Period Ending 28 November
One good thing about the latest lockdown is that construction is still allowed to continue. This allowed us to engage contractors to repair the void on the cutting crest at Bishops Cleeve. After finding the big hole under the pipe along the crest drain it was realised that a repair had to be a priority. Another wet winter like last year might have seen the the slope washed out onto the track.
The problem originates on the down side cutting crest, this is where a stream runs in under a lane that is parallel to the line. The void is under the length of twinwall pipe extending from the 90° bend, it's a roughly 2 cumtr irregular washout that is draining away under the slope surface.
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Existing arrangement on the crest
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The cess drain along this stretch is another length that has been topped with hollow concrete blocks, these have been discovered to be stopping the water draining in, this section is particularly bad as the blocks had filled with clay. This short section is being replaced with 40 mm clean stone.
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Cess drain exposed to improve drainage removed blocks can be seen across the track |
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Excavation for the new manhole ring on the crest
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Trench down the slope for the void drainage
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A rainy day, it has shown how much the elbow is leaking
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Elbow on the inlet pipe
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Slope drain going in
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Standard catchpit rings in the cess for the new chamber |
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Manhole ring cut out for pipe installation
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Drain down the slope to the cess
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Void filled lined with permeable membrane
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Void exposed and lined with membrane
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New manhole on the crest on the end of the inlet pipe |
The void has been filled with 5 tonnes of 75mm stone, this will stabilise the area while still allowing the ground water to pass though.
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Extended crest drain pipe to reach the falling ground
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Slope drain installed into a new catchpit in the cess |
There's still a few finishing off jobs to do, but the bulk of the work is out of the way.
A big thanks to the intrepid reporters for popping in to capture the pictures 😉
Thanks for the report and this shows the importance of drainage, one of the the least known about jobs that keeps the line running. Hopefuly a permanent fix to this part.
ReplyDeleteRegards
Paul & Marion
Good to see progress is still being made! I hope you all aren't missing Alastair too badly.
ReplyDeleteNoel