Assessment of layer thickness and uniformity in railway embankments with Ground Penetrating Radar

• Main Author: Fernandes, Francisco Manuel Carvalho Pinto
• Publication Date: 2008
• Other Authors: Pereira, M., Correia, A. Gomes, Caldeira, Laura, Lourenço, Paulo B.
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/1822/17209
• topic: Science & Technology

In the aim of a national research project entitled “Interaction soil-rail track for high speed trains”, a protocol was established between the National Railway Network and four national research institutions to develop the knowledge concerning the methodology for the construction and quality control of the railway embankments and railtrack layers for high speed trains. One of the objectives of this protocol is to establish a methodology for quality control of construction layers by different available test methods. Nondestructive testing (NDT) methods are currently very attractive due to their ability to provide information about layer thickness and state condition without causing damage or requiring the removal of material samples. Within the NDT available, ground penetrating radar (GPR) is a very fast and reliable technique, whose advantage is the repeatability and the capability of acquiring continuous data. To reach the proposed goal, a trial embankment was constructed with different materials, layer’s thicknesses, water contents and compaction energy levels. GPR was used in two embankments, in order to detect the thickness of the sub-ballast layer located over the compacted sand layer and its uniformity along the track, but also along the cross-section of the track. In order to control some parameters of the sub-ballast layer, like thickness and uniformity, several metallic plates had been used in the base of the sub-ballast layer, along an alignment. It shows clearly the ability of GPR to detect the sub-ballast layer and its thickness variations along the profile.