A226 closed due to partial collapse

[RichardA35]

Which is the only nuclear power station currently being constructed in an area of soft rock which needed stabilised faces of 30m height?
Clue: it's in Somerset

[2 Sheds]

Seems to me that if the highway authority needs this road open then the only option is going to be something like a Mabey 'quickbridge'. https://www.mabeyhire.co.uk/MabeyHire/m ... f?ext=.pdf I think these can be up to 80 metres span. Costs would no doubt dictate a single lane bridge with traffic signal control. Obviously Mabey would need to be satisfied that their bridge has adequate support. If further sections of the road are at risk of collapse these must be stabilised to provide stable foundations, or else bridged over too.

[KeithW]

Which is the only nuclear power station currently being constructed in an area of soft rock which needed stabilised faces of 30m height?
Clue: it's in Somerset

Here is one for you, there is not and never has been a railway connection to Hinkley Point, the nearest rail connection is 8 miles away in Bridgwater which is where machine to load spent fuel flasks is located, just here in fact,
https://www.google.com/maps/@51.1308616 ... authuser=0

So I did a more generic search and here is the government plan for improving transport to Hinkley Point.

What I also found interesting was the latest update from Hinkley Point C


The improved transport infrastructure for Somerset will support the area’s long term economic growth by providing public transport and cycle access to a nationally-important construction project.

The Hinkley Point C power station will employ at least 5000 people, generate business for local suppliers, and comes with significant investment in training and skills for local people. Transport to the power plant will be easier, safer and more environmentally friendly following these improvements.

Hinkley Point C will play crucial role in the UK’s future energy security.

The transport schemes have been agreed by the Department for Transport and the Heart of the South West Local Enterprise Partnership (LEP), which is made up of local councils and representatives from the private sector.

The 4 schemes are as follows:

£295,000 for a cycle route linking Bridgwater to Hinkley Point - this will see improved cycle facilities from Bridgwater to the site to begin in 2014 to 2015, it will include a cycle route separated from the road
£150,000 for a scheme linking Taunton’s new DfT-funded inner distributor road to the rail station, improving connections between the railway and power station, helping the workforce that is expected to travel by rail - the Taunton Northern Inner Distributor Road is due to be completed in 2014 to 2015
£800,000 for rail station improvements at Bridgwater, with the emphasis on linking trains with local bus services to allow the Hinkley workforce to get to and from the power station - the funding will ensure that the critical first phase improvements to the station and access are in place in good time
£1.6 million for roads maintenance - this early funding will allow existing roads to be improved in advance, reducing disruption and avoiding costs to the taxpayer for preventative work further down the line

What it amounts to is the provision of a cyclepath and a free bus service to Hinkley Point C from Bridgwater. In the case of Dungeness B we did the same thing to Ashford, Hythe and Folkestone. Note

But hey maybe I missed something , a web search didn't find anything nor did a look at aerial views on Google and Bing maps. What I did was the jetty that allows bulk materials to be delivered by sea, that however opened in 2019.

[KeithW]

Back to the A226

I took a look in Google Earth and it seems after the road first opened around 2000 the quarry kept nibbling away making the road ever narrower

Today
https://www.google.com/maps/@51.4498673 ... authuser=0

2004

[Phil]

Back to the A226

I took a look in Google Earth and it seems after the road first opened around 2000 the quarry kept nibbling away making the road ever narrower

Today
https://www.google.com/maps/@51.4498673 ... authuser=0

2004

That pic you posted is NOT the same place you have linked too!

The picture is of the section of road replaced by a bridge over the HS1 rail line!

They built it by diverting the A226 to the south (as per the pic) on a new temporary embankment so as to build the bridge on its existing alignment.

Once that was done the diversion and the temporary embankment was removed so they could finish building the rail line.

The site of the collapse is WEST of the HS1 bridge and has been unchanged in quarrying terms for two or three decades at least.

[KeithW]

That pic you posted is NOT the same place you have linked too!

The picture is of the section of road replaced by a bridge over the HS1 rail line!

They built it by diverting the A226 to the south (as per the pic) on a new temporary embankment so as to build the bridge on its existing alignment.

Once that was done the diversion and the temporary embankment was removed so they could finish building the rail line.

The site of the collapse is WEST of the HS1 bridge and has been unchanged in quarrying terms for two or three decades at least.

