Badger Sett Infill – London to Brighton Railway, East Sussex
Background
A section of railway embankment on the London–Brighton main line in East Sussex was identified as a potential source of track faults following the discovery of multiple badger setts. In total, 35 setts were found within the 8-metre embankment. These burrows created approximately 25m³ of voids, posing a risk of collapse and subsequent track misalignment or failure.
To protect the track infrastructure and prevent the return of the badgers, the client required a permanent infill solution that could be delivered quickly during limited track possessions.
Customer Alternatives
In situations like this, conventional options are limited. One possibility was to use a cementitious grout to fill the voids; however, this would have extended curing times, potentially impacting the overall programme, which included other critical works. Additionally, the added weight of a cementitious fill posed structural risks to the existing embankment.
Site access was also constrained by geography and the short window of each possession, limiting the feasibility of traditional infill approaches.
Why Geobear
Geobear was selected for this project due to its lightweight, fast-curing geopolymer technology, which has been widely used across UK infrastructure to remediate voids left by animal activity. The solution cures within minutes and is fully effective within each short possession window.
Geobear’s rail-ready injection unit allowed the team to be fully operational on-site within 30 minutes and demobilise just as quickly—an essential capability for this location.
The selected geopolymer is impenetrable to badgers, offering a permanent deterrent, but can be removed mechanically in the future if access or modifications are needed.
Geobear Solution
Once ecologists confirmed the safe removal of all badgers, the setts were netted and monitored for 30 days to ensure they remained unoccupied before any infill works commenced.
The solution involved injecting a two-part expansive geopolymer resin directly into each burrow. The setts—averaging 500mm in diameter and extending 2–5 metres in length—were accessed using injection rods inserted directly into each hole.
Geobear’s custom-built rail injection unit housed the materials and pumping equipment. This was delivered to site by road-rail vehicle, positioned approximately 1,000 metres south of Hassocks station, with the unit itself loaded by telehandler onto a trailer.
The geopolymer resin components were pumped through hoses to the injection point. Mixing occurred at the top of each injection tube, and the expanding material filled the voids as rods were progressively withdrawn. CCTV cameras were used throughout the operation to confirm complete settlement infill.
Project Outcome
The entire works were completed in just 12 hours across two weekend possessions. All badger sett voids were successfully filled, restoring embankment stability and removing the risk of future track faults due to void collapse.
This project demonstrated Geobear’s ability to deliver targeted, efficient infrastructure remediation under tight access and time constraints, using a proven method that protects both railway operations and the surrounding environment.
