Category: 罗宾斯博客

The Latest Updates: Records in Toronto, the News from Nepal, and More

Much like the face of a TBM, tunneling’s wheels of progress are always turning. Join us as we check in on projects across the globe—including a breakthrough in Japan, record setting progress in Canada, and a new project ramping up in Nepal.

Setting Citywide Records in Toronto

Exciting progress is being made deep below Lake Ontario. The 7.95 m (26.1 ft) Single Shield Robbins TBM boring the 3.5 km (2.2 mi) long Ashbridges Bay Outfall tunnel is seeing record setting progress for the City of Toronto, ON, Canada. The machine, operated by contractor Southland Holdings, has recently completed 30 rings in a single day, at 1.5 m (5 ft) per ring, equating to 45 m (148 ft). With this accomplishment, the machine and crew surpassed a previous best day of 21 rings at a project with similar specifications. The Ashbridges Bay Outfall is anticipated to be the largest wastewater outfall in Canada and will improve the city’s shoreline, beaches, and Lake Ontario’s water quality.

Ashbridges tunnel pic

The record-setting machine at Ashbridges Bay Outfall placed 30 rings in one day.

A Third Set of Records in Esme, Turkey

If two sets of records weren’t enough, the 13.77 m (45.18 ft) diameter Robbins Crossover (XRE) TBM boring Turkey’s Esme-Salihli Railway Tunnel has just set another precedent. In July and August 2021, the speedy machine outdid its previous records in the size class of 13 to 14 m (43 to 46 ft), boring 167.4 m (549.2 ft) in one week and 651.6 m (2,138 ft) in one month. The rates are the fastest ever recorded for any TBM over 13 m (43 ft) in diameter! They even surpass those set  over a decade ago at the Niagara Tunnel Project by a Robbins 14.4 m (47.5 ft) diameter Main Beam TBM. Check out the records here. 

Esme Salihli XRE

The Crossover TBM at the Esme-Salihli Railway Tunnel is now the world’s fastest TBM over 13 m (43 ft) in diameter.

Breakthrough at Tamagawa

In June, JV contractors Obayashi & Kumagai celebrated their final breakthrough at the Tamagawa HPP #2, Lot 2 project in Yamagata Prefecture, Japan. During the bore, the crew faced unpredictable soft ground conditions and other challenges. To surmount these issues, an airborne electromagnetic survey was conducted for predicting soft ground conditions ahead of the tunnel surface and tunnel face stability was improved by using forepiling. The project, completed with the use of a Robbins 4.5 m (14.7 ft) Main Beam TBM, will supply 14,600 kw of renewable power to the region.

The Obayashi & Kumagai JV celebrate their final breakthrough at Tamagawa.

Double Shield to Bore Second Nepalese Tunnel

A record-setting 5.09 m (16.7 ft) Robbins Double Shield TBM is currently being rebuilt to tackle its second project for Nepal. The machine, which set multiple records and finished a year early at the Bheri Babai Diversion Multipurpose Project, has been chosen to bore the 13.3 km (8.2 mi) long Sunkoshi Marin Diversion Tunnel. Upon completion, the structure will divert part of the flow of the Sunkoshi River into the Bagmati river to irrigate farmland in the Tarai district. The project has been awarded to contractor China Overseas Engineering Co (COVEC), who will be bringing their expertise and experience from the Bheri Babai tunnel to this new endeavor.

The veteran Robbins Double Shield will now be rebuilt to bore a second tunnel for Nepal.


Most Momentous: 2021 Global Project Updates

From China’s largest Crossover TBM launch to an epic 13.77 m diameter XRE that began boring recently in Esme, Turkey, we’ve compiled the year’s most momentous events thus far. Read on to find out about Robbins machines embarking on tunnels large and larger.

Twin Crossover TBMs for Chongqing

Two 6.91 m (22.6 ft) diameter XRE machines are currently boring sections of the Chongqing Metro Phase 2 in ground conditions ranging from weathered mixed granite to weathered pegmatite and adamellite. The twin machines are the first of their kind in China, and are part of a trend towards more geologically challenging tunnels in China. To date, the machines have achieved up to 365 m (1,197 ft) advance in one month, with rates expected to ramp up as the machines progress.

Chongqing Metro Team

The team takes a moment to mark the assembly of one of two Robbins Crossover machines in Chongqing, China.

An Epic XRE Launch in Esme

In Esme, Turkey, a massive 13.77 m (45.2 ft) diameter Crossover XRE TBM began its bore for contractor Kolin Construction. Launched in late March 2021, the unique TBM is designed to tackle mixed ground conditions including sandstone, gravelstone, claystone and siltstone along the 3.05 km (1.9 mi) Esme-Salihli Railway Tunnel. The XRE can swiftly convert between hard rock mode using a belt conveyor and EPB mode using a screw conveyor, as both remain in place inside the machine.

Esme XRE TBM Launch

Launch of the 13.77 m diameter Robbins XRE TBM for Turkey’s Esme-Salihli Rail Tunnel.

Tunneling below Lake Ontario

A Robbins 7.95 m (26.1 ft) diameter Single Shield TBM launched recently on March 26th from an 85 m (280 ft) deep, 14 m (46 ft) diameter shaft. The machine, for the Ashbridges Bay Outfall with contractor Southland Holdings LLC in Toronto, ON, Canada has the task of boring a 3.5 km (2.2 mi) long tunnel below Lake Ontario. The completed tunnel will connect up to 50 in-lake risers to enable efficient dispersion of treated effluent over a wide area of the lake.

Asbridges TBM Launch

The Robbins Single Shield TBM for the Ashbridges Bay Outfall Tunnel launched on March 26, 2021. Photo: Alfredo Garrido

China’s Largest Crossover TBM

The largest ever Crossover (XRE) TBM in China launched in late March 2021 in Guangzhou for contractors Sichuan Jinshi Heavy Equipment Leasing Co., Ltd and CREC Bureau 2. Onsite First Time Assembly (OFTA) was utilized to build the 9.16 m (30 ft) diameter Robbins TBM, taking just four months from contract signing to machine launch. The hybrid machine is boring the 2.5 km (1.6 mi) long Pazhou Line Lot PZH-1 of the Pearl River Delta Intercity Railway Project, which will offer better commutes for Guangzhou residents traveling to and from University City.

Pearl River Delta TBM Assembly

The Robbins Crossover XRE TBM at the Pearl River Delta site was assembled using Onsite First Time Assembly in just four months from contract signing.


