Hands on experience to assist legal hearings

Dec 2012

Article references: Expert witnesses and forensic consultants - TunnelTalk, Dec 2012

Dear TunnelTalk,

I believe hands on experience alongside academic expertise are invaluable when seeking help with arbitrations to assist the legal team to put forward a fully rounded case.

Regards,
Ray Naughton, TBM Operator at Crossrail

'Imminent' and 'eminent' dangers

Dec 2012

Article references: Tunnel ceiling collapse kills in Japan - TunnelTalk, Dec 2012

Dear TunnelTalk,

Apparently, in addition to failing bolts, some of them were missing. This is a perfect example of failure resulting from failing to consider 'imminent' and 'eminent' dangers.

Regards,
Peter J. Tarkoy, Geotechnical and Underground Construction Consultant

From the Editor: An article to expand on this topic is to be published on TunnelTalk.

Being short-changed by 'local practice'

Oct 2012

Article references:
Rekindled NATM debate - SCL debate opens - TunnelTalk, Aug 2012
Defining NMT as part of the NATM SCL debate - TunnelTalk, Sept 2012

Dear TunnelTalk,

It seems that the opinion of the unnamed UK correspondent (see below) that: 'local practice should decide' on the method of tunnelling selected and applied to any project is 'sticking' as if recommended.

Is this the best we have? I do not think so. If this were so then some good aspects of NATM or NMT or hybrids of both as appropriate to conditions, would be lost and time and cost would suffer in relation to the 'local practice'.

Regards,
Nick Barton, International Consultant, Rock Engineering, Norway

Adding to NATM, SCL, NMT definitions

Sep 2012

Article references:
Rekindled NATM debate - SCL debate opens - TunnelTalk, Aug 2012
Defining NMT as part of the NATM SCL debate - TunnelTalk, Sept 2012

Dear TunnelTalk,

This may be a very naive view but I find the debate about the difference between SCL and NATM very confusing.

I have always thought that the term SCL (Sprayed Concrete Lining) simply refers to the use of sprayed concrete to form a tunnel lining. There are of course numerous philosophies and design methods surrounding this technique but to me the term SCL is simply a term for a specific construction method.

As for NATM, the way I have viewed that is the use of convergence confinement principles applied to a deep tunnel with the use of Sprayed Concrete Lining to enable the installation of a tunnel lining at the appropriate level of convergence. With a definition like this it becomes obvious why NATM is not applied to typical tunnelling in the UK (or at least urban tunnelling in the UK).

Firstly one of the primary aims for urban tunnelling is to avoid excessive ground movements and this approach is fundamentally different to NATM where ground movement, up to a certain point, is actively encouraged to develop arching in the ground around the excavation.

The depth of a typical NATM tunnel is also important because with large depths significant arching can be developed. For shallower tunnels the lack of overburden can inhibit the amount of arching of vertical loads that can occur.

There are also issues related to ground behaviour; the magnitude of loads applied to the lining; and the required structural thickness of the lining that also prohibit a typical urban UK SCL tunnel being designed to pure NATM principals.

Regarding the difference in philosophy between the Norwegian Method and NATM, I see these as just differences in philosophies. Local practise often dictates what is considered to be a good, safe, efficient, tunnel and what is considered poor construction practice. In different parts of the world, with different geologies, different histories, different construction constraints and different operational constraints, it is inevitable that different local construction practice applies. This seems to be particularly the case in rock engineering where you can find large differences in support in different regions. All too often one method is not necessarily better than any other. It is just different.

Maybe in one region a thick shotcrete arch is a preferred solution, despite the fact that it is stiff and can attract extra loads. Elsewhere, for a similar tunnel, heavy bolting and a thin shotcrete shell might be the preferred solution for just as valid reasons. It is the skill in selecting from a suit of different design philosophies and tools to suit local geology, local construction practice and local constraints that separate an adequate design from a good design. No one philosophy is necessarily the right one for all tunnels.

UK contributor, name withheld by request

NMT added to the NATM-SCL-SEM debate

Sep 2012

Article reference: Rekindled NATM debate - SCL debate opens - TunnelTalk, Aug 2012

Dear TunnelTalk,

Congratulations on a masterful summing-up and reminder of earlier NATM contributions to UK tunnelling. It is nice to know that good quality shotcrete as 'single-shell' has now found its way into English tunnelling (Hindhead, Crossrail etc).

Although the authors of three articles in T&T recently, who stimulated the TunnelTalk moderating comments, made reference to 'the Norwegians' and we could throw NMT into the pool of names, as this is a reflection of what has been going on in Norway/Sweden/Finland for many decades, first B+S(mr), then, after about the 1978-1983 transition, B+S(fr).

NMT principles (single-shell) are not just applied in the granitic gneisses of the Fennoscandian bedrock, as many assume. There were, in fact, 50 rock types in just 212 cases in the 1974 Q-system development. Application of S(fr) in over consolidated London Clay via the Q-system logic was suggested in 1994. See pdf download: Updating the NATM

Regards,
Nick Barton, International Consultant, Rock Engineering, Norway

NATM-SCL-SEM definitions and debate

Sep 2012

Article reference: Rekindled NATM debate - SCL debate opens - TunnelTalk, Aug 2012

Dear TunnelTalk,

I read with interest your supplement to David Hindle's article on NATM-SCL-SEM.

