marcy Posted June 26, 2007 Share Posted June 26, 2007 It won't burst... i agree but ive thought that for a few hours now Link to comment Share on other sites More sharing options...
Emzy21 Posted June 26, 2007 Share Posted June 26, 2007 im not quite sure.... you would have thought if it was going to it would have by now Link to comment Share on other sites More sharing options...
ox720 Posted June 26, 2007 Share Posted June 26, 2007 Anyone know what areas of Sheffield will be without power if/when the substation goes down? I have tried looking on the National Grid website but can't really find what I'm looking for...(Like I even know what I'm looking for:confused:) Link to comment Share on other sites More sharing options...
goldenfleece Posted June 26, 2007 Share Posted June 26, 2007 Its not very clear on the TV pics what has happened....looks like water from the overflow has washed away some of the dam wall? cant see any actual cracks in it as described...... Link to comment Share on other sites More sharing options...
melter Posted June 26, 2007 Share Posted June 26, 2007 Dams don't generally 'burst' as such, unless the rainfall is still filling them up. As stated earlier, in the worst case scenario, the Dam will breach in several places, those breach's will gradually open up and the water will drain from the reservoir into the 'flood valley' below. As said earlier, the area will still flood, but at a lot slower pace, hopefully not causing as much damage! This was the reason for the 'Bouncing Bomb' exploding at the base of the Rhur (sp?) Dams, not the top of the walls. (I realise that Ulley is a different design, but it's the same theory) Link to comment Share on other sites More sharing options...
DancinJay Posted June 26, 2007 Share Posted June 26, 2007 As my limited understanding of dam walls goes, if water cascades over the top this (naturally) causes erosion of the wall. This is made a LOT worse if there are cracks in the dam wall as the water flows over the top of the wall and then into said cracks and essentially errodes the wall internally. This can cause quite quick degradation in the structural integrity of the wall, which then can collapse slightly internally, thus letting more water over the top and into the cracks and you end up with a feedback loop until the wall then collapses in on itself. As I mentioned before I could be wrong and the dam design may be different to what I know about, but given the concern about cracks and stopping it overflowing the situation does seem to make sense in my fragile mind. Link to comment Share on other sites More sharing options...
melter Posted June 26, 2007 Share Posted June 26, 2007 Quite correct, DancinJay, you've describe it exactly. I hope you'd agree though, this wouldn't be a 'bursting dam', however fast the wall erodes [Edit] I would class a 'bursting dam' as one where a large section of concrete wall collapses outwards (again, Ulley isn't this design) Link to comment Share on other sites More sharing options...
Paul2412 Posted June 26, 2007 Share Posted June 26, 2007 I think we will be fine unless theres any more rain as the pumps are managing to keep the situation under control. However, looking at the weather forecast things look abit grim... http://www.bbc.co.uk/weather/5day.shtml?world=4897 Link to comment Share on other sites More sharing options...
Tony Posted June 26, 2007 Author Share Posted June 26, 2007 Dams often fail when a horizontal fissure and / or water conspire to form a slip plane inside the structure which then allows the upper section of the earthwork to rotate about the lower section - imagine your right fist rotating out of the palm of your upturned left hand. However, on this occasion the water isn't going over the top (from what we know, but it might have in the night) and the earthwork is being undermined from the rear face which of course will reduce the water mass that it can withstand, so it may well 'burst'. However, semantics aside, and the fact that I could be talking total tosh (it's nearly 20 years since I studied any civil engineering) I'm sure that the engineers on site have a grip on things - even if they are struggling to come up with a satisfactory solution in the short term. Let's hope that things work out for the best. There is a lot of land, property and infrastructure below that dam wall. Link to comment Share on other sites More sharing options...
littlemissy Posted June 26, 2007 Share Posted June 26, 2007 Anyone know what areas of Sheffield will be without power if/when the substation goes down? I have tried looking on the National Grid website but can't really find what I'm looking for...(Like I even know what I'm looking for:confused:) I've been trying to find out, without much luck Link to comment Share on other sites More sharing options...
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