Tunneling in Karst: Your Questions Answered

On November 18, 2020 we held a webinar on a unique recent project, France’s Galerie des Janots. Crews utilized a 3.5 m diameter Robbins Main Beam TBM to bore a 2.8 km long tunnel through limestone with karstic features, with some surprises: Two uncharted caverns up to 8,000 cubic meters per size in the bore path of the TBM. To find out how the crew overcame the challenges, watch the video here:

We held a question and answer session during our event that was not recorded and wanted to share some selected Q & A with you below.

Question and Answer Session

Q: What type of karst was predominant along the alignment?

A: The karst was a kind of weak limestone formation. Very soft with a tendency to get pasty – like chalk in water.

Q: Could another type of TBM have been used in the geological conditions (limestone with karst)?

A: It was a rather small diameter tunnel and the less structure you have with the machine, the better. A shielded machine with segments at this diameter can work – but when in bad rock and you need to do something, the shield can become an obstacle to access the rock. We think the Main Beam machine was the best option and provided full access to the tunnel walls and strata.

Q: Do you think an EPB or Slurry machine could have been used in this tunnel?

A: I do not think so. When in rock, you will struggle with EPB or Slurry TBMs–producing conditioned muck or building up a filter cake and pressurizing the chamber will be very difficult to make happen in these conditions.  However, our Crossover type machines do provide for operation in various modes and can run from rock into soft material.

Q: One of the typical challenges faced with karst is high water ingress. Can an open face machine deal with that?

A: Here we did not have water ingress, and did not have karstic aquifers either, so it was sufficient to employ normal water pumping. An open machine provides full access to the tunnel walls and the face. So, you can inject and fight the water ingress better compared to a shielded machine.

Q: In the Middle East, we had a project that, during pilot tunnel drilling in front of the cutterhead, resulted in sudden inrush of water ,which led to flooding inside the TBM. What types of mitigations measures do you recommend to overcome flooding risk?

A: A TBM can be furnished with doors and chutes at the relevant points to stop water ingress. A very appropriate tool is a so-called Guillotine Door, which is assembled to the muck chute above the TBM conveyor and allows for quick closing. Also, TBM conveyors can be furnished with a water-tight plug door, which can seal the machine when pulling back the conveyor. For sure, submersible pumps are needed, and to stop the water ingress, injection grouting should be used.

Q: What is BEAM Technology and was it able to successfully predict any real detected cavities before the TBM excavation?

A: BEAM Technology stands for Bore-tunneling Electrical Ahead Monitoring.  BEAM is a ground prediction technique using focused electricity-induced polarization to detect anomalies ahead of the TBM. Yes, they were able to predict a cavity using BEAM on this TBM, see drawing below courtesy of Geo Exploration Technologies. The red spot spot in the colored band clearly indicates the location of the cavity, and the picture verifies that it was found at that location.

Detection of a cavity using BEAM at Galerie des Janots.

Detection of a cavity using BEAM at Galerie des Janots.

Q: What type of material did you use to fill the cavities?

A: It was mainly concrete reinforced with steel mesh and wood structures.

Q: How did they move past the first cavern and did ground support change during tunneling?

A: To cross the cavern space, crews erected a 4 m high wall of concrete so the TBM would have something to grip against (see picture below).  The TBM was started up and was able to successfully navigate out of the cavern in eight strokes without significant downtime to the operation.  Shotcrete was also employed – as long as necessary. Rock conditions changed often in this tunnel.

Reinforcement of the first cavern at Galerie des Janots.

Reinforcement of the first cavern at Galerie des Janots.


The Next Push: Robbins TBMs on the Move Around the Globe

Robbins machines continue to advance in 2020, with essential projects ongoing and starting up the world over. From a proven Main Beam starting its fifth tunnel in Switzerland to a triumphant small diameter breakthrough in Norway to continued Crossover success in India, we’ve got all the tunneling highlights below.

ASSEMBLY UNDERWAY IN TORONTO

Assembly is underway on a  Single Shield TBM for the Ashbridges Bay Treatment Outfall in Toronto, ON, Canada. The 7.95 m (26.0 ft) diameter machine and Robbins continuous conveyor will bore a tunnel to replace a 70 yr old existing outfall. The video below shows the machine acceptance in Mexico before being shipped to Canada. Due to coronavirus protocol, this was the first all-remote machine acceptance that Robbins has conducted.

SMALL DIAMETER TRIUMPH IN NORWAY

On June 16, 2020, crews wrapped up tunneling at the Salvasskardelva Hydroelectric Power Project (HEPP), located far above the Arctic Circle at 68.7 degrees north latitude near Bardufoss, Norway. The site may well be the world’s northernmost TBM-driven tunnel.  The 2.8 m (9.2 ft) diameter specialized Main Beam TBM known as “Snøhvit”, or “Snow White”, was provided to contractor Norsk Grønnkraft for use on several of their hydroelectric tunnels. A continuous conveyor was also provided. The small hydro tunnels featured moderate to steep positive gradients up to 25 percent. The TBM was able to achieve rates of up to 44 m (144 ft) in 24 hours.

NGK Breakthrough

A small diameter Robbins Main Beam TBM broke through in June 2020 in Northern Norway.

PROVEN MACHINE RAMPS UP FOR 5TH BORE

In Oberwalden, Switzerland a 6.50 m (21.3 ft) diameter Robbins Main Beam TBM, originally built in 1993, is ramping up to begin boring in December 2020. The machine, rebuilt by Swiss contractor Marti, will bore the 6.4 km (4.0 mi) long Sarnen Stormwater Relief Tunnel through hard rock. As the bore proceeds, wire mesh, shotcrete, and invert segments will be installed.

Sarnen Stormwater Relief 2

The 6.50 m Robbins Main Beam TBM will begin boring in December 2020 in Oberwalden, Switzerland.

UNIQUE CONVEYOR SYSTEM FOR NEUTRINO FACILITY

In Lead, South Dakota, a unique Robbins conveyor system is gearing up to begin hauling muck.  The conveyor system will be used to build the Long Baseline Neutrino Facility (LBNF) for Fermilab. Contractor Kiewit will renovate a disused gold mine into a world-class neutrino research facility. Two caverns will be excavated by drill & blast and roadheader deep below the surface.  Rock will be transported by cable hoist up a 1.5 km (0.9 mi) deep mine shaft to a rock crusher at the surface using much of the original but refurbished mining equipment, and from there will be transported via conveyors. The Robbins conveyor systems are designed for the unique application, and include the longest overland conveyor Robbins has ever provided (550 m/1,800 ft), which travels over a main road and city park and near a residential area.

