In recent years, the technology of optical fibers has rapidly gained ground in many areas of science and industry, including the construction industry. In this article, the technology of optical fibers based on a fiber Bragg grating (FBG) was used to determine tensile forces acting in a basal reinforcement of a scaled down physical model, which included piled embankment and basal reinforcement. Installing FBG sensors on the geogrid made monitoring of axial strains possible, thus allowing determination of the behavior of the basal reinforcement of the piled embankment. On the basis of three tests performed on the physical model, numerical model calibration with the physical model was carried out using the software PLAXIS 3D Tunnel 2.4. The results showed accurate predictions, especially for the low and middle part of the measured deformations where the numerical analysis proposed a solution that can be considered as safe. Installing FBG sensors on biaxial geogrids was a bold idea that was not easy to implement. However, other possibilities have been successfully tested, such as high-frequency measurements of the response of reinforced soil structure under dynamic loading.

Deformation resistance of the formation of the subgrade is the main indicator of the quality of the designed structural layers of the subgrade formation. Deformation resistance is determined in Slovak Railways (ŽSR) by a static plate load test and is expressed by the modulus of deformation E_s . The static load test not only verifies the correctness of the design of the type of structural layers of the body of the railway subgrade, but it is also an indicator of the quality of the performed construction works. On modernized ŽSR lines, is designed for subgrade type No. 3 and in the most unfavorable geotechnical conditions also the type of structural layers of the formation of the railway subgrade No. 6. The required value of deformation resistance at the level of the formation of the subgrade is designed with regard to the speed zone of the railway line. ŽSR corridor lines are designed for speeds up to 160 km/h, so they belong to the RP4 speed zone. Such lines also include a section of the ŽSR modernized Plevník-Drienové-Bytča-Žilina line.