Indeed it is - here is the section you mention, however you look at I am somewhat concerned by the building of a road on a narrow, high chalk escarpment that has failed after less than 20 years in service, as I suggested earlier I would recommend bringing in a geological survey team but I cannot help noticing some rather worrying signs on Galley Hill Road

here
https://www.google.com/maps/@51.4500598 ... authuser=0

cracking here
https://www.google.com/maps/@51.4501616 ... authuser=0

From Manor Way there are clear signs of vegetation lower down on the cliff which tends to make one suspicious of what is happening there.
https://www.google.com/maps/@51.4505648 ... authuser=0

In geological terms 20 years ago is the blink of an eye and I notice in the latest report that the burst water main is said to have been running under the road - Oops.
https://www.itv.com/news/meridian/2023- ... ing-issued
https://www.itv.com/news/meridian/2023- ... f-collapse

So we have a narrow, high chalk escarpment with a water main running under the road - what could possibly go wrong !

[Owain]

Which is the only nuclear power station currently being constructed in an area of soft rock which needed stabilised faces of 30m height?
Clue: it's in Somerset

Here is one for you, there is not and never has been a railway connection to Hinkley Point, the nearest rail connection is 8 miles away ...

He didn't say there was any rail connection to Hinkley Point....

You assumed he was working at Sizewell, and posted a link to a possible 'green rail route' for Sizewell C!

Now I actually worked on the construction and commissioning of Dungeness B Nuclear power Station so I would be interested in which power station. Hinckley Point C is well beyond the stage of digging out foundations so I suspect you are talking about Sizewell C. In that case I do hope somebody is talking notice as just 4 miles north Dunwich is still being swallowed up by the sea ! Fortunately the geology at Sizewell is more favourable and drainage was improved for Sizewell B.
[ ... ]

The whole shebang is online at
https://sizewellcdco.co.uk/wp-content/u ... 1_of_3.pdf

Unfortunately the assumption in the blue text is incorrect so the remainder of the post is moot (notwithstanding the link goes to a study of a possible rail line for Sizewell, adjacent to, but not actually the power station development itself, that I am able to click, read and fully understand for myself without the need for a summary).
[...]

[RichardA35]

But hey maybe I missed something , a web search didn't find anything nor did a look at aerial views on Google and Bing maps.

What was missed was that the mention of a rail link came from a link provided which purported to be the geological report of Sizewell C but was, in fact, of the possible rail link some way onshore from the power station. As I stated, I managed and organised the design and construction methodology for excavation and stabilisation of 30m+ soft rock slopes for the power station I was involved with, so I feel I have sufficient experience to give a view on the stabilisation of a pinnacle of soft rock.

[Phil]

That pic you posted is NOT the same place you have linked too!

The picture is of the section of road replaced by a bridge over the HS1 rail line!

They built it by diverting the A226 to the south (as per the pic) on a new temporary embankment so as to build the bridge on its existing alignment.

Once that was done the diversion and the temporary embankment was removed so they could finish building the rail line.

The site of the collapse is WEST of the HS1 bridge and has been unchanged in quarrying terms for two or three decades at least.

Indeed it is - here is the section you mention, however you look at I am somewhat concerned by the building of a road on a narrow, high chalk escarpment that has failed after less than 20 years in service…

But ‘They’ haven’t built a road on a narrow high chalk escapement!

Nor has that road only been exsistance for 20 years!

The road has ALWAYS run on that alignment for centuries.

The escarpments on either side came AFTER the road was well established and is the direct result of quarrying activity dating from the 1900s and finishing in the 1980s.

It is NOT the result of anything done in the past 20 odd years! - If you want someone to blame it’s the authorities who allowed the quarrying companies to extract so much chalk in the first place.

As is a common theme these days (and a big problem for railway earthworks) the problem is the Victorian’s / Edwardian’s didn’t give soil mechanics the respect it deserved.

This is largely due to an over emphasis in profit - in the case of the A226 leaving more of the chalk behind would have meant less chalk extraction and less profits (on the railways it was a case of the wider the cut / bank the more land you needed to purchase plus more cost in terms of building the thing).

Were the quarries in work now then I can’t imagine they would be permitted to leave a sheet edge so close to a road - but we can’t go back in time and correct that.

To be honest the best option would probably to actually knock down the escarpment and turn it into a viaduct - the problem with that is it’s going to be hugely expensive and cash strapped local authorities are having a hard time dealing with the basics.

[KeithW]

What was missed was that the mention of a rail link came from a link provided which purported to be the geological report of Sizewell C but was, in fact, of the possible rail link some way onshore from the power station. As I stated, I managed and organised the design and construction methodology for excavation and stabilisation of 30m+ soft rock slopes for the power station I was involved with, so I feel I have sufficient experience to give a view on the stabilisation of a pinnacle of soft rock.