Overland conveyor

Crews install the completely enclosed box truss for the overland conveyor, which will traverse a roadway and other features.

CROSSOVERS CONTINUE BELOW MUMBAI

Tunneling continues on the Mumbai Metro Line 3, where two 6.65 m (21.8 ft) diameter Crossover XRE TBMs are on their third drives for the L&T/STEC JV. TBM 1 has bored 2,178 m (7,146 ft) with another 765 m (2,500 ft) left to bore. TBM 2 has bored 2,352 m (7,716 ft) with another 592 m (1,942 ft) left to bore, and is scheduled to bore fourth drive later this year. Two 6.65 m (21.8 ft) Robbins Slurry TBMs are also boring for the Dogus-Soma JV with one machine starting its second drive after boring 2,181 m (7,155 ft), and the other being reading for its second drive after boring 2,100 m (6,890 ft).

Mumbai Metro Crossover Breakthrough

One of two 6.65 m (21.8 ft) Robbins Crossover XRE TBMs at India’s Mumbai Metro during a recent breakthrough.


To Grout or Not to Grout? In Rock Tunnels encountering High Water Pressure, Grouting can offer Great Benefits over Slurry

An NCP-TBM with grouting (left) can be just as effective (and more efficient) than Slurry tunneling in rock with water (right).

When you’re faced with a hard rock tunnel where there are expected significant sections under high water pressure, which tunneling method do you choose?

While Slurry Shield tunneling has a long history of addressing this problem, this method has not always been problem free. I would argue Slurry tunneling in rock is not, in most cases, the lowest risk or the most cost-effective method.

At recent projects around the world, we have seen that two non-slurry methods can be highly effective: use of a shielded, Non-Continuous Pressurized (NCP)-TBM in rock with a comprehensive grouting program, or sequential advance in EPB mode.  Both types of tunneling operations have proven themselves safe, and have saved a significant amount of money for both contractors and owners.

Grout vs. Slurry

There are certain inherent traits to a Slurry tunneling operation that appear to give a lower level of risk: the entire operation is sealed; the slurry itself is conveyed to the surface through a system of pipes. But is this low risk truly the case?

Interventions

Hyperbaric interventions are high-risk operations, particularly as water pressures go up. In water pressures over 6.5 bar, divers are often not permitted to enter the cutterhead, so grout must be used or there must be an alternate plan to bring down the high pressure. Higher pressure hyperbaric interventions up to approximately 12 bars have been successfully performed, but at what risk? Pressures in some tunnels have far exceeded 12 bars and would make hyperbaric interventions even more costly, risky and time consuming or impossible.

Slurry Separation

In ground with fines, slurry separation can be costly and difficult. Slurry tunneling is also not immune to problems such as blowouts/loss of face pressure when a fault zone or low cover zone is encountered, as is well-known in our industry from projects such as Hallandsås in Sweden and the SMART Tunnel in Malaysia.

Probing and Grouting

In an NCP-TBM operation, crew members may be more exposed to the tunneling environment but risks are not increased. With a good geotechnical baseline report and ground investigation tools, contractors can determine the zones requiring grouting ahead of the machine. It is now common to drill probe holes accurately of plus 100 meters with Down-the-hole (DTH) drills.

While grouting does take time and cost money, this cost has to be balanced against the cost and time to do hyperbaric intervention during slurry tunneling. Even 100% grouting in a rock tunnel could require less time than high-pressure hyperbaric interventions. The practice of pre-grouting has been done for years in drill & blast rock tunnels in Scandinavia and worldwide.


This video shows the basic process of probe drilling and grouting in a shielded rock TBM.

Grouting can also be done from a Slurry TBM of course, and is normally done to set up safe zones. However, it is worth noting that based on having a pressurized face filled with slurry, drilling through the head is very difficult. Sealed pipes/ports need to be installed in advance, eating up space and compromising the working conditions during hyperbaric interventions.

Cutter Changes

There has been recent development to enact cutter changes by accessing the cutters through the cutterhead under atmospheric pressure.  However, this system requires a large diameter machine as well as a deep cutterhead structure. The deep structure severely affects muck flow and substantially increases the need for more frequent inspection and cutterhead repairs. These atmospherically accessed cutterheads do not address the problems of cutterhead repair, changing center cutters, or replacing scrapers, all of which are high wear items in rock tunneling at large diameters.

Geology Rules

Are there times when a Slurry TBM has an advantage over an NCP-TBM in rock? Yes. Rock properties can drive the decision: Some rock formations are very difficult or nearly impossible to grout, and therefore the success of pre-excavation grouting will not be a given.  If significant water inflows are predicted and the rock will not readily take common grouting material, or chemical grouting is not an approved option, a slurry TBM is the logical TBM selection.

Lining requirements are another potential reason not to go with Slurry: The operation of a slurry TBM goes hand-in-hand with the use of an (often expensive) segmental lining. Pre-excavation grouting using an NCP-TBM offers tremendous cost savings when done in a non-lined tunnel or when the liner can be installed independently after excavation.

In cases where a final liner has to be installed with tunnel boring, and often in cases where excessive water inflows are predicted, a slurry TBM may make more sense.  Under excessive water inflows a grouting operation may still experience leakage after the initial tunnel construction, making installation of a final liner afterwards potentially costly and time consuming.

In Depth: Slurry Tunneling vs. NCP-TBM Shielded Tunneling in Rock

Cutterhead Inspections

Cutterhead inspections in rock must be viewed with a different mindset than in soft ground tunneling. When tunneling in abrasive rock with any type of machine, inspections should be performed regularly; once per shift can be a requirement. This is in contrast to tunneling in soft ground, where cutterhead inspections are often planned and based on a set number of meters, for example every 100 m.

The Contractor Experience

Contractors who are used to tunneling in soft ground may not realize that when using a Slurry TBM in rock, inspections must be frequent due to increased cutter consumption. We have seen this borne out on recent projects such as the Hiroshima Expressway Line 5 in Japan. On that project, a 13.7 m diameter Robbins Slurry TBM is boring in granitic rock. The contractor opted for a Slurry machine because that was their historic experience, and they were expecting up to 13 bar water pressure. This high pressure water zone was only in a small section of the overall tunnel length, about 5 percent.

