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Strange tunnel under embankment, local mystery, anyone shed some light?
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If it helps, I found a 2.5sq foot square entrance to another tunnel, on the left side of the original tunnel, camoflauged in ivy. A fellow dog walker commented that when he was a kid in the 80's before they got barred up by the council, they would crawl in and find other tunnels branching off and he said it was very strange and has no idea why it was constructed!
Guys I've just gained entry to this new tunnel that sits beside the one already mentioned and it's much the same as the other one, other than the fact that it is back to front, so the brick partitions begin first, then the remainder of the tunnel carries on however what they've done with this arch is brick the tunnel off completely, but left an aperture high up on the wall that i had to jump and grab and pull myself up which revealed the remainder of the arch filled-in with rubble 2 feet below the ceiling and the very top apex of this arch can be seen on the other side of the embankment here...
Very strange, and again if anyone knows what these tunnels are please say.
Very strange, and again if anyone knows what these tunnels are please say.
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WatcherZero
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Definetley flood plain tunnels. They've been blocked off because they are no longer as needed with a new line of flood defences following the southern line of the fields north of Holme Road up Radcliffe Road to the bridge then closely following the banks of the river past the football ground and onwards as far as Clifton Blvd.
However Environment agency still shows the area as being greater than 1/100 chance of flood each year if flood defences failed.
http://maps.environment-agency.gov....bmit.y=1#x=457902&y=337885&lg=1,2,10,&scale=8
Key to the map
Hatched area protected by flood defences
Dark Blue greater than 1/100 chance of river flood without flood defences (if not hatched)
Light Blue greater than 1/1000 chance of river flood without flood defences
No colouration, less than 1/1000 chance of flooding
Dotted pink line, flood defences
However Environment agency still shows the area as being greater than 1/100 chance of flood each year if flood defences failed.
http://maps.environment-agency.gov....bmit.y=1#x=457902&y=337885&lg=1,2,10,&scale=8
Key to the map
Hatched area protected by flood defences
Dark Blue greater than 1/100 chance of river flood without flood defences (if not hatched)
Light Blue greater than 1/1000 chance of river flood without flood defences
No colouration, less than 1/1000 chance of flooding
Dotted pink line, flood defences
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hi there, there are 5 arches side by side with the first one being the one I gained access to last night and the second one being the strange, identical tunnel I've documented earlier in the thread (with photos). It is identical to the first other than that they are laid out in opposite ends so the weird brick partitions are opposite ends of the arches and the other difference is the first arch has been packed with rubble almost to the roof whereas the other one is open, see photos.
I still don't know why they went to the trouble of building 5 of these, I mean why not 2 or 3, or even just one? Each one is very large at 10 meters wide and 30 meters in length, and pretty tall at about 5 meters high!
And to block them off why not just build a wall each end why go to the trouble of creating these strange bricked partitions inside?
I must admit, air raid shelters is the ONLY theory that i can possibly come up with, but wouldn't there by plans and records?
I still don't know why they went to the trouble of building 5 of these, I mean why not 2 or 3, or even just one? Each one is very large at 10 meters wide and 30 meters in length, and pretty tall at about 5 meters high!
And to block them off why not just build a wall each end why go to the trouble of creating these strange bricked partitions inside?
I must admit, air raid shelters is the ONLY theory that i can possibly come up with, but wouldn't there by plans and records?
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WatcherZero
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From your description which isn't always clear as I understand it.
As built there were 5 open arches to allow substantial flood plain flow. (5 arches are stronger than one big arch and allow a longer length of void beneath than a single large one)
Flood defences built elsewhere so arches and approach of unimpeded flood transition no longer necessary/welcome so two of them were completely filled in while 3 received culverts with partitions which restrict the capacity of water that can flow across the natural barrier of the embankment. If you simply had an entrance and an exit partition and there was a sizeable drop in height across the length of the culvert then the outlet pressure would be considerably higher than the inlet pressure through weight of water and a height of water could build up behind the retaining wall, potentially knocking it over. To mitigate that there are partitions which gently restrict the flow through the culvert so the pressure does not rise too high.