There are only 2 nuclear power stations under construction, Sizewell C and Hinkley Point C, dont take my word for it - see for yourself.
https://www.edfenergy.com/energy/nuclea ... d-projects

There is no practical rail link to Hinkley Point C which is why they built a jetty so heavy equipment and bulk materials can be brought by ship.
https://www.google.com/imgres?imgurl=ht ... egUIARDZAQ

There is however a plan to build a rail link to Sizewell C
https://sizewellcdco.co.uk/wp-content/u ... 1_of_3.pdf

The title of this section of the above document is fairly clear.

Sizewell C: Green Rail Route
Phase 1 Desk Study Report
EDF Energy
January 2020

[KeithW]

But ‘They’ haven’t built a road on a narrow high chalk escapement!

Nor has that road only been exsistance for 20 years!

The road has ALWAYS run on that alignment for centuries.

The escarpments on either side came AFTER the road was well established and is the direct result of quarrying activity dating from the 1900s and finishing in the 1980s.

It is NOT the result of anything done in the past 20 odd years! - If you want someone to blame it’s the authorities who allowed the quarrying companies to extract so much chalk in the first place.

As is a common theme these days (and a big problem for railway earthworks) the problem is the Victorian’s / Edwardian’s didn’t give soil mechanics the respect it deserved.

This is largely due to an over emphasis in profit - in the case of the A226 leaving more of the chalk behind would have meant less chalk extraction and less profits (on the railways it was a case of the wider the cut / bank the more land you needed to purchase plus more cost in terms of building the thing).

Were the quarries in work now then I can’t imagine they would be permitted to leave a sheet edge so close to a road - but we can’t go back in time and correct that.

To be honest the best option would probably to actually knock down the escarpment and turn it into a viaduct - the problem with that is it’s going to be hugely expensive and cash strapped local authorities are having a hard time dealing with the basics.

The quarrying activity created the narrow escarpment - as for timing see this from Google Earth in 2004 when the bridge was being built.

View now.

[KeithW]

That pic you posted is NOT the same place you have linked too!

The picture is of the section of road replaced by a bridge over the HS1 rail line!

They built it by diverting the A226 to the south (as per the pic) on a new temporary embankment so as to build the bridge on its existing alignment.

Once that was done the diversion and the temporary embankment was removed so they could finish building the rail line.

The site of the collapse is WEST of the HS1 bridge and has been unchanged in quarrying terms for two or three decades at least.

Indeed it is - here is the section you mention, however you look at I am somewhat concerned by the building of a road on a narrow, high chalk escarpment that has failed after less than 20 years in service…

But ‘They’ haven’t built a road on a narrow high chalk escapement!

Nor has that road only been exsistance for 20 years!

The road has ALWAYS run on that alignment for centuries.

The escarpments on either side came AFTER the road was well established and is the direct result of quarrying activity dating from the 1900s and finishing in the 1980s.

It is NOT the result of anything done in the past 20 odd years! - If you want someone to blame it’s the authorities who allowed the quarrying companies to extract so much chalk in the first place.

As is a common theme these days (and a big problem for railway earthworks) the problem is the Victorian’s / Edwardian’s didn’t give soil mechanics the respect it deserved.

This is largely due to an over emphasis in profit - in the case of the A226 leaving more of the chalk behind would have meant less chalk extraction and less profits (on the railways it was a case of the wider the cut / bank the more land you needed to purchase plus more cost in terms of building the thing).

Were the quarries in work now then I can’t imagine they would be permitted to leave a sheet edge so close to a road - but we can’t go back in time and correct that.

To be honest the best option would probably to actually knock down the escarpment and turn it into a viaduct - the problem with that is it’s going to be hugely expensive and cash strapped local authorities are having a hard time dealing with the basics.

Indeed but the bridge along Galley Hill Road only goes back to 2005 as is clearly shown on Google Earth, it was needed when HS1 was built as the old route along London Road was considered not to be suitable for a level crossing

[RichardA35]

There are only 2 nuclear power stations under construction, Sizewell C and Hinkley Point C, dont take my word for it - see for yourself.

Having worked at HPC for 4 years, I need no instruction in how to suck eggs.

[Phil]

The quarrying activity created the narrow escarpment - as for timing see this from Google Earth in 2004 when the bridge was being built.

View now.

You are still not getting it!

That picture you keep posting is during construction of HS1 - NOT DURING QUARRYING ACTIVITIES!

