Stonehenge - The bored tunnel option

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JammyDodge
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Re: Stonehenge - The bored tunnel option

Post by JammyDodge »

jervi wrote: Thu Apr 01, 2021 17:01 I could understand the reasoning behind having 1 ERA per bore. With the tunnels being 3.2KM long I think it is understandable to have 1, since that will give an ERA every 1.6km, which was the basically standard a few years back for an ALR motorway, typically with 4 lanes of traffic.
Of course now the standard is every 1km, which would require 2 ERAs. However the tunnels here will only ever be 2 lanes per bore, so that's give or take half the capacity of the D4 routes that the 1km spacing is for.
It would make sense to have one or two, but sense doesn't talk, money does sadly.

I suspect that HE will be arguing that cameras, vsl and average speed cameras will be able to replace the ERAs. But that is yet to be seen
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hoagy_ytfc
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Re: Stonehenge - The bored tunnel option

Post by hoagy_ytfc »

Given the date, I'm surprised someone hasn't suggested that the tunnel remains D2, while the hard shoulders, given how little they'll be used, can following the existing ground level route.
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Post by KeithW »

biffvernon wrote: Thu Feb 12, 2004 07:22 T1(M)<on Ian Hindle's map of prehistoric routes>
Which map is that or is it Paul Hindle?
And who allowed the A1 so close to the Devils Arrows at Boroughbridge ? These stones are much bigger than those at the Stonehenge though less fanous. Some archaeologist have suggested they are the first road signs, pointing the way to the ritual landscape of the Thornborough Henges.
Biff
Well in the first instance that would gave been the Brigantes who were running the area when the Romans arrived. In fact it was the site of their capital. It has been a strategic crossing point throughout recorded history, originally there was a ford, I believe pretty much where the Marina is today.

Evidence of this was found during archaeological excavations done when the A(M) was being built. It was only in the 11th century that a bridge was built to the east by the Normans. The crossing point was not just used by people but it was used by cattle drovers taking there beasts to Wetherby and York
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Re: Stonehenge - The bored tunnel option

Post by Micro The Maniac »

jervi wrote: Thu Apr 01, 2021 17:01 I could understand the reasoning behind having 1 ERA per bore. With the tunnels being 3.2KM long I think it is understandable to have 1, since that will give an ERA every 1.6km, which was the basically standard a few years back for an ALR motorway, typically with 4 lanes of traffic.
The Hindhead Tunnel is 4 miles (or 6.4km) - it is a 70mph dual carriageway, and has no hard-shoulder and (IIRC, unless I've blinked at the same spot every time) ZERO refuges.


Edit: I'm talking BS, as corrected below... the tunnel is only one-and-a-bit miles
Last edited by Micro The Maniac on Mon Apr 26, 2021 12:17, edited 1 time in total.
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Re: Stonehenge - The bored tunnel option

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Micro The Maniac wrote: Fri Apr 02, 2021 14:59
jervi wrote: Thu Apr 01, 2021 17:01 I could understand the reasoning behind having 1 ERA per bore. With the tunnels being 3.2KM long I think it is understandable to have 1, since that will give an ERA every 1.6km, which was the basically standard a few years back for an ALR motorway, typically with 4 lanes of traffic.
The Hindhead Tunnel is 4 miles (or 6.4km) - it is a 70mph dual carriageway, and has no hard-shoulder and (IIRC, unless I've blinked at the same spot every time) ZERO refuges.
But now we have expressway standards which require eras (although there is an exception to the rule if physical limitations are there such as tunnels/bridges). While it doesn't appear that this scheme will be an expressway (either legally or with SM tech), having an ERA will make it potentially easier for it to become an expressway in the future.
When the Hindhead Tunnel was built, those standards were not a thing, hence why it's got none.

