The Surrey village has now reopened after an extensive repair programme following a major ground collapse in February 2025. Investigations into the incident identified complex ground conditions beneath the village centre, including historic shallow sand mine workings and void migration, requiring a multi-disciplinary remediation strategy.

Working as part of the project team appointed by Surrey County Council, Mainmark delivered targeted ground improvement works beneath High Street and Salisbury Road using its Teretek® resin injection technology. Following remediation of the deeper mine workings by the wider project team, Mainmark strengthened weakened and disturbed ground within the upper soil layers to support the long-term performance of the highway network.

The programme was completed within three weeks and involved the installation of approximately 600 resin injection points across the two treatment areas, with treatment depths reaching up to four metres below ground level. The works were designed to improve load-bearing characteristics, strengthen weakened ground and address potential pathways for future void migration, all while minimising disruption to the surrounding area.

David Hedley, Infrastructure Lead at Mainmark UK, said:

"This project demonstrates the value of selecting the right ground engineering solution for the conditions encountered on site. The challenges at Godstone required a combination of remediation techniques, with our role focused on strengthening disturbed and weakened ground in the upper layers beneath the roadway.

"We were able to deliver ground improvement across multiple load points within a short programme while maintaining minimal impact on the surrounding area. The fully monitored process provides confidence in both performance and consistency of results."

As part of the quality assurance process, Mainmark utilised continuous laser level monitoring capable of detecting movement to ±0.5mm throughout the injection programme, alongside digitally recorded injection volumes, depths and flow rates. Pre and post-treatment Dynamic Cone Penetrometer (DCP) testing confirmed measurable improvements in ground strength across the treated areas.

The successful completion of the project has helped support the reopening of this important local route and demonstrates how innovative ground improvement techniques can be used to strengthen weak ground conditions quickly and efficiently, avoiding the need for more disruptive excavation and replacement methods.

Mainmark UK specialises in ground improvement, foundation repair, void filling and asset preservation solutions for infrastructure, commercial and residential projects across the UK.

Read the full case study: Strengthening Ground Conditions Following a Highway Collapse in Godstone.