WP5 Assessment and improvement of tunnels and bridges

Madelene Sandbom, Swedish Transport Administration, is workpackage leader of WP5 – Tunnels and Bridges.

Tunnel Substructure Investigation Radar (TSIR)

Ground Penetrating Radar (GPR) is a geophysical method that utilizes ultra-wideband radio frequency (RF) pulses with centre frequencies typically in the VHF/UHF spectrum, which is capable of limited subsurface imaging. It is used extensively in civil engineering to locate buried assets and structures, locating voids, geological and archaeological surveys as well as investigating areas of land for development and reclamation.

Although GPR is a capable geophysical method, traditionally it has not enjoyed widespread acceptance, due to timely data collection, operational challenges in areas of undulating terrain, lengthy data post processing and onerous data interpretation.

Following a lengthy research program which pushed the physical limits of what is possible with terrestrial based GPR systems, a unique data acquisition method was created that would lead to the successful granting of European (EP) Patent No: 3380873 currently under development in IN2TRACK3, the patent is set to eliminate many of the challenges that have previously prolonged the progression of GPR technology.

The project goal of TSIR, is a significant progression from the use of off the shelf components assembled and deployed in IN2TRACK2, featured in this short video. The TSIR system will be created using fully bespoke components designed during a 4 month, computationally intensive, simulation period carried out in 2022, yielding a novel focusing system for optimising data collection in rail tunnels.

Unlike current infrastructure investigation radar systems which must collect multiple 2D transects to form 3D subsurface datasets, TSIR will use helical scanning to natively collect 3D subsurface data from a single collection run.