However, whenever the A303 corridor is finally upgraded to an expressway, the requirement for ERAs (at least to their current standard) would of been removed, since car will be more reliable and almost entirely be self driving if not 100% self driving.
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Re: Stonehenge - The bored tunnel option

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Micro The Maniac wrote: Fri Apr 02, 2021 14:59
jervi wrote: Thu Apr 01, 2021 17:01 I could understand the reasoning behind having 1 ERA per bore. With the tunnels being 3.2KM long I think it is understandable to have 1, since that will give an ERA every 1.6km, which was the basically standard a few years back for an ALR motorway, typically with 4 lanes of traffic.
The Hindhead Tunnel is 4 miles (or 6.4km)
It's 1.15 miles/1.85km.
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JammyDodge
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Re: Stonehenge - The bored tunnel option

Post by JammyDodge »

Micro The Maniac wrote: Fri Apr 02, 2021 14:59
The Hindhead Tunnel is 4 miles (or 6.4km) - it is a 70mph dual carriageway, and has no hard-shoulder and (IIRC, unless I've blinked at the same spot every time) ZERO refuges.
[/quote]

The entire scheme was 6.4km, but the tunnel is only 1.85km of that. The tunnel at Stonehenge will be around 3km long, more than 50% longer in comparison
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Re: Stonehenge - The bored tunnel option

Post by KeithW »

jackal wrote: Fri Apr 02, 2021 16:57
Micro The Maniac wrote: Fri Apr 02, 2021 14:59
jervi wrote: Thu Apr 01, 2021 17:01 I could understand the reasoning behind having 1 ERA per bore. With the tunnels being 3.2KM long I think it is understandable to have 1, since that will give an ERA every 1.6km, which was the basically standard a few years back for an ALR motorway, typically with 4 lanes of traffic.
The Hindhead Tunnel is 4 miles (or 6.4km)
It's 1.15 miles/1.85km.

And it has cross passages every 100m that connect the two tunnels so in case of an emergency you can escape via the other bore.
https://www.google.co.uk/maps/@51.11009 ... 6656?hl=en

There are also emergency points with phones, fire extinguishers and escape routes. Its probably the safest road tunnel in the UK.
https://www.google.co.uk/maps/@51.11069 ... 6656?hl=en
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Re: Stonehenge - The bored tunnel option

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"Highways England rules out Stonehenge Tunnel ERAs".

The ERAs/HS seem to have been rejected at least three weeks ago, around the time they were first reported.

https://www.constructionenquirer.com/20 ... -shoulder/
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Re: Stonehenge - The bored tunnel option

Post by Norfolktolancashire »

jackal wrote: Fri Apr 23, 2021 15:12 "Highways England rules out Stonehenge Tunnel ERAs".

The ERAs/HS seem to have been rejected at least three weeks ago, around the time they were first reported.

https://www.constructionenquirer.com/20 ... -shoulder/
In that article it states construction is likely to begin in 2023?
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Re: Stonehenge - The bored tunnel option

Post by Herned »

Norfolktolancashire wrote: Sat Apr 24, 2021 12:44 In that article it states construction is likely to begin in 2023?
There's loads of archaeology to be done before construction begins. And presumably if they find anything really significant then it could delay it further, or worse
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Re: Stonehenge - The bored tunnel option

Post by hoagy_ytfc »

Do they use TBMs for this sort of work? I imagine so, unless digging through inappropriate ground. The lead time on building those must be fairly long, I'd have though, given that they tend to be custom built
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Re: Stonehenge - The bored tunnel option

Post by KeithW »

hoagy_ytfc wrote: Sun Apr 25, 2021 13:17 Do they use TBMs for this sort of work? I imagine so, unless digging through inappropriate ground. The lead time on building those must be fairly long, I'd have though, given that they tend to be custom built
Given that its 2 miles long I suspect not, they will probably use similar techniques to those used at Hindhead where they used mechanical diggers with the tunnel behind the face having a sprayed concrete lining.
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Re: Stonehenge - The bored tunnel option

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HE says that a TBM will be used, but the final decision is the contractors
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Re: Stonehenge - The bored tunnel option

Post by Vierwielen »

KeithW wrote: Sun Apr 25, 2021 14:09
hoagy_ytfc wrote: Sun Apr 25, 2021 13:17 Do they use TBMs for this sort of work? I imagine so, unless digging through inappropriate ground. The lead time on building those must be fairly long, I'd have though, given that they tend to be custom built
Given that its 2 miles long I suspect not, they will probably use similar techniques to those used at Hindhead where they used mechanical diggers with the tunnel behind the face having a sprayed concrete lining.
It is not only the length of the tunnel, but also the geology that determines whether or not a TBM will be used.
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Re: Stonehenge - The bored tunnel option

Post by wrinkly »

Vierwielen wrote: Thu Apr 29, 2021 22:16 It is not only the length of the tunnel, but also the geology that determines whether or not a TBM will be used.
Though nowadays there are several types of TBM for different geological conditions. I think two or three different types were used on Crossrail, for example.
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Re: Stonehenge - The bored tunnel option

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"ESSENTIAL work is scheduled to start in September to supply electricity for Highways England’s controversial £1.7 billion A303 Amesbury to Berwick Down upgrade past Stonehenge which is opposed by some archaeologists and environmentalists.

