Identifying frost-susceptible areas on Finnish railways using the ground penetrating radar technique

Abstract

In Finland, the railway is a vital transportation system. A large quantity of raw materials, goods and passengers are transported on mixed traffic tracks. Due to freeze–thaw cycles, differential frost heave can affect the track performance and results in speed restrictions. The maintenance of winter-related problems on heavy haul railway lines is expensive and causes difficulties for the flow of rail traffic. In order to make maintenance cost-effective and sustainable it is essential to identify the problem areas and determine their causes. During the last decade the ground penetrating radar (GPR) technique has proven to be an effective and non-destructive method to measure railway structures and various material properties. This paper presents and discusses the key results obtained in a research project that studied the potential of the GPR method to locate track sections on Finnish railways experiencing frost problems and produce input data for preventative maintenance planning for areas at risk of developing differential frost heave. The GPR data, digital video and GPS coordinates, collected from the railway sections were combined with reference data and railway databases using the Railway Doctor software. This integrated data was then interpreted and analysed using multiple parameters specifically selected for the purpose of identifying the frost-susceptible sub-ballast structures and subgrade soils and defining the root cause of frost problems using the GPR frequency analysis techniques. This paper originated from the 2011 IHHA Conference.