While I sympathise with the general thrust of some of Dave's comments, especially the desire to avoid over-conservatism, many of his detailed points are misguided.

For example, a lining sprayed in four passes - well, what happens in a traditional shotcrete supported lining? An initial sealing layer, a first layer of mesh, the main shotcrete pass, a second layer of mesh, a final shotcrete pass and then the secondary or final shotcrete or in-situ concrete lining inside. Is not that four passes? Except of course, because bars and lattice girders are used, a client like LUL would not accept the primary shotcrete passes as part of the permanent works. That itself is a point Dave has completely missed in his critique. The drive to use fibres in a (largely) unreinforced lining is partly to assuage the concerns of clients who doubt the durability of a bar reinforced primary lining.

There are numerous points in Dave's comments on the Crossrail design which are inaccurate and, had he known or spent the time to find out the constraints, he would understand why it is how it looks. I daresay that it could be improved and I believe some in the Crossrail SCL design team have sent a detailed response to the original article published in T&T, elaborating on the misguided nature of the comments.

Perhaps I misunderstood the thrust of the TunnelTalk article but at one point it seemed to imply that, after Channel Tunnel, UK designers had pinned a badge to themselves as SCL experts without bothering to try to understand the method. A few people in Mott MacDonald, for example, might take issue with that suggestion, given their own contribution to the Channel Tunnel's SCL design alongside ILF of Austria, their subsequent work on Roundhill (there are other contemporary SCL road tunnels too, including Pen-y-Clip) and the SCL trials at Heathrow, as well as Red Cross Way, the SCL trial tunnel for the Jubilee Line Extension of the London Underground near London Bridge, and the major investment in SCL R&D thereafter, including a series of PhDs and joint research projects, such as Brite Euram. It is worth noting that UK engineers have played a role in innovation of SCL tunnelling in recent years and in fact, in some cases, lead a path that the Austrians and others have followed.

Dave did ask for a definition and some explanation on the role of monitoring (in soft ground applications). If it helps, here is my definition:

"An SCL tunnel is a tunnel with a Sprayed Concrete Lining. The Sprayed Concrete Lining interacts with the ground and, through the choice of excavation sequence, this interaction can be optimized to minimize the loads on the ground support. Monitoring is required for 'performance verification', to ensure that the tunnel is performing within the limits required by the design (given natural variations, for example, in advance rates and ground conditions), to determine when certain contingency measures are needed (such as temporary inverts)."

Regards,
Alun Thomas, BA PhD CEng MICE,
Author, Sprayed Concrete Lined Tunnels
Tunnels Head of Department, Ramboll, Denmark

Sprayed Concrete Lined Tunnels - TunnelTalk, Books & Reports

Personal friends and character appreciations

Sep 2012

Article reference: Rekindled NATM debate - SCL debate opens - TunnelTalk, Aug 2012

Dear TunnelTalk,

I think that you have done Dave an injustice.
"For those who know Dave Hindle personally", you missed out a cantankerous Lancastrian who does not wear fools gladly.

Regards,
Phil Richardson, Natural Cement Distribution Ltd, UK
Personal friend and colleague

High speed, early strength shotcretes

June 2012

We at Natural Cement Distribution in the UK have been producing fast setting, fast curing, high early strength, waterproof shotcretes since 1996 that will out-preform the product described in the article War on terror heralds shotcrete breakthrough. We have shotcretes that are not a mixture of many additives, will not poison future generations, and are better for the environment than the product describe. May I suggest that you look at Shotcrete 513 in the Shotcrete section of our website to know more.

Regards,
Phil Richardson, Natural Cement Distribution Ltd, UK

War on terror heralds shotcrete breakthrough - TunnelTalk, June 2012

Fatal ring-build accident at Lake Mead

June 2012

Detail is not provided but from the read it seems the thrust ring was retracted to be ready for the next set. If so, the TBM was not moving forward so the tapered segment would not have been pulled.

Might the taper have been the source of the movement? The exterior pressures were reported to be quite high. The resulting squeeze might have been sufficient (depending on joint friction) to cause the movement. Sort of like squeezing a watermelon seed in your fingers.

Carl Linden, P.E., Senior Construction Manager, URS Corporation (Los Angeles office)

Fatal ring-build accident at Lake Mead - TunnelTalk, June 2012

Sochi winning on the Olympics alpine route

February 2012

Further to the story:
Two of the TBMs used on the project are in fact refurbished Robbins TBMs. The 10m double-shield machine that excavated the 4,564m rail tunnel for the Tunnel System 3 started its working life as a new Robbins machine as did the 6.2m TBM used for the3,197m System 3 service tunnel. Once refurbished and delivered to the project by Lovat-SELI, Robbins was contracted to supply service and technical support in the mobilization, operation and maintenance of the equipment. This included the supply of critical spare parts for continual TBM operation.

Sochi winning on the Olympics alpine route - TunnelTalk, Feb 2012

Tunnel death leads to $55,000 fine

October 2011

In reading this item the level of fine seems relatively low considering the loss of life, which is tragic under any circumstances. One wonders if the contractor knew fine levels were low and therefore permitted a superficial culture on safety and operation to exist.

