From: @earthsciencepartnership.com> Sent: 14 October 2024 15:52
To: @npt.gov.uk>
Cc: @earthsciencepartnership.com> Subject: Godre’r Graig Bund
Hi ,
We’ve looked into the records, lab data and run some initial slope models.
There are a few things that are not favourable when considering the stability of the recently constructed bund and for completeness we’ll discuss these in our report.
We have looked at its ‘as built’ condition and location; there are different materials within the bund; the two mains ones are: a large boulder material with a finer component and a grey fine-grained material. The testing has indicated that the finer-material was possibly put in wetter then optimum condition. Whilst the bund was created, there looks to have been loose filling/tipping of the former school undercroft area. The topographic information doesn’t quite show where the toe of the bund and top of the old retaining wall to the undercroft area and have had to make some assumptions based upon previous information.
We modelled the bund with the different soil conditions encountered and also looked at the end tipped material in the undercroft area. The modelling has shown that the bund will likely fail in the long term, probably/possibly not significantly, but enough to need repair. Visual estimations on where such failed material may go indicates that it would likely remain on site, and not escape on to the road. Its likely that monitoring long term and repairs would be needed at some point in the future. If this is not desired by NPTCBC we’d recommend reengineering the bund in accordance with an earthworks specification.
From conversations on site, I know the contractor may still be making the bund a little longer, and we would recommend this. One of the aims of the bund was to generally replicate/mimic the location of the previous school building. This was to limit potential risks to residents that live to the east of the school, from possible instability events in the quarry spoil tip upslope of the school. The as built position of the bund is a little shorter than the school was.
We’ll be generating some drawings to explain the above and will continue with our report and look to issue next week.
