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April 2008 Issue 7

The magazine for the tunnelling professionalThe magazine for the tunnelling professionalThe magazine for the tunnelling professionalThe magazine for the tunnelling professionalThe magazine for the tunnelling professionalThe magazine for the tunnelling professionalThe magazine for the tunnelling professional

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CovIWT0804.indd 1 8/4/08 13:01:59

Earth Pressure BalanceSlurry Pressure BalanceHard RockPipe - JackingRolling Stock

BREAKTHROUGHSOLUTIONS

Lovat.indd 1 24/8/07 10:09:04

More skills, better effi ciency

SINCE becoming president of the International Tunnelling and Underground Space Association, l have been struck by the fact that

although much work is available, the resources needed to take on that work are in short supply.

In the next fi ve-ten years, many of those born in the late 1940s and early 1950s will be retiring, eliminating at least 20% of the current professional engineering (and tunnelling) resource. The crunch could come when the requirement for tunnelling professionals will coincide with projected gaps in energy and engineering resources.

Right now in the UK and the US, and possibly Western Europe, it is almost impossible to recruit more experienced tunnel engineers. One solution is to better use the engineer-ing talent that we do have and supplement it with skilled labour from the developing world.

Projects can be better delivered by increasing teamwork, reducing complex procurement methods and minimising duplication of

responsibilities. Owners should understand that effi cient integrated teams ensure better quality and more effi cient resource utilisation. Why should a contract involve so much reporting or engineering auditing in order to achieve a common aim?

Young engineers should be given more responsibility to keep them focused and inspired. Procedures and contracts should refl ect tighter, more effective and

cooperative management using fewer engineers. At the same time, this scarce resource must be better trained in order to retain it.

By these means, our industry can encourage and keep those who have chosen to be in underground engineering – and reward them appropriately.

Martin Knights, President, International Tunnelling and Underground Space Association

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advertisersFRONT COVER

Two Herrenknecht double-shield TBMs drive the 4km-long North-South Bypass Tunnels in Brisbane,

Australia. The S-375 (cover picture) and S-376 have a diameter of 12,340mm and are the largest

TBMs of this kind made by Herrenknecht.www.herrenknecht.com

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CONTENTS

contacts

April 2008

26

12-13 Project: fl ood alleviation, UKRodney Craig looks at a drill-and-blast scheme through varied ground

14-15 Project: Hindhead, UKTom Ireland and Tony Rock on the Hindhead tunnel’s development

17 CommentThe ITA’s Martin Knights examines some issues confronting EU countries

18-21 Technical: drill bits & buttonsVeikko Kuosa of Robit examines these essential rock-drilling tools

22-25 Technology: tunnel machine guidanceBill Hollinshead and Prof M Krcik discuss tunnel machines

26-29 Show preview: ConExpo 2008Las Vegas was the venue for the trade convention that saw record visitors

Features

01WT0804.indd 1 10/4/08 11:06:04

April 2008

2NEWS

Caterpillar acquires LovatUS

Canada

TBM manufacturer Lovat, one of the leading names in large-bore tunnelling, has been acquired by earth-moving equipment specialist Caterpillar.

An announcement to this effect was made by both companies on April 2, although, at the time of going to press, no fi nancial details of the deal had been made known.

The move has taken the tunnelling world by surprise. Illinois-based Caterpillar has hitherto only been associated with tunnelling projects by providing support machines.

Caterpillar also has a global mining division that manufactures equipment for surface and underground hard-rock mining. The Lovat acquisition now means that the company will have a very real presence in underground space infrastructure developments.

Caterpillar’s sales and revenues amounted to $44.958 billion last year. Clearly. the company has identifi ed considerable market potential in large-bore tunnelling, particularly in the emerging markets of China, India and Russia, so the acquisition is well-suited to its long-term growth strategy.

Caterpillar group president

Stu Levenick said: “This acquisition is Caterpillar’s entry into the rapidly expanding tunnel-boring machine business, and it represents an excellent strategic fi t for our companies and the customers we serve around the world.”

Toronto-based Lovat produces around 50 TBMs per year and employs about 400 people. Its president, Rick Lovat, will join Caterpillar’s global mining division and be responsible for growing its tunnel-boring business.

Mr Lovat said: “We are honoured to be part of Caterpillar. Just like Caterpillar’s machines and engines, Lovat’s tunnel-boring machines have a reputation for durability, reliability and performance while working in some of the most demanding applications. Our customers should look forward to the integration of Lovat into Caterpillar.”

SWEET Leilani, a 440t, 6.4m-diameter, Lovat mixed-face,earth-pressure balanced TBM, holed through on 2 March at the site of Canada Line’s proposed Waterfront Station in downtown Vancouver, thereby completing the second of two parallel, bored tunnels that form part of the city’s metro system.

This breakthrough marks the completion of the TBM-bored section of tunnel on the 19km-long line stretching from Waterfront to Richmond, which includes a spur to Vancouver airport. Breakthrough on the fi rst tunnel occurred on April 7, 2007, after which the TBM was dismantled and relocated to a new worksite at False Creek.

The US$1.9 billion project is being constructed by numerous means: 2.3km bored by TBM;

7km of cut and cover; 7.6km of elevated track; and the remainder made up of an at-grade section (1.52km) and bridges.

Including a relatively high percentage of cut and cover represents what the main contractor, InTransitBC, regarded as the lower risk associated with the technique as far as timescale and costs are concerned. It also allows stations to be constructed closer to the surface.

Extending from Waterfront Station at the northernmost extremity of the line to the Olympic Village, the 5.3m i.d. TBM-bored section of tunnel lies at depths of 10-30m. About 20,000 pre-fabricated, concrete, tunnel-lining segments have been used to construct the 4.6km of tunnel walls.

Geology along the alignment comprises mainly weak sandstone, interspersed with cemented, sand-stone pockets and consolidated glacial deposits of silt, sand and clay (till).

With the second (inbound) tunnel now excavated, the TBM will be dismantled by Italian contractor Seli, a process expected to take around four weeks. The line is scheduled to open in November 2009.

Caterpillar enters tunnel boring

SOUTH Korea’s fi rst immersed tunnel took a step closer to fruition recently after the fi rst, 180m-long, reinforced-concrete element was submerged.

The 3.2km-long tunnel forms part of the US$5.8 billion, 8.2km-long Busan-Geoje Fixed Link Project. Eighteen elements will be submerged for the tunnel, which, when opened to traffi c in 2010, will be the world’s deepest, immersed roadway at 48m below the mean water level.

Each of the 18 parts consists of eight, 22.5m-long concrete segments, measuring 26.5m wide by 9.9m high, forming two dual-carriageway roadway bores with a central gallery. These are assembled with PT tendons as one body during marine operation – fl oated and transported using normal catamaran pontoons.

For the fi rst time, double water-tight joints will be used at segment junctions. Tolerances between the elements following connection are expected to be +/- 40mm. At one end of the tunnel, two wider elements with climbing lanes will be used, each weighing 48,000t.

Each segment is cast in full cross-section in a purpose-built, dry-dock facility and four are built at a time. Following fi t-out at a temporary mooring area, the elements are towed 35km to the alignment and immersed into a pre-dredged trench by specialist sub-contractor Mergor Under-water Engineering (Netherlands).

Challenges include: exposure to strong Pacifi c currents; weak subsoil, necessitating extensive soil improvements; a short operations window due to the typhoon season; the seismic zone location, and having to use the largest-ever immersion equip-ment to accommodate swell waves.

Daewoo Engineering leads the consortium of contractors, with consultancy provided by Halcrow working with Tunnel Engineering Consultants of the Netherlands.

First piece of Korean tunnel jigsaw placedFirst piece of Korean tunnel jigsaw placedFirst piece of Korean Korea

Sweet Leilani holed through on 2 March in Vancouver

Second Canada Line breakthrough

02,04-06,08-10WT0804.indd 2 9/4/08 12:31:28

Committed to your superior productivity.

Atlas Copco Underground Rock Excavationwww.atlascopco.com

Man v. Machine

Drill rod handling is not for the human body – It’s heavy, wearing and physically damaging. For drill rod handling, you need the RHS E – a new drill rod handling system specially developed for Atlas Copco’s highly successful Boomer E-series. The entire process is controlled from the rig operator’s panel, eliminating all heavy and dangerous aspects. The RHS E can carry eight ten-foot extension rods. This opens the way to high productivity drilling, even of long holes, completely eliminating the need to handle drill rods manually.

One of them is not built for lifting 2 tonnes an hour.

Annons_RHS.indd 1 2008-03-19 16:19:27

April 2008

4NEWS

ROAD traffi c can at last travel through the world’s deepest undersea tunnel – the 7.8km-long Eiksund, between Eiksund and Rjånes, on the west coast of Norway. Norwegian minister of transport Liv Signe Navarsete declared the tunnel open on February 23, following fi ve years of construction.

As the latest addition to Norway’s impressive list of subsea tunnels, which total about 100km, the new one is part of a US$190 million, 14.9km fi xed link, which comprises the Ry 653 trunk road, two other tunnels (the Helgerhorn and Morkaås on the mainland) and a bridge.

With its lowest point at 287m below sea level (61m below the seabed), the tunnel will benefi t the

island communities of Hareid, Herøy, Sande and Ulstein, and the mainland towns of Ørsta and Volda. It will also mean that the 22,000-strong, offshore community will no longer be reliant on the ferry.

Driven mostly by drill and blast through solid rock that was mainly banded with augen gneiss and some gabro intrusions, support has

been primarily by inserting rock bolts at a rate of around 3-4 per tunnel metre. A 70mm layer of shotcrete was then applied.

Higher than expected water seepage necessitated the use of injection-grouting at some points, with excess water evacuated by fi ve pumping stations spread out along the tunnel’s length.

World’s deepest undersea tunnel now open

Norway

ADIT tunnelling on the Ceneri Base Tunnel in Sigirino, Switzerland, has begun following a cutterhead ceremony on February 15, which marked the start of the excavation of the 2.4km-long access tunnel by a 9.7m-diameter Robbins TBM.

Having previously bored a 14.6km-long headrace tunnel at the Kárahnjúkar Hydroelectric Project in Iceland, the TBM was transported to a facility near Milan, where it was refurbished and its diameter altered for the Ceneri project. Now, it will bore through rock comprising schist, Swiss molasse, and Ceneri ortho-gneiss with a UCS of 30-130MPa.

Two installation caverns, to be excavated by drill and blast at the end of the adit tunnel, will include an internal, concrete batching plant and also serve as starting points for the excavation of the 15.4km-long Ceneri main tunnels.

Carrying out the work will be the responsibility of the Consorzio

Monte Ceneri (CMC) JV – a consortium of CSC, Lugano, Frutiger SA, Thun, Rothpletz, Lienhard + Cie, and Aarau.

Contracts for the main Ceneri tunnels, which will combine both drill-and-blast and TBM-driven excavation, have yet to be awarded.

The fi rst contract, for the north-running main line, will include two 8km sections of drill-and-blast tunnels. The second contract, for

the south-running line, will include two 1.8km sections of drill-and-blast and two 4km sections of TBM-driven tunnels.

Excavation of the adit tunnel and installation caverns will take about two years, although tunnels are scheduled to be operational by 2019. The new tunnels are part of AlpTransit’s project to provide more effi cient freight and passenger rail routes through the Gotthard and Ceneri mountain ranges.

TWENTY-NINE tunnels, totalling around 37km in length, on a new 350km-long, four-lane highway in Turkey are to be equipped with a Siemens operations-management and traffi c-control system worth US$87.5million.

The route skirts the Black Sea coastline and links Espiye with Sarp/Batumi at the border with Georgia. It is claimed the improve-ments will make it one of the world’s most progressive highways in regard to traffi c management.

The aim is to alleviate the traffi c problems caused by increasing numbers of heavy, long-distance goods vehicles.

In addition to Siemens supply-ing a central control station and seven control substations, it will also supply systems for fi re protection and fi refi ghting, as well as for power, lighting, ventilation communication and monitoring.

Switzerland

Siemens system updates highwaySiemens system updates highwaySiemens system Turkey

IN A recent communiqué update on the current progress of construction works on the Gotthard and Ceneri tunnels in Switzerland, AlpTransit recently confi rmed that, as of March 1, a total of 108km of tunnels, galleries and passages have been excavated.

This means that around 70.4% of the total 153.5km length of tunnels has been completed.

Headquartered in Lucerne, Switzerland, AlpTransit is a subsidiary of Swiss Federal Railways (SFR).

AlpTransit is constructing the Gotthard axis of the New Rail Link that passes through the Alps, and comprises base tunnels at Gotthard, Zimmerbeg and Ceneri.

Ceremony starts Ceneri adit drive AlpTransit makes good progressAlpTransit makes good progressAlpTransit makes Switzerland

Cutterhead-turning ceremony on February 15

7.8m-long Eiksund

02,04-06,08-10WT0804.indd 4 9/4/08 12:35:15

10 μm

5NEWS

BREAKTHROUGH has occurred on one of the two bores on Malmo’s US$1.58 billion Citytunnel project. After 500 days of excavation, ‘Anna’ – an 8.89m-diameter Herrenknecht EPB TBM – broke through at Station C last month to complete the 4.5km drive that began in November 2006.

