Indraratna, B, Navaratnarajah, SK, Nimbalkar, S, Rujikiatkamjorn, C & Neville, T 2015, 'Performance monitoring — case studies of tracks stabilised by geosynthetic grids and prefabricated vertical drains', in PM Dight (ed.), Proceedings of the Ninth Symposium on Field Measurements in Geomechanics
, Australian Centre for Geomechanics, Perth, pp. 233-246, https://doi.org/10.36487/ACG_rep/1508_13_Navaratnarajah
This paper focusses on assessing the performance of rail track through field trials conducted in the towns of Bulli, Singleton and Sandgate in the state of New South Wales (NSW), Australia. In Bulli and Singleton, different types of geosynthetics (geogrid, geotextile and geocomposite) were installed to investigate their relative advantages in relation to various aperture sizes and types of subgrade. A key objective of this study was to evaluate the effect of these artificial inclusions on the vertical and lateral track deformation as the largescale laboratory tests provided evidence that grids reduce particle breakage by restraining the movement of aggregates and by increasing the effective confining pressure such that excessive dilation is curtailed. The geogrids were more affective at controlling displacement when the track was constructed on a soft subgrade such as estuarine soil.
With the tracks constructed directly onto estuarine planes consisting of the inevitable deep and saturated soft clay and silt deposits at Sandgate, prefabricated vertical drains (PVDs