Charles W. Egerton

Tunnel death leads to $55,000 fine - TunnelTalk, Oct 2011

Allowable volume loss calculations

September 2010

In reference to maximum allowable volume losses as discussed in the Crossrail settlement control measures article.

When I worked in the UK I always wondered how to get along with the historical progression of allowable volume losses. According to the British Standard some companies told me that they do some calculations about volume losses in every phase of design, let's say C then D, E, and by F, and for most design-build criteria as well, they go from 3.5% to 2.5% then 2% and arrive later at 1.5% or 1% in Stage F. Good practice would be to use the same allowable volume loss criteria during all stages of design and invoice the client accordingly. Instead of using the actual allowable volume loss from the beginning, the actual rate they will use for the final design turns up in stage F. In this way the design hangs on a rate that for some tunnel shapes will not be accepted in design stage C because the maximum allowable volume loss is too high! If they would use the actual 1% rate from the start it would be fine.

Further this calculation is very conservative for the actual volume of the tunnel shape x percentage of the actual progress, or let us say the indicator time. How long will the excavation and support go on? Also, the method of excavation, whether by TBM or NATM (SCL), is not indicated in this calculation. So it is just a total guess and will never reach true accuracy.

Tunnelling in London has been going on since Brunel's Thames Tunnel in 1825 and it is only now, in the last few years, that there is a real start to calculate this issue. By now we should be able to know what is feasible or what is not doable. With regard to applying the reduced assumption of 1% face loss on Crossrail, has someone just woken up and started thinking about this? Let us hope for better news from the island.

Robert

Crossrail geotechnical series - 3 - Settlement control measures - TunnelTalk, Aug 2010

Dublin Port Tunnel's successful DRB panel

August 2010

We have learned the composition of the DRB that facilitated settlement of outstanding claims between the owner and the design-build contractor of the Dublin Port Tunnel in Ireland. The three-member panel comprised:

Peter Chapman, Chair (UK), Brian Eggleston (UK), and Dr Terry Mellors (UK).

Contributing to the debate about the selection of a successful DRB, we can confirm that all three members of the panel are engineers, with one also a qualified barrister.

Chapman is an engineer, as well as a qualified UK Solicitor, and a past President of the DRB Foundation (2004-2006). He is a well-respected member on dispute resolution, mediation and arbitration panels.

Eggleston is an engineer and involved in dispute resolution through mediation and arbitration. He is regarded as the expert on the application of NEC3 Contracts and has written several books on the subject.

Mellors has a degree in civil engineering, an MSc in Engineering Geology and a PhD in Engineering Geology, all from Imperial College London, and has extensive experience as a design consulting engineer. He is a past Chairman of the British Tunnelling Society (BTS) (1999-2001) and was Joint-Chairman of the Working Group that produced The Joint Code of Practice for Risk Management of Tunnel Works in the UK, prepared jointly by the BTS and the Association of British Insurers as well as a primary author of the international version.

Further discussion on the topic reveals that most commentators agree that DRBs need an engineering pragmatism to succeed, and a agree concern that DRBs in both Europe and in the United States are tending towards appointing more lawyers. Another point of concern expressed was that members on DRBs in the USA are becoming partisan, adopting a position of protecting the Party that has appointed them, which is contrary to the understanding that appointees are meant to be independent and strictly non-partisan.

The debate continues.

DRB scores success in Dublin - TunnelTalk, Aug 2010
Advocating for more DRBs in Canada - TunnelTalk, Aug 2010
Dublin Port Tunnel settles claims disputes - TunnelTalk, Aug 2010
DRBs in North America - knowing and playing by the rules - TunnelTalk, Aug 2008
Enhancing the success of DRBs - TunnelTalk, Oct 2008

Safety first!

August 2010

We are grateful to Jim Hinze, Senior Safety Engineer with Cal-OSHA, who pointed out that a photo we published last week on the Caldecott fourth bore start of excavation included evidence of safety violations.

Visitors watching the launch of the roadheader at the start of the Caldecott highway tunnel fourth bore excavation in Northern California are photographed not wearing a hard hat. As Hinze said: "Down in a deep portal cut with all kinds of possible overhead hazards is no place to be without a hard hat!"

Remember guys, accidents are not selective. A hard hat is as essential as steel-toed boots, ear defenders, goggles and an acute awareness of your surroundings when visiting any job site.

We have removed the photo from the Digging begins at Caldecott article and post it here as a reminder that safety is always first.

Thanks to Jim Hinze for making the point once again.

Learning from mistakes

July 2010

Interesting report on collapses!

One could add a long list of other collapses (NATM, TBM or not), like Glendoe and Gigel Gibe II etc.

I also agree with you: one should learn from successes not mistakes. Confucius says: "Experience is like a lantern in your back. It lights only the already traveled path!"

If you look at the top sports trainers, they never tell of the mistakes you've made. Only of what you've done well and to improve on it!

