Fugro has developed SealSafe: an innovative monitoring system based on infrared lasers. SealSafe consists of a series of compact, contactless sensors which are placed inside the tunnel joints, directly adjacent to the Gina seal itself and along the entire circumference of the tunnel. Each sensor measures the deformation and displacement of the Gina at its position in the ring. By combining the data from all sensors, SealSafe gives an accurate measurement of the Gina shape and the tunnel joint circumference.
Raw data from the sensors in the tunnel are uploaded to Fugro’s cloud servers via a 4G internet link, where they are stored in Fugro’s Gaia.Monitoring platform. Tunnel owners and other stakeholders can interactively view the data in custom-built, intuitive visualisation dashboards designed to display both the actual state of the seals, as well as the evolution over time.
SealSafe provides real-time, continuous insight into the state of the Gina seals, which are otherwise difficult to inspect. It provides early warning in the event of potential movement inside the seals joint, such that remedial measures can be taken before leakages or structural damage to the joint construction occurs.
Immersed tunnels are a common technique for road and rail crossings of rivers or sea channels. They are composed of concrete segments constructed elsewhere and then floated to the tunnel site, where they are sunk into place and linked together. Large rubber gaskets (so-called Gina seals) are placed in the space between adjacent elements to ensure watertight sealing of the tunnel.
The Gina seals are prone to movement within the segment joints. Due to a combination of factors, including relaxation of the rubber, differential movement of the tunnel segments and increased soil pressure outside the tunnel, the seals can move away from their original position, potentially causing leakages or damage to the joint construction. Such problems can lead to unexpected closures of the tunnels and high repair costs.
SealSafe provides continuous monitoring over the position of the rubber Gina gaskets. It provides early warning in case of movement or deformation of the seals inside the joint, avoiding leakages or structural damage to the joint construction.
In addition to monitoring the Gina seals, SealSafe can also be used for long-term monitoring in other applications. In essence, SealSafe is a contactless distance sensor that can be used in diverse situations, such as monitoring of bridge supports, moving bridges, etc.