GPR method for continuous monitoring of compaction during the construction of railways subgrade

Abstract

Design solutions used in the construction of roadbeds require homogeneity of the properties of the structure over long sections. At the same time, the verification of quality of the construction of railways and highways roadbeds is based on local determination of density and other mechanical characteristics of structural layers. In this work, to overcome this drawback, a method is proposed for continuous determination of the properties of structural layers under construction. It is based on the GPR method calibrated by direct measurements of the construction material density. The algorithms of the developed method are implemented in the form of a computer code adapted for use in the construction of roadbeds of railways. The effectiveness of the developed method and computer code were tested on the section of a roadbed under construction. Field measurements were carried out using the series “OKO” GPR and the antenna unit operating at a frequency of 1700 MHz to estimate the density of the subgrade soil in various depth sections. A good agreement is shown between the GPR data and the direct measurements. The obtained radargrams were used to estimate the density of the subgrade soil at depths up to 0.6 m. A good matching between the results obtained by processing the GPR data with the developed computer code and the ones obtained by direct measurements is demonstrated.