Hiroshima Slurry TBM

A full view of the 13.67 m (44.8 ft) Robbins Slurry TBM for the Hiroshima Expressway Line 5. Photo Credit: Mario Recena Areces

The contractor in Hiroshima had grouted off from the surface a planned safe zone in which to inspect the cutterhead without requiring a hyperbaric intervention, but this strategy did not go according to plan. The abrasive rock damaged the cutters and cutterhead before they could reach the safe zone, resulting in unplanned delays.

By far the biggest benefit of using a shielded NCP-TBM in rock, rather than Slurry, is the ease of cutter and cutterhead inspections. In areas with no pressure and with frequent or continuous grouting, the cutterhead can be inspected regularly and without the requirement of expensive, time consuming, and often risky pressurized interventions or complicated procedures to remove slurry from the cutterhead. Frequent inspections mean that cutter and cutterhead damage can be caught early before they cause significant downtime.

Robbins Single Shield TBM "Nora"

The Delaware Aqueduct Repair TBM, used in hard rock and designed to statically hold high water pressure, is a good example of an NCP-TBM.

Abrasive Wear

To go along with the above point, abrasive wear in any type of TBM is obviously always higher in rock than in soft ground, particularly when the rock has a high quartz or other abrasive mineral content. However, in Slurry machines, which crush the rock and send the rock chips through a system of pipes, abrasive wear is of even greater concern. Even with using durable slurry piping, transfer points and pipe elbows will require higher rates of replacement, causing more delays associated with muck removal than a typical NCP-TBM operation using a conveyor belt.

Dealing with Water Inrushes

If sudden water inrushes at high water pressure are a known risk, NCP-TBMs can effectively be designed to statically hold the pressure using sealable muck chutes in the bulkhead.  This type of design can be used as a pressure-relieving gate in semi-EPB mode, opening by pressure and allowing muck to be metered out onto the belt. Or in extreme cases, the sealed gates can be activated and probe/grout drills can be used to forward drill and grout for ground consolidation and to seal off the water. Extra seals around the main bearing can be filled with pressurized grease and other vulnerable points can be sealed off in the same manner.

A Crossover TBM can also be designed to keep boring under pressure by implementing a center-mounted screw conveyor.  A long screw conveyor can be used to draw down high water pressures and abrasion resistant hard facing can be added to the screw conveyor flights for abrasive wear. Under such conditions, a machine could operate continuously with, say, 3 bar pressure and sequentially in high pressure of 15-20 bar.  An example of this is our ongoing project Mumbai Metro, where two Robbins Crossover TBMs are excavating in mixed ground. In these machines, the center screw conveyor is able to seal itself off/hold pressure so the TBM can continuously bore or operate using the screw conveyor in a sequential fashion. Boring is done when there are not enough fines to form a plug. Take a look at the below figures for a summary of sequential boring operation.

Sequential Operation Step 1. Muck chute gate is open with high pressure water and cuttings flowing onto the screw conveyor as machine advances forward.

 

Sequential Operation Step 2. Muck chute gate is closed and water pressure is lowered, then muck is removed from the screw conveyor onto the back-up conveyor.

Dealing with Gasses and Contaminated Ground

In Slurry tunneling, dealing with gasses in the tunnel is relatively easy because the gasses are contained in the slurry pipes. Gasses can also effectively be contained and safely dispersed on non-pressurized TBMs using scrubbers and high volumes of air. On a recent Robbins TBM in Australia a machine was capable of operating in open mode with gasses using a bulkhead fitted with suction ports to draw any gas from the top of the cutterhead chamber and directly into a sealed ventilation system.

Contaminants such as asbestos may be better contained in slurry pipes, but many other types of contaminants may not be easily separated from the slurry and therefore easier to deal with using NCP- TBMs.  In Slurry operation the quality of Bentonite itself can vary widely, with some lower cost material containing heavy metals, which has the potential to be detrimental to the environment. The slurry solution itself also tends to bind well with heavy metals, contaminating the slurry and making separation difficult.

In Conclusion

The conclusions to draw from this discussion are straightforward. Is Slurry tunneling still a valid option in rock with potential of high water pressure?  The simple answer is yes. Is it the most cost-effective option? Is it safer than any other option? In many circumstances the answer is no.

Slurry TBMs need a level of expertise in operation that NCP-TBMs simply don’t require. The operation of most NCP-TBMs is both simple and straightforward, which in turn saves on personnel costs.

My hope is that consultants and owners realize that Slurry TBMs are not the only option when high water pressure is expected.  Slurry TBMs are not in most cases the lowest cost, and other methods can be just as safe while being simpler to operate. While grouting takes time, so does slurry tunneling with its typically lower advance rates and possible need for expensive, high risk hyperbaric interventions. When Slurry machines operate in rock, the need for frequent cutterhead inspections ultimately makes their use questionable. In most cases NCP-TBMs are the better option.

For Further Reading: Recent Industry Examples
The Mumbai Metro Project
Delaware Aqueduct Repair


On the Move: Robbins TBMs Around the World

At any given time Robbins TBMs are operating in dozens of countries around the world at all project stages. Thus far, 2020 has been no exception to the rule: From an icy visit to the world’s northernmost TBM to breakthroughs across the U.S. to a vast hydropower project on the verge of completion in China, we’ve got the latest updates from Robbins tunnels around the globe.

TBM Tunneling Above the Arctic Circle

Robbins engineers paid a visit to what is likely the northernmost TBM ever to operate in the world, at the Salvasskardelva HEPP near Bardufoss, Norway, 68.7 degrees north latitude. Robbins personnel and the contractor, Norsk Grønnkraft , have been braving frigid winter temperatures, ice and snow to excavate the 2.8 km long tunnel with a Main Beam machine at an upward gradient of 5.8 percent. As of the first quarter of 2020 they are nearly two thirds complete. Once breakthrough occurs the machine will be moved to bore a second tunnel 1.3 km long.

Ice and snow at the Salvasskardelva HEPP

Sindre Log of Robbins Norway visits the wintry jobsite at Salvasskardelva HEPP, possibly the northernmost TBM operation ever.

A Trio of U.S. Tunneling Breakthroughs

Meanwhile in the U.S. multiple machines ranging from 2.2 to 6.5 m in diameter broke through.  First up is the Deer Creek Interceptor using a 6.5 m Main Beam TBM and continuous conveyor. The machine holed through on January 29, completing a 6.3 km long tunnel below St. Louis, MO for contractor SAK. Watch this great video from the owner, MSD Project Clear, below.

