Abstract Summary
Transition wedges are widely used in Spain, Portugal and other European countries to mitigate transition problems in railway tracks. These wedge shaped backfills are used to smoothen the stiffness transitions as experienced by the moving load. On the one hand, this solution has proved to be promising as it results in a decrease in elastic deformations under the moving load in railway transition zones. However, on the other hand, the measurements have shown its poor long-term performance over the operational period of 1-2 years. Despite an improvement in stiffness transition, the reasons for the poor long term performance of the transition wedge remain unknown. In this work the behavior of an embankment-bridge transition with a wedge of granular material mixed with cement is studied and compared to the behavior of a transition without any wedge. It is known that internal friction leads to inelastic dissipation in material and that the external friction at the interface is responsible for the joint behavior. The time gradient of the mechanical energy can be associated to frictional forces . Hence, the performance of the wedge is evaluated by investigating the variations of mechanical energy along the track in each trackbed layer (ballast, embankment, subgrade) and frictional sliding at the interface of the wedge and trackbed layers. In the end, this will lead to possible explanations behind an increased long-term settlement of railway transition zones with granular wedges.
