Abstract:
Railway tracks frequently show higher degradation rates at transition zones from
earthworks to bridges, or to other structures. In order to guarantee the safety and
comfort of passengers, this aspect results in higher maintenance costs and disturbs
railway operations. The behaviour of transition zones is rather complex and its poor
performance has been mainly attributed to variations in the vertical stiffness of the
track and to differential settlements. These two aspects amplify the dynamic loads of
the trains and cause further track degradation.
The Portuguese railway network manager has reported the poor structural
behaviour of a few transition zones in some of its lines, which constrain train
operations and present high maintenance costs. Thus, a research project is currently
underway aiming at contributing to a better understanding of the phenomena that
occur at transitions, and at optimizing their design for conventional and high-speed
railway lines. In this article, we present some aspects of this research project,
namely: a review on the design of backfills for transition zones; a comparison
between numerical models found in the literature that were used to study the
problem; some results obtained during the construction (characterization of materials
and layers) and operation of the line.
