Review on Geosynthetic Inclusions for the Enhancement of Ballasted Rail Tracks
Currently, there is an increasing demand for rail transport from a growing and urbanizing population worldwide as it is a resource-efficient transport system. Moreover, its popularity among people is due to safety, reliability and economic profit. The rai
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Abstract Currently, there is an increasing demand for rail transport from a growing and urbanizing population worldwide as it is a resource-efficient transport system. Moreover, its popularity among people is due to safety, reliability and economic profit. The rail track system consists of rails, fastening systems, sleepers, ballast, subballast and subgrade. Ballast is a highly angular coarse granular material which is the major load-bearing component as it transmits the stresses exerted by moving trains from sleepers to the subballast and subgrade at a reduced level. Ballast degradation is a major problem caused by the high dynamic and cyclic loads from faster and heavier trains as well as the impact loads due to wheel and rail irregularities and tracks at stiffness transition zones. It affects the track longevity together with the track geometry thereby a necessity of regular monitoring and maintenance. Ballast fouling is accompanied by ballast degradation as the broken ballast particles intrude into the voids of the ballast layer and obstruct the drainage. The popular method to reduce the excessive ballast deformation and degradation is the inclusion of geosynthetics such as geogrids, geotextiles, geocomposites, and geocells to the track foundation. This paper provides an extensive review of past studies on geosynthetics to reinforce the track foundation. In conclusion, this review presents the limitations of existing studies and provides recommendations for further studies. Keywords Rail track · Ballast · Degradation · Ballast fouling · Geosynthetics
1 Introduction The rail track system is divided into two parts: (i) Superstructure consisting of rail, fastening systems, ties or sleepers; (ii) Substructure consisting of ballast, sub-ballast or capping and compacted subgrade base or a concrete base. Ballast is divided into four subdivisions as crib, shoulder, top ballast, and bottom ballast. Short-term and S. Venuja (B) · S. K. Navaratnarajah · C. S. Bandara · J. A. S. C. Jayasinghe Department of Civil Engineering, Faculty of Engineering, University of Peradeniya, Peradeniya 20400, Sri Lanka e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 R. Dissanayake et al. (eds.), ICSECM 2019, Lecture Notes in Civil Engineering 94, https://doi.org/10.1007/978-981-15-7222-7_38
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long-term deformations of the ballasted rail tracks depend on the substructure components’ characteristics. Ballast degradation is high under stiff subgrade conditions and heavy cyclic loads which affects the track stability and longevity [11, 15]. It also leads to increased maintenance costs, speed restrictions, track and vehicle component failures, stoppage and delays [4, 14]. One of the most widely used techniques in reducing ballast degradation is the inclusion of geosynthetic material to the track foundation. There are planar (geogrids, geotextiles, and geocomposites) and cellular layers (geocells) that are extensively adopted in the improvement of ballast performance. In this review paper, many
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