Also in January, the Turkey Creek Interceptor finished up: a project using a 3.0 m diameter Robbins Double Shield TBM to bore three short drives below Kansas City, MO. Contractor Radmacher Brothers bored a total of 220 m with the machine. Check out the video of the final breakthrough, and image of its first breakthrough several months earlier.

Turkey Creek TBM Breakthrough

The Turkey Creek TBM, a Robbins Double Shield, during its first breakthrough in Kansas City, MO, USA.

Lastly, in San Antonio, TX a 2.2 m diameter Robbins Double Shield TBM achieved a breakthrough at the SAWS Central Water Integration Pipeline, Segment 5-1. The tunnel, for owner San Antonio Water System, was excavated by contractor Atkinson.

SAWS TBM Breakthrough

The 2.2 m Robbins Double Shield TBM for the SAWS Central Water Integration Pipeline in Texas.

A Massive Project Nears Completion in China

Two of three long-running Double Shield TBMs have completed their epic drives at China’s Great Hydro Network in Shanxi Province in recent months. The Great Hydro Network sprawls thousands of kilometers and is a feat of engineering. The Robbins machines at Tunnel 2 and Tunnel 4 bored from 15 to 23+ km in length. The machines overcame fault zones, water inflows and karst cavities to forge fast advance rates up to 865 m in one month.

GHN T4 Breakthrough

The Robbins Double Shield TBM at Tunnel 4 of the Great Hydro Network.

Tunnel 2 Breakthrough Celebration

Officials celebrate the breakthrough of the Robbins Double Shield TBM at Tunnel 2 of the Great Hydro Network.


What it’s Like to Live at a Jobsite for a Year (or More): An Interview

Debbie Swival, Robbins Field Service Support, is no stranger to tunnel sites. Over her last 12 years at The Robbins Company she has worked on TBMs around the world, from the San Francisco Central Subway to the Moglicë Headrace Tunnel in a remote area of Albania to Turkey’s Bahce-Nurdag High Speed Railway and more. But her longest stay was in Newburgh, NY, USA for the Delaware Aqueduct Repair tunnel.

Swival remained on the jobsite from November 2017 until the TBM’s breakthrough in August 2019—a duration of 21 months.  Her role in assisting the crew and troubleshooting issues was integral to the project’s success.

Boring Below the Hudson

The 6.8 m (22.3 ft) diameter Robbins Single Shield TBM for JV contractor Kiewit-Shea Constructors (KSC) bored a total of 3,794 m (12,448 ft) over 582 days with instantaneous penetration rates of 6 m (20 ft) per hour.  The unique machine was designed to statically hold up to 20 bar pressure as it bored below the Hudson River to repair a section of the Delaware Aqueduct, the world’s longest continuous tunnel (137 km/85 mi long). 

The New York City Department of Environmental Protection (NYCDEP), project owner, discovered that a section of the aqueduct below the Hudson River was leaking up to 75 million liters (20 million gallons) of water per day.  On average the aqueduct—built in the 1930s and 1940s—supplies about 50 percent of the water consumed by 8.6 million residents of New York City and an additional 1 million residents in four counties north of the City.  A swift repair of the tunnel section was essential. 

The tunnel depth—ranging from nearly 270 m (900 ft) deep where the TBM was launched in Newburgh, New York to over 180 m (600 ft) deep at the exit shaft—the water volume, and pressure were all challenges.  Probe drilling was mandatory ahead of the TBM and required the use of down-the-hole water hammers for accurate boring under pressure.

Delaware Aqueduct Repair Breakthrough

Debbie Swival, third from right, of Robbins Field Service, stayed on the Delaware Aqueduct Repair jobsite for a total of 21 months to keep the machine running smoothly.

What was it like to be at the jobsite for 21 months?

Swival: Being on site for that long was a fantastic experience. I typically stay on a jobsite for 6 to 8 weeks so I do not see the machine in full production. Staying for the boring of the length of tunnel allowed me to see the way that the machine is actually used, as opposed to the theoretical understanding of how different operations should be done. This has given me new insight for programming the machines to better meet the customer’s needs.

Being there for that long also gave the opportunity to create a strong working relationship with the customer. I was part of the team, with everyone working together to get the job done safely and successfully.

What were your main roles at the jobsite?

Swival: Initially I worked with the crew on the machine’s electrical systems and PLC (Programmable Logic Controller) programming changes. Other members of Robbins Field Service conducted training on hydraulics and machine operation. We had three operators at the jobsite who needed training, so I also spent time afterwards reinforcing that training they received.  Much of it was on-the-job style training.

As the job continued my role shifted to supporting the machine for any issues that came up. I assisted with troubleshooting hydraulic and mechanical issues as well as continuing to work with the electricians for any problems that arose there. I worked with the customer to implement changes that they requested to the PLC program and to the HMI (Human Machine Interface) screens. I also assisted the customer with interfacing with Robbins engineering to obtain information that they needed.

What was a typical day at the jobsite like for you?

Swival: My typical day started with a 7:30 am meeting with the engineers and supervisors to go over the plan for the day and address any technical issues that had occurred since the previous day. At 8:00 am, a quick safety meeting with the crew, then head to the cage where we all got to be up close and personal during the 6-1/2 minute ride down the shaft. Once at the bottom we got on the mantrip to ride in to the machine. Near the end of the drive it took around 20 minutes to get to the TBM.

Once in the machine, it was time to tie in with the night shift for information on what had happened during the night and where they were in the mining process. At that point it was time to start troubleshooting any problems that had occurred. If all was well I went through and checked the machine for any signs of something getting ready to fail such as wear marks on hoses or cables, low tank levels, loose mounting on sensors and other things that could be fixed before they broke and caused an issue. I spoke with the mechanics and operators to see if there was anything they needed assistance with and also got feedback from them on what they liked as well as what could have been done differently to make their job more efficient.

Conditions in the tunnel were as you would expect – loud and dirty, although there were only a few times when dust was an issue and respirators needed to be worn. The crew often said it was hot in the tunnel, but I love the heat so I didn’t really notice it. We ate lunch on the machine. Since we did not leave the tunnel until the next shift came in, something that is normally overlooked is the need for the crew to relieve themselves. On this machine there was a really nice toilet that was kept cleaned, which made life there so much better! Around 4:30 pm “Mantrip coming in!” was announced over the mine phones as the next shift started their way in to relieve us. We got back to the surface a little after 5 pm and it was so nice to be back in the fresh air!

