How much do tunnels cost

Alert Signup. In , as the Alaskan Way Stakeholder Advisory Committee considered options for the replacement of Seattle's Alaskan Way Viaduct, Arup North America Ltd was commissioned by the Cascadia Center at the Discovery Institute to report on recent developments in the implementation of large-diameter highway tunnel projects around the world.

Details of this report are presented here to provide insight into the benefits of large-diameter bored tunnels for urban highway projects in difficult ground conditions and to examine the importance of evaluating tunnel cost from a whole-life approach. Fig 1. Completed large-bore tunnels.

Fig 2. Shanghai river crossing, two 51ft-diameter tunnels. TBM technology Over the last two decades, the ability of TBMs to construct large-diameter tunnels in weak ground and significant groundwater pressures has increased significantly. Fig 3. Increasing TBM diameters over the last 20 years. Fig 4. Different road tunnel configurations Serebryany Bor, M, and A, respectively. Fig 5. Survey of tunnel costs. Fig 6. Fig 7. Whole-life costs. Author references Compiling real costs for true infrastructure construction comparison.

Reilly, John. Probable cost estimating and risk management. North American Tunneling Proceedings. Lifting the lid on mixshield performance. Tunnels and Tunneling International June Tunnel boring machine development. North American Tunneling Conference State of the art in TBM tunneling.

Ishii, G. Current issues regarding mechanized and automated tunneling. Tunnels and Underground Structures Parker, Harvey W. Bold and visionary planning of tunnels and underground space.

TunnelTalk Articles. TunnelCast Videos. Diary Dates. World News Briefs. Career Moves. Could they be reduced? These are important questions. To help answer this question, Alon Levy at Pedestrian Observations compiled a nice dataset of construction costs for rail tunnels part 1 , part 2. He gathered data for over 40 rail tunnel projects that have been completed or planned over the last decade or so.

While the data is a bit imprecise — based on a mix of ex-ante cost estimates and ex-post contract costs, and converted between currencies using purchasing power parity exchange rates — it provides a useful basis for benchmarking CRL costs. As CRL is 3. Note that a number of the projects on the lower-cost end of the scale had significant above-ground portions that tend to be cheaper to build.

This shows a few important facts:. Lastly, we should be asking: What can we do to be more like South Korea or Spain when it comes to tunnelling costs? Some of the differences between locations are likely to be impossible to change, as they depend upon geography.

But others are possible to change, as they relate to construction methods, design standards, and processes. A few years ago, Alan Davies Crikey identified a few of these factors :. Both lines opened at the same time. The key differences Mr Munro identifies are:. Physical factors like geology explain a lot of the difference between Sheppard and MetroSur, but so too do standards. Community expectations on a range of variables — for example environmental standards, engineering and operating standards, safety standards, the level of citizen input — appear to be key drivers of higher costs in Toronto.

I suppose they are digging through a swamp, and flat, which will simplify things. This is probably a fairly key factor to consider in the cost comparisons.

Number of stations per km. Absolutely; tunnelling, as a rule, is pretty straightforward, always depending on the geology. Building buildings for thousands of of people underground, especially in the middle of cities, is an expensive and tricky business. On geology, it is no surprise that London had the first subsurface, then truly underground, railways, as that is pretty easy clay to work [Budapest was second!

As anyone who follows the travails of the 2nd Ave extension will know. Another issue Peter mentions above is the building up of an industry and practice of doing it.

In fairly different conditions; Italy is a very rugged topography and to build pretty much any transport link will require digging or bridging, and that is true in the north of Spain too.

In both cultures the people expect a high standard of Transit provision and place quality in their cities, and expect their governments to fund both. In my experience stormwater tunnels the tunneling aspect is pretty straight forward. The time and cost of digging the shafts, would surprise people. It takes months to dig the hole, weeks to machine the tunnel. As RossR alludes to NZ is a small and distant country so the costs are going to be high.

IF central government and Auckland came up with a long term pipeline for tunneling works to give a couple of contractors continuity of work i would say these costs would come down. And i do hope Auckland Council bring in experience to manage the construction because contractors are experts in variations these can end up being considerable.

If the contractors think this tunneling job will be their last they will try and make hay. The reality of tunneling is there is a relatively small core of people working worldwide in this field.

As such crews tend to stay together across projects in diverse geographic areas and companies employing them, with occasional changes in team members. The additional laboring crews, electricians, carpenters etc can get up to speed relatively quickly. A key factor has to be the large, experienced contractors based in Spain and Korea. I think there probably is a second order effect between length and cost per km, simply because short tunnels tend to be done in very constrained situations, while long tunnels will logically have a greater probablility of sections being done under less constrained conditions.

Case in point, the CRL is entirely built under the city centre with deep level stations every m or so, in places that are quite awkward to build, in other words every metre of the 3km tunnel is difficult. Of course the real magic of the CRL is that 3km of tricky tunnel work is the last upgrade that buys us what amounts to km of metro system with 40 stations on it when it is finished.

I wonder what the costs of a rail tunnel under the Tamaki Estuary into Pakuranga and eventually surfacing to connect the eastern rail line to a line down the middle of Te Irirangi Drive would be. Correlation is not causation. In general there are mobilisation and demobilisation costs and other costs such as the transportation and assembly of the TBM that are independent of the length of the project.

Seems a no-brainer that once we have the tunnelling machine working, to keep it occupied for an extended time doing a sequence of tunnels throughout the city. It always seemed silly to me that after each tunnelling project, the machine would be packed up and shipped out of the country again.

Even mild subsidence can damage pipes, rail tracks or buildings above. So during the s, Japanese and German engineers learned to use water and air pressure to stabilize the ground around a borer.

They developed tunnel-boring machines that could robotically install precast concrete tunnel-lining panels immediately behind the cutting face, leaving a nearly completed thoroughfare in their wake. The savings from automation can be dramatic. Other recent advances in tunneling technology include precision guidance to thread around existing infrastructure and electronic monitors to track vibrations, which let tunnelers stop at the first hint of trouble.

Advances in chemistry allow engineers to thicken loose ground or soften hard terrain. These innovations have enabled tunneling in areas once considered impassable. Miami recently dug a traffic tunnel beneath a busy waterway by eating through a mix of saturated ground and porous coral rock that previously defied affordable excavation.

He can be reached at dan. A record 4. Home Personal Finance. The high-tech, low-cost world of tunnel building Published: May 10, at a. ET By Daniel Michaels. My wife is a stay-at-home mom.