Johan Brantmark, assistant project manager at subproject Tunnels, said: “Boring has been very successful, with no major surprises or setbacks, and we are on time.”

Anna has made several planned stops along the way, one of which was for three months of maintenance at the rock cavity at Triangeln, in addition to a break for Christmas and other short maintenance stops.

According to Citytunnel, the last leg, between Triangeln and Malmö C, was the most diffi cult to bore due to the sharp bend, high water content and fractured limestone.

Shortly to join Anna, and currently only 500m away from the excavation wall at Malmo C, is ‘Katrin’ – an identical TBM that has been boring the second tube

and is scheduled to achieve breakthrough in one month’s time.

Malmö’s Citytunnel project comprises 17km of railway, of which 6km runs beneath the city

centre and the remainder on the surface. It will connect Malmö Central Station with the Öresund Bridge. The project is scheduled for completion in 2011.

‘Anna’ makes Malmö breakthroughSweden

THIEVES in Brisbane have stolen about US$80,000 worth of specialised, tungsten-coated, steel drill bits that were being used on roadheader equipment to construct the city’s North South Bypass tunnel.

About 3,000 tungsten-tipped picks, weighing around 11t, disappeared overnight from the Lamington Road warehouse near

the tunnel’s northern portal. Ten pallets marked ‘Sandvik’ were broken into between February 4 and February 20.

At present, police are unsure why anyone would want so many of the pieces, which though with no street value, are worth around US$27 each.

A spokesman for the tunnel project said the items were so

specialised that they could only be of use to someone who already kept a roadheader at home.

Police have appealed for public help to track down the robbers.

The 4.8km-long North South bypass tunnel, currently under construction, will pass under the Bribsane River and eventually connect Bowen Hills and Woolloongabba.

HIGH-SPEED 1 (HS1), the UK’s new railway connecting the Channel tunnel with the recently restored St Pancras international terminal in central London, has won the accolade of ‘Project of the Decade’ at the London Transport Awards.

Costing US$11.6 billion to construct, the HS1 line is 109km-long and forms a main link in the high-speed London to Paris, and London to Brussels rail route.

It became fully operational in November 2007 when it was opened by Queen Elizabeth.

Commenting on the award, David Begg, chair of the Judging Panel said: “There was one project which stood out from all the others in terms of scale and magnitude that the judges felt deserved a special award. It really is the transport project of the decade, if not of the last generation.

“At a time when Whitehall has questioned the value for money from transport projects, particularly rail, this project has restored faith in our ability to deliver and has enhanced the case for rail investment.”

Responsible for managing the delivery of HS1, Rail Link Engineering (RLE) collected the award on behalf of London & Continental Railways, the company behind HS1.

RLE, a consortium of Arup, Bechtel, Halcrow and Systra, was responsible for the design and project management.

Channel Tunnel line scoops top award

UK

Australia

Thieves pick bits off Brisbane tunnel project

02,04-06,08-10WT0804.indd 5 9/4/08 12:35:24

MORGAN Est PLC, the contractor for the Croydon Cable Tunnel project in England, has announced that a Lovat ME140SE Series 23000 TBM has commenced work on the second phase of the project.

Following the recent completion of the fi rst drive, the 3.6m-diameter, mixed-face, earth pressure-balance TBM was removed from Rowdownshaft and returned to Kent Gate Way for the second drive – to

Beddington via Lloyd Park. The TBM will now have to

bore 7km through moderately

weak to fractured upper chalk with fl int beds.

By October, when the TBM breaks through at Beddington, it will have excavated a

total of 9.8km of tunnel.

NEWS

Lovat plans October breakthroughUK

JF SHEA and Traylor has been awarded the US$305 million contract to build a 8.8km-long drainage tunnel that will serve around 40% of Cobb county in northeast Georgia, US.

The 8.2m-o.d South Cobb tunnel alignment will be located in mainly granitic rock, at depths averaging 76m. It will run through bedrock near Douglas County and then be routed east to a treatment plant on the Chattahoochee River.

The contract will also include four smaller tunnels, totalling about 1.6km in length, with diameters of 1.8-3m.

Shea Taylor JV will use a modifi ed and remanufactured, Herrenknecht hard-rock, single-gripper, tunnel-boring machine that was used previously on the nearby Atlanta West Area CSO Projects A and B.

The main tunnel will have a concrete lining, and include construction and drop shafts, inlet structures and smaller, connector tunnels. A lift station will convey fl ows from the tunnel to the South Cobb water-reclamation facility.

Designed to replace existing wastewater infrastructure, the tunnel removes the need to replace 25km of ageing sewers and two pumping stations. Construction is scheduled to begin in June and last six years.

JF Shea and Traylor wins Cobb contractJF Shea and Traylor wins Cobb contractJF Shea and Traylor US

weak to fractured upper chalk with fl int beds.

when the TBM breaks through at Beddington, it will have excavated a

total of 9.8km of tunnel.

ANOTHER successful break-through that has occurred, this time by Downer engineering with Lovat’s help, has been on the C302 cable tunnel project for Powergrid Ltd in Singapore.

A 6.14m diameter LOVAT RME242SE Series 18500 TBM,

completed its drive on February 21 2008. The mixed face, EPB machine had bored 2,629m of tunnel on an alignment that comprised multiple compound, 130m radius S-curves, achieving production rates of up to nine rings per shift.

Boring through the Jurong formation, the TBM encountered an alignment geology that comprised sandstone, mudstone, siltstone and limestone, with varying degrees of unconfi ned compressive strengths up to 175 MPa.

ONE of the few, perhaps only, tunnelling fairs to be actually held in a tunnel, the IUT (Innovation Underground) exhibition will be at the Hagerbach Test Gallery near Sargans, Switzerland, on September 17-18. On the following day there will be an excursion to a tunnel.

Since 1979, the Hagerbach Test Gallery has been conducting research, testing and development under real conditions in a tunnel system that is 5.2km long. It is being constantly developed.

This, the fi fth IUT, will showcase the latest trends and developments from companies in the tunnelling sector.

More than 5,000m2 of exhibition space plus an open area of 2,500m2 will be available in the large cross-section tunnels, arranged in a circular system to

give exhibitors easy reach to the stands. And, for the fi rst time, the rear tunnel section will be accessible by shuttle train.

According to the organising committee, a new IUT theme stage has been designed, to provide the ‘optimal’ platform for product presentations, launches and discussions.

As you would expect from such a high-profi le event, there will

be an extensive seminar programme, based around the theme of ‘Modern

Tunnel Finishing for Road and Rail’.

Further details from www.iut.ch

NEXT month sees the release on to the market of a Robbins TBM that will be up for sale after it completes work at the Karahnjukar Dam Project in Iceland.

With its 7.23m machine diameter and diameter range of 6.5-9.7m, it has a cutterhead power of 3,000kW (10 x 300kW) and speed of 0-8.3rpm. The back-up power is 600kVA. Made in 2003, the TBM weighs in at 600t.

Singapore

…and achieved another in Singapore

April 2008

666NEWS

Iceland

TBM for sale

Switzerland

IUT tunnel fair takes underground stage

be an extensive seminar programme, based around the theme of ‘Modern

Tunnel Finishing for Road

Transferring a TBM from one drive to another on the Croydon Cable Tunnel project

02,04-06,08-10WT0804.indd 6 9/4/08 12:35:30

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April 2008

8NEWS

ON-SITE assembly of a massive 10m (32.8 ft), double-shield TBM has been completed in Andhra Pradesh, India.

A ceremony was held on March 18 to mark the offi cial launch of the Robbins machine; the fi rst of two TBMs that will bore a 43.5km-long water tunnel for the Alimineti Madhava Reddy (AMR) Project.

The second machine will be assembled on-site later this year and launched at the opposite end of the portal – the inlet end.

Previous Robbins projects have proved that initial on-site assembly, rather than pre-assembly in a manufacturing facility, can save both time and money for the contractor.

Anil Kamat, project manager at Jaiprakash Associates, the contractor for AMR said: “The assembly has gone quite smoothly, with some minor mismatch problems that were worked out. Even with that, the assembly on-site has resulted in cost savings

in terms of transportation.” Four months of round-the-clock

work was required to complete the demanding schedule.

Built in a large launch-pit, using gantry cranes to hoist the components into place, machine parts such as the cutterhead,

gripper system, forward shield, and telescopic shield were assembled in a concrete ‘cradle’. The assembled TBM and back-up then crawled forward by reacting against invert, segment pieces, installed progressively up to the tunnel entrance.

When it comes to disassem-bling the TBMs and back-ups, a special chamber will be excavated using drill-and-blast,

and it will include poured-concrete inverts and a 170-metric-ton gantry crane.

The project is expected to take fi ve years to complete, with the tunnel operational in December 2012.

Landmark assembly of Robbins double-shieldIndia

BIDDING for contracts to build Bangkok’s Purple Line mass-transit project could be delayed from next month, thanks to the new govern-ment’s plans to expand such projects in the capital, reports Syed Rashid Ali.

Deputy prime minister Sahas Banditkul said recently that a traffi c masterplan, developed by the Traffi c and Transport Policy and Planning Offi ce, would need to be adjusted to accommodate prime minister Samak Sundaravej’s plans to expand mass-transit works. “This could lead to a delay in the Purple Line, but the bidding process will not be cancelled,” he said.

Bidding for a multi-billion line, linking Bang Sue and Bang Yai (part of the Purple Line), was planned for next month after a public hearing next Monday.

Mr Sahas, who oversees transport policy, said a detailed study of how the existing master-plan could be integrated with the prime minister’s proposals would

be conducted by various agencies.“As far as I could learn from the

state agencies, there is no diffi culty in integrating the plans. The differ-ence between them is just the coverage of the extended routes, which will reach into the suburban area in eight directions, and the inner and outer loops,” he said.

However, Mr Sahas declined to specify the framework for the study, saying there was no need to speed up the process and that the project must proceed prudently.

Pranot Suriya, deputy director-general of the Transport and Traffi c Policy and Planning Offi ce, said his agency may have to do another

feasibility study of investment in the train routes if there were adjustments to the original plan. His offi ce has already completed one such study of investment in 10 mass-transit routes during the Thaksin Shinawatra administration.

“However, I don’t think it will take too much time if we have to do the study again, given that both plans share common basic details,” he said.

MRTA governor Prapat Chongsanguan said adjustments to accommodate the prime minister’s plans would not affect the masterplan. It was only a matter of more work needing to be done.

Thai Govt delays mass-transit expansionThailand

Staff of Robbins’ India offi ce with the 10m-diameter, double-shield machine in Andhra Pradesh

Bangkok

Phot

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Xcha

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MCL, publisher of World Tunnell-ing/Trenchless World (WTTW), ing/Trenchless World (WTTW), ing/Trenchless Worldhas been acquired by Aspermont, one of Australia’s fastest-growing specialist-media companies.

In adding WTTW to its stable, WTTW to its stable, WTTWPerth-based Aspermont can boast one of the world’s foremost publications in tunnelling, which uniquely combines large and small-bore developments. MCL also publishes Mining Journal, itssister title Mining Magazine and GeoDrilling International.

The combined company will constitute a global mining and tunnelling resource, encompass-ing print, online, conferencing and other information services. It will offer over 40 products and employ about 140 staff.

WTTW publisher Rob Barrow-WTTW publisher Rob Barrow-WTTWman said: “I am delighted by the merger as it not only strengthens MCL, but will also boost our edit-orial resource, with more focus on Australia and Asia. It will enhance our circulations in the region, including China, which is experi-encing huge change with massive tunnelling and trenchless projects.”

Acquisition adds new dimension to MCLAcquisition adds new dimension to MCLAcquisition adds new UK

02,04-06,08-10WT0804.indd 8 9/4/08 12:36:25

20 – 22 may 2008 Lingotto Fiere, Turin, Italy

INTERtunnel 2008 is the event for you:the exhibition is aimed at companies and suppliers involved in buildingand equipping tunnels and at firms providing the systems and expertisefor their safe and efficient operation.

Do you want to find out about the latestinnovations in tunnelling technology?

Italy’s premiertunnelling event!

Exhibit categories include:● Construction and contracting services● Tunnel construction equipment and plant● Construction products and materials● Microtunelling and trenchless technologies● Fire protection and safety systems● Communications and security equipment● Pollution control and ventilation equipment● Electrical and lighting systems● Consultancy and design services

Tel: +44 (0)1727 814 400Email: [email protected]

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Visit www.intertunnel.com to view the exhibitor list and to order yourvisitor badge!

Copyright: GTT/ALPTransit AG

NEWS999

NEWS

Obituary: Robert JennyUS

ROBERT Jenny, one of the world’s leading authorities on the planning, design and construction management of tunnels and underground structures, has died, aged 76.

He was the founder and CEO of Jenny Engineering Corporation (1965), based in Springfi eld, New Jersey, US.

Mr Jenny is best remembered for pioneering the use of innovative tunnelling techniques in the US, particularly the fi rst use in the country of fully-encapsulated, epoxy-resin, ground-support dowels for tunnels, which was in 1970.