TBM launch shaft at Delaware Aqueduct repair

A view looking up from the bottom of the 270 m (900 ft) deep launch shaft in Newburgh. Photo: NYCDEP (www.nyc.gov/dep)

How important are knowledgeable field service personnel for the success of a project?

Swival: It’s absolutely imperative to have knowledgeable personnel. At the Delaware Aqueduct site they had me there because I knew the equipment well and could solve problems quickly. For example, it’s beneficial to have a PLC person on site because it’s a specialized piece of equipment. Although after commissioning there are not many problems with the PLC, when there is an issue it requires the code to be changed. Some PLC hardware failures or changes can also require that the program is modified. When an electrical or hydraulic issue occurs on the machine, I can use the program as a troubleshooting tool, find out what physical device isn’t working then describe the problem to the crew and educate them on how to fix it. This shortens downtime from 12 hours for a crew without PLC personnel on site, to around two hours.

What are some other examples of challenges that you were able to overcome at the site?

Swival: I helped to optimize the boring parameters, such as reducing thrust pressure, adjusting ring build procedures, and fine-tuning articulation cylinder pressure to avoid downtime and keep the machine moving. There was a section of the tunnel where the rock transitioned from shale to granite, and the difference in rock strength meant we had to set new limits for the thrust pressure to extend the life of the disc cutters.

There was an issue with the segment unloaders where the forward unloader was in the lowered position and the rear unloader was raised. The setup didn’t provide any clearance for when the train moved out. Typical sensors were not able to be mounted in the location. I worked with the mechanical team to find a solution for sensing the positions of the unloaders and prevent this from happening in the future. Lights were added to give a visual indication to the operator of the fully raised and lowered positions, and I changed the logic to incorporate the modifications. Those are just a few examples of what I helped with.

What is your favorite memory from the project?

Swival: It was amazing to be able to climb through the hole in the cutterhead and stand in front of the machine when it broke through.  The support from everybody throughout the project was incredible. Everyone worked together, and the level of community on the job was exceptional. It was simply a great place to work.


Video courtesy of NYCDEP (www.nyc.gov/dep).

For more on the unique tunneling operation at the Delaware Aqueduct Repair, check out these resources:

White paper: https://www.robbinstbm.com/managing-high-water-inflows-2/

Press release: https://www.robbinstbm.com/delaware-aqueduct-repair-breakthrough/


3 Ways to Bore More Efficiently in Extremely Hard Rock: Maximize your TBM Advance through Minimized Downtime

When the rock seems unbreakable, stresses are multiplied: The cutters must be stronger, the TBM more durable, and the operation optimized to keep equipment running smoothly. Once rock hardness rises beyond 180 to 200 MPa UCS, the limits of cutting tools are put to the test.

Given the clear risks of excavating massive, hard rock, how can tunnellers set themselves up for the best possible chance of success?  The combination of knowledgeable personnel, properly designed equipment, and rigorous TBM operation and maintenance are making excavation of hard rock—even extremely hard rock strengths of 300 MPa UCS or more—possible.

1: Consider your Cutting Tools

Cutters are a significant factor for efficient excavation when rock is extremely hard. To that end, Robbins has developed Extra Heavy Duty (XHD) rings for projects where Heavy Duty (HD) rings are close to their design limit in terms of the thrust force required to break the rock.  The XHD rings resist chipping, mushrooming, and other damage that can occur in very hard rock conditions. Enhanced heat treatment gives the discs increased hardness and strength without the normally-associated reduction in fracture toughness.

The rings have a proven track record: they’ve been put to the test at several jobsites, including Norway’s Røssåga headrace tunnel bored in rock from 200 to 280 MPa UCS. Initially, HD cutters mounted on the Main Beam TBM’s cutterhead experienced low cutter life in the range of 100 to 150 cubic meters bored per cutter. XHD rings were gradually introduced onto the cutterhead to determine what, if any improvement in cutter life could be obtained. It is likely that the performance in the very hard sections was improved by a minimum of 25%. The benefits of the XHD are also likely to explain the superior cutter life for the remainder of the project, even in the relatively softer ground.

Rossaga HEPP cutterhead inspection

The rock at Norway’s Røssåga headrace tunnel averaged from 200 to 280 MPa UCS, requiring XHD rings.

2: Optimize Penetration Rate

Harder rock requires equipment that can stand up to high stresses.  Penetration rate and thrust are exponential functions. The first rule is: Push as hard as you can. The more thrust the better. A machine with a robust steel structure is needed to take the higher loads without damage.

But penetration rate is trickier: The overall goal in hard rock should be to operate TBMs as efficiently as possible to maximize production. This means increasing penetration per revolution as much as possible.  Consumption of cutterhead wear parts is related to the number of revolutions of the cutterhead, so it follows that increased penetration per revolution will result in fewer total revolutions of the cutterhead, reduced consumption of wear parts and fewer cutter changes for the duration of the tunnel.

The TBM Operator should therefore be looking for the best advance at the lowest RPM, because lower RPM reduces wear on the outer cutters and periphery of the cutterhead. Robbins has conducted site tests at multiple sites over several years showing that a lower RPM achieves the same and often better penetration rates than a higher RPM in hard rock. This can be clearly seen in the data: For example, on an 8 m diameter cutterhead, the circumference is 25.12 m. At 10 RPM during TBM operation, this would mean 251.2 m of travel in one minute. If the speed is reduced to 8 RPM, the distance would be 200.9 m of rotation—a full 50 m less in one minute. That is 3000 m less per hour, reducing wear substantially.

Malaysia’s Pahang Selangor Water Tunnel was a good example of this phenomenon. What is now the longest tunnel in Southeast Asia, at 44.6 km, required excavation using three 5.2 m diameter Main Beam TBMs mounted with 19-inch disc cutters. The machines operated in abrasive granitic rock exceeding 200 MPa UCS, up to 1,200 m below the Titiwangsa Mountain Range.  RPM trials were conducted on the three TBMs, showing that an increase in penetration rate per revolution of 15 to 20 percent could be achieved by decreasing the RPM from between 11.5 and 12 to just 9.5. While the overall advance rate was lower because of fewer revolutions, downtime was decreased and cutter changes were reduced by as much as 19%. The overall time savings more than made up for the decreased advance rate.