Carlo Bretz
Switzerland

Discussion Forum - Symptoms of the collapse syndrome - TunnelTalk, July 2010
Rock falls shut down Glendoe power plant - TunnelTalk, Aug 2009
Glendoe rockfalls more serious than initial fears - TunnelTalk, Oct 2009
Recovery contract for failed headrace at Glendoe - TunnelTalk, Feb 2010
Collapse of headrace tunnel after grand opening - TunnelTalk, Feb 2010
Repair of limited collapse in Ethiopia - TunnelTalk, Mar 2010

Fundamental contributors to industry problems

July 2010

Big problems for the industry, in my personal opinion, are price dumping, budget cutting, assssnd time saving - and that in a field of highest safety requirements. Tunnelling industry has sometime not too much respect for its own achievements, and should not let advocates make the business. Most importantly on the negative side is talking badly about competition and badly about the industry itself.

A reader in Germany

Discussion Forum - Symptoms of the collapse syndrome - TunnelTalk, July 2010

Adding to the symptoms of the collapse syndrome

July 2010

You touch on the fact that supervision at night tends to be lessened and that the construction team is often the B team. It has been observed on many occasions that junior newly qualified engineers on the night shift are placed with an experienced team headed by a foreman or supervisor who is usually older and in theory should have more experience. Whilst many young engineers see things being done that they consider as being wrong, they cannot comment for the reason that they will be referred to as being 'wet behind the ears' and by being told that "this is the way it has to be done". Another syndrome that takes place on the night shift is that the absence of watching eyes results in the cutting of corners.

Any senior engineer on the night shift will be working alone and will have been left with a list of functions related to sorting out the back-up infrastructure and completing unfinished paper work.

There are two things that should be dispensed with:
a) Advance rate bonuses, which have the effect of making it almost inevitable that requirements in other areas will be forgotten. An example is quiet simply blocked annular grouting pipes resulting in not being able to keep grouting at the same speed as TBM advance, but carrying on with excavation regardless.
b) 12 hour shift patterns, which lead to workers, in an already stressed environment, being over tired and taking their minds off the ball. Cutting down shift times is an area that meets with considerable hostility. It is time for projects to be managed by the engineers (managers) who must face the flack of any incident, rather than finding someone lower down the chain of command to take the blame.

You also mention the failure in Cairo, in which you mention that bolts were "forgotten". Were they forgotten or did someone come to the conclusion that bolts are to be removed later, so why put them in the first place! People forget the rotational forces applied by the TBM. Cutterhead torque has to go somewhere. As Newton's Third Law that states: "For every action there is an equal and opposite reaction." I have observed personally segment joints opening up as a result of cutterhead torque. In some instances this has sheared both dowels and bolts and opening up the longitudinal segment joints.

Charles W. Egerton
North Ayrshire, UK

Discussion Forum - Symptoms of the collapse syndrome - TunnelTalk, July 2010

Learn young and from small mistakes is the key

July 2010

I think you might want to modify slightly your comments on learning from failures to include the following:

All of us should be lucky enough to start in our 20s learning from our own small failures. More is learned from bad jobs than good jobs. Perhaps as important is to pay attention to details of mistakes that "almost" or "could have" resulted in very serious consequences.

I believe that most of the serious cave ins you write about would not have occurred had a couple of the people in charge (including designers, owners, engineers, contractors, etc) had more 'failure' experiences in their 20s. Unfortunately that kind of good experience is less common now and perhaps the reason why we are seeing more of these unnecessary problems.

Thank you for writing about this topic in your editorials. It needs more knowledgeable discussion.

A reader in the USA

Discussion Forum - Symptoms of the collapse syndrome - TunnelTalk, July 2010

Filling in the list of giant TBMs

June 2010

Thanks to the readers who let us know of the missing entry on our list of mega +14m diameter TBM projects. The 14.2m diameter Herrenknecht Mixshield used to excavate the 4^th Elbe River Road Tunnel in Hamburg in 2000 is added to the list along with the two highway tunnels in Moscow that the machine went on to excavate. Also added is the 14.4m diameter Robbins open main-beam gripper machine working on the hydro scheme water diversion tunnel at Niagara in Canada.

Good to know you are paying attention.

Taking mega TBMs to greater diameters - TunnelTalk, June 2010

Natural cement contributes to waterproofing of the Hindhead project

March 2010

In reference to the spray-on waterproofing of the Hindhead tunnel, I would wish to advise of some of further information.Among several methods tried to prevent and divert areas of water ingress ahead of application of the spray-on membrane, one the most effect ways was application of a natural cement based shotcrete call Shotcrete 513. Many tonnes of this material were used to stop the water ingress and allow the application of the Masterseal. the day joints were not always water proof and that by over spraying afterwards with our Shotcrete 513 it stopped the ingress of water allowing the application of the Masterseal which cannot be applied to areas of tunnels where there is an ingress of water.

Regards,
Phil Richardson, Natural Cement Distribution Ltd, UK

TunnelTalk: While the text doesn't state the case specifically, it does address the "permeability specification of 1 x 10^-12m/s for the primary shotcrete provides a waterproofing barrier of quality itself". The natural cement based product would have contributed to achieving that quality.

Phil Richardson: The problem was that the day joints were not always waterproof and that by over spraying afterwards with our Shotcrete 513 it stopped the ingress of water allowing the application of the Masterseal.

