Dynamic Laboratory Testing of Mechanically Stabilized Layers for Railway Applications

The application of mechanically stabilized layers with stiff geogrids is an effective way for sustainable and durable construction of under sleeper structures in railways. The paper explains the basics of the theory of mechanical stabilization of granular material by geogrids. Determining the mechanical properties of mechanically stabilized layers is still a practical problem. The paper describes possible laboratory approaches combined with inverse analysis of the 3D finite element method. Smaller laboratory models are used to observe differences in the performance of different geogrids even with different grain fills. Parameters describing these differences were specified and demonstrated in specific laboratory models. The inverse finite element method was used to calibrate the measured parameters with those modelled. Some approximation of the mechanical properties of the mechanically stabilized material, such as the modulus of deformation and the Poisson’s ratio, has been achieved. Determining the mechanical parameters of mechanically stabilized layers with geogrids is very useful for evaluating their possible contribution to the structure under the sleeper in comparison with unstabilized granular material. A new innovative generation of stiff geogrids was included in the research.