RPM vs Penetration Rate

In site tests, reduced RPM resulted in increased TBM penetration rates.

3: Your Crew is the Key

Knowledgeable operators are key in hard rock: there needs to be a balance between cutterhead speed and thrust force. An experienced TBM Operator will be able to identify when ground conditions change and react accordingly.  In addition, knowledgeable operators know how to react if varying rock strengths are present in the excavation face.  The most effective way to prevent impact loading in such conditions is to reduce cutterhead speed and penetration rate per revolution.

Maintenance is another key point and is especially important for extremely hard rock conditions. At the start of a project it is recommended to set a maintenance period for each day, say four hours out of each 24-hour period, which enables the crews to become familiar with the maintenance regime. This equates to approximately 24 hours of maintenance in a 6-day working week. Cutter change time can take up substantially more than four hours per day in hard rock tunnels, so once the crews are familiar with the maintenance tasks they are best carried out concurrently with cutter change operations.

Cutterhead inspections should be carried out on a regular basis to enable worn, damaged or blocked cutters to be replaced as soon as possible. Boring with even one blocked cutter can result in a cascading type wipe-out, which will progress rapidly in a chain reaction effect through multiple cutters if not immediately recognized. In hard rock this can also result in damage to the cutterhead over the course of just a couple of boring strokes. The same applies to the inspection of the bucket lips—these should be performed regularly and the bucket lips kept in good condition.

Inspecting the TBM cutterhead

A crew member inspects a TBM cutterhead.

The Takeaways

Overall, ensuring success in some of the most difficult rock in the world requires pre-planning with proper machine design, good cooperation by all parties involved, a knowledgeable crew, and dedicated maintenance. More than that, it also takes some experimentation on the part of the contractor or those overseeing the TBM operation. Contractors can look at different cutter types and test the parameters of TBM operation, do regular penetration tests, vary the RPM, and vary the thrust to see what gets the best cutter life and the best TBM performance. Taking the time to do such testing can make all the difference between a successful project and an unsuccessful one.

Lastly, new and innovative cutter designs and housing designs exist for extremely hard rock. Consider XHD cutter rings, cutter mountings with hardened replaceable seats, and other designs that may be in development or available for testing.

 

 


6个史诗性项目|国际劳动节迎来罗宾斯世界各地的一系列贯通

几十个罗宾斯掘进机在世界各地的工地同时作业是很平常的事。但这个五月很特别,我们迎来了一次贯通的盛会。2019年4月,6个项目贯通的捷报纷纷传来,相信还有更多贯通接踵而来。

法国格勒瑞德嘉鲁项目(Galerie des Janots)

2019年4月3日,罗宾斯一台直径3.5米的主梁式掘进机贯通后进入洞穴,完成了2.8公里长的引水隧道。这不是机器第一次遇到洞穴:在隧道掘进过程中,设备两次碰到了未知的洞穴,其中最大的洞穴大小达到惊人的8,000立方米。

Galerie des Janots Robbins TBM breakthrough

4月3日,承包商Eiffage土建施工在法国卡西斯庆祝罗宾斯掘进机的贯通

Galerie des Janots Robbins TBM makes breakthrough

尽管在含有粉状粘土和岩溶石灰岩这样难以置信的地质条件下作业,罗宾斯隧道掘进机每天都能实现高达25米的掘进速度

奥地利GKI项目

2019年4月8日,两台直径6.5米的罗宾斯双护盾硬岩掘进机中的第一台完成了奥地利Gemeinschaftskraftwerk Inn(GKI)项目的作业,实现贯通。这条在高山小镇Pfunds附近长22公里的引水隧道,在片岩的高埋深(最大埋深高达1,200米)地质下作业。第二台双护盾掘进机预计也将在今年晚些时候实现贯通。

GKI Robbins Double Shield at launch

4月8日贯通的这台双护盾掘进机始发时的情景

美国迪津迪隧道系统

2019年4月10日,罗宾斯掘进机完成了美国印第安纳波利斯迪津迪隧道项目(Digindy)中的两个隧道段,即白河(White River)和低洼浦兹(Lower Pogues)隧道。这台36岁、直径6.2 米的翻新罗宾斯主梁式掘进机于2013年在印第安纳波利斯始发,并且表现得非常好。在这项作业中,打破了6至7米直径范围内的多项世界纪录,包括“最高日掘进”(124.9米)、“最高周掘进”(515.1米)和“最高月掘进”(1,754米)。整个项目中,隧道掘进机将计划开挖超过40公里长的隧道。

The Robbins Main Beam TBM at DigIndy, USA

作为迪津迪隧道系统的一部分,罗宾斯主梁式掘进机完成了两个隧道的掘进任务

尼泊尔巴瑞巴贝引水综合项目

2019年4月16日,尼泊尔总理和其他政府官员、承包商COVEC以及罗宾斯齐聚一堂,共同庆祝尼泊尔国家骄傲工程—巴瑞巴贝引水隧道的贯通。这台罗宾斯掘进机不单是首台在尼泊尔国内使用的全断面掘进机,更是全球史上第一台穿越喜马拉雅山脉的全断面双护盾硬岩掘进机。在月掘进超过1,000米的表现下,这台设备比计划提前了7个多月完成掘进。

The Bheri Babai Robbins Double Shield TBM breakthrough in Nepal

罗宾斯直径5.09米的双护盾硬岩掘进机穿过砂岩和泥岩,在18个月内完成12.2公里长的行程

印度孟买地铁三号线

2019年4月18日,两台直径6.65米罗宾斯跨模式掘进机 (XRE)中的第一台在孟买地铁三号线上首次实现了中段贯通。这台设备完成了从克夫普瑞(Cuffe Parade)到维旦巴文(Vidhan Bhawan)站长1.2公里的隧道挖掘后,现在也已经准备就绪开始挖掘长2.8公里的第二段隧道。

Mumbai Metro XRE TBM breakthrough

承包商Larsen&Toubro和上海隧道工程公司合资企业(L&T-STEC JV)于4月18日与罗宾斯人员共同庆祝跨模式掘进机的贯通

 

智利的秃鹰水力发电项目

2019年4月25日,直径4.56米的罗宾斯双护盾掘进机完成了为智利毛利地区(Maule)秃鹰水力发电项目(Los Condores HEPP)建造的一条长12公里的引水隧道。承包商Ferrovial Agroman克服了高埋深混合岩土和高涌水的困难地质条件贯通了隧道。第二台直径4.56米的罗宾斯跨模式掘进机(XRE)将在今年晚些时候开挖另一段隧道

Los Condores Robbins Double Shield TBM

4月25日完成12公里引水隧道的罗宾斯双护盾掘进机始发时的情景


快速开挖7个关键点的简史

Rapid Excavation: It’s a term bandied about throughout our industry, but what does it mean? It’s considered by many to be the ultimate goal in TBM tunneling—machines that reliably complete projects on time (or early) with faster rates of excavation, regardless of conditions. However, speeding up a project schedule is not as straightforward as pushing a machine harder, working longer hours, or increasing your crew size. The issue is complex, and we’ve put together 7 key points to help you navigate it.