As built there were 5 open arches to allow substantial flood plain flow. (5 arches are stronger than one big arch and allow a longer length of void beneath than a single large one)
Flood defences built elsewhere so arches and approach of unimpeded flood transition no longer necessary/welcome so two of them were completely filled in while 3 received culverts with partitions which restrict the capacity of water that can flow across the natural barrier of the embankment. If you simply had an entrance and an exit partition and there was a sizeable drop in height across the length of the culvert then the outlet pressure would be considerably higher than the inlet pressure through weight of water and a height of water could build up behind the retaining wall, potentially knocking it over. To mitigate that there are partitions which gently restrict the flow through the culvert so the pressure does not rise too high.
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Paul180
Member
Thanks paul I just sent them an email with a link to this thread, hope they get back to me with an answer!
@WatcherZero, you seem pretty confident with that explanation. Have you seen these types of tunnel partitions elsewhere, and correct me if I'm wrong but it seems madness to build these types of partitions for no other reason than controlling the flow of water so that it doesn't build-up too much pressure... I just don't get that!?
Also there is no height difference to the land either side of the arches.
Also why go to the length of filling-in half the length of the first tunnel. When I climbed up the blocking-wall through the narrow aperture they had filled the tunnel in with rubble, looked very surreal! Very strange as there's no logical reason for all this work and effort.
--- old post above --- --- new post below ---
just got a reply...
@WatcherZero, you seem pretty confident with that explanation. Have you seen these types of tunnel partitions elsewhere, and correct me if I'm wrong but it seems madness to build these types of partitions for no other reason than controlling the flow of water so that it doesn't build-up too much pressure... I just don't get that!?
Also there is no height difference to the land either side of the arches.
Also why go to the length of filling-in half the length of the first tunnel. When I climbed up the blocking-wall through the narrow aperture they had filled the tunnel in with rubble, looked very surreal! Very strange as there's no logical reason for all this work and effort.
--- old post above --- --- new post below ---
just got a reply...
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EveningStar
Member
Needs treating with caution. The EA maps are indicative and prepared using an automated system that has a 1 km reach resolution. The scientists preparing this system published a paper in the Journal of Natural Hazards and note that the methodology can "show differences in more complex areas". In other words, it can produce some odd results, including a site where the indicative mapping showed the higher river bank flooding in preference to a clearly defined flood plain. As consultant for a building owner on the higher bank, that was 18 months of negotiation, and a lot of supporting calculations, before the EA made a local revision to the mapping.
Edit: Paper is, 'National Floodplain Mapping: Datasets and Methods – 160,000 km in 12 months', by Bradbrook, K., Waller, S. & Morris, D. Nat Hazards (2005) 36: 103.
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WatcherZero
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Yes but we also have the historical snippet of people walking the embankment because the surrounding area was flooded.
Yes in fact the playing field next to these tunnels is known to flood like a lake every 10 or so years. The area is indeed at risk of flooding however 5 massive arches is overkill I would of thought. And the first 2 of the 5 arches with the weird brick partitions is still a mystery.
The livestock shelter theory may be true as the area was all farmland when the embankment, railway and arches were built in 1865, but only 20 years later all the current roads and houses popped up, leaving only the current playing field as grazing land, I have no idea if livestock was kept on that field, but I do know sheep were kept in nearby Bridgford park until 1900 or so.
The livestock shelter theory also makes sense due to the size of the entrance ways being only 2.5 feet tall, perfect for pigs and sheep.
But then again the brickwork looks more modern than the arches, indicating the partitions were built inside at a later date, when the surrounding fields would of become the current housing streets we see today thus negating the need for these shelters for the animals?
I'm still wanting to know for sure!
The livestock shelter theory may be true as the area was all farmland when the embankment, railway and arches were built in 1865, but only 20 years later all the current roads and houses popped up, leaving only the current playing field as grazing land, I have no idea if livestock was kept on that field, but I do know sheep were kept in nearby Bridgford park until 1900 or so.
The livestock shelter theory also makes sense due to the size of the entrance ways being only 2.5 feet tall, perfect for pigs and sheep.