In 1992, he pioneered the use of NATM in soft ground for underground stations and tunnels in the US.

For the Washington metro, Mr Jenny was involved extensively in the design, management and

construction of shafts, tunnels and substations.

On the international scene, Mr Jenny was responsible for the design and management of major tunnel projects, which included

acting as consultant for the undersea cross-over cavern in the Channel Tunnel, as well as on the Shanxi Wanjiazhai Yellow River Diversion Project in China.

He lectured widely and co-authored two books: Tunnelling – The State of the Art and – The State of the Art and – The State of the ArtTunnelling – The State of the Industry.

Born in 1932, Mr Jenny served in the Korean War with distinction and went on to study civil engineering at Newark College of Engineering.

He later gained a master’s degree in civil engineering, with a specialisation in geotechnics.

In 1993, Mr Jenny won the Engineer of the Year accolade from The American Society of Engineers.

He is survived by his wife, Marceline, two children and four grandchildren.

NEWS reaches the WT newsdesk WT newsdesk WTthat Russian billionaire and Chelsea FC owner Roman Abramovitch has ordered a TBM from German maker Herrenknecht in a contract valued at US$160 million.

His Russian construction fi rm, CJSC Infrastructura, is reported to have signed the contract for the 19m-diameter machine last month.

The TBM will be used for metro infrastructure projects in Moscow, St Petersburg and Sochi on Russsia’s Black Sea Coast.

Believed to require about two years to build, the machine will be the largest ever produced by Herrenknecht and also the biggest in the world.

The acquisition will go some way to increasing the stature of Abramovitch’s construction company in terms of its ability to carry out Russian urban-infrastructure projects.

Robert Jenny

Abramovitch buys Herrenknecht TBMAbramovitch buys Herrenknecht TBMAbramovitch buys Russia

02,04-06,08-10WT0804.indd 9 9/4/08 16:30:17

April 2008

10NEWS

THAMES Water has announced the appointment of CH2M Hill as programme manager for its Thames Tideway Tunnel scheme – the so-called US$4 billion ‘super-sewer’ that is being designed to prevent overfl ows from London’s sewers entering the River Thames.

Steve Walker, major projects director for Thames Water, said: “The Tideway Tunnel scheme is Thames Water’s biggest single investment project by far. These exceptional tunnels will have enough capacity to store millions of litres of diluted sewage and transfer it to our Beckton sewage-treatment works.

“This scheme is essential if we’re to improve the quality of the river and reduce the environmental impact of sewage overfl ows. We are delighted to have CH2M Hill on board to help us deliver a sewer

system fi t for the 21st Century and beyond.”

As London’s deepest ever tunnel, lying at depths of up to 80m, the 32km-long, 7m-diameter inter-ceptor tunnel will run from west to east London, much of it under the River Thames. It will also dip below the intricate network of metro tunnels and services making up London’s underground infrastructure.

Work is expected to start in 2009 and be completed by 2014.

GREECE’S longest tunnel ever, at Driskos, near Ioannina in northwestern Greece, will open to traffi c this month.

The 4.8km-long road tunnel, which cuts through mountains and connects the Ioannina Plateau with the Aracthos River valley, has taken a total of seven years to complete.

The twin-bore tunnel will carry a 24.5m-wide, dual-carriageway with two lanes, along with an emergency lane in each direction.

It is one of a total of 76 new tunnels being constructed on the US$5.37 billion Egnatia Odos – a 670km-long motorway route connecting northwest Greece with the Turkish border.

Currently one of Europe’s largest civil-engineering projects, the tunnels will have a combined single-bore length of 99km when completed.

Greece

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Thames Water names Tideway manager

UK

The Egnatia Motorway’s two-way tunnel at Driskos, Ioannina, in north-western Greece (March 26, 2008)

Greece’s longest tunnel to open this month

02,04-06,08-10WT0804.indd 10 9/4/08 12:37:04

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gallery completed in hard rock using the same machine… the list goes on and on.

All these examples and more speak volumes about the strength, the performance and the reliability of our tunnel borers. Covering all types of geological conditions and capable of diameters

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AP 200x275 UK.qxd 28/02/08 9:53 Page 1

April 2008

12

WESSEX Water is investing in a multi-million-pound scheme to improve the sewer network in Bristol, Eng-Wthe sewer network in Bristol, Eng-W

land, and to reduce stormwater fl ooding in the city centre.

The topography of the centre of Bristol rises sharply to the north towards Clifton, so during very heavy storms there is quick runoff which overcharges the combined sewers and causes fl ooding of the basements of some of the properties in the centre.

One scheme designed to alleviate the problem is the Bristol City Centre Flood Alleviation Phase II project. Aimed at reducing fl ooding, it will remove 57 properties from the fl ooding register by April 2009. After a number of studies, the scheme chosen was for a new tunnel to take the excess water from the area north to the Northern Foul Water Interceptor Sewer.

POTENTIAL SCHEMESWessex Water (WW) carried out modelling and optioneering studies to look at a number of schemes to reduce the fl ooding in the area.

These included a separate scheme to remove the water, transferring the high quantities of water during heavy storms to other tunnels or the construction of new tunnels for temporary storage.

These studies led to two main schemes being developed:Ë Option 1: to provide a number of large

storage chambers at strategic locationsË Option 2: to transfer the water in tunnel to

other parts of the existing sewer system.

These studies showed that the two schemes were of the same order of cost, about US$19 million. The second option, to remove the water to another area of the sewer system, was the preferred option, and was approved by the WW Board as a sustainable scheme.

SCHEME DEVELOPMENTFour years ago, Wessex Water established Wessex Engineering and Construction Services (WECS) to carry out its new projects. An internal company, it turns over around £500 million of work annually. WECS is the project manager for the Bristol project, responsible for design and the construction within the project budget and programme, as approved by the Wessex Water Board.

For the Bristol project, WECS is being advised on the permanent works by Donaldson Associates, and on the geological aspects of the tunnelling by Dr Brian Hawkins of Bristol University.

WECS and its consultants developed the project to tender stage by studying the tunnel scheme, taking into account criteria such as the method of construction, health & safety, timescale and costs. The tunnel could be constructed by drill-and-blast methods or with a tunnel-boring machine (TBM).

The scheme is to construct a bored tunnel of around 800m in length, up to 70m below ground level, through soft to very hard ground ranging from weak, saturated clays and mudstones to very hard sandstones with compressive strengths up to 480Mpa. The potential water pressure is up to six bar and there is the likelihood of faulted ground at the end of the tunnel, close to the reception shaft. The tunnel’s internal nominal diameter is 1.5m.

For a tunnel of this length and for health & safety considerations, the minimum internal diameter is recommended at 1.8m and so a nominal internal diameter of 2m has been chosen. The programme is also extremely tight as the works have to be in operation by April 2009.

TENDER PROCESSWECS decided it would go out to tender only for the tunnelling work. It would be responsible for the surface works and its subcontractor would be responsible for the tunnelling works. The subcontractor would be responsible for the works within the tunnel but the site back-up would remove the spoil from the site: soft and weak rock would be removed to a spoil tip and the hard rock to recycling and reuse.

Discussions were held with six contractors on their capabilities, their proposals for the tunnel construction, their method of working with a TBM and drill & blast, and their availability. Having reviewed the submissions, WECS decided the proposals for a TBM drive, although having the distinct advantage of a possible early completion, also posed potentially major risks in successfully completing the drive under an urban environment.

Delays in the drive could result from the very abrasive ground conditions, with potentially 160 changes of ground condition along the drive and the likelihood of many complete changes of face tools in diffi cult conditions and under potentially large heads of water. There was no guarantee that the drive could be completed without a major incident and it would be very diffi cult and very expensive to remove a TBM. WECS therefore decided that the only solution, on the basis of risk, health & safety, programme and cost criteria, was to opt for drill and blast. Although slower, this posed the least risk and the project could be completed safely and with a realistic programme by April 2009.

The tunnel construction was let as a subcontract to Special Engineering Services (SES), from Nottingham, a company with substantial experience in coal mining and roadways, which was fl exible and with which WECS could work. It was known that there were

Rodney Craig looks at an interesting scheme in Bristol, UK, where a tunnel excavated by drill and blast through much varied ground conditions will eventually form part of a much-needed fl ood alleviation scheme

PROJECT: Flood alleviation, UK

Alleviating fl oods in the heart of Bristol

Map showing the route of the drive relative to the street locations

Diagram showing the cross-section of rock strata

12-13WT0804.indd 12 9/4/08 09:58:21

April 2008

13

potential delays in the starting date for the works with the necessary planning, approvals and consents. During the contract negotiation, it was agreed that the fi rst 50m of the tunnel drive would be priced on a ‘cost plus’ basis, due to the diffi cult and little-known ground conditions with its many potential problems and uncertainties. The remaining 750m would be on an NEC Target Price Contract. SES employed Parsons Brinkerhoff to design the temporary works for the tunnel construction.

SHAFT CONSTRUCTIONThe main site between the Trenchard St car park and the ice rink is very restricted, with very little storage capacity. The shaft is 16m long by 6m wide and 8m in depth. The temporary works for the shaft have been provided by 300mm-diameter steel piles backfi lled with concrete and with shotcrete sprayed between the piles. The piles were installed into the bedrock. As the ground level and rockhead are very variable in the area, the spacing of each pile was based on the depth and strength of the rock found by the previous pile. This iterative method meant that the number of piles installed has been reduced and their spacing increased with a saving of some 13 piles. The piles on the ice rink side were closer at a minimum of 0.6m centres, while those on the car park side were spaced at up to 3.0m centres. Ritchies, from Scotland, carried out the pile installation.

TUNNELThe specifi cation gives a maximum vibration restriction at the surface during blasting of 10mm/s². The route passes below Bristol

University and several sensitive buildings, including the Civil Engineering Department and its Earthquake Table.

The fi nal tunnel design has a nominal internal diameter of 2m. The choice of the fi nal lining has not yet been decided and could be concrete pipes or cast in-situ concrete. SES’s choice for the excavated tunnel is 3m high by 3.5m wide with a fl at roof. For the fi rst 50m, the width is increased to 4.5m to allow for plant movements and for other logistic reasons and there are other width increases along the route for additional plant movements.

The Parsons Brinkerhoff design for the temporary works uses 170mm by 150mm RSJs (rolled steel joists) with a horizontal beam in the crown and inclined side supports with pin joints between the members. There are nine ground support categories with steel support spacings of 500-1,250mm with mesh between the arches. The tunnel face is inspected daily and the ground support category for the next

day’s tunnelling jointly decided by the site team. The tunnel drive began in September 2007.

Break-out from the shaft was excavated under a piled canopy and 4m-long rock bolts. The fi rst 50m of the drive in the fractured ground was slow and was completed by late January 2008. The general explosive charge used is 50kg per 2m pull, in 40-45 holes drilled with a twin-boom jumbo.

During the initial section, a blast curtain was used to minimise any blast damage outside the tunnel. Initially, the spoil was excavated with an Eimco shovel and removed to the shaft by conveyor. The spoil is now being removed by a ‘scooptram-type’ loader by GHH Fahrzeuge.

The 750m-long Target Price section of the drive started on January 25 and weekly progress has been in the 11-16m range. Overall progress, including the initial 50m of the drive, to March 3 was 140m. The drive is programmed to be completed by the end of 2008. Currently, the site team is working fi ve days a week with two 11-hour shifts, with up to two pulls per day. Blasting is allowed between 7am and 11pm.

Probing ahead is being carried out up to 20m ahead of the face to test the water pressure and ingress. The maximum water fl ow anticipated is 70 litres/s, but only low fl ows have been encountered to date. During the weekend, the invert is removed and concreted and general maintenance carried out.

The progress is a little slower than anticipated but it is still early in the drive. However, the programme for the completion of the drive by the end of 2008 is not in doubt; if necessary, measures to improve weekly progress will be considered in the coming months, such as increasing the number of shifts to three eight-hour shifts or by working seven days a week.

Alleviating fl oods in the heart of Bristol

Thanks to WECS for arranging the site visit and for providing illustrations. Thanks are also due to Donaldson Associates for supplying information and the geological profi le.

PROJECT: Flood alleviation, UK

The restricted working site at the launch shaft

In various locations, the shaft was enlarged to allow the equipment to turn around

The geology was studied by Donaldson Associates in conjunction with Dr Hawkins, initially with a desk study followed by some 20 boreholes along the route to a maximum depth of 93m. Geophysical downhole surveys were carried out, as was lab testing. These studies and site investigations were carried out in 2005/06 at an overall cost of US$2 million.

The tunnel alignment passes through the Quartzitic Sandstone Group and the Hotwells Group (Cromhall Sandstone

Group) with a maximum depth of 70m. The strata are inclined into the face along the alignment and will pass into a fault zone near to the reception shaft.

The ground conditions will range from inter-bedded mudstones, siltstones, sandstones and limestones to conglomer-ates, with a maximum compressive strength of 480Mpa. The face during the site visit was blocky, with thin horizontal clay layers between the rock layers. There was little water in the face.

