Description
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.
; Pereira, M. 
