IOP Business Innovation Award: Geoptic Infrastructure Investigations

Geoptic’s tunnel muon survey service provides railway asset engineers the ability to look through and X-ray the overburden from tunnel roof to the surface. Given that the average age of the UK’s railway tunnels is around 170 years old, old concealed construction shafts pose a significant hazard to the tunnel’s integrity, especially if the shaft’s location is not known and with increasing amounts of rain due to climate changes.

Over the last two years, Geoptic has worked with Tier 1 suppliers to Network Rail to survey over 10km of tunnels on the network, leading to a number of identified concealed shafts, some dating to Brunel’s time building the network.

The historic construction shafts were manually excavated in order to speed up a tunnel’s completion. Just before the tunnel was completed, some of the construction shafts along the tunnel would be sealed at the surface and the tunnel. If you are standing inside the tunnel, or on the surface, there is typically no sign that the shaft is close by. On the UK’s railway network, either the shaft’s location was not initially recorded, or the records have been misplaced or destroyed since the tunnel’s construction, leading to a significant information gap. When concealed construction shafts are not properly maintained, accidents such as the Clifton Hall tunnel collapse, that destroyed three houses and killed five people, may occur. Geoptic’s imaging solution allows tunnel asset engineers to locate and characterise shafts and voids above the tunnel.

Geoptic uses part of Earth’s natural radiation, a highly penetrating source of muons, to image through the tunnel’s roof in an analogous manner to medical X-ray imaging. By taking muon images at steps along the tunnel, the team has pioneered and delivered 3D tomographic data to the asset engineers, providing a clear structural view of the hazards above railway tunnels.