Mitigation of railway induced vibrations by using heavy masses next to the track

摘要

The effectiveness of heavy masses next to the track to reduce railway induced vibration is discussed. These heavy masses next to the track could be built as a gabion wall also used as noise barriers or as a concrete wall. Since the performance of mitigation measures on the transmission path is strongly determined by local ground conditions, a parametric study has been performed for a range of possible designs in a set of different ground types. A 2.5D coupled finite element - boundary element methodology was adopted, assuming that the geometry of the problem is invariant in the longitudinal direction along the track. It is found that the gabion walls start to be effective above a mass-spring resonance frequency which is determined by the mass of the gabion wall and the stiffness of the soil. A gabion wall will be more effective at sites with a soft soil. Increasing the mass will improve the insertion loss at lower frequencies. The effectiveness at higher frequencies is increased by making the footprint of the gabion walls as large and stiff as possible, and by placing the masses next to each other without any connection. For homogeneous soil conditions, the effectiveness is nearly independent of the distance behind the walls. When a softer lop layer is present, the wave impeding effect is strongly decreased with increasing distance behind the walls.