SIMULATION OF THE EFFECTIVENESS OF THE SCOURING PREVENTION STRUCTURE AT THE EXTERNAL RAIL BALLAST USING PHYSICAL MODEL

Abstract

Rail ballast is a rockfill construction that serves to bind sleepers and rail which distributes
trainload to ground. The function of rail ballast is vital to the quality and strength of the rail track, but are
prone to overtopping. The relationship between overtopping high and scouring has been investigated, as well
as the effect of the high external prevention structure against the length of scouring. This study focuses on the
effectiveness of external prevention structure at downstream in its ability to dampen and reduce the length of
scouring due to overtopping by the mean the physical model. This research simulates the scouring prevention
structure at downstream of ballast with several variations of type (T) and structures distance (L) so that the
most effective structure is obtained, i.e. the structure which can maximum reduce the length of scouring.
From the research, the most effective structure is the Type T1 at L1 distance. The modeling was carried out
at the Hydraulic Laboratory of Civil Engineering Diponegoro University, with the prototype of the
Mangkang-Semarang Railway KM.12 Indonesia, with the scale of 1: 5. The structure types which are
simulated consist of T, T1 and T2 with the variation of structure distance L1 = 40 cm and L2 = 60 cm from
downstream of toe ballast. The results of this study can be utilized by railway operator as a safety measure
and especially against the danger of scouring due to flooding.