Folkestone-Dover sea wall wash-out

jamie92208 · May 2, 2016

Mmm...Interesting....

But it seems modern UK decision making has to be 'short-termist'.

A hundred years? Forget it!

Lets focus down onto forseeable cashflow....

...oh! And (to self) will I still be in this job in two years time?

dh

I think that that is a tad pessimistic. Many recent railway projects have been future proofed even under Railtrack. When Leeds was rebuilt around 2000 Railtrack decided to put back the double crossing from the S & C to Holbeck in case coal and other freight took off. A wise decision. When York Minster caught fire the spec for the replair materials was a minimum life of 500 years was specified ruling out Concrete. Yes we do see a lot of short termism but it is not universal.

Jamie

David Todd · May 2, 2016

This train is listed for arrival at Shakespeare beach site tomorrow .

The Stationmaster · May 2, 2016

I think the iPhone calculation may well have been "if we don't *ever* re-open, what's the long term impact on the rest of the network/capacity/revenue/publicity..." That would have been a big number.

So, being the Govt, you then look at how to do it right, for a not-unreasonable-sum, in a way that provides ~100 years of service.

The NR engineers will have had a lot of say - and probably worked very closely with private industry to develop a workable solution.

Whilst it would have been a relatively unknown geotech (as shown by the need for test holes drilled prior to real work starting), the principles would not have changed much once from the original concept - and in reality, it's just a 2016 version of the timber trestle built all those years ago - just a question of how much embedment depth to give all those piles. And in the overall scheme, a 35m pile will not cost exponentially more than a 20m pile. The extra materials would not have been much - a bit of steel and concrete - but the time to drill could have been - however as we've seen from dt's photos, they seem to drill down each hole very quickly.

That measure - the number of piles/day or day/pile - will have been a key calc for estimating the cost, as you multiply any work by 120+ times, you then can get a solid idea of the overall duration, which would have been the biggest risk for the contractor I'd suggest. And the biggest opportunity, too: if they planed and costed the work on averaging 4 piles a week for 30 weeks, but were able to install 6 piles a week, all of a sudden the duration drops from 30 weeks to 20, and that 10 weeks of overhead costs becomes profit... (gains are never likely to be that large, but I used simple numbers to make a point: time=$ )

*edited and expanded for clarity

You're assuming that NR has engineers with the necessary knowledge and experience to make a fully informed decision. Far more likely in this day and age particularly that if they wanted any sort of second guessing of what contractors etc are proposing they would have engaged consulting engineers to act on their behalf (let's face it - NR couldn't even find the drawings of the seawall design and all other relevant technical paperwork). So - just like Dawlish - they engage specialist contractors to do the work plus contract out the design as well in all probability.

The real decision is that having been given some costs estimates based on what their consulting engineers have agreed is likely to be the best solution it is totally up to NR to do the sums and make the decision. They will obviously know the daily cost of having the line closed as a very large part of it will be represented by real money they are paying to train operators etc. They will also know the political (small 'p') pressure to not only get the line reopened but even more importantly to make sure it is reopened and they might even be able to put some money estimates against the effect of that. They and their consulting engineers can no doubt put together a financial case for doing the job a particular way and prove that the chosen way is the best long term value and part of putting that together would be the cost of repeated closures and repairs if the job isn't don properly this time round.

The DfT, for all their shortcoming, would (or at least should) be able to get a pretty fair estimate of the costs involved long term in closure of the line and its impact on the value of the franchise and that will feed into their view to which they will add the impact of both political and Political pressures (= their future in the jobs they hold).

So overall getting at realistic numbers - albeit with possible technical risk - isn't difficult. The remaining question is again largely technical and centres on the duration of the works - where as much as anything it's a balance of feasibility and time (as confirmed by the consulting engineers) against the short term compensatory payments and any longer term costs. In other words - number crunchers heaven.

Gwiwer · May 2, 2016

The geologist (BSc Hons) in me says that piling through chalk will be relatively quick as it is a soft rock. What delays the process is dewatering. Had the chalk been packed full of flint bands as it is farther west then the time taken and materials consumed could have increased significantly as flint is one of the most resistant sedimentary rocks there is. It's both hard and brittle meaning it flakes and chips - as any napper or stone-waller would know - but doesn't yield happily to any form or drilling. A decent band of flint has a potential to completely mangle a piling rig's drill bit.

bigherb · May 3, 2016

Had the chalk been packed full of flint bands as it is farther west then the time taken and materials consumed could have increased significantly as flint is one of the most resistant sedimentary rocks there is. It's both hard and brittle meaning it flakes and chips - as any napper or stone-waller would know - but doesn't yield happily to any form or drilling. A decent band of flint has a potential to completely mangle a piling rig's drill bit.

There are some flint bands in Dover. Probably p****d off the 172nd Tunneling Company RE having it right in the middle of their tunnel.

And another old fossil too.

