Calibration of test probes and experimental monitoring of changes in moisture of selected materials of subgrade structures

The paper describes experimental activity carried out at the Department of Railway Engineering and Track Management of the Faculty of Civil Engineering, University of Žilina. It focuses on monitoring moisture changes in individual structural layers of the railway track body and its subgrade, performed on the railroad model, (1:1 scale). The Introduction characterizes the experimental stand models of the Department, used for monitoring the moisture changes in the structural layers. The second part of the paper focuses on the characteristics of the moisture determination method - time reflectometry (TDR method), and on the calibration of TRIME PICO IPH T3 probes for real materials of the experimental stand DRETM (crushed aggregate, fr. 0 / 31.5 mm - protective layer, crushed aggregate, fr. 0/63 mm - embankment, clay with the addition of river gravel – foundation). The calibration was a substantial prerequisite for the subsequent humidity monitoring of the railway models. The next part of the paper presents the recorded moisture values of the structural layer materials, built in the measuring profiles of the experimental stand DRETM, measured before and during the winter period 2017/2018. The Conclusion evaluates the measured values and the determination of the input moisture values that will be used for the numerical modeling of the thermal regime of subgrade structure by the SoilVision software.