To facilitate the supply for future construction and the proposed 2.1-mile long tunnel, a section of the A360, between the junction of The Avenue and Longbarrow junction on the A303, will be closed from the first week of September to December."

https://www.thisiswiltshire.co.uk/news/ ... ion-works/
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Re: Stonehenge - The bored tunnel option

Post by Jim606 »

As mentioned on another thread the High Court has ruled against Grant Shapps and the A38 Derby Junctions. The result of a similar challenge against the A303 Stonehenge Tunnel still hasn't been announced. What the Derby ruling indicates is major schemes are not immune to such challenges. The following article make some interesting points;
https://www.derbytelegraph.co.uk/news/f ... nt-5648111
Fresh doubt over A38 improvement scheme in Derby
Campaigners with environmental concerns against the major project - which has seen people forced to move homes - lodged a claim for permission to seek a judicial review of the decision to grant the development consent order.

The campaigners believe the scheme is a "waste of taxpayers' money", will increase air pollution and result in loss of public space. Now, it has been officially confirmed that the consent order for the project has been quashed - meaning more doubts now cloud over the major project which has been designed to make significant improvements to Derby's road network and boost the economy. A Department for Transport spokesperson told the Local Democracy Reporting Service that the plans will now have to be "redetermined". But it is unclear at this stage how long this redetermination could take and what it will actually mean for the project's future. The Department for Transport spokesperson said: "We’ve consented to the development consent order for the A38 Derby Junctions being quashed.
If the Stonehenge scheme also ends up having to be 're-determined' what would this actually mean in practice? Another couple of green bridges might do the trick? But, would the Gov. DfT Highways Eng. etc. just decide the whole thing isn't worth the effort and kick it into the long grass?
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Re: Stonehenge - The bored tunnel option

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Jim606 wrote: Thu Jul 15, 2021 17:58 As mentioned on another thread the High Court has ruled against Grant Shapps and the A38 Derby Junctions. The result of a similar challenge against the A303 Stonehenge Tunnel still hasn't been announced. What the Derby ruling indicates is major schemes are not immune to such challenges. The following article make some interesting points;
https://www.derbytelegraph.co.uk/news/f ... nt-5648111
Fresh doubt over A38 improvement scheme in Derby
Campaigners with environmental concerns against the major project - which has seen people forced to move homes - lodged a claim for permission to seek a judicial review of the decision to grant the development consent order.

The campaigners believe the scheme is a "waste of taxpayers' money", will increase air pollution and result in loss of public space. Now, it has been officially confirmed that the consent order for the project has been quashed - meaning more doubts now cloud over the major project which has been designed to make significant improvements to Derby's road network and boost the economy. A Department for Transport spokesperson told the Local Democracy Reporting Service that the plans will now have to be "redetermined". But it is unclear at this stage how long this redetermination could take and what it will actually mean for the project's future. The Department for Transport spokesperson said: "We’ve consented to the development consent order for the A38 Derby Junctions being quashed.
If the Stonehenge scheme also ends up having to be 're-determined' what would this actually mean in practice? Another couple of green bridges might do the trick? But, would the Gov. DfT Highways Eng. etc. just decide the whole thing isn't worth the effort and kick it into the long grass?
The PM in his levelling up speech made reference again to the A303 so despite all the issues - he knows like many others that its a scheme which needs to go ahead.
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Re: Stonehenge - The bored tunnel option

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The PM in his levelling up speech made reference again to the A303 so despite all the issues - he knows like many others that its a scheme which needs to go ahead.
I agree that the scheme is 'likely' to go-ahead, in fact some preparation work is about to start such as the power and byway diversions. The campaigners always argued 'no tunnel' or a 'much longer tunnel'. It makes me wonder if they have the ability to extract some more concessions if the High Court ruling goes against the DfT? As mentioned earlier in this thread a longer tunnel isn't possible without a lot of extra money and some ventilation shafts. However, as I have always thought the scheme still isn't good enough. Personally, I would ask for two extra green bridges, one along the line of what would become the old A360 near Longbarrow roundabout and another by the eastern portal. Here I would lower the road level down by 10-15m and sink into much more into the landscape hiding it from view.
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