Non-destructive technologies for sustainable assessment and monitoring of railway infrastructure: a focus on GPR and InSAR methods

Health monitoring of ballast in railway infrastructure is crucial to assure long-term structural stability. An efficient and sustainable management of maintenance operations is therefore fundamental for asset owners in setting up strategic and effective action plans. Amongst the available methods to assess the conditions of railway infrastructure, non-destructive technologies (NDT) are gaining popularity due to their capability to overcome main drawbacks from conventional routine methods, such as digging trenches and visually inspecting sections along the track. The present study reports an overview on the use of the ground penetrating radar (GPR) and the interferometric synthetic aperture (InSAR) technologies for a sustainable monitoring of railway infrastructure. Main conventional and non-destructive methods utilised for maintenance of railway ballast materials are presented, with a special focus on their sustainability. A review about research methods on the use of GPR and InSAR technologies for railway infrastructure monitoring is also reported, including main investigations carried out in the laboratory and the real-life environments. Furthermore, a conceptual framework based on an integrated approach between satellite-based and ground-based investigations is proposed, where network- and local-level information can be merged for a more effective detection of critical sections and the implementation of an advanced predictive maintenance system.The present study reports an overview on the use of the Ground Penetrating Radar (GPR) and the Interferometric Synthetic Aperture (InSAR) technologies for a sustainable monitoring of railway infrastructures. Specifically, main conventional and non-destructive methods utilisedd for maintenance of railway ballast materials are presented, with a special focus on their sustainability. A review about research methods on the use of GPR and InSAR technologies for railway infrastructure monitoring is also reported, including main investigations carried out in the laboratory and the real-life environments. Furthermore, a conceptual framework based on an integrated approach including satellite-based and ground-based investigations is proposed, where network and local level information can be merged for a more effective detection of critical sections and the implementation of an advanced predictive maintenance system.