David Todd · May 3, 2016

Not a lot going on today, GBrf 66 and a Colas 66, wagons being loaded with spoil.

David Todd · May 3, 2016

Today's train.

P1380380 by David Todd 2012, on Flickr

P1380381 by David Todd 2012, on Flickr

P1380382 by David Todd 2012, on Flickr

P1380383 by David Todd 2012, on Flickr

P1380389 by David Todd 2012, on Flickr

P1380400 by David Todd 2012, on Flickr

P1380387 by David Todd 2012, on Flickr

David Todd · May 3, 2016

Today,at the site.

P1380396 by David Todd 2012, on Flickr

P1380397 by David Todd 2012, on Flickr

P1380399 by David Todd 2012, on Flickr

David Todd · May 3, 2016

P1380406 by David Todd 2012, on Flickr

P1380408 by David Todd 2012, on Flickr

P1380412 by David Todd 2012, on Flickr

David Todd · May 3, 2016

Decapping.

P1380499 by David Todd 2012, on Flickr

P1380500 by David Todd 2012, on Flickr

P1380501 by David Todd 2012, on Flickr

P1380507 by David Todd 2012, on Flickr

P1380515 by David Todd 2012, on Flickr

P1380517 by David Todd 2012, on Flickr

jcredfer · May 3, 2016

? ...................... ? ............................ ? .......................

J

David Todd · May 3, 2016

AndyH, videoed the spoil train,climbing the gradient to Lyden Tunnel, from Dover, Ewell/Kearsney, in the link below.

https://www.facebook.com/andy.howard.1485/videos/10154125456504253/

David Todd · May 3, 2016

? ...................... ? ............................ ? .......................

J

The concrete and metal capping were removed,to expose the top of the cage, next ? am not a betting man.

P1380539 by David Todd 2012, on Flickr

David Todd · May 3, 2016

This bit of kit,was trundled up the site, then, taken back again ?

P1380524 by David Todd 2012, on Flickr

P1380529 by David Todd 2012, on Flickr

P1380528 by David Todd 2012, on Flickr

David Todd · May 3, 2016

P1380499 by David Todd 2012, on Flickr

P1380500 by David Todd 2012, on Flickr

P1380501 by David Todd 2012, on Flickr

P1380517 by David Todd 2012, on Flickr

David Todd · May 3, 2016

P1380487 by David Todd 2012, on Flickr

P1380489 by David Todd 2012, on Flickr

P1380487 by David Todd 2012, on Flickr

P1380489 by David Todd 2012, on Flickr

runs as required · May 3, 2016

I've lost count of how many bearing (as distinct from test) piles have been placed so far - are there any at all yet on the seaward side?

2

My bet is that the trimming of the head of the pile is preparation for an in-situ conc ground beam/ slab. The beam/ slab re-inforcement will have to overlap;. A problem sometimes encountered with nervous structural engineers is they don't leave enough space in between the re-inforcement bars to enable concrete aggregate to be vibrated around

dh

NB some lovely pics of Shakespeare cliff for a Back drop (hint hint)

David Todd · May 3, 2016

I've lost count of how many bearing (as distinct from test) piles have been placed so far - are there any at all yet on the seaward side?

2

My bet is that the trimming of the head of the pile is preparation for an in-situ conc ground beam/###### slab. The beam/###### slab re-inforcement will have to overlap;. A problem sometimes encountered with nervous structural engineers is they don't leave enough space in between the re-inforcement bars to enable concrete aggregate to be vibrated around

dh

NB some lovely pics of Shakespeare cliff for a Back drop (hint hint)

I have been looking to chose a photo,to put into paint and encircle the said piles,with the exception of the test ones.

That's why I go to the site when there is no workings and it is tidy .

To date,the nearest pile seaward is the one you see being de capped today, no others have been attempted .

The majority being land ward for the first section of raft.

Also you can see the piles formed for the centreline of the 1&2 rafts.

NB. I am working on the staircase in the depressed area,not that I can get to be depressed so much.

I have applied for Modellers Licence, have been informed,there is a hell of a Q. Before I am granted one.

Age, does not count in seniorority terms,apparently.

PS. It is more akin to a building fire escape, than a cliff side staircase to a foot over bridge !

Edited May 3, 2016 by David Todd

David Todd · May 4, 2016

I have been looking to chose a photo,to put into paint and encircle the said piles,with the exception of the test ones.

That's why I go to the site when there is no workings and it is tidy .

To date,the nearest pile seaward is the one you see being de capped today, no others have been attempted .

The majority being land ward for the first section of raft.

Also you can see the piles formed for the centreline of the 1&2 rafts.

NB. I am working on the staircase in the depressed area,not that I can get to be depressed so much.

I have applied for Modellers Licence, have been informed,there is a hell of a Q. Before I am granted one.

Age, does not count in seniorority terms,apparently.

PS. It is more akin to a building fire escape, than a cliff side staircase to a foot over bridge !