2021
Sherford, Devon
Taylor Wimpey/Vistry/Cannon Kirk
Groundfix
Geo-Consulting
Karst Ground Stabilisation for Housing Development Using Geogrid Reinforcement
Typical karstic voids exposed on site
Void spanning mitigation on estate roads
ParaLink® unrolled into position
Using site-won fill provides environmental and cost benefits
Backfill dumped and distributed onto ParaLink®
Estate roads construction on top of ParaLink® void spanning
Challenge
A large-scale, multi-phase residential development, constructed over several years by multiple developers, faced significant geotechnical challenges due to underlying karstic and epikarst weathering features. Ground investigations revealed the presence of void-prone strata beneath both residential plots and adoptable highways, increasing the risk of ground instability and potential collapse.
Although a strategy was in place to grout any voids encountered during construction, the unpredictable nature of karst geology meant that long-term ground movement and future void formation remained a concern. In particular, there was a critical need to protect the adoptable road network from potential subsidence, ensuring durability, safety, and compliance with infrastructure standards.
Solution
Maccaferri provided an engineered ground stabilisation solution using high-performance ParaLink® geogrid reinforcement to mitigate the risk of future collapses beneath the highway network. Working in collaboration with a specialist geotechnical consultancy, a void-spanning reinforced soil system was designed to act as a structural safeguard in the event of subsurface failure.
The solution was developed in accordance with BS8006-1:2010+A1:2016, ensuring best practice in reinforced soil design. ParaLink® geogrids were selected due to their advanced polymer structure and protective coating, which allow for reduced material partial factors. This enables the use of lighter, more efficient geogrid grades compared to conventional alternatives, delivering both technical and commercial advantages.
Maccaferri’s expertise also enabled the integration of site-won fill materials into the design, eliminating the need for expensive imported structural fill. This approach reduced construction costs, minimised waste removal, and lowered the environmental impact associated with transport and material handling.
The final solution delivered a cost-effective, sustainable, and robust ground engineering system, ensuring long-term stability for the road infrastructure while addressing the unique challenges of karstic ground conditions.
Used Products