UK applies spray-on waterproofing – TunnelTalk, March 2010

Various support products but spray-on is the waterproofing system throughout

March 2010

The natural cement product was used but as one of a number of measures that were adopted for the purpose of dealing with areas of water ingress. The project adopted a methodology of having a suite of solutions available to the construction team allowing them to respond immediately to the conditions that presented themselves. We used it to cover damp blooms or to cover strips of water channeling Delta membrane. There are a number of products used to assist in the application and performance of the Masterseal. There are no areas of the mined section of the tunnel where other products are operating instead of the Masterseal.

Roger Bridge,Tunnel Manager, Balfour Beatty,Hindhead Project

UK applies spray-on waterproofing – TunnelTalk, March 2010

Providing useful information

March 2010

Dear TunnelTalk,

In reference to the Hindhead spray-on waterproofing article, you published all the right info - very useful. All too often key productivity and other data that lets the reader estimate costs are omitted from articles. Observations of crew size, equipment, and time to perform, including work schedule, go a long way to letting readers conclude for themselves how cost effective is the process.

With thanks,
John M. Stolz, PE, Principal,
Jacobs Associates,
San Francisco, California

TunnelTalk: Thank you. Reporting information for advancing the art and science of successful tunnel and underground space excavation is the mission.

UK applies spray-on waterproofing – TunnelTalk, March 2010

NATM more cost effective than TBMs for Santiago Metro

March 2010

Last week, when reporting on the consequences of the massive 8.8 earthquake on underground structures in Santiago, Chile, we included by mistake reference to TBM driven tunnels for the Metro system. The error was pointed out to us by a reader and has since been corrected. All underground sections of the Metro de Santiago are either cut-and-cover structures in earlier times, or NATM excavations for stations and running tunnels since the mid-1990s.

Reprint of articles from our archive explores the introduction and development of the NATM concept as a highly cost effective method of metro construction in Santiago and and refers to the results of a study that confirmed the advantages of NATM over the TBM alternative for construction of metro running tunnels in the Chilean capital.

Santiago goes underground with NATM – TunnelTalk, April 2003
Optimised NATM designs for Santiago Metro – TunnelTalk, April 2003
Santiago Metro withstands massive earthquake – TunnelTalk, March 2010

Inclined TBM drives and a rival TBM decline record holder

February 2010

11m diameter drive on a 30° decline

Last week we published news of a new 8.03m diameter Aker Wirth TBM claiming to drive the world's largest inclined TBM tunnel. On order by a Swiss contractor, the TBM will drive a 4km long, 24% inclined access tunnel for a hydropower plant expansion project in Switzerland.

We have since had news from Lovat claiming a larger, steep gradient TBM drive although this time on a decline rather than an incline. An 11m diameter mixed ground machine was used to excavate a 150m long x 30° declined escalator access shaft for the Moscow Metro system in Russia. The first of many planned escalator access drives for the Metro was completed in January 2009 and the machine now awaits start of the second drive, once funding allows.

LOVAT EPBM ready to head to Moscow

From our Archive we publish an article about another Lovat TBM incline of 30° completed in 1997 as part of an emergency to finish the top 400m of the steep penstock for the Cleuson-Dixence hydro project in Switzerland and not a long way from where the new Aker Wirth TBM will work on its steep incline for the Linth-Limmern power plant expansion project in the Canton of Glarus, south of Zurich.

While there is a difference direction, an incline and a decline are both working off grade and a decline can be considered the more challenging and potentially dangerous. There have been many steel inclined TBM tunnel drives but we know of only the Lovat Moscow Metro system large diameter TBM decline drive. If you know of other incline or decline TBM drives, do let us know and we will keep the record.

Top down TBM escalator drives - TunnelTalk, February 2009
Steep TBM drive for Swiss hydro scheme - TunnelTalk, February 2010
Steep incline drive saves critical deadline - TunnelTalk, April 1997

EPB and slurry machine mix up

October, 2009

A reader has informed us of an error in the our report about the Cairo Metro tunnel sinkhole article. In it we mentioned other TBM metro tunnel collapses and wrongly stated that it was a Mixshield working on the Porto metro project in Portugal. It was in fact an EPB machine that was working on the project and on which a tunnel sinkhole caused a building to collapse and claimed the live of one victim.

Cairo Metro TBM tunnel collapse – TunnelTalk, September 2009

Ring beam erector still there at Jinping

October 5, 2009

TunnelTalk stated recently and incorrectly in the London conference report, that the ring beam erector on the 12.4m diameter Robbins TBM working on the Jinping project in China had been removed. Lok Home, President of The Robbins Company, has corrected the information saying that in fact Robbins had wanted to remove the ring erector as part of the rock-support installation equipment modifications but that the client insisted that it be rebuilt and retained. That was done and the ring erector is still on the machine, with the introduction of the man-carrier booms making it easier to access the large diameter span and install the ring beams. Home remains of the opinion however, that ring beams have no place as rock support elements in tunnels of 8m in diameter or more and that NATM support elements of rockbolts, mesh and shotcrete are more effective and easier to apply on such large diameter rock-TBM tunnels.