1. Consider the Entire Project Schedule

First of all, consider that increasing the excavation rate may not be the only way—and indeed may not be the best way—to speed up a project schedule. The generalized graphic below illustrates my point: TBM excavation often makes up around 25% or less of the total time to complete a public works tunnel. In fact this is a conservative value as by many estimations the total project time is often 15 years. Even if we were to increase the excavation rate by several times what TBMs are currently capable of, it wouldn’t significantly speed up project delivery.

Generalized process of delivering a public works tunnel. TBM excavation show in red.

Figure 1. Generalized process of delivering a public works tunnel. TBM excavation show in red.

Shortening the decision-making process or the design and consulting process is much more feasible than creating a “super-fast TBM” and would have a bigger impact on the project schedule as well.

2. Know the Facts about TBMs

TBMs are fast, and they’ve been fast for decades.  In fact, 50% of all known TBM world records were set more than two decades ago. Much of the seeming lack of progress is illusory–it has to do with the fact that modern tunnels are being built in ever more difficult geology, while more stringent health and safety standards put necessary limits on the excavation process, among other things. Today’s TBMs are capable of boring in harder rock, in higher water pressures, in mixed ground conditions and a host of other environments that would have been impossible in the 1970s and 1980s. And they do it while performing well; indeed, at much higher rates than conventional excavation. The below chart is a good illustration of just how far TBMs have come in recent years.

The long way that TBMs have come since the 1970s.

Figure 2. The long way that TBMs have come since the 1970s.

3. Know That Productivity Has Vastly Improved

There have been some recent articles looking at decreasing productivity in the construction industry overall, such as this article in The Economist.  While the productivity of the overall construction industry is up for debate, productivity is not decreasing in the tunneling industry. Moreover, productivity is incredibly reliant on each project’s limitations and requirements.  When considering productivity, think about logistics, geology, and data.

Based on decades of field data, we’ve found that a typical TBM heading is two to three times faster than a drill & blast heading. This effect is more pronounced the longer the tunnel drive, and more than makes up for the typically longer lead time to acquire and mobilize a TBM.

TBMs are two to three times faster on average than drill & blast and multiple times faster than a roadheader

Figure 3. TBMs are two to three times faster on average than drill & blast and multiple times faster than a roadheader.

So it’s safe to say that TBMs are the way to go for more productive tunneling in all but the shortest tunnels. Logistics is the other key: scheduling of crew and materials, particularly in long tunnels, is so important. This is doubly so if using muck cars. For this reason, using continuous conveyors for muck removal is more efficient, as the removal process does not need to stop for personnel and material movements. In fact at least 75% of all TBM world records were set while using a continuous conveyor for muck removal.

Conveyors enable fast excavation

Figure 4. Today’s conveyors are capable of hauling 1,800 metric tons per hour or more.

Lastly, consider geology when planning the construction schedule. Even a customized machine with streamlined logistics will bore more slowly in fractured volcanic rock with significant fault zones than in competent sandstone.  Setting the excavation schedule requires a close look at geology and the excavation rates of recent projects in those conditions.

4.  Identify the Bottlenecks


The bottlenecks must be identified and alleviated if productivity is to be increased. Think about the operations that can be done simultaneous with boring that are now done separately:

  • Applying a Concrete Lining: Continuous concrete lining can be done concurrent with boring in many cases. This type of lining eliminates the separate operation of lining a tunnel with segments. Waterproofing membrane can be applied with a membrane gantry if needed
  • Increasing Automation: Processes such as cutter changes and segment erection can and are being fully automated on research projects in the industry. Full automation could significantly reduce downtime
  • Eliminate re-grip time: When setting segments and thrusting off rings, elimination of re-grip time could be key to increasing advance rates. New innovations such as helical segments are promising to do this through a simple change in segment architecture
Continuous Concrete Lining behind a TBM

Figure 5. Continuous concrete lining applied behind a Main Beam TBM.

By boring and lining the tunnel simultaneously with a final, continuous concrete liner, a substantial amount of time—perhaps six months—could be shaved off of the excavation schedule.

Figure 6. By boring and lining the tunnel simultaneously with a final, continuous concrete liner, a substantial amount of time—perhaps six months—could be shaved off of the excavation schedule (as compared to previous example that showed two years’ excavation time).

5.  Understand the Limitations

There has been talk in our industry of making TBMs excavate up to ten times faster. While this is all well and good to aim for, in many cases it may not be realistic. For example, when boring in soft ground using EPB TBMs the penetration rate is limited by material flow and additive permeation. Boring at faster rates could cause heave in front of the TBM followed by subsidence at the surface.

So how could we bore faster in softer ground? It would require a change in the mechanism of excavation—no short order. It would require a better way of holding pressure than the screw conveyor can currently achieve. This is just one of many examples where physical limitations are the barrier to speed, not efficiency.

6.  Think Outside the Circle

The possibilities for tunnel construction in the future are intriguing. Consider non-circular tunneling machines, of rectangular, square or other shapes. How much efficiency could be gained by creating a tunnel that requires no back-filling or invert segments to create a flat tunnel invert? Robbins has been exploring these types of machines for decades, with machines such as the Mobile Miner, seen here.

The Mobile Miner was developed in years past to bore non-circular tunnels.

Figure 7. The Mobile Miner was developed in years past to bore non-circular tunnels.

7. Promote Industry R&D

Lastly, there are things all of us in the industry can do to advance technology towards faster and safer tunneling. R&D in our industry is necessarily incremental as technology must be tested for safety and efficacy. But the rate of advancements could be sped up with better funding and closer cooperation between owners, consultants, contractors and TBM suppliers.