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Marple Flight


Kris9128

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My experience is similar to David's. 

Some of this is driven by CDM regulation where design detail is needed as part of a proper O&M manual .  The rest is mostly self preservation.

 

Working as a  sub- consultant the IP rights go up the chain to the end client, enabling some of  the less scrupulous intermediates  to copy, re-orient  and re-sell ones work., or use it as a basis for bringing a capability in-house.  Not much to be done there, except seek a suitably enlarged fee at the start.

 

N

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On 17/11/2023 at 15:59, magpie patrick said:

The wall has become detached from the surrounds, as a result of voids, voids caused by penetration of water when the lock is full. Leaky walls is a feature of all the Marple locks (except possibly 14 and 11 now they have been rebuilt) and has been for as long as I can remember, which is fifty years since they were restored

 

They withstood at least twenty years, probably a lot more, of hardly even being used and were empty most of that time. Most restoration schemes have struggled with locks that moved but not Marple

 

Keeping locks full to keep the walls apart is a great theory - practice doesn't really bear the theory out. 

 

When the locks were planned, there were dissenting voices in the canal company committee on the basis that such deep locks might be ill-advised - it is possible they were far sighted voices who saw 220 years ahead, but other shallower locks elsewhere have suffered inward movement too.

I suspect that, often, not enough care is taken to ensure that the puddling at the top of the lock is fully watertight. As a result, there can be a flow from the upper canal level behind the lock walls which creates the voids. Many of our canals had little use in the 1940s and 1950s, and the result could be that some of the puddle dried out and cracked, to become permeable. Little is said about the subject in contemporary books on canal engineering as it is, basically, common sense. I have seen drawings where there was a puddle trench at right angles to the chamber wall from the upper quoins to prevent water getting behind the chamber walls.

 

There was also the problem of ground water, and where this formed running streams, canal engineers were usually very careful to provide a culvert of some sort so the flow did not damage the chamber walls. Ground water in general was not a problem as it does not flow quickly, and can be helpful in keeping the clay puddle damp. The classic example of damage from ground water was the river lock at Toulouse during construction of the Canal du Midi. At high river levels, water got behind the lock walls, quickly causing a collapse. As a result, the canal was completed with locks having concave side walls to the locks, though this is not a good solution, and straight lock walls are better.

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  • 1 month later...

This is lock side 3 of 32. It is not totally unexpected to those of us that understand Marple locks. This is not a new problem. When we were attempting to restore the locks back in the 1960's , many had voids behind the walls. The solution when restoration came was to get a firm in from Liverpool called rock pool & grouting or some such name. They pressure injected the walls of all the chambers on the flight to stop up these voids, which it did to some extent. It also put a lot of concrete onto the floors of the chambers of some locks, which was hell to dig out.
The foreman of Marple locks at this time was a guy called Tommy Woods, he told us it would all end in failure and that what they use to do, was dig down behind the chamber walls and re puddle the clay, and that this had been a standard process, until after the war sometime, when they stopped, probably due to lack of traffic. I am not sure when the last commercial traffic went down Marple locks, probably late 50's.
The thing is, even by the early 1970's there were laws against digging deep trenches, so this is never going to happen, the only way now is to keep on top of the voids with squirty concrete and if that fails then do a rebuild with a back shell of concrete as was done at locks 15 and 11.

Pluto talks of ground water, this is normally accommodated for by having wooden lock floors, several of the Marple locks have wooden tail bays, my memory is not good enough to know if lock 7 was one such lock.
Other locks with this construct that I know of are
Dungbooth Lock 22W on the HVNC - which explains why the lock walls have rotated and made this lock narrower than most.
Locks 50 & 49 on the Rochdale canal both of which have been replaced, recently
Lock 2 on the Rochdale
 

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I would expect wooden lock floors to be used where there was no solid foundation. The method was used across the Low Countries, and in many coastal areas, with the photo showing the reconstruction of one of the locks at Stade, in north Germany. The Yorkshire end of the L&LC has several examples, with River Lock in Leeds being illustrated. Where a lock was to be built on unstable land, a wooden frame was built fitted over a series of wooden piles. The stone or brick lock sides were then built on top of this platform. Any serious ground water was accommodated by culverts to lead the water away. I have just come across a contemporary description of this in the engineering reports for the construction of the Lancaster Canal.

Voids behind lock walls can be attributed to ground water, but leakage from the upper canal level is also a problem. To protect against this, canal builders would use either a series of wooden piles or a puddle wall at right angles to the chamber wall, usually from around the quoin.

An additional 'modern' problem is that building development around a canal will have altered ground water flows, and these flows will not have been fully recognised. Such things happened when canals were built, such as the drying up of wells in Foulridge when the L&LC was built. One old canal employee told me, 'You have to remember that water has narrow shoulders, it can get in anywhere.'

1994 Stade 142 lock reconstruction.jpg

 River Lock breast wall and paddle culvert.jpg

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13 hours ago, Ian Mac said:

The thing is, even by the early 1970's there were laws against digging deep trenches, so this is never going to happen, the only way now is to keep on top of the voids with squirty concrete and if that fails then do a rebuild with a back shell of concrete as was done at locks 15 and 11.

I don't think the problem is so much the digging of deep trenches as putting people down them. I can't help wondering whether if the chamber was suitably scaffolded it would be possible to run an excavator with a long reach bucket along the lock to dig out a trench down to the voids and then to backfill and ram puddle in with a modified vibrating poker with a flat plate on the end? I suspect this will remain a completely hypothetical approach though.