Conference report: London's eye on the underground scene – TunnelTalk, October 2009
Onsite build for giant Jinping-II TBM – TunnelTalk, October 2008

Safety regulations grow from disaster

September 17, 2009

Kudos to Tunnel Talk and the author of the Hawk's Nest Tunnel Tragedy Article. Modern miners often forget how many lives were lost during the dark times of lax and/or criminal neglect regarding environmental and workplace safety in underground excavations.

Sincerely,
Gordon Revey, P.Eng.

Hawk's Nest Tunnel tragedy – TunnelTalk, September 2009

Contract termination - the expensive no-return option

April 2009

On a recent e-alert, the “From the Editor's Desk” message asked: "How do relations between Owner and Contractor become so intractable when contracts get into trouble and end up in termination?" It went on to ask: "Where was the dispute resolution process? Where was the co-operation to work through a difficult situation? Is termination the only solution when relations breakdown? Is the cost of rebid always fully appreciated by the boards of public owners ahead of termination?"

With respect to some of the questions about this topic, one of the ways these things fall apart is when the parties take the back-and-forth rhetoric personally. Once you begin to think in terms of “making a point”, and lose the focus on “how do I finish the job”, all hell can break loose. I’ve seen it happen, especially with big egos on either (or both) sides of the table.

William W. Edgerton, P.E.
Principle and President,
Jacobs Associates
San Francisco, California

TunnelTalk: Would it not serve the public and the project better to include a clause in the contract that senior management on both sides be turned out and new negotiators brought in before failure of discussions heads towards contract termination? There will be contract terminations in the future but the damage, the delay, and the cost make it no easy or simple solution. Recent rebid of the terminated Seymour-Capilano project in Vancouver is double the original contract price and the same was true for rebid of the DRO-2 outfall tunnel project in Detroit, which has been recently terminated for the second time due to financial constraints. The appointment and operating procedures of DRBs (Dispute Review or Resolution Boards) and methods of enhancing their potential for success has also been the topic of Discussion Forum.

Seymour-Capilano restart comes at a high price – TunnelTalk, April 2009
Detroit outfall contract terminated – TunnelTalk, April 2009
DRBs - knowing and playing by the rules – TunnelTalk, August 2008
Enhancing the success of DRBs – TunnelTalk, October 2008

Detroit water tunnel projects crippled

April 2009

Anonymous

Shouldn't the alert headline this week read; "Detroit is incompetent in more areas than just the motor industry"? They seem to be able to destroy any decent contract from any position. I cannot imagine the ground conditions are so overwhelmingly bad that it is impossible to mine. Amazing!

Detroit outfall contract terminated – TunnelTalk, April 2009
Funding crisis cripples Detroit tunnel projects – TunnelTalk, April 2009

Brightwater under pressure

February 2009

Lionel Suquet, Project Manager for the Vinci/Parsons RCI/Frontier-Kemper JV

“There have been more than 250 hyperbaric man-entry interventions at up to 4.8 bar pressure during the 12,500ft (3,800m) of tunnel completed to date by the two Herrenknecht slurry Mixshields being used on our Central Tunnel contract for the project. This allows only 45 minutes of work in the air by our compressed air maintenance crews with three hours in decompression. There are up to six three-member maintenance crews available in a 24-hour period and it is taking up to three times 45 minutes to change just one cutter.”

Name withheld

Investigation reveals that factory testing of the integral airlocks delayed delivery of West Tunnel contract’s TBM to site. Contract documents set rigorous pressure loss vs time specifications that had to be met before acceptance and ex-works delivery of the machine.

Name withheld

The remote camera sent in to check cutters on the LOVAT EPBM working on the West Tunnel contract, confirmed them as “like new” after 700 rings (1.5km) of tunnel excavated. This is a positive situation in the abrasive glacial conditions of the alignment.

Brightwater under pressure – TunnelTalk, February 2009

In response to the article, 'AMR India Project'

January, 2009

It seems the Alimineti Madhava Reddy (AMR) Project with it 43km long irrigation tunnel to deliver water from the Srisailem Reservoir to a vast drought-prone area of farmland and villages in the central state of Andhra Pradesh in India has a long history. Feedback and anecdotes from readers in the UK tell of an attempt in the 1970/80s to design and build the tunnel.

Let us know if you recall earlier attempts to develop this benchmark project.

Maurice Gooderham, Retired, Formerly Director of Thyssen (GB) in the UK, Surrey, UK

“I read with interest the Srisailem article. In 1986 Thyssen GB was interested in the project with designers Howard Humpreys. The original documents noted that the tunnel route traverses "an area inhabited by wild and ferocious beasts”. I assume the risk of a survey team being eaten by tigers was avoided by the current availability and use of GPS.

Maurice Gooderham, Retired
Formerly Director of Thyssen (GB) in the UK
Surrey, UK

David Hindle, Tunnelling Engineer, Director, OTB Consultants, London, UK

“Believe it or not, this is the project that first got me working with Maurice Gooderham back in 1978. I was a grubby junior tunnelling engineer working for Howard Humpreys, fresh out of the mines of Africa and the burning deserts of Oman.

We got an enquiry from the Government of Andrah Pradesh to bid for the project in partnership with a suitable international tunnelling contractor. I ring Maurice and he suggested we should meet that very afternoon to discuss the options.

