Tuesday, 12 July 2011

Jammed!

As we explained the other day, the framesets are held into the ground using duckbill anchors and nylon anchor lines. These need to be be driven into the ground with a mechanical driver which pounds the anchors into the ground with a long 'driving rod'.

However, on 7th July, we ran into a problem. The driving rod became jammed in the ground and we could not extract it. This was because the hard ground, combined with the pounding action causes the hardened steel of the rod to 'mushroom out' at the end. Because it is slightly wider, it can get lodged in the anchor, thus jamming the rod.

The first time this occurred, we managed to lever it out again. We switched to a different rod and carried on. However later it jammed again (we suspect there was a large piece of rock underground, as we had a row of problems.

But, this time it was really stuck and all our levers and efforts were unable to extract it.

So, in the end, we brought in the HIAB lorry and used that to pull it out.


As it turned out, not only was the end of the driving rod mushroomed, but the entire end was also bent.


No wonder we couldn't get it out by hand!


Photos: D. McKay-Bukowski

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