 

Alec

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15 hours ago, Ian Mac said:

This is lock side 3 of 32. It is not totally unexpected to those of us that understand Marple locks. This is not a new problem. When we were attempting to restore the locks back in the 1960's , many had voids behind the walls. The solution when restoration came was to get a firm in from Liverpool called rock pool & grouting or some such name. They pressure injected the walls of all the chambers on the flight to stop up these voids, which it did to some extent. It also put a lot of concrete onto the floors of the chambers of some locks, which was hell to dig out.
The foreman of Marple locks at this time was a guy called Tommy Woods, he told us it would all end in failure and that what they use to do, was dig down behind the chamber walls and re puddle the clay, and that this had been a standard process, until after the war sometime, when they stopped, probably due to lack of traffic. I am not sure when the last commercial traffic went down Marple locks, probably late 50's.
The thing is, even by the early 1970's there were laws against digging deep trenches, so this is never going to happen, the only way now is to keep on top of the voids with squirty concrete and if that fails then do a rebuild with a back shell of concrete as was done at locks 15 and 11.

Pluto talks of ground water, this is normally accommodated for by having wooden lock floors, several of the Marple locks have wooden tail bays, my memory is not good enough to know if lock 7 was one such lock.
Other locks with this construct that I know of are
Dungbooth Lock 22W on the HVNC - which explains why the lock walls have rotated and made this lock narrower than most.
Locks 50 & 49 on the Rochdale canal both of which have been replaced, recently
Lock 2 on the Rochdale
 

I have 3 of the old planks to prove it, awaiting a round tuit to make a garden bench. 

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2 hours ago, agg221 said:

I don't think the problem is so much the digging of deep trenches as putting people down them. I can't help wondering whether if the chamber was suitably scaffolded it would be possible to run an excavator with a long reach bucket along the lock to dig out a trench down to the voids and then to backfill and ram puddle in with a modified vibrating poker with a flat plate on the end? I suspect this will remain a completely hypothetical approach though.

 

Alec

A vibrating flat plate is not the way to make a watertight puddle. It needs to be cut up and chopped at the same time as compacting to make a homogeneous layer about 150mm thick, and then built up with similar layers.. However, it does depend upon the quality of the clay, judging by the engineer's reports given during the construction of some canals.

Compacting is something modern civil engineering is very poor at, judging by the number of road works which end up after a few months with sunken sections of tarmac.

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2 minutes ago, Pluto said:

A vibrating flat plate is not the way to make a watertight puddle. It needs to be cut up and chopped at the same time as compacting to make a homogeneous layer about 150mm thick, and then built up with similar layers.. However, it does depend upon the quality of the clay, judging by the engineer's reports given during the construction of some canals.

Compacting is something modern civil engineering is very poor at, judging by the number of road works which end up after a few months with sunken sections of tarmac.

I wondered whether the two operations could be separated out - essentially a pugging operation to prepare material which is fed directly in, followed by compaction. I agree that vibration may not be the most appropriate compaction method but couldn't think of an alternative piece of modern equipment that would replicate pairs of navvies' boots!

 

Alec

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Water leakage is not a new problem, with the following dating from a L&LC report on the Rufford line in 1801:

 

Rufford Lock gates both top and bottom are nearly new and also the paddles, but the masonry is leaky, as the water gets into the walls when filled and passes through the backing and round the hollow coins and out at the lock tails.

Baldwin Lock gates are nearly new and in good repair except the breast of one gate which was broken by a vessel running violently against it. The masonry work is in leaky and shattered, and part of the ground that backs the locks has been washed away partly by the waster and partly by the water that gets through the lock wall.

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19 hours ago, Pluto said:

 

Compacting is something modern civil engineering is very poor at, judging by the number of road works which end up after a few months with sunken sections of tarmac.


It seems to be a job that can use or save much time/ money in labour costs so tends to get minimised. After a few months the contractors shell company changes so little can be done to make the contractor effect repairs. 
The 5G contractors locally have changed 3 times in a year, same blokes doing the work. Their compactor remains in unused condition appt from being moved on and off the lorry. 
Council fully occupied in trying to get the sunken trenches safe. 
 

It’s a race to the bottom. An answer could be to insist on a huge deposit these companies slowly receive back should the work hold up satisfactorily over time. 
 

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On 29/12/2023 at 14:16, agg221 said:

but couldn't think of an alternative piece of modern equipment that would replicate pairs of navvies' boots!

 

I've read that flocks of sheep were often driven up and down freshly-puddled canal beds to compact the clay. 

I think they still make them.

 

 

 

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3 minutes ago, MtB said:

 

I've read that flocks of sheep were often driven up and down freshly-puddled canal beds to compact the clay. 

I think they still make them.

 

 

 

I would imagine driving flocks of sheep up and down in narrow trenches behind lock walls may be somewhat frowned upon, although they are probably stupid enough to put themselves down there given half a chance!

 

Alec

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11 minutes ago, beerbeerbeerbeerbeer said:


could be an ideal job for someone who knows how to walk on stilts 👍

Yeh right, it would be worse than a muddy event field, sinking in up to where one's knees used to be!

6 minutes ago, MtB said:

Sheep on stilts. That's the answer!!

 

 

Now now, you'll get the Yorkshire stiltwalkers all excited...

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19 hours ago, MtB said:

 

I've read that flocks of sheep were often driven up and down freshly-puddled canal beds to compact the clay. 

I think they still make them.

 

There is also a device known as a sheep-foot compactor which does the same job - note it doesn't compact the sheep's foot, just mimics it

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