Howard Humpreys (now Jacobs Engineering) was based in Leatherhead, Surrey in England and the Thyssen’ offices were in Llanelli in Wales. It is a fair old way between the two and after starting at 11am and travelling on several connecting trains I arrived hot and bothered some time after 6pm, thinking I would be too late and they would have all gone home. Not a bit of it. I was ushered into Maurice’s grand office and money changed hands between Maurice and a colleague who had laid a bet on whether I would get there that day. "Never mind lad," said Maurice. "It’s not urgent we can talk about it tomorrow.” It marked the beginning of a beautiful friendship.

The Srisailem job died a death at that time and has been resurrected several times over the years - a bit like other major projects, including Crossrail in London, except that it is being built at last.

David Hindle, Tunnelling Engineer
Director, OTB Consultants
London, UK

In response to the article, 'Rebid Reprieve for Seymour-Capilano'

January, 2009

John Penner, Manager, Contracts, Bilfinger Berger Canada Ltd.

Dear TunnelTalk,

In the article Al Johnson, Regional Director for Construction, WorkSafeBC, discusses shutting down work operations on the Seymour Capilano project and comments that he could not recall if workers exercised their right to refuse to work.

Bilfinger Berger notes that his statements are misleading and inaccurate.

First, on January 22, 2008, WorkSafe BC issued orders to Metro Vancouver and Bilfinger Berger Canada and verbally directed and required the delivery of an investigation report and a safe design before any work was to proceed. To date, neither of the orders has been rescinded. In addition, WorkSafe BC has not approved any plans to resume tunneling or varied its directives to allow any tunneling.

Second, the three unions representing workers on the project all agreed with Bilfinger Berger's decision to stop tunneling after workers were injured. In a May 30, 2008 letter to Metro Vancouver's Greater Vancouver Water District, the three union leaders stated: "After our members were injured and exposed to unsafe conditions at the site, Bilfinger Berger made the correct decision to temporarily suspend the work pending a review and analysis of the rock behavior."

The safety of Bilfinger Berger workers is the company's No. 1 priority. The fact is representative worker unions and their workers are fully onside with Bilfinger Berger's position: They agree that working conditions were not safe; they agree that suspending work was the correct decision; and they have asked Metro Vancouver to review its decision to terminate Bilfinger Berger's contract.

Yours sincerely,

John Penner
Manager, Contracts
Bilfinger Berger Canada Ltd.

California fixes high-speed rail route

July, 2008

Name withheld

I am working on a study for upgrading a rail system for the east coast of the United States. This is new investment to increase rail capacity to accommodate separate intercity, commuter and freight services. These are co-mingled in most places at the moment and separation is essential ahead of projected doubling of freight rail in the region by 2030. Rail must relieve highways.

Alameda Corridor LA

TunnelTalk: Separating freight from passenger traffic is the conundrum the world over. Japan and Europe bit the bullet early with construction of d edicated high-speed lines for passengers but the needs of the freight traffic have really come into their own and especially with the dramatic rise in fuel prices for truck t ransportation. The Swiss baseline rail tunnels were promoted as the green alternative to trucks that were killing off the trees through the mountains with acid rain - remember that? - but they will be ahead of the game now on the more urgent need to address fuel prices. Discussions on all these topics - and particularly about the cost of building passenger train tunnels as opposed to freight train tunnels - was very interesting at the project in Austria. It seems to be the beginning of a sea change in high-speed rail thinking in Europe. Another issue that the US is yet to address seriously is the issue of grade separations to be rid of the many disruptive and dangerous level crossings on their networks.

Alameda Corridor map

Much of the $950 million set aside by the California HSR Authority for service upgrades on existing feeder lines is to construct the over and under passes to eliminate level crossings. The $2.4 billion Alameda rail corridor linking the ports of Los Angeles and Long Beach to East Los Angeles rail yards was designed in large part t o eliminate traffic congestion at road grade crossings. http://www.acta.org Some 30 roads were elevated above the tracks while more than 200 other grade crossings were elimin ated depressing the two express rail tracks in a 10m deep cut for a distance of more than 15km.

Name withheld

Grade separations to avoid level crossing are the required course for speeds in excess of 160kph but the bigger issue is more tracks entirely for capacity for both freight and passengers and still not have the footprint of big highways.

Australia’s highway tunnel pain continues

February, 2007

City Link Tunnel
David Baxter, CPEng. FICE; MIE(Aust) Melbourne, Victoria Australia

Recent events on Melbourne’s City Link highway tunnel in Australia underscore FIDIC’s view that the Silver Form Conditions of Contract (EPC/Turnkey Projects) are not suitable for underground work (reference: Introduction to First Edition).

In essence Australia’s design-build contracts adopt a Silver Form approach by having detailed performance specifications, putting all the risk on the contractor including ground conditions and so-called reference material and workmanship specifications as provided by the client’s consultant, which the contractor is free to adopt or write it’s own.

In January 2007, Transurban, the owner/operator of the City Link Burnley Tunnel issued a statement saying it plans to sue the contractor, Transfield-Obayshi JV, because the tunnel was unlikely to last its’ forecast 100-year lifespan because its’ cast concrete walls were too thin. City Link has been plagued with problems on the tunnel since design and construction began. Many of the issues have been reported in the media. A settlement of the claims between all parties back in 2001 was mediated behind closed doors, losing a prime opportunity to improve industry practices.

