, will complete the loop in 2014. This paper discusses the ventilation design of the CECT, considering operation for four functions:1. normal (unmanned),2. access (manned),3. purge, and4. emergency fire modes.The dominant design criterion which determines the required ventilation capacity for CECT is the specification of an upper air temperature limits of 35°C (dry bulb) and 24°C (wet bulb) for manned access, during all ambient weather conditions and cable heating loads. Simplistic static heat transfer analyses do not yield a sufficiently accurate calculation of tunnel air temperature and humidity to provide a safe and yet economical design. The primary refinement in the analysis discussed in this paper is associated with modelling of the system’s dynamic behaviour.Our means of analysis is through a thermo-fluid-dynamic simulation of the interactions between the diurnally and seasonally varying loads (cable heat generation, ambient air conditions and groundwater inflow), tunnel airflow and the resulting tunnel air temperature and humidity. These simulations are validated using experimental data from the existing city south and city west cable tunnels.Fire life safety scenarios are also analysed and discussed in association with the ventilation design. Ventilation strategies are developed for dealing with such emergency fire situations.The understanding and insight provided by the work offers the ability to optimise ventilation plant provisions in future cable tunnels, particularly long and high energy density tunnels.

Mar 8, 2011

By I Lamb

Past experience of ground settlement and groundwater monitoring for tunnelling projects in Melbourne has provided an appreciation of the value and importance to owners of establishing a broad baseline monitoring program of the ground surface movements and groundwater movements well in advance of the commencement of any excavation and tunnelling activities. For the Northern Sewerage Project (NSP) tunnels in the northern suburbs of Melbourne, a baseline monitoring network of ground settlement points and groundwater wells was established in early 2006, 18 months prior to the commencement of project construction, and has continued throughout the tunnelling and project construction activities. This baseline monitoring network provides insights into the superposition and interpretation of both tunnelling and non-tunnelling effects, such as seasonal effects, which result in ground settlement.In the case of the NSP the baseline monitoring and construction phase excavations coincided with several years of drought. The reduced rainfall developed overall downward settlement trends project wide that could easily be mistaken at the local site level to be construction effects if the baseline monitoring was not available to show otherwise. There are lessons to be learned from the NSP experience for tunnel projects where there are variable surface soil types and where project-specific settlement criteria are to be established for the protection of property prior to construction.This paper presents examples of the baseline monitoring, how the tunnelling-specific settlement was identified and determined, and what this means in terms of how settlement criteria should be established and set for project consenting and in the construction contract documents.

Mar 8, 2011

By M Hawkins

The Clem Jones Tunnel (formally known as the North-South Bypass Tunnel), a A$2.88 billion road tunnel project in Brisbane, Queensland, was successfully completed almost seven months ahead of schedule. The project included two parallel 4.7 km long road tunnels, 740 m of intermediate roadway access ramps and two auxiliary ventilation tunnels. The tunnels incorporate intelligent tunnel systems, best practice fire and life safety standards and typical civil tunnel elements.Over the duration of the project the Parsons Brinckerhoff (PB) and AECOM (formally Maunsell) design joint venture (MPB) were Lead Designers to the Leighton Contractors and Baulderstone Bilfinger Berger Joint Venture (LBBJV). Construction of the toll road commenced in September 2006 and was completed in March 2010, with the tunnel opening then. Contributing to the success of this project was the continued support the lead designers gave throughout the construction period.This paper will focus on some of the structural elements that contributed to the success of the project – in particular the cable tunnel structure, a small precast, culvert shaped element under the pavement of the mainline tunnel, and the fit-out of the Gibbon Street shaft which were designed to be constructed in a combination of precast and in situ concrete.The cable tunnel was incorporated early in the design phase and runs the length of much of the tunnel. This paper will outline the challenges faced by the designers with implementing this system which provided significant construction advantages, among which were being able to install a separate ventilation duct during construction and to start fitting out the mechanical and electrical conduits and drainage system while tunnelling was still underway.The Gibbon Street shaft had a length and width of 20 m by 40 m and an overall depth of 38 m. A 20 m high structure of precast and in situ concrete was constructed in the base to accommodate mechanical and electrical equipment and provide a take-off access for the southern ventilation tunnel. The construction purpose for this structure was to provide a junction between the tunnel boring machine (TBM) and the roadheader-style tunnels, a staging platform for commencing the roadheader tunnelling, and a platform where the TBMs could be dismantled and removed.The design was assessed and reviewed many times throughout the construction process to address the needs of each of these stages. Innovative use of precast concrete was used to minimise construction time.Additionally, the designers provided support to the construction team from the time of design completion through to the tunnel opening. This meant that the changes to the design and adjustment of construction loadings could also be assessed. The fi nal outcome resulted in an efficient construction sequence and a project that has provided an excellent outcome for the client, stakeholders and community.

Mar 8, 2011

By J Q. Cooper

The New Zealand rail authority, Kiwi Rail and Auckland Regional Transport Authority (ARTA), are jointly planning a new mainline rail link between Auckland’s downtown Britomart Station and the existing Western Line at Mt Eden. In 2009, APB&B, a consortia of Aecom, Beca, Parsons Brinkerhoff and Hassell Architects where commissioned to develop the conceptual design, Assessment of Environmental Effects (AEE) and business case for the new 3 km rail line towards preparing a Notice of Requirement to protect the route through Auckland’s central business district.This paper describes the engineering challenges in the development of the conceptual design for the three proposed underground stations, the running tunnels and connections to the existing network. Feasible alignment and station location options were developed and evaluated using multi-criteria analysis based on key client functional requirements, constraint mapping and environmental impacts. The resulting preferred scheme was then developed to a conceptual design suffi cient for assessment of environmental effects, risks, and the development of a robust construction methodology to allow high level capital cost estimates.The paper describes some of the major challenges overcome to develop the concept, including steep gradients, narrow street envelopes with existing buildings and structures, the need for large platform spaces with low ECBF rock cover and complex connections at Britomart and the main line near Mt Eden.The development of the conceptual design of the underground stations in particular demonstrates the need for a holistic value engineering approach to satisfying the architectural and functional requirements, in a highly constrained dense urban environment and at lowest practical cost. The construction methodology was a key input to the conceptual design development throughout.The conceptual design will be used as the fundamental basis for the development of the AEE and business case for the project in the future.

