Emergency ground stabilisation protects rail works near Salford Central

Emergency ground stabilisation works have been completed near Salford Central Railway Station after significant water ingress threatened the stability of a disused tunnel beneath a new private rail line. The tunnel is located below a buffer stop on a rail connection being installed by Kier Group to serve a concrete plant, creating a structural risk shortly before track installation was due to begin.

The problem was linked to severe water ingress and the tunnel’s proximity to a nearby canal. As the tunnel became heavily saturated, the tunnel crown was significantly compromised, raising concerns over its ability to safely support future rail loads.

Several traditional remediation options were initially considered, including cementitious grouting, sheet piling and excavation of the existing infill. However, these options were abandoned because of the site’s proximity to live railway infrastructure and the limited understanding of the tunnel’s condition.

Excavation or other intrusive works could have further disturbed the compromised structure, while also adding programme, safety and environmental risks. The nearby canal created an additional constraint, as any ground treatment solution needed to minimise the risk of contamination or material migration into the water environment.

A non-invasive ground improvement approach was therefore selected. The scheme was designed to target the weakened tunnel zone directly, without requiring excavation or major disruption to the surrounding construction activities.

According to project reports, Geobear designed the ground improvement scheme and secured stakeholder approval within two weeks, with Network Rail among the stakeholders involved. Technicians were then dispatched to site and worked rotating 12-hour shifts, allowing the works to be completed over a single weekend.

The fast-curing solution restored the tunnel zone’s load-bearing capacity without delaying the wider construction programme. Geobear also stated that the material used is non-leaching and has a 120-year design lifespan, helping to reduce environmental risks near the canal.

The project highlights the importance of rapid ground risk assessment in constrained rail environments. The main challenge was not only to stabilise the tunnel, but also to restore load-bearing capacity beneath a future rail asset. This required a solution capable of improving ground stiffness, limiting further movement and maintaining the integrity of adjacent infrastructure.

The works also demonstrate how modern ground improvement techniques can provide an alternative to conventional excavation-based remediation. In locations where unknown buried structures, groundwater, canals and live rail constraints intersect, non-invasive stabilisation can reduce programme risk while improving safety.