It required the long narrow ridge of chalk to be replaced by a high bridge carrying the A226 over the railway - and to do so a temporary embankment has been built with the A226 diverted onto it so that the new bridge could be built on the original A226 alignment.

This is what you are seeing on your picture - it is NOT quarrying activity.

The quarrying at this location had ceased decades before HS1 arrived on the scene - which was part of the reason Ebslfeet station was built as all those ex quarries were supposed to be reclaimed for housing and other development purposes.

Take a look at these Arial photo from the 1950s
https://historicengland.org.uk/images-b ... 036_v_5118
https://historicengland.org.uk/images-b ... 036_v_5119
Although its upside down (north is at the bottom of the picture) you can quite clearly see that the A226 running along a spur of chalk between two old quarry sites! (the station seen is Swanscombe)

Indeed HS1 was actually built through the old quarries at this point (Ebsfleet station sits in part of one of the quarries) and moreover the digging of the Thames tunnel meant there was lots of extra spoil being generated - some of which was no doubt used to rearrange the levels around the Ebsfleet site.

Before HS1 construction commenced then the area in the photo it looked exactly the same as the section of the A226 further west (i.e. the bit which has collapsed) - namely a road running on a high chalk ridge between two DISUSED quarries.

[SouthWest Philip]

Before HS1 construction commenced then the area in the photo it looked exactly the same as the section of the A226 further west (i.e. the bit which has collapsed) - namely a road running on a high chalk ridge between two DISUSED quarries.

Having allowed the quarries to edge up to the road on other side, perhaps they should have diverted to the road down to the new level and joined the quarries together? I wonder if that will be ultimate solution to the current problems?

In fact, isn't it usual for roads to be diverted around active quarries rather then maintaining a thin strip of elevated land in between?

[Keiji]

Before HS1 construction commenced then the area in the photo it looked exactly the same as the section of the A226 further west (i.e. the bit which has collapsed) - namely a road running on a high chalk ridge between two DISUSED quarries.

Having allowed the quarries to edge up to the road on other side, perhaps they should have diverted to the road down to the new level and joined the quarries together? I wonder if that will be ultimate solution to the current problems?

In fact, isn't it usual for roads to be diverted around active quarries rather then maintaining a thin strip of elevated land in between?

Yes - not being from the Kent area, I was surprised to see these photos and read that this road was left 35m(?) up from the ground level for decades(?) after the quarrying finished so close to either side... The quarry would want to extract all the chalk possible, so it would be reasonable to divert the road somewhere else so they could get at the chalk available under the existing road.

Which is exactly what happened in 2013ish with the road in Devon (local to me) that goes between Newton Abbot and Chudleigh. The quarry had dug out everything useful either side of the road, and the council (or whatever state body) wanted a better road. So in a rare case of brilliant joined-up thinking between the public and private sectors, they built a new road, closed the old one and then started digging it out. A win-win for everyone involved: the new road has one of the most excellent cycle paths I can think of in this area and is built to modern standards with no awkward kinks or narrow points, so there's no more trouble between the frequent HGVs, cars and cyclists, and the quarry was able to start extracting what was left under the old road.

[Fenlander]

It looks to me like a simple metaphor for the current state of Britain, from Grenfell to the pothole pandemic....

I have an image to go with that too, drove past a subsidence crack a good 20m long earlier that's opened up 1-2" for most of its length. Right in the middle of it is a 12" x 12" repair that makes it look like they've stuck a plaster on it.

[Darren]

An update, one month on:

https://www.kentonline.co.uk/dartford/n ... ne-286639/

Highlights include absolutely nothing being done as far as anyone can see, and KCC declining to comment to the press. Water is still being tanked in for people and others are still waiting to get Internet access restored.

I'd like to think behind the scenes plans have been drawn up and are about to be brought into action...

[Hdeng16]

It’s a shame last months argument didn’t carry on - and I have the awful blocking system to thank for seeing it at all. Really did make me laugh out loud at points - I’m surprised Richard and Phil didn’t get an apology. Or am I.

Anyway… why is it not possible to divert water (and broadband) around the problem site? Seems pretty poor/unusual to have a single point of failure in a built up area?

[KeithW]

Running a large water main is not a minor task especially when the original route is no longer available. That said a notice of works on Galley Hill Road has been made regarding repairs to the water main extending to at least 16 June, which is optimistic in my opinion.
https://one.network/?tm=132969162

See also
https://swanscombeandgreenhithetowncoun ... -closures/

Broadband depends on the individual provider but at a minimum some level of service should be possible via 4G/5G wireless.