Geology

12-13WT0804.indd 13 9/4/08 09:58:24

April 2008

14

PLANNED since 1983, the A3 Hindhead project, in Surrey, UK, is a 6.7km dual carriageway trunk road that includes a

1.83km tunnel. Delivered on behalf of the UK Department for Transport under a Highways Agency Early Contractor Involvement (ECI) con-tract, the project is being constructed using the sequential excavation method (SEM) and will complete the dual carriageway link between London and Portsmouth. The tunnel is due to be opened in July 2011.

The horseshoe-shaped tunnel will be constructed using progressive, mechanical excavation with the aid of robotic spraying equipment to install shotcrete close behind the face. The tunnelling medium is a ‘soft rock’ sandstone for which there was little previous tunnelling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240m-long portal section though sandy material using a steel pipe umbrella is also required.

The geology of the Hindhead area comprises a sequence of fi ne grained, Lower Cretaceous sedimentary deposits. The tunnel is within the Hythe Beds – a 90m-thick sequence within the Lower Greensand Series formation – which are variably sorted, highly glauconitic, variably bioturbated and cross-bedded sands and sandstones. The Hythe Bed unit is divided into six litho-stratigraphic subdivisions, four of which are on the tunnel alignment.

TUNNELLING CONDITIONSAt its southern end, the tunnel passes through what is described as “medium dense, clean to silty and clayey fi ne and medium sand, with subordinate weak to strong sandstone, cherty sandstone and chert”.

The majority of the tunnel passes through the more competent Upper Hythe C and D, and Lower Hythe A units – very weak to moderately strong, slightly clayey, fi ne to medium sandstone with occasional thin beds of clayey/silty fi ne sand. Typical UCS values lie between 2 and 5MPa; the ground is heavily fractured with six joint sets, including the sub-horizontal bedding, with mean fracture centres varying between 190 and 815mm. The tunnel also intersects a small number of discrete, thin, bentonitic Fuller’s Earth beds, formed from air- and water-borne volcanic ash, including crystal and lithic tuffs.

The tunnel alignment lies mostly above the historically observed water table, with the maximum predicted water table exceeding the invert level in only one location by a depth of less than 1m.

ALIGNMENTThe tunnel’s horizontal alignment was based on road design considerations and environmental constraints, resulting in a reverse curve through the tunnel with a minimum radius of 1,050m.

Vertical alignment was determined by geological constraints. The aim was to

minimise the length of tunnel through the sand at the southern end to keep it above the water table and to maximise the vertical clearance to the Lower Hythe B material, which has insuffi cient strength to carry horizontal stresses around the tunnel opening.

The tunnel passes beneath the Devil’s Punch Bowl, which provides a cover constraint to the tunnel. Cover changes rapidly from a minimum of 16m to a maximum of 58m within a horizontal distance of 130m.

DESIGNThe Hindhead tunnel layout comprises twin two-lane bores. Refer to the typical cross section below. Each bore has two 3.65m lanes, with full batter curbs and 1.2m wide verges on each side of the tunnel. The verge width is suffi cient to allow for sight-lines due to the horizontal curvature of the tunnel, to accommodate electrical services and also to provide wheelchair access to the cross passages and emergency points at 100m nominal centres along the tunnel.

The vertical traffi c gauge is 5.03m with an additional clearance of 250mm to the equipment gauge to allow for fl apping tarpaulins and other transitory gauge infringements.

A continuous drainage system is used, located beneath the curb and verge alongside the cable duct bank. Other services such as the fi re main, high voltage cables and pump mains are buried beneath the carriageway, with jet fans, lighting and communication cables contained within the crown. These requirements result in a horseshoe-shaped tunnel with an internal diameter of 10.6m and an excavated diameter of 11.6m.

FIRE AND LIFE SAFETY PROVISIONSThe tunnel has cross passages at 100m nominal centres to allow emergency escape to the non-incident bore. Cross passages include fi re hydrants, dry pipe connections, fi re extinguish-ers and emergency telephones. Emergency points (EPs) are also provided at 100m nominal centres located at the mid-point between cross passages. Each EP has an emergency telephone and fi re extinguisher.

A longitudinal ventilation system comprising 20 jet fans per bore is provided for smoke control – a fi re suppression system could not be justifi ed on cost benefi t grounds but remains a future option.

The design team focused on minimising whole life costs and developing the requisite design details.

PROJECT: Hindhead, UK

Going undergroundTom Ireland and Tony Rock of Mott MacDonald describe the design of the Hindhead tunnel and its innovative ‘permanent’ primary lining design

Cut-away drawing of the tunnel to be built as part of the A3 Hindhead scheme

Excavation works at Hindhead in Surrey

14-15WT0804.indd 14 9/4/08 17:18:20

April 2008

15PROJECT: Hindhead

TUNNEL EXCAVATION AND SUPPORTThe presence of sand layers, in one location up to 2m thick, led to the choice of the sequential excavation method, where shotcrete is sprayed at the face following each excavation advance, a process known in the UK as sprayed concrete lining. Standard hard rock tunnel support techniques such as pattern bolting were not considered suitable due to the sand layers and the very low bond stress impacting negatively on the effectiveness of rock reinforcement.

CONSTRUCTION SEQUENCE AND SUPPORT TYPESFour basic support types have been designed for the standard tunnel cross sections, with minor variations required at cross passage junctions and emergency point niches. There is one main support type for the sandstone section, with three support types covering the section through sand and the transition from sand to sandstone.

At the northern end of the tunnel (chainage 3120 to 4650), excavation is in rock (UHC/D, LHA) and support type 1 is specifi ed throughout. The tunnel is generally excavated with a full face heading followed at a distance by the bench excavation. Due to the generally stable nature of the ground and tunnel location above the water table, a closed invert is not required and the horseshoe-shaped primary lining is supported on elephants’ feet.

In addition to the sequences and support

requirements for each of the support types, contingency additional support measures have been specifi ed. The requirement for contingency measures will be triggered by geological inspection, mapping and monitoring results.

At the south end of the tunnel (chainage 2880 to 3120 (m001)), excavation is in sand (UHA/B) and support types 2, 3 and 4 are specifi ed. Due to constraints on working hours, the excavation will be carried out on dayshift only and will be made stable using steel pipe umbrella and face dowels. The pipe canopy comprises 12m-long, 114mm diameter tubes at 400mm centres with an overlap of 4-5m. The advance length is a maximum of 1m for these support types.

Support type 2 has sandy material (UHA/B) in the heading only, with the heading elephants’ feet supported on the sandstone material (UHC/D). This means self-drilling glass-reinforced plastic (GRP) face dowels are required in the heading only, and the heading can advance ahead of the bench. The face dowels are 12m long with a 4m overlap and are installed with the same drill jumbo used to install the pipe canopy.

Support type 3 has a full face of sandy material, with the elephants’ feet of the bench supported on the sandstone material. As the heading elephants’ feet are not supported on sound material, the heading must be advanced with the bench, with a 2m separation provided to maintain face stability. Face dowels are required for both the heading and the bench.

Support type 4 has a full face of sandy material that extends below the tunnel, therefore a closed invert is required. The heading must be advanced with the bench, with the invert closed a maximum of 6m behind the face.

DESIGN APPROACH AND METHODOLOGYThe excavation sequences outlined above are designed to control strains in the ground, so that as much as possible of the ground load bearing capacity is used and the strains are maintained at levels that minimise yielding.

Non-alkaline accelerators are now available with no loss in shotcrete strength with time. A recent innovation is the use of 3-D scanning survey equipment that provides excellent shape control for both excavation and spraying, and allows shotcrete-lined tunnels to be construct-ed without lattice girders. This technique has been recently used successfully for the London Heathrow Airport T5 project (Williams et al. 2004).

Historically, the inclusion of lattice girders meant the primary lining had to be considered temporary due to the corrosion potential of the steel lattice girder within the lining. Spiling is envisioned in several locations due to adverse soil layers. This will be carried out with self-drilling GRP dowels, again with no adverse durability issues.

The sprayed concrete will be reinforced with steel fi bres as is required for safe installation; however, the design does not rely on the fl exural capacity of the steel fi bres, and the lining is designed as plain concrete. This is possible due to the curved shape of the section with all moments resisted by axial forces within the lining.

A secondary lining is provided to support the proposed sheet waterproof membrane, and also to provide fi re resistance to the tunnel. Made of plain concrete, all tensile loads in the lining are resisted by the tensile capacity of the concrete.

Fire resistance is achieved by adding 1-2kg/m3 of polypropylene fi bres to the concrete mix in order prevent explosive spalling. The precise dosage of fi bres will be confi rmed by fi re testing.

Design initiatives➜ Provision of spare HV conduit and blind pits to allow replacement of life-expire HV cables in routine closures➜ Modular hydrant connections allowing replacement in routine closures without disturbance of cable ducts and other services➜ Relocation of in-tunnel sump to outside the tunnel by using a directional drilled gravity drain, allowing maintenance access to sump without a tunnel closure

AcknowledgmentsThe authors wish to thank Paul Arnold of the Highways Agency for his constructive comments and Paul Hoyland and Roger Bridge of Balfour Beatty who have provided valuable input in developing the bored tunnel design.

References➜ Bieniawski, ZT 1984 Rock Mechanics Design in Mining and Tunnelling. Rotterdam: AA BalkemaBritish Tunnelling Society, 2006 Occupational Exposure to Nitrogen Monoxide in a Tunnel Environ-ment. London http://www.britishtunneling.org➜ John, M, Mattle, B 2003 Shotcrete Lining Design: Factors of Infl uence. Rapid Excavation and Tunnelling Conference, pp726–734➜ Williams, I, Neumann, C, Jäger, J & Falkner, L 2004 Innovativer Spritzbeton-Tunelbau für den neuen Flughafenterminal T5 in London. In Proc. Österreichisher Tunneltag 2004 Austrian Committee of the ITA, Salzburg, pp41–62. Salzburg: Die SIGN Factory

Excavation works at Hindhead in Surrey

14-15WT0804.indd 15 9/4/08 17:18:26

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Tunnelling to a better world

UNDERGROUND infrastructure works look set to increase in Europe over the next ten years in new-build, refurbish-

ment and maintenance. It is astonishing that our industry is witnessing a huge demand for resources and skills. All this is happening at a time when societal constraints and infl uences are either encouraging increased use of the underground or are infl uencing how we use this realm.

There are a number of contemporary issues facing our industry that will involve:ËBuilding sustainable infrastructureËProviding safe and secure infrastructure and energy for the community ËEnsuring the provision of energy effi ciencyËProviding climate change-resistant infrastructure.

The ability to meet these issues is affected by: ËAccess to skills and resourcesËCostËInnovationËInfl uence and communication.

Shortage of resources is a big issue for our industry, whether it’s professionals or skilled labour. This will require us to attract new recruits, retrain people from other industries and provide ongoing training of existing skills.

We might need to attract people from the developing nations that are building under-ground infrastructure in the Far East and South East Asia, and our current workforce will need to be more mobile. We will also need more collaborative working to make more effi cient use of human resources.

In the future, costs will be infl uenced more by effi ciencies in construction, increased mechanisation and automation. They will also be infl uenced by the nature and method of forming contracts, while more collaborative working will be needed to reduce costs. And, sooner or later, we will have to address the issue of more standardised methods of construction and installation.

Innovation will depend on investment by government and private industry, and incentives need to be available for people to spend time and effort in innovation. We need to inspire confi dence to embrace innovation. Ours is a conservative industry, as we know. We have to

be prepared to take commercial risks to promote the sustained use of new techniques, and we also need clients and owners to encourage this leap of technological faith.

Communication and infl uencing opinion is also required to raise awareness of the benefi ts of going underground. International Tunnelling Association (ITA) member nations should be doing more lobbying. We must agree on concerted European issues, and prioritise how we promote or address infrastructural problems with underground solutions. So, l believe our industry has a great deal to address.

From an ITA perspective, our strategy has focused on these needs within the efforts of working groups/taskforces: ËWG3 – maintenance and repairËWG11 – immersed tunnelsËWG14 – mechanised tunnellingËWG 15 – underground and environmentËWG17 – long tunnels at depthËWG18 – trainingËWG 20 – underground solutions

In addition, other groups are working on contemporary issues. ITA’s strategy is focused on: ËPublic outreach and infl uenceËTrainingËFacilitation of innovative ideas between nationsËEncouraging more sustainable solutions in the use of underground technology.

My own concerns for the future use of under-ground infrastructure are how to improve the use of management to reduce the risks of underground projects, thereby lowering project costs and safeguarding our workforce and the public. In the past, tunnelling suffered from poor publicity, and it is up to us to promote better processes to manage our industry and project a better image. Further issues include reducing the unnecessary conservatism in our industry and addressing the skills shortage.

A few days ago, I asked a UK transport client with close ties to future underground projects what he felt the tunnelling industry needed to address to create a better future. These were:ËRecruitment and training of alternative resources ËOutreach to other global resources ËExploiting technology

ËDocumenting knowledge of scarce skillsËManaging competence.

At a recent tunnelling meeting at the Westminster parliament building in London, l asked a well-known professor of engineering about his big concerns for the future of our industry. His concerns were for better use of reliable remote sensing in geological exploration; better prediction of ground conditions; more intelligent monitoring of the construction and operational behaviour of tunnel environments; reducing conservatism in lining design; organisational structures using the above as a ‘smart’ means of working, and more knowledge sharing through organisations such as the ITA.