Mar 8, 2011

By R Shelton

The Big Wainihinihi River and tunnel are located on the western side of the Southern Alps of New Zealand within the active Alpine Fault zone, which marks the boundary between the Pacific and Australian Tectonic Plates. The tunnel was built over 100 years ago to supply water for gold mining, but it now conveys water from a high-energy intake to a canal that supplies three of TrustPower’s hydro-electric power stations with a combined installed generating capacity of 10 MW. Part of the tunnel passes through an unstable 50° schist slope, which fi rst suffered a wedge failure in the 1929 Arthur’s Pass Earthquake and was reinstated in the mid-1970s for hydro generation. In 2008, TrustPower’s monitoring system showed that the wedge failure had remobilised and that urgent remediation was required.Harker Underground Construction (Harker) was awarded a design-build contract to restore the tunnel to service by tunnelling a new central section. Their geotechnical engineers, Peters and Cheung, reviewed the tunnel’s stability and proposed a new, safer tunnel alignment, deep behind the failure wedges. This work was based on their failure model, cost-benefit studies, and engineering geology completion mapping at the time of re-opening.Construction innovation was an important factor in ensuring the project’s success, as were detailed geological and geotechnical information, a robust methodology, strong client relationship and planning. To suit the varying rock conditions and restricted space, Harker combined a traditional drill-and-blast method with light-weight modular steel sets and timber supports to reduce construction costs and mitigate support risk. To make material handing easier in the tight conditions, a special electric locomotive was designed and built and blasting confi gurations were adapted to suit varying rock conditions in the highly fractured schist.The isolated site meant interesting and unexpected challenges, particularly communications and resources (both human and material). Despite that, the project was completed within budget, on schedule, and with no lost-time injuries.

Mar 8, 2011

By D FitzGerald

A critical component of any new tunnel design in a complex geological setting is the development of an integrated three-dimensional (3D) geology model with a full set of geotechnical properties of the rocks present. A novel means of predicting the geology based upon sparse observations of structural geology at the surface and from drill holes has been developed and used in several major tunnel studies in Europe.An example of this is the Lyons-Turin twin rail tunnel which is still in a development phase. This tunnel has been in planning and development for over 15 years already. An important aspect of this work is to characterise geological uncertainty along various possible tunnel paths as an input into early design optimisations for time, cost and risk avoidance strategies. Once the tunnel works commence and more detailed geological data is collected by daily mapping, progressive refi nement of the geological model is desirable; geological conditions still to be encountered can be more accurately predicted. Faults and their offsets, dykes, geological unconformities, folding, as well as standard sedimentary processes are all correctly modelled in the software. It is important to allow for seamless interchange of geological models at various scales with CAD workflows so that sufficient detail can be readily accessed at the required scale. Also, the proposed tunnel in its correct geometry can become a ‘section’ in its own right. Progressive detailed local geology models in the vicinity of the advancing head are created from the regional scale work by cutting and pasting a starting model, then adding all the extra detail for the required engineering geology work.For all rocks, most standard geotechnical quantities such as sonic velocities, Young’s modulus and Poisson’s ratio are handled. These and any other phenomena from borehole observations can have variograms calculated and stratigraphically constrained estimations made in a least biased geostatistical manner, in advance of the tunnel. RQD, or a prediction of rock fractures, is handled by the faulting and folding modelling facilities. This is probably the more interesting issue to pursue, as the fractal nature from small scale fractures and joints, to large-scale faults, can now be characterised more convincingly.

Mar 8, 2011

By J Palise

As cities become more populated and the need for tunnelling increases, we continue to dig deeper urban tunnels in more challenging ground conditions. At the same time our expectations for durability and long-term performance are increasing.It has become increasingly apparent in recent years that repairing water leaks in tunnels can be very costly and unplanned infiltration can cause undesirable outcomes for long-term maintenance costs, structural durability and environmental impacts. For this reason, tunnel constructors are investing more time and effort upfront into drainage and waterproofing systems.Tunnel membrane systems are becoming accepted as a necessary part of tunnel construction, however the knowledge surrounding selection of appropriate systems, design detailing and installation methods has not increased at the same rate. Currently Australia relies heavily on International Standards from Europe and the United States with no immediate program in place to establish our own locally relevant industry standards.This paper gives an overview of where the industry in Australasia is heading in terms of adopting relevant standards. Current basic waterproof detailing options for drained and undrained tunnels with success and failure of various methods are also addressed. Finally we look at the Brisbane Airport Link as a case study for how tunnel waterproofing contract methods, design and installation issues are being addressed in context with recent projects including the Epping to Chatswood Rail Link in Sydney, Auckland Northern Gateway Tunnel, Eastlink Tunnel in Melbourne and Sydney City West Cable Tunnel.This paper’s primary objective is to propose guidelines for how tunnel waterproofing could be implemented on large infrastructure projects in the future and to map a path for preparing and introducing a ready to use document for selecting appropriate tunnel membrane and drainage systems whilst implementing detailing methods which are appropriate for local conditions.

Mar 8, 2011