But then again the brickwork looks more modern than the arches, indicating the partitions were built inside at a later date, when the surrounding fields would of become the current housing streets we see today thus negating the need for these shelters for the animals?
I'm still wanting to know for sure!
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edwin_m
Veteran Member
As I posted near the beginning of this thread, West Bridgford flooded to well inland of this location in 1948 - my mother in law recalls water near the Devonshire Road underbridge, beyond which the ground starts to rise. There was a flood defence scheme soon afterwards and no such problem here in recent years other than the occasional local flood due to blocked or inadequate drains and heavy rain.
I'm not an expert on flooding but I would expect that this would not be standing water, as the Trent is a major river at the best of times and in this situation would have much more flow than usual. So if there were only a few routes for the water to pass through, these would have strong currents that could undermine the structure by scouring or be a danger to anyone foolish enough to try to wade through.
I wonder too if this argument can be flipped on its head to explain the later bricking up. Once the area was built up there might have been a need to reduce the amount of opening, which would also reduce the amount of current passing nearby houses.
I'm not an expert on flooding but I would expect that this would not be standing water, as the Trent is a major river at the best of times and in this situation would have much more flow than usual. So if there were only a few routes for the water to pass through, these would have strong currents that could undermine the structure by scouring or be a danger to anyone foolish enough to try to wade through.
I wonder too if this argument can be flipped on its head to explain the later bricking up. Once the area was built up there might have been a need to reduce the amount of opening, which would also reduce the amount of current passing nearby houses.
Trog
Established Member
Making the openings smaller is going to restrict the flow through them, allowing more of a differential of water level between the two sides of the structure. That means more pressure and a faster more destructive flow even if the total volume of water passing is reduced.
I wonder if the arches are weak and the walls are propping them up, with the openings being to allow inspection. Of what can be seen of the arches are there any cracks or are the arches distorted in any way.
I wonder if the arches are weak and the walls are propping them up, with the openings being to allow inspection. Of what can be seen of the arches are there any cracks or are the arches distorted in any way.
Yep in one of the tunnels, the arch brickwork does have the odd fracture here and there however the other arch is completely sound, structurally, not a single crack. The photo showing the roof of the arch in one of the partitions is what the rest of the arch looks like.
I have an architect friend that told me not only do arches rarely if ever fail, but also that these brick partitions are not the way in which they would reinforce a failing arch.
I have an architect friend that told me not only do arches rarely if ever fail, but also that these brick partitions are not the way in which they would reinforce a failing arch.
Trog
Established Member
The most likely way for an arch to fail is if the abutments either side move apart or if one was to settle, as other wise evenly loading an arch just makes it stronger up until the bricks or stone it is made from are crushed. With a viaduct if one arch were to fail you could then get a domino effect as the adjacent piers to the damaged/missing arch are pushed into the void left by the missing arch by the weight of the arches either side. Your walls might make sense as props to prevent sideways movement of the piers, if one of the filled arches had started to fail but then they would not need to reach right up to the top of the arch.
Hey guys I gained access to the other tunnel and took some photos. It is much like the other tunnel other than that the brick partitions are built in the first half of the arch, and another difference is that the remainder of the arch has been filled-in with rubble and I had to jump up and pull myself up to an 9ft high aperture (5th photo) to take a photo of this filled-in arch. If you look closely you can see the spot of sunlight at the very end. This is the top of the arch on the other side of the embankment you can see in the final photo below.
Interestingly, the other side of the embankment where you can see the very top apex of the arch looks like there was a partial collapse of the last 1-2 meters of the arch. Maybe this is why it was filled-in, but still doesn't explain the intricate brick partitionings!
Note in the third photo below is a cast iron rod/hook embedded in the wall high up. Maybe a lantern hanger or what???!
Interestingly, the other side of the embankment where you can see the very top apex of the arch looks like there was a partial collapse of the last 1-2 meters of the arch. Maybe this is why it was filled-in, but still doesn't explain the intricate brick partitionings!
Note in the third photo below is a cast iron rod/hook embedded in the wall high up. Maybe a lantern hanger or what???!
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