Slab Re-levelling and stabilisation
Project Summary
Geobear were called in to treat a settlement issue at Farnham rail depot that was posing a major threat to rail operations around the South East. The base slabs at the depot in Farnham, south of London, were experiencing subsidence, which was making the ground and tracks above uneven. The slabs were 60 years old and had succumbed to drainage issues, compacting fill material and the pressure of heavier modern rolling stock.
The rail maintenance shed at Farnham was crucial to operations and for keeping timetables running as normal. The settlement issues meant that the depot was on the verge of becoming unsafe and having to be closed.
This is where Geobear came in – to solve the subsidence issue swiftly and with no timetable disruptions.
Objective
The aim of this project was to stabilise the base slabs, which spanned over 6000 metres squared, and raise the railway tracks to make them level.
The slabs settling had meant trains needed to restrict their speed, while there were concerns that the state of the tracks could lead to derailment.
Using ballast would have taken too long to carry out, and in any case would have only been a temporary solution. Piling was not a viable option due to its high cost. And because such a large area needed to be treated, breaking out the slabs and replacing them again was also not a practical option. What was needed was a quick solution that wouldn’t be disruptive to the day-to-day operations of the depot.
As a result, Geobear’s re-levelling and stabilisation processes were the perfect choice. Our team applied our techniques to the 6000 square metre area of slabs to swiftly rectify the issue.
Outcome
Geobear carried out work on a convenient schedule agreed with the client, completing the process in a period of just five weeks. Operations at Farnham depot were not obstructed during this period.
6,072 square metres of slabs were lifted to tolerances of +/- 10mm over 10 metres squared.
Thanks to Geobear’s innovative technology, the issue was rectified quickly, affordably and without causing major disruption.