In summary, l think the focus for improvement and innovation to help our industry’s future is:ËMuch better knowledge sharingËTechnology/automation effi ciencies to reduce costs and fi ll resource gapsËMore collaborative working relationships ËProactively managing risks ËEnsuring that sustainable, environmentally- friendly design is cost-effective.

The ITA is addressing these issues through congress themes, working groups, taskforces, strategy and the ITA Committee on Underground Sub-Surface. But, l suggest that we need to be more effective at communicating and convincing the EU of the need to invest in research to help resolve future issues, and make tunnelling a logical and sustainable choice for infrastructure.

Martin Knights is president of the International Tunnelling Association (ITA) and executive director of Jacobs Engineering UK

Martin Knights of the ITA examines some of the issues confronting EU countries with respect to tunnelling and the development of underground spaces

April 2008

17COMMENT: Martin Knights

17WT0804.indd 17 11/4/08 10:26:12

ALTHOUGH small, the bit is an essential tool in rock and ground drilling. When it works well, nobody notices, but woe

betide if it ever fails. The whole drilling process might grind to a halt, which can, of course, be a very costly process. For it is not only the cost of the bit, but also the associated costs such as that of the labour involved, machine hours and the investment cost of the drill bit, to name a few. All of this will eat into the contractor’s profi t.

Every driller has an opinion as to what bit type works in particular circumstances. This article will look at the key criteria of bit selection for rock and ground drilling in tunnelling applications. Rock and ground drilling are handled separately since the products they each require are very different from each other.

BIT SELECTION FOR ROCK DRILLINGA button bit comprises fi ve basic elements: body, face, buttons, fl ushing holes and thread. When selecting the bit, the correct combination of these elements will give the best drilling results. Drilling conditions should be

known, particularly the rock hardness, abrasiveness and its homogeneity, or lack of. Regardless of the application, whether production drilling or tunnelling, the same conditions apply.

Buttons are the part of the bit that actually breaks the rock. Typically made of tungsten carbide, they can usually be divided into three groups: spherical, semi-ballistic and ballistic.

Spherical buttons are probably the most commonly used group. They do not break easily,

but their breaking action on the rock is slow. Ballistic buttons are longer and sharper than their spherical counterparts, enabling faster drilling, although with the downside being a greater risk of button breakage. Semi-ballistic buttons are a compromise that aim to combine the benefi ts of both button types.

Face design determines the button layout and face formation. It has the greatest infl uence on drilling performance and is thus the most important parameter when selecting the correct bit for the prevailing rock conditions.

Even though all manufacturers have their own special face types, there are two basic face types that can be defi ned: fl at face and dropped centre.

Flat face is a general, all-round model. Dropped centre should create a certain hole profi le against the bit face that helps to keep the holes straighter.

Veikko Kuosa of Robit Rocktools outlines the basic characteristics of these essential rock-drilling tools, with some case studies where they have been used

Know your bits from your buttons

April 2008

18

Installing tubes at the face of the SAAS tunnel

Flat face Drop centre

Two basic button types

TECHNICAL: Drill bits & buttons

18-21WT0804.indd 18 9/4/08 12:49:44

April 2008

19TECHNICAL: Drill bits & buttons

Know your bits from your buttons

The best button layout for the conditions is determined by the hardness, abrasiveness, and homogeneity of the rock. For hard rock, the rule of thumb is to choose a bit with many small buttons. For abrasive rock conditions, larger gauge buttons are used to protect the bit wearing out prematurely. In heterogeneous rock conditions, ballistic buttons are not recommended because of the high risk of button breakage.

Holding the buttons in place is the bit body’s primary task, thus the quality of the material must be emphasised. There are two basic bit body designs in use. The standard body can be used in most cases, but when extra hole straightness is required, a ‘retrac’ body is used. This is usually the case with long hole applications, but in tunnelling the holes are rarely longer than 6 metres.

However, in faulted rock conditions, a retrac body can bring benefi ts, and in tunnelling applications too. The wide tail of the retrac bit bears against the hole walls and helps to steer the bit in a straighter line.

Flushing is essential as it uncovers the underlying rock by moving the broken rock fragments up from the hole. If fl ushing does not work properly, the bit sticks in the hole, requiring more drilling power, which could result in rod breakage. The bit can also heat up excessively, leading potentially to bit failure.

The bit is threaded on to the rod. If the diameter of the thread is increased in relation to the bit diameter, there is a higher risk of bit-body breakage due to the bit’s walls being too thin. Conversely, excessively decreasing the thread diameter could lead to rod breakage due to the torque induced in the bit.

Luckily, the choice of the correct bit-thread ratio is made by bit manufacturers who usually only make bits with proven threads in their standard ranges. Every now and then, some manufacturers create new thread types, but there are some standard thread types that are available from all manufacturers. In tunnelling, the most typical are R32 and R35.

Now that we know the rudiments of bit selection, things get a lot easier. However, it is important to bear in mind that all applications are unique and compromises might need to be made to reach the best bit choice. Ultimately, it is up to the driller and his preferences.

TUNNELLING UNDER HELSINKI At street level in Fleminginkatu 36, Helsinki, life carries on as normal, but beneath the surface a great tunnelling project is taking place. Kallior-akennus Yhtiöt Oy is building an underground carpark for SOK. The tunnelling project began in September 2007 and should be ready by the end of June 2008. Meanwhile, 66 000m3 of rock

will be excavated to provide room for the cars.

Drilling and blasting in urban areas sets high standards on drilling accuracy and loading the explosives. The whole process has to be under tight control. In underground applications like tunnelling, the process causes vibration that could be harmful for buildings.

In Helsinki, a further challenge is posed by groundwater levels, which should not be adversely affected by the tunnelling work. To ensure this is so, cracks and fi ssures are fi lled with grout, injected through the drilled holes.

Three-boom Sandvik Axera 10 with HLX5 drifters are being used for face drilling. The rock is a fairly homogeneous, grey granite, so drill bits with a fl at face and small, sharp buttons were selected.

Robit button-bit models 35R48S2 and 38C55S, both with ballistic buttons, were used. Robit’s S model features numerous small-diameter buttons, making it a fast drill option. And 102mm-diameter reamers are also being used.

To extend bit life, the buttons were grinded by Robit’s grinding service in Lempäälä. By grinding the buttons, bit life can be three to four times longer than without any maintanance.

According to Juha Selin, site manager of Kalliorakennus Yhtiöt Oy, Robit’s bits have performed as expected and have not exceeded the budget.

“Face design determines the button layout and the face

formation. It has the greatest

infl uence on drilling

performance”

The two basic body types

Normal body

R-Retrac

Ë

18-21WT0804.indd 19 9/4/08 12:49:48


CASING FOR TUBE UMBRELLASWhen drilling a tunnel in overburden or broken rock conditions, the challenge is to stabilise the tunnel roof so that it will not collapse. A widely-used method for achieving this is with a tube umbrella; a technique also known as forepoling. Steel tubes fi lled with grout and placed in an umbrella formation support the tunnel roof, and they are installed according to the tunnel profi le. Typically, the tubes are 15m long and formed by 3m steel casings.

The most common casing sizes are 88,9/8, 114,3/10, and 139,7/10 (casing diameter/maximum casing wall thickness). Different countries have their own standards, and the casing used usually depends on the engineers who plan the tunnel. Casings are drilled in the wall by jumbos with a basket boom to allow a worker to set the casings in place.

Several different systems are available for casing drilling. Some are based on eccentric and

others on concentric rotation. In eccentric drilling systems, there is a high risk of delay due to jamming and hole deviation, especially in fractured rock conditions or in overburdens with big boulders.

With concentric drilling systems, straighter holes are achieved with lower torque, regardless of the ground formation. In addition, concentric systems result in solid contact between the ground and the casing. They are more common in tube umbrella projects.

The main elements of a concentric casing system are the pilot bit, ring bit and casing shoe.

Some manufacturers offer all system parts separately. In Robit’s case, the casing shoe and ring bit are pressed together during manufacture.

The pilot bit is locked to the system by feeding the rod and applying some rotation at the same time. The easy, automatic connection between the pilot bit and the ring bit is easy for a novice to grasp initially, and allows fast drilling for experienced users.

Casing shoes are usually welded to casings on site. To save time, there are usually several casing shoes welded to the casings beforehand. Also, drill rods with pilots are ready-installed in their place on the casings.

SAAS TUNNELThe Saas tunnel in Switzerland is one of many tunnel projects in that country, but it is becoming a very challenging drilling project, thanks to its practical importance and technical challenges arising from ground conditions.

Two basic button types

Standard/spherical/round Ballistic/semiballistic

Ë

Face drilling

“The main elements of a concentric

casing system are the pilot bit, ring bit and

casing shoe”

18-21WT0804.indd 20 9/4/08 12:49:52


Local Presence – Global Competence TUNNELING SYSTEMS

www.dsi-tunneling.com

Headquarter TunnelingALWAG Tunnelausbau Gesellschaft m.b.H.Pasching/Linz, AustriaPhone +43-7229-6 10 49 0Fax +43-7229-6 10 49 80E-mail: [email protected]

GROUND CONTROL SOLUTIONS

NottinghamUNITED KINGDOM

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Rebar Rock Bolts and Spiles

IBO, IBI & DYWI® DrillSelf-Drilling Bolts and Spiles

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Steel Arches and TH-Beams

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Pantex Lattice Girders

AT – LSC-Elements Lining Stress Controllers

AT – Casing System

AT – Pipe Umbrella Support System

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AT – GRP Injection System

Each tunnel has a different geology and requires specific customized products and systems. DSI Tunneling Products and

Systems match these requirements perfectly.

Our extensive R&D activities guarantee innovative, flexible and reliable underground support products to control every imaginable condition. We offer a complete line of high-quality ISO 9001:2000 certified and patented products. DSI is a leading company in the development, production and application of ground control solutions for the tunneling market. In line with our strong service approach, we are always committed to satisfying our customers’ demands.

The tunnel is part of a 27-year-old project designed to alleviate the traffi c problems on the A28 road going from Landquart and leading to the famous city of Davos in the Canton of Grison.

As already achieved in the villages of Klosters and Küblis, the traffi c problem in Saas will be solved by the construction of a by-pass tunnel.

Awarded the contract for the construction of the tunnel was the joint venture ATUS (ARGE Tunnel Umfahrung Saas), consisting of the companies Walo Bertschinger AG, Zürich, CSC Impresa Construzioni SA, Lugano, Rothpletz, Lienhardt + Cie AG, Aarau and Gebr. Vetsch, and Küblis.

The Saas Tunnel is 2,580m long, including open-cut stretches of 130m at the Saas West junction, as well as 15m at the Waldhof portal. The smallest radius is 600m.

Starting at the Saas West junction, the gradient of the tunnel is 2.6% in the direction of

Waldhof. The transversal slope is 6.5% on curves and 3% along straight lines.

As a consequence of the diffi cult geological conditions of 20% of the tunnel, the descending

excavation will be achieved under the protection of tube umbrellas along a total length of 380m, starting from the newly-built Hexentobel bridge.

Ground conditions along this diffi cult section could be described as an alternation of hard broken rock and soft ground. Most of the tools available for forepoling applications cannot be used in this type of condition due to the high drilling requirements.

While most forepoling products are made for relatively soft ground, the Robit Casing System, called RoX, was designed to be used from the softest conditions to the toughest rock.

ATUS has chosen Robit, among several suppliers, for the supply of the casing system to drill the totality of the arches. The reinforcement of the roof consists of 30 arches of 30 piles. Each pile will be 14m long, with the casing having a diameter of 114.3mm and a thickness of 6.3mm.

“The Saas tunnel in Switzerland is one of many tunnel projects in that country, but it

is becoming a very challenging drilling

project”

On the left, a top hammer pilot bit from two different angles and on the right a ring assembly (ring bit + casing shoe) from two different angles

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April 2008

22

HOW do today’s tunnelling machines do it? TBMs and roadheaders must ma-nipulate through questionable soil

conditions and negotiate a snaking underground alignment of known obstacles, also hitting inter-mediate stations on target, to end up within ±5mm of the design goal, regardless of the dis-tances involved.

It is a complex process that begins as a concept at the tunnel designer’s desk, well before the first shaft is sunk, and ends with an on-target hole-through celebration. Between this austere beginning and celebratory finish is the concerted and dedicated effort of many, involving personnel from diverse disciplines including mechanics, plumbers and electricians, to name but a few.

But, maintaining line and grade is the job of the thankless surveyor and his staff, utilising the guidance method of choice. These guidance tools have evolved over the years from rudimentary theodolites and measuring tapes used on drill and blast tunnels, through lasers and grid targets, to today’s modern electronic guidance systems.

We marvel now how land surveyors of yesteryear, using those primitive theodolites and measuring tapes, could start on opposite sides of a mountain and successfully meet in the hostile darkness beneath the huge mass of rock. If those surveyors were to have the capability to see into the future, they would be astonished at the proliferation of today’s available toolkit, which includes GPS for above-ground project setup, north-seeking gyros for precise establishment of direction, and the marvel of distance measure-ment with light beams.

