~ Geobear’s ground improvement scheme restores load capacity under strict time constraints ~
Specialist ground engineering firm Geobear has carried out emergency ground stabilisation works on a disused tunnel near Salford Central Railway Station. At risk of collapse due to significant water ingress, the tunnel is located beneath a buffer stop on a private rail line being installed by contractor Kier Group. The tunnel was successfully stabilised using a non-invasive ground improvement scheme,restoring its ability to support heavy loads without disturbing the wider construction project.
The new Salford rail line connects Salford Central to a concrete plant, with a buffer stop located above a disused tunnel. Given the adjacency of the tunnel to a nearby canal, severe water ingress resulted in heavy saturation of the tunnel and significant compromise of the tunnel crown. Cementitious grouting, sheet piling and excavation of the existing infill were initially proposed as potential solutions. However, these proposals were quickly abandoned, largely due to the site’s vicinity to live railway infrastructure as well as an incomplete understanding of the tunnel itself.
With just four weeks remaining until the track installation, and mobilisation and design constrained to a two-week window, Kier group required rapid assistance. Within two weeks, Geobear successfully designed a ground improvement scheme and had its proposed solution approved with stakeholders, among whom included Network Rail.
Geobear technicians were dispatched to the site immediately and worked rotating 12-hour shifts to ensure continuous progress, allowing for completion of the ground improvement scheme in a single weekend. With no excavation required to install the fast-curing solution, no delays or disturbances were posed to the overall construction project. Geobear’s ground improvement solution is also both non-leaching and has a 120-year lifespan, allowing for decades of tunnel zone stabilisation while minimising risks to wildlife and preventing contamination of the canal environment.
“We gave Geobear an incredibly tough ask to turn around a design and plan the shift in such a short space of time,” explained Tom Highton, project manager at Kier Transportation. “This is a fantastic product that solved a complicated engineering issue and eliminated several risks from our initial proposals. From the initial engagement to the completion of the works on site, the expertise and knowledge of the Geobear engineers have helped us to deliver a safe and successful job.”
Stephen Farr, Rail Manager at Geobear, stated: “Conventional remediation methods were less suitable to the structural sensitivities of the compromised area. Our repair process allowed us to target the affected area directly while maintaining the integrity of the surrounding infrastructure. Rail infrastructure is only as strong as the ground beneath it, and so enhancing the load bearing properties of some tricky soil conditions was vital to keeping this project moving forwards.”
To learn more about how Geobear’s resin injection can aid ground and structural stabilisation for rail projects, visit the Geobear website.