Recent reports in the Australian media refer to walls not being built to specification. This implies a breakdown of the contractor's quality assurance system leading to a construction defect - not a design error. The self-certification process, intended to certify construction integrity without the need for independent checking, was relied upon by the client to indicate that construction quality was adequate.

A newspaper article in late January alleges claims by the independent assessor that he was pressured to approve the tunnel for opening. If this was so, and no denial has been published so far, the Melbourne public should be somewhat alarmed that the check to avoid faulty design and/or construction has been subverted.

There have been claims in the industry that the City Link’s Burnley Tunnel situation is a worse indictment of the industry’s ills than the circumstances that led to the Heathrow Express station cavern collapse in London in 1994 (Heathrow failures highlight NATM misunderstandings). It certainly has similarities due to inadequate construction standards. Reliance on design-build procurement and self-certification procedures on these projects certainly vindicate FIDIC’s reservations about the use of the Silver Form of contract for underground works.

Responsibility: Why We Don't "Just Do It"

February, 2007

William Edgerton, Jacobs Associates, San Francisco, USA

As I read the article about the Lane Cove tunnel collapse, it occurs to me that we need to have a better understanding of our responsibility for safety of both workers and the general public. I wondered how we as engineers, and indeed as an industry, are able to bear the burden of responsibility that we should feel for the performance of the projects we design. And it occurred to me that perhaps we bear it by not keeping it in the forefront of our minds as much as we should. A failure should always remind us to review our practices, because a failure offers more opportunities to learn than a success ever will. Success sometimes happens "in spite" of our efforts; failures always happen because of things we did wrong. In this respect, our projects are a bit like Tolstoy’s view of families as expressed in Anna Karenina: “Happy families are all alike; every unhappy family is unhappy in its own way.” We each fail to assume our responsibilities in unique ways.

Each party in an underground project has a set of responsibilities when it comes to safety. Owners set the stage for a safe project and serve as the behavioral model for all of the other team members. Not only do they approve the concept, but they significantly influence the safe design, construction, and operation of the facility by: (1) establishing realistic schedules and budgets for investigations, design, procurement, construction, and operational testing, (2) requiring detailed occupational health and safety plans to be implemented during construction, and most importantly, (3) insisting upon inter-team communication protocols that enable all project participants to be made aware of previously-collected information that can influence their judgment and affect their own responsibilities. Designers must recognize all potential risks, and present to the clients recommendations for ways to manage them. It is incumbent upon the designer to identify and convince the client of the importance to fund appropriate site investigations, geotechnical and otherwise. Not only must we establish design and material parameters for the final facility that enable it to perform to the intended criteria, but we must perform the detailed analysis, including necessary modeling, to indicate the ground and structure behavior during construction, and to ensure that the work can be constructed without damage or injury to third parties. And most importantly, we must evaluate the actual ground conditions during construction to verify that they agree with the assumptions made during the design process, and notify our client in the event that they do not. On design-build projects, in serving our contractor clients, we are obligated to assist in developing economical means and methods of excavation support, but in so doing we must never compromise our obligations to public safety that result from our engineering licenses. Contractors have an obligation to their workers to provide a safe work place. To do this they must plan the work in advance, establish appropriate work methods to accomplish it, employ workers who are competent for the work anticipated and have a safety focus, provide suitable training, and supervise the day-to-day activities such that workplace safety is paramount in everyone’s mind. Many construction contracts make the contractor responsible for the design of initial excavation support in portals, shafts, and tunnels. As a result the contractor must employ and direct suitably licensed professionals to perform the necessary analysis in order to ensure safety of the resulting underground openings.

Though I've outlined these responsibilities separately, owners, designers, and contractors don't fulfill their responsibilities in isolation. The responsibilities of one party overlap with those of another, and the actions of one party cause reactions and impacts. Yet, the actions that need to be taken are themselves relatively clear. So why don't we take them?

Sometimes, the parties are ignorant of their responsibilities. An owner may be building a project of a type they haven't built before, or a designer or contractor may be working with material that hasn't been used on similar projects. Other times, we may know of a responsibility or opportunity to be more thorough, and simply ignore it. Or, we may be so focused on a particular goal that we lose sight of some of the other aspects of the project that require our attention and planning. We have to guard against each of these tendencies, in ourselves and in the people with whom we collaborate. In a true partnership, the parties help bring each other into balance to achieve success. Only when we recognize the ways in which we fail to assume our responsibilities can we begin to correct our habits and build projects that are successful because of us, not in spite of us.

CERN's success, an underground triumph

September, 2008

Trans-border SSC
Clair Murdock, Heavy Construction Consultant, Ottawa, Canada

Even more distressing than collapse of the SSC in mid-tunnelling were the raw politics that sited it in Texas; not across the Canada-USA border near Malone, NY. Better rock, cheap electricity from Canada, and Canadian (and other international) funding possibilities ignored. The trans-border site would have been seen as international, not as Domestic, and some of the funding since committed to CERN would have supported the project. A compounded tragedy, with the best and brightest scientists going to CERN, not Montreal.