And then, when the tunnel excavation begins, the wonders of technology further provide us with today’s electronic guidance systems – PPS, TACS, VMT, ZED and others – that provide virtually hands-off, precise presentations to the machine operator of real-time machine position relative to design line and grade.

But, as high tech as these systems are, they all utilise the same concepts that were fundamental to the surveyors who met under that mountain –

namely the theodolite (known today as a ‘total station’) for measuring angles, and the equations used in calculation of location. Those theodolites of the past used metallic Vernier scales to display angles. The surveyors used a magnifying glass to enlarge the numbers sufficiently to read them accurately. Distances were measured with steel tapes that required the user to manually compensate for the variation in tape length due to temperature variations.

Today’s total station measures angles electronically with great accuracy and integrates electronic distance measurement to remote targets. Minor mechanical variations in manufacture of the total station, and the impact of atmospheric conditions on distance measurement, are all automatically compen-sated for by the total station.

In addition, total stations use motorised hand controls for aiming toward the target. And finally, these ultra-smart total stations contain target-seeking capability, which, when pointed reasonably close to a target, will automatically centre on the target and complete a full set of angle and distance measurements to that target.

These capabilities of the total station enable it to be fully computer-controlled and become the central core of the hands-off capability of today’s modern tunnelling machine guidance system. ‘Guidance’ is somewhat of a misnomer, in that the systems don’t control the tunnelling machine but present the machine operator with a display showing accurate indications of the machine’s real-time location rela-tive to the design line and grade.

Using the gUidance systemsSo, what is the general operating procedure to effectively utilise these high-tech guidance systems?

In the tunnel, a total station is mounted on a bracket fixed to the tunnel wall. A reference prism is mounted separately in a similar manner. The positions of each are ‘surveyed in’ by the survey staff to determine the 3D locations of each in the coordinate system of the project. These stations provide the known locations from which measurements of the tunnelling machine position are to be made.

Under computer control, the total station automatically measures to targets that are mount-ed in fixed positions on the excavating machine. (See Figure 1) The total station measures angles and distances to these targets as related to the fixed total station location, whose position is fully defined. A dual-axis electronic inclinometer is also mounted on the tunnelling machine to

technOLOgy: Tunnel machine guidance

From a to B: the art of tBm guidance Tunnel machine navigation systems have moved on a bit since the days of the traditional theodolite. But just how do they navigate in the bowels of the earth? Bill Hollinshead reveals how it is done

Figure 1: fixed targets on the excavatng machine

Figures 2 (above) and 3 (left): block diagrams of a PPS Machine Guidance System

22-23WT0804.indd 22 9/4/08 11:37:48

April 2008

23

precisely measure roll and pitch.Then, using a robust onboard computer, to

which the inclinometer and total station are electronically interfaced, the measurements are processed by many of the same equations employed by those surveyors of yesteryear, to calculate the precise location of the machine for presentation to the operator. (Figures 2 and 3 are block diagrams of a PPS Machine Guidance System.)

The ‘gold standard’ used to determine this final location is the design line and grade to which the measurements are compared. For instance, toward this end, the PPS system uses a customised data file, which combines design line and grade, and which has been previously installed in the guidance system computer at job startup. It is this data to which the real-time total station measurements are compared in order to provide the current differential positioning information to the machine operator on an ‘at-a-glance’ graphics-oriented display. Other useful information is also presented on the operator’s display screen. (See Figure 4.)

An ancillary, but important, capability of today’s electronic machine guidance systems is the real-time calculation, selection and orientation of pre-cast liner segments. This feature combines manufactured ring geometry and theoretical ring sequence (both stored in the system computer) with ‘just-mined’ values of shield position, extension cylinder values and tail clearance, to provide optimised recommen-dations for ring type selection and keystone positioning. Graphical presentations of recommended ring selection and orientation are available for in-tunnel use. A database of the installed ring sequence is provided for analytical use by tunnel management.

Operation of the modern tunnelling machine guidance system is generally hands-free. Exceptions are the periodic relocation of the total station and reference prism mounting brackets to new positions immediately behind the tunnelling machine. However, even these events are computer-assisted to enhance movement accuracy and minimise the time and

personnel required for the move. The necessity for this move-up is generally determined by line-of-sight considerations (such as when negotiating curves) and other physical parameters.

The primary factors contributing to successful guidance system operation are:

1) A clear optical path between the total station and the tunnelling machine-mounted targets;

2) Stable brackets for the machine-mounted targets, as well as the tunnel wall-mounted total station and reference prism;

3) Precise knowledge of the locations of machine-mounted targets relative to the machine centre line; and

4) Regular independent survey of the as-mined tunnel to confirm agreement between the guidance system and final tunnel location.

There are many advantages to the use of an electronic guidance system, as compared to manual techniques such as laser and grid targets. Among these are:

1) Reduced ongoing requirement for survey personnel;

2) Steady consistency and high accuracy of as-mined line and grade;

3) Reduction of reading errors; 4) High productivity due to significantly

reduced time required for ongoing survey operations;

5) Ability for arbitrary placement of total station, as opposed to the requirement for

a laser to be placed on a precise alignment;

6) Automatic database archiving of as-built tunnel information; and

7) Automatic creation of as-built ASCII files and PDF files for external analysis of system data.

Most of today’s electronic machine guidance systems have their genesis in a common source. In the early 1980s, Mr Alwin Poltinger led a group of engineers and surveyors who created a guidance system for internal use by the DYWIDAG Construction Company, based in Germany. Some of the personnel from that group went their own way to create alternative guidance systems. With the demise of the DYWIDAG construction activities, Mr Poltinger continued with his guidance system, which is now the much-respected PPS (Poltinger Precision Systems) Machine Guidance System.

The surveyors of the past who met under that mountain set the groundwork requirements. Today they have been fulfilled by modern electronic tunnel machine guidance systems – tools that are now a widely accepted technology that adds to the high technology base of PLCs, variable-frequency drives and real-time machine performance data communications.

William (Bill) Hollinshead is an electronic engineer with Precision Centerline, Inc., the North American distributor of PPS Machine Guidance and Control Systems, Suwanee, Georgia, US. E-mail: [email protected]

technOLOgy: Tunnel machine guidance

Calculating segmental lining ringsThe reinforcement of a tunnel with tubings can be simplified and standardised with the optional PPS ring calculation software. Ring geometry and theoretical ring sequence are the basis for the calculation. Based on shield position, cylinder values and tail clearance, the PPS program chooses – from pre-defined ring types – the one that keeps the TBM on line with the smallest offsets or to bring it back to the tunnel axis. When using universal rings, it shows the position (rotation) of the keystone.

This feature is a very good example of the integration of the guidance system in the excavation process. It helps the operator to keep on track during standard excava-tion. When the machine stops to prepare for ring erection, the program asks for additional geometrical values (cylinder extraction and tail clearance). These can be provided by manual measurement or come from automatic systems installed on the machine. Very quickly, the fully automated process can present the best-fitting ring type for the present position. This allows the crew to focus on their original tasks without distraction.

Once the ring is finished, all related data can be stored in the database. From there it is possible to print out a ring build protocol, which is an essential part of documentation.

Software displays the best-fitting segmental ring type

Figure 4: the operator’s display screen

22-23WT0804.indd 23 9/4/08 11:37:50

Figure 2: cross-section of 11.62m-diameter railway TBM

Figure 4: cross-section of 15.2m diameter

TECHNOLOGY: Non-circular TBMs

Non-circular, full-face TBMs In this paper from the World Tunnel Congress in Prague last May, Professor M Krcík of the Geotechnical Design Offi ce in Bojnice, Slovak Republic, looks at various non-circular concepts in TBM design

RAPID development of full-face tunnel-boring machines has resulted in the use of very large machines that are often

more than 14m in diameter. However, only two-thirds of those excessive cross-sections are used effi ciently. Therefore, the development of these machines focuses on excavating ideal cross-sections, similar to those that are typical of the New Austrian Tunnelling Method (NATM). The above-mentioned developments mainly take place in countries such as Japan and Germany, but also in Slovakia where private enterprise plays a major role. Several concepts associated with these machines are described below.

INTRODUCTIONTunnel-boring machines with diameters in excess of 14m can be found working on various projects: in Madrid, a Herrenknecht 15.2m-diameter EPB shield; at Niagara Falls, a Robbins 14.4m-diameter, hard-rock TBM; in Switzerland, a 14.4m-diameter Wirth machine, and in the Netherlands, there is a 14.87m-diameter TBM from French manufacturer NFM.

However, a disadvantage of such large tunnel-boring machines for traffi c tunnels, railway or road tunnels with two-to-three lanes is that the

excavation in the bottom part of the profi le is not utilised and often in-fi lled (see fi g 2). This is a consequence of TBM-driven tunnels, where the road pavement is supported by columns or nibs along the full length of the tunnel, similar to a bridge deck (see fi g 4).

But, non-circular types of full-face, tunnel-boring machines, which have cross-sections that create the profi le achieved in drill-and-blast and NATM, solve this problem.

SUCCESSFUL NON-CIRCULAR TBMsJapan is well-advanced in the design of non-circular, tunnel-boring machines. However, these are mainly designed for soft, sedimentary rock, probably due to the fact that all big industrial cities in Japan are situated along the coast, which is typifi ed by this type of ground.

An advantage of Double-O-Tube (DOT) tunnel-boring machines that have circular cross-sections is that the excavated tunnel takes up less space – in terms of both height and width – and it has a lower overburden compared to a single, circular tunnel tube (see fi g 5). However, due to static reasons, the disadvantage is that column support is required at the intersection of the two circles. This is also the case with multi-circular shield machines, which have been used successfully for subway stations (see fi g 6).

Various cross-sectional shapes (fi g 7) can be achieved with a shield machine’s circular disc

cutter located at the centre of the face and featuring multiple planetary cutters at the extremities (fi g 8). The orbit of the planetary cutters can be changed by adjusting the angle of the swing arms attached to them. Various cross-sections, such as rectangles, ovals and arches, can be created relatively easily.

Figure 9 shows the DPLEX (developing parallel link excavation) shield method as used in Japan by the Hitachi Company for the construction of Subway line No. 11 in Tokyo.

CONCEPTS IN NON-CIRCULAR TBMsFOR SOFT GROUNDFor soft ground, there are two interesting shield concepts designed for full-face tunnelling. One is the DPLEX shield for a three-lane motorway tunnel with an economical cross-section of 17.2m wide and a total length of 12.8 m. The other is a quadripartite cutterhead (fi g 11) that, for stability, has the face of a pre-EPB shield and the rotational speed of a screw conveyor.

The TBM concept, combining rotational and sliding cutter methods, is also interesting (fi g 12). The TBM is of the slurry-shield type.

SUCCESSFUL NON-CIRCULAR, HARD-ROCK TBMsThis area has been Wirth’s main focus for the past 15 years and for The Robbins Company for the past 20 years. Since 1991, Wirth has developed and manufactured the Continuous Miner Machine, which has been successfully used in Canada. Its undercutting

Fig 4: cross-section of 15.2m diameter

Figure 5: cross-section of a DOT (Double-O-Tube)

Horizontal configuration

Figure 6: a triple-circle shield tunnelling machine excavated two railways and a platform

Figure 7: variations of cross-section

Figure 8: three-part articulated OK (muddy soil pressure) shield

Figure 9: DPLEX shield, 4m wide, in Narashino City

24

April 2008

Figure 2: cross-section of 11.62m-diameter railway TBM

Figure 4: cross-section of 15.2m diameter

Fig 2: cross-section of an 11.62m-diameter TBM-driven tunnel

Fig 6: railway line and platform excavated by a triple-circular, shield-tunnelling machine



















Fig 7: cross-section variations

Figure 17: profile driven by means of NATM with the use of the ‘two plus two face’ TBM

Figure 18: 3D view of the TBM with partial section through upper barrel-shaped cutting head







Fig 5: cross-section of DOT (Double-O-Tube) against conventional excavations

24-25WT0804.indd 24 9/4/08 16:44:03

TECHNOLOGY: Non-circular TBMs

technique distinctly increases the excavating performance per cutter.

This development has now been applied for the fi rst time to the reaming (undercutting) principle. Wirth’s TBE 500/1440 H-HST is a reaming tunnel-boring machine, capable of boring diameters of up to 14.4m. Used to drive the Uetliberg tunnel in Zurich, Switzerland, last year, the machine has a slightly elliptical profi le at 14.4m wide by 14.2m high.

The American tunnelling machine, a hard-rock excavator made by Robbins that belongs to the class of machine with conventional radial chisels, has also been used with success.

NON-CIRCULAR, HARD-ROCK TBMsThe idea of developing technologies that would enable us to excavate an economical profi le rapidly is based on the fact that the construction of more than 50km of motorway tunnels are required in Slovakia. As there is no need for an invert in the majority of long Slovak tunnels, the horseshoe-shaped economical profi le seems reasonable and advantageous.

