A study on the deformation characteristics of ballasted track at structural transition zone by multi-actuator moving loading test apparatus

At a structural transition zone between concrete structure and embankment, settlements of ballasted tracks generally become larger than those in a general section. To investigate the deformation characteristics of ballasted track at the transition zone, scale model tests using multi-actuator moving loading test apparatus were carried out. This test apparatus is equipped with sixteen electric–hydraulic actuators to simulate a moving train load traveling on the rails. In the test case without any buffering structure at the transition zone, large local settlement appeared even under the condition of constant moving load without any dynamic wheel load change. Conversely, by installing an approach block (wedge-shaped backfill with well graded and well compacted crushed stone) at the transition zone, local large settlement did not appear. Similarly by installing an approach slab (reinforced concrete slab) or a resilient mat (resilient polyurethane mat installed on the concrete structure), settlement at the transition zone became less than that in the case without any buffering structure.