The ‘two plus two face’ TBM concept

comprises four rotary-cutting heads (fi g 17). The front two have the same circular shape. Behind them are two other cutting heads, of which the barrel-shaped higher one excavates the crown while the lower one, which may be barrel- or drum-shaped according to the nature of the rock, excavates the invert. Such a confi guration enables the excavation of a

fully-economical cross-section.Another advantage of the ‘two plus two face

TBM’ concept, compared to the circular one, is that in the case of geological dislocation it can lower the upper head by means of hydraulic jacks (fi g 18). This allows access to the space ‘over the barrel heads’ without the need to make additional excavations.

Two possible tandems can be attached behind the ‘two plus two face’ TBM cutting-head system:ËTBMs with expanding hydraulic jacks pressed against the tunnel liningËTBMs with extruded, concrete lining systems, enabling the sort of rapid tunnelling that is well-known, particularly in Japan.

A TBM concept can also be used to excavate the horseshoe-shaped profi le associated with NATM. This comprises one non-circular head with two additional, pear-shaped cutting heads (fi g 20) for fi nishing and excavating the horseshoe-shaped profi le. The power supply for the fi nishing cutting head is situated inside the barrel, which provides electricity and cooling via a non-rotating shaft.

In soft rock, it is possible to use this type of TBM with the shield and segmental lining. The concept of TBM that has only one non-circular head and two fi nishing pear-shaped cutterheads behind, which excavate a horse-shoe shaped profi le, is well-known in the NATM sector. The power supply to the fi nishing cutterhead is inside a barrel in which electricity and cooling is provided by means of a non-rotating shaft. Both TBM concepts are patented.

In softer rock, it is possible to use the concept with shield and segmental-lining system. Apart from the use of pear-shaped cutters for the TBM gripper, it is also possible to use fi nishing cutters for a shield-type TBM. Hydraulic jacks for pressing against the tunnel lining adjacent to the fi nishing cutting heads have a telescopic design.

CONCLUSIONThe economic advantages of a non-circular TBM with a horseshoe-shaped profi le is useful for long, full-face traffi c tunnels. The cost of excav-ating a tunnel is lower than with a circular TBM:Ë The cost of rock excavation is 20-30% lower due to the smaller profi le, i.e. lower costs for electric energy and changing of cutting discsËThe construction cost of lining a smaller tunnel circumference can be 15-20% lowerËBackfi lling and compacting of the space beneath the road pavement or railway increases the speed of driving

Disadvantages of the non-circular TBM are:ËHigher capital cost associated with making a more complex TBMËMore rings for the tunnel lining.

For tunnels longer than 3km, these disadvan-tages are mitigated and the advantages of non-circular TBMs prevail.

ReferencesYukihiko ISHIKAWA 1998, Attachment Type Three-Centred Station Shield; Ing. Marián KRCˇ ÍK 2002, A possibility of designing TBMs for economical cross section tunnels Geotechnics 2002 Bratislava; Hitachi Construction Machinery Co., Ltd. 2006, Activitie 2006Underground Space – the 4th Dimension of Metropolises – Barták, Hrdina, Romancov & Zlámal (eds) © 2007 Taylor & Francis Group, London, ISBN 978-0-415-40807-3i

Non-circular, full-face TBMs for the 21st CenturyFigure 5: cross-section of a DOT

(Double-O-Tube)












Fig 8: three-part articulated OK (muddy soil pressure) shield

Fig 9: 4m-wide DPLEX shield, Narashino, Japan

Figure 11: developing parallel link excavating 4-division type

Figure 12: combination of the rotation cutter and sliding cutter methods

Figure 11: developing parallel link excavating 4-division type

Figure 12: combination of the rotation cutter and sliding cutter methodsFig 11 (left): quadripartite cutterhead. Fig 12 (right):

combination of rotation cutter and sliding cutter methods





Figure 20: profile of NATM driven with use of full-face TBM with the finishing pear-shaped cutters

Figure 23: sample cross-section of the motorway tunnel by means of the non-circular TBM with

a smaller area compared to the circular TBM

Figure 24: sample cross-section of the railway tunnel driven by means of the TBM

Fig 20: TBM with pear-shaped cutters for NATM profi le

Fig 18: 3D-view of TBM with partial section through upper barrel-shaped cutting head

Fig 17 (left): ‘two plus two face’ TBM

April 2008

25

24-25WT0804.indd 25 9/4/08 16:44:16

April 2008April 2008April 2008

262626SHOW REVIEW: ConExpo 2008

SUNNY, multi-themed and gambling-mad Las Vegas was the venue for ConExpo, which was held between March 11-15.

Not perhaps the best place you might think for a major trade exhibition, but the Las Vegas Con-vention Centre is probably as good a venue as you’ll get anywhere on the planet, and probably a lot better than most.

ConExpo is North America’s largest trade fair of any industry, setting records for attendance, exhibit space and exhibiting companies, and is one of the largest shows of its kind anywhere in the world.

In terms of exhibition space, it provides a truly vast expanse: 211,966m2 spread over many halls fi lled with every conceivable construction product or service from over 2,182 exhibitors. It proved an all-encompassing construction show.

Attendance fi gures were impressive, as anyone who was there would have confi rmed. In just fi ve days, ConExpo had 144,600 visitor registrations; a seminar programme offered 130 sessions on all aspects of construction.

Yet despite all this success, ConExpo can in no way be regarded as a major tunnelling (or indeed trenchless) event, despite the presence of major players such as Atlas Copco and Sandvik. So why go there and write a review in the fi rst

place? Simply because, despite the small number of tunnelling-orientated manufacturers, the show boasts many other companies, products and services which, although of a general nature, are as applicable to tunnelling as to other construction sectors but are not normally reviewed. So, below is a selected list of those services and products that fall into this category. The only downside to it all is that the next ConExpo will be held in Las Vegas in three years time – but as the saying goes, ‘what happens in Vegas stays in Vegas’.

ANTRAQUIPMaryland-based Antraquip says that its rock and concrete cutting attachments have taken the construction industry by storm. The company’s rotary cutters, ranging from the AQ-1 to the AQ-6, are designed to excavate rock and concrete without undue noise and vibration, and can be used with excavators ranging from 1.5 to 120 tons. The company is now offering a number of cutting drums for tunnelling, as well as numerous types of carbide cutter bits (picks) for different applications. Some of the benefi ts claimed for the company’s cutter boom attachments include rugged gears and housing; powerful high-torque hydraulic motors; and a

swivel mechanism that allows the cutter to be turned at 22.5º increments without having to remove the cutterhead from the excavator.www.antraquip.net

ATLAS COPCOTunnelling afi cionados would have found various items of interest that were newly unveiled at Atlas Copco’s press launch. This included the Secoroc RC 50 (Reverse Circula-tion) hammer, which has been designed for 140-152mm holes and built for tough conditions. Its open standard bit shank means easy compatibil-ity so that drillers are not tied to using equipment from one supplier. It also has a through-hardened centre recovery tube for a longer service life.

Also of relevance to tunnelling is the new

The latest ConExpo show offered a number of products and services that are as applicable to the tunnelling world as to other construction sectors

The Antraquip hydraulic cutter boom attachment

ConExpo raises the bar

26-29WT0804.indd 26 9/4/08 16:32:35

April 2008

27

Dynapac range of articulated asphalt rollers. Covering the 10-13t range, the new high-frequency (HF) tandem rollers are aimed at large projects such as highways and airports, but suited equally for use on both thin and thick asphalt layers.

Atlas Copco says the new machines have been designed to be simple to service and are also modular so they can be supplied to suit the particular needs of customers. They are powered by a Cummins QSB 4.5 water-cooled turbo-diesel engine with after cooler, with rated power at 82kW or 93kW at 2200 rpm for the Dynapac CC424HF; 93kW or 112kW for the CC524HF and CC624HF. The new models have operating masses ranging from 10.5t to 12.6t, with the weight split evenly between front and rear drum modules.www.atlascopco.us

BRUNNER & LAYBrunner & Lay manufactures a wide range of tools for the tunnelling sector, supplying many of the well-known drill rig manufacturers. The company’s range of drilling accessories have been designed for hard-hitting rock drills and include rock bits. Taper bits and button bits are available in numerous diameters. Also available are shanked rods, drifter rods, drill steels, couplings and shanked rods.www.brunnerlay.com

CHEMGROUTGrouting equipment supplier ChemGrout’s stand was bristling with new developments. This included the CG-542 Series of Rock Bolt and Cable Grouters (pictured) that have a low profi le designed for confi ned spaces, such as tunnels and mines. Hailed as being ideal for non-fl owable, cement grouts with water/cement ratios as low as 0.35-0.40, the units have two 22-gallon mix tanks, a 10-gallon holding hopper and progressive cavity pump for continuous, non-stop pumping. A further benefi t is that mix tanks have removable tops to facilitate clean-up. An auger in the 10-gallon holding hopper ensures that the material is kept well mixed while awaiting to advance to the pumping stage.

Units come in air, hydraulic, electric/hydraulic and diesel/hydraulic power options.

Also new from ChemGrout is the CG-680

High Pressure Colloidal Series of skid-mounted grout plants that can mix and pump slurries of cement, fl yash, bentonite and lime fl our. They come in output sizes of 10, 15, 20 and 32 gallons/min and can be powered by hydraulic, electric/hydraulic and diesel/hydraulic options. www.chemgrout.com

CON-ARCHBuilding cut and cover tunnels may be facilitated by the Con Arch system, hailed by its maker as a cost-effective method of designing and building strong, reinforced concrete arch tunnels. It can also be used for culvert and storm sewers.

An innovative and effi cient forming and concrete placement system lies at the heart of each project. Heavy gauge re-useable steel arch formers are bolted together in sections up to 24m long, creating travelling formwork that is ready to accept poured concrete and strong enough to be stripped and moved the day after the concrete has been placed. Backfi lling can begin, using light equipment, within 48 hours of concrete placement. The fi nal step in the process is to apply any required decorative treatment to the head and wing walls. A wide range of standard forms is stocked in widths up to 15m, although larger spans up to 30m can be catered for using a custom steel-ribbed forming system. The maker claims that using the system over conventional methods can result in cost savings of 10-20% or more.www.con-arch.com

DITCH WITCHRecently launched by Ditch Witch is the JT 3020 Mach 1 all-terrain directional drill rig. Key features of the new machine are a Cummins 116kW turbocharged diesel engine which can automatically increase torque, if needed, during tough drilling operations; a heavy-duty rack-and-pinion thrust drive with welded-on double rack claimed to offer lower maintenance and better reliability; and a well-equipped operator station. The company claims that the heavy-duty anchor system uses as much torque as drills twice the size “so as to anchor and hold in virtually any drilling operation”. And because open-top vice wrenches are angled towards the operator, a good view is afforded of the tool joint. In driving mode, the unit measures 5.59 long x 2.03 wide x 3.02m high. www.ditchwitch.com

EQUIPOS MINEROSPerhaps known more for its mining rigs than its tunnelling equipment, Equipos Mineros is also a supplier of equipment for the tunnelling sector. From its base in Santiago in Chile, the company has been manufacturing rock-drilling equipment for over 32 years. Typical of its output is the EM-RS27 rock-splitting drill rig (pictured) which has diesel hydraulic tramming and is designed for secondary reduction with a hard rock splitter.www.equiposmineros.com

FLYGTFlygt, part of ITT Industries, manufactures submersible dewatering pumps that can all be used for tunnelling applications. The company has enjoyed signifi cant success following the introduction of its N-Impeller programme introduced in the 1990s and designed primarily to reduce clogging. The range can be introduced in any application that requires dewatering and this includes the heavy-duty models such as the HS 3000 series and the HS 5100/5500 series that has been designed to handle extremely abrasive slurries containing sand, gravel, grit or ash without damage. www.fl ygt.com

GODWIN PUMPSAmong the products on display on the stand of Godwin Pumps was the company’s latest launch, the new, single stage HL110M Dri-Prime Pump. Ideal for tunnel shaft dewatering as well as applications in mining and quarrying, the 100 x 75mm unit can pump maximum fl ows of up to 115m3/h, passing solids of up to 19mm in diameter and is capable of heads up to 185m. The automatically priming pump, which can prime from dry to 8.5m (28ft), has been Ë

long, creating travelling formwork that is ready to accept poured concrete and

day after the concrete has been placed. Backfi lling can begin, using light equipment, within 48 hours of concrete placement. The fi nal step in the process is to apply any required

www.equiposmineros.com

Atlas Copco Dynapac articulated ashpalt roller

Ditch Witch JT 3020 Mach 1 directional drill rig

ConExpo raises the barSHOW REVIEW: ConExpo 2008

26-29WT0804.indd 27 9/4/08 16:32:38

April 2008

28

Ëdesigned to run dry indefi nitely without damage during intermittent fl ows. Several of Godwin’s pumps are currently in use in a major tunnelling project at Niagara Falls. www.godwinpumps.com

HAAG ENGINEERING COMPANYThere has been a structural collapse in a tunnel under construction and no one is sure why it has happened. Or a serious fi re has halted the operation of a tunnel for months. Who do you turn to for an objective analysis of where things have gone wrong in these situations? One solution might be to consult Haag, an engineering consulting fi rm that provides a forensic service that determines the cause and scope of damage. The practice performs investigations and analyses into failures, damages, defects, accidents and collapses, and can provide expert witness testimony in litigation. Specialist engineering staff provide comprehensive, technical reports for clients, private companies, corporations, manufacturers, insurance companies and law fi rms.www.haagengineering.com

MAITMait claims that it is one of the few drill rig manufacturers to make all the components of its rigs, other than motors and hydraulic compo-nents. According to the company’s Mariano Antonelli, Mait is not currently focusing on tunnel drill rigs but can manufacture them to special order. Typical of this genre is the GEA 550J fully-hydraulic crawler drill, claimed to offer power and versatility and “dedicated to sub-horizontal drilling”. Typical applications of the rig include jet grouting and micro-piling (fore-poling) for pre-consolidation and support of large diameter tunnels. One of the interesting features of this rig is that the controls are mounted on a fully moveable panel, allowing operators to work from any position within a 10m radius of the rig. It comes equipped with both electric and diesel power units. www.mait.it

MICHELINHaving your picture taken with the Michelin Man was not the only attraction on the tyre

manufacturer’s stand at ConExpo. Also on display was a range of the company’s ‘workhorse’ tyres designed to reduce operation costs for end users. This included the Michelin X Quarry S Tyre, which is designed to offer optimised, even tread wear, long life and machine protection for haul trucks in high speed operations. It is also claimed to allow for higher tonne kilometres per hour than the standard X Quarry tyre. Also on display was the company’s XDT Tyre, which is claimed to reduce wheel spin and improve traction, thanks to its long, even-wearing tread pattern.

The XHA Tyre is designed for a wide range of construction equipment and can be used on loaders, graders, dozers, scrapers and truck- loading applications.www.michelin.com

MOXYNorway-based Moxy Trucks was represented by US distributor Moxy Trucks of America. Numerous new models were on display, including the Ejector Truck range, which can be used in restricted height applications, such as tunnelling. Moxy’s ADT (Articulated Dump Truck) range includes the MT26, which has a pay load of 24,100 m3 and can also be fi tted with an ejector for applications where the usual tipper type of confi guration cannot be accommodated due to height restrictions. The latest update of this vehicle seen at ConExpo can be fi tted with wet disc brakes all round. www.moxytrucks.com

QUALCOMM ENTERPRISESQualcomm Enterprises Services provides wireless fl eet management solutions, such as the GlobalTracs Suite, that is designed to ensure companies get the most out of their vehicles. It allows them to keep an eye on equipment, where it is, how it is being used, if it is being used correctly, for how long and if it is being used for the purposes for which it was intended.

The system uses a variety of methods including GPS, satellite mapping and location updates. The OmniVision System for Transporta-tion is designed as a mobile computing platform for the enhancement of safety, productivity and effi ciency. www.qualcomm.com

RED ROSE USAFor situations where built-up cement needs to be removed quickly and easily, Red Rose USA offers Speedy-Clean, a liquid compound formulated to dissolve built-up cement on tools and equipment associated with the concrete ready-mix industry. The liquid compound has been formulated to have enough acidity to dissolve hardened concrete, although it contains no sulphuric, muriatic, hydrochloric or phosphoric acid. It is

also claimed to be non-corrosive, non-fuming, non-fl ammable and 100% biodegradable.

Once concrete is ‘softened’ by the applica-tion of the liquid, it can be washed away with high-pressure cold water. The manufacturer claims that the product, available both in aerosol and large tub formats, can remove cured cement, concrete, mortar, grout or stucco from any surface, as well as removing old rust and oxides. Yet it does not harm paint. It could be useful where cement has been allowed to harden over that shotcrete nozzle.www.redroseusa.com

ROBIT ROCKTOOLSThere was plenty to see on the stand of this Scandinavian drilling tools manufacturer. Robit’s drill and button bits use top-quality Scandina-vian steel and are exported to more than 30 countries worldwide, having been used on many major tunnelling projects. The company’s Hard Top Series of button bits covers all the diameters used in various top hammer drilling applica-tions. And Robit’s Casing System has been designed to be a robust and reliable solution for major top hammer and down the hole applications.www.robit.fi

SAFETY MANAGEMENT SYSTEMSAccidents happen. Reporting and analysing why they happen is part of the investigation process that could be facilitated by Airsweb software from Safety Management Systems.

Developed by former engineers with British Aerospace, the web-based incident and accident reporting software provides a full range of incident recording, investigation and analysis tools that have been designed to manage all aspects of an organisation’s safety, health and environmental management programme.

Airsweb is claimed to monitor every incident that occurs in real time, with the information gathered forming the basis of future investiga-tion; to allow companies to better understand the causes of losses, thereby helping to ensure that repeat events do not occur; to improve the quality of a company’s reporting while at the same time reducing data input; and to measure performance, forming the basis for reporting and reviewing.www.safety-software.com

SANDVIKSandvik launched numerous tunnelling-related products at the show, and this included a new generation of patented guide bits designed to help improve productivity and economy. Special guiding gauge buttons are at the heart of the new design, enabling, the company claims, fast and accurate rock cutting while retaining the ability to drill good, straight holes. Effi cient

Godwin HL110M Dri-Prime Pump

SHOW REVIEW: ConExpo 2008

26-29WT0804.indd 28 9/4/08 16:32:39

29SHOW REVIEW: ConExpo 2008

fl ushing capabilities means that cuttings are removed quickly from the bit front – helping to reduce bit wear – so all buttons have ‘new’ rock to break at every blow of the piston. All buttons have a robust ballistic shape to cut aggressively and achieve faster penetra-tion. All this, says Sandvik, means long bit service life, high penetration rates and high productivity.

Also aimed at tunnelling is the RT300 range of cemented carbide button bits that are claimed to have up to twice the service life, higher productivity and lower costs compared to similar products; this, says Sandvik, can save ‘big money’ in aggressive rock formations. The new button bits are aimed at all rock formations but especially those where button breakage is a problem.

Traditionally, achieving the right balance between hardness and toughness has been a compromise between one or the other. Sandvik claims it has now created the optimum formulation in its cemented carbide buttons that can drill a wide range of rock formations, thanks

to the introduction of XT48, a multi-purpose hard metal for rock bits that has increased toughness without compromising high wear resistance.

www.sandvik.com

SKFBall bearings are one of those

products which, although perhaps not the most exciting to look at or even write about, are nevertheless indispensable to industry, with tunnelling being no exception. Associated with the manufacture of ball bearings is SKF, a German company with a history that goes back to 1895. The company is still going strong, and recently supplied replacement ball bearings for the TBM that was involved on the Big Dig in Boston.

SKF recently launched a new, energy-effi cient, tapered roller bearing that is designed to reduce friction by 30% and more. Key benefi ts of the new bearing design include lower bearing temperatures, reduced risk of skidding and smearing, higher reference speeds and full interchangeability with standard tapered roller bearings.www.skf.com/trb

VERMEERFresh from recent acquisitions, Vermeer’s stand was packed with a variety of new and existing products refl ecting the various companies Vermeer has bought. Typical of these was equipment from the recently acquired Texas-based Horizontal Rig and Equipment (HRE), a manufacturer of horizontal drilling rigs (HDD).

On display was the impressive 1Mlb pull-back HDD rig from HRE, which will be manufactured at the Vermeer manufacturing plant in Pella, Iowa, along with the other two models in the HRE range having 500,000 and 750,000lb pullback. All HRE’s drill rigs will now carry the Vermeer brand and be sold through Vermeer’s distribution channel.

Dave Wisniewski, senior director of underground solutions for Vermeer, said: “The market for drill rigs of this size is robust, as gas, oil and major water and sewer projects have a strong global outlook. While there are competitors in this range of drills, we feel our global sales and service distribution network will distinguish Vermeer in this market.”www.vermeer.com

The next ConExpo will be at the Las Vegas Convention Centre in Las Vegas, USA, on March 22-26 2011. Further details: www.conexpoconagg.com

Sandvik guide bit

26-29WT0804.indd 29 9/4/08 16:32:41

The Celtic Miner 1500 is ideal for tunnelling

First choice

High-Shear Mixers up to 2500 litres

Grout pumps up to 200 bar

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30TECHNOLOGY: Innovation

Compact miner launchedSOUTH Wales-based Metal Innovations Holdings plc has launched the Celtic Miner 1500, a small, tracked, hydraulically powered excavator. The manufacturer says the machine – designed primarily for small seams in drift mines – is also ideal for tunnelling, thanks to its power, size and versatility.

At 3m long and 660mm high, the Celtic Miner 1500 can simultaneously cut and feed coal onto an in-built conveyor. For a lower capital investment, the unit is claimed to be able to give smaller operations the output normally associated with much larger mines.

The 1500 joins the ranks of other units in the company’s ranges, such as the Celtic Miner 4500 and a range of other machines, including hydraulic power packs, tracked chassis and conveyor systems, also developed by MI. The company has provided bespoke engineering solutions for the past ten years.

Managing director Gareth Thomas said the company planned a substantial expansion of its mining interests, in Wales and England, through purchases and joint ventures, using its own machinery to gain a cost-effective edge. On the tunnelling side, it is holding talks with a leading

international construction company that wants a modifi ed Celtic Miner 4500 to carry out excavation trials in service tunnels for a high-profi le project.

www.metalinnovations.co.uk

Ultra lightweight tablet rolled out Ultra lightweight tablet rolled out Ultra lightweight

FOLLOWING on from last month’s Innovation announcement concerning its P470 notebook designed for rugged environments, Getac has now announced the launch of the E100 lightweight tablet. Designed to be light enough for fi eld workers to carry their computing requirements on the move, the E100 is said to be the lightest, fully rugged tablet available, weighing only 1.4kg.

Designed not only to

Getac’s E100 is light yet tough enough for harsh conditions

30-31WT0804.indd 30 9/4/08 14:51:14

resist damage from accidents, the laptop is also aimed for use in harsh weather conditions, complying to MIL-STD-810F, and is also IP-54-compliant.

Up to fi ve hours’ use is possible from the Li-Ion battery, and a second battery can further extend life. The shock-mounted hard disc drive is designed to be vibration- and shock-resistant while the G-sensor prevents data loss from sudden impact.

One of the more interesting features of the unit is the 205mm (8.4”) TFT SVGA display, with touch screen functionality and Getac’s proprietary anti-refl ection technology, designed for hassle-free data input. Even in bright sunlight, the option of a Sunlight-Readable LCD display can ensure continuous use under bright, ambient lighting conditions.

The magnesium alloy case not only contributes to the overall low weight of the E100 but is also durable and protective. There are also sealed I/O caps and doors to prevent solid particles and moisture such as dust, rain and spillages from entering the unit, meaning that the E100 remains operable at most times, thereby helping to avoid downtime.

www.getac.com

World’s biggest breakerATLAS Copco’s HB 10000 ProCare is working on the enlargement from twin-track to four-track of the railway line from Sandvika (via Oslo City) to the Gardemoen airport.

Expanding the existing track trunk line required some 71,000m3 of rock to be removed over a distance of 900m. However, blasting was out of the question, due to nearby residential buildings and the high costs involved in environmental and safety aspects. The entire project is scheduled to take 11 months and the contractors were looking for ways to increase the rock breaking capacity.

The solution came in the form of the HB 10000 ProCare, the world’s biggest hydraulic breaker, which can achieve some 2,000m3 per

week, around 50% more than its little brother, the HB 7000, a 7t class hydraulic breaker.

Another valuable asset, according to Hegna Maskin of contractor Notodden, is the Atlas Copco ProCare servicing contract. “We now have a clear idea of the operating cost of our equipment and can profi t from the know-how of the Atlas Copco people who are planning and carrying out the service and maintenance.”

www.atlascopco.com

High-speed EthernetUK-BASED Westermo Data Communications has launched what it hails as an innovative new Ethernet line extender that can establish a reliable, high-speed, remote connection between Ethernet networks using any existing twisted pair copper cables. The DDW-220 combines the functions of two Ethernet line extenders and a four-port managed switch, enabling users to build complete Ethernet networks.

Its ability to connect networks over distances of up to 10km means that the DDW-220 is suitable for applications in tunnelling, as well as in highways, railway signalling, power stations and industrial plants. Data travels at speeds from 192 Kbit/s to 5.7Mbit/s in both directions.

Standard Ethernet networks are limited to 100m for point-to-point transmis-sions over copper cables. For longer distances, expensive fi bre optic cabling or radio links must be used. However, by employing a line extender such

as the DDW-220, it is possible to create a high-speed link between two distant Ethernet networks using any twisted pair cables or a multidrop network covering potentially hundreds of kilometres.

Intended for easy use, the DDW-220 is designed for extremely harsh industrial environments, with a metal case for robustness and the ability to be used in operating temperatures between -40°C and -70°C. The unit is also said to be able to handle indirect lightning strike transients, power induction and short circuit problems.

Westermo Data Communications Ltd is a subsidiary of Westermo Teleindustri AB of Sweden.

www.westermo.co.uk

April 2008

31TECHNOLOGY: Innovation

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30-31WT0804.indd 31 9/4/08 14:51:15

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32WT0804.indd 32 10/4/08 12:14:20

One breakthrough after another. Innovation.

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Robbins Innovations.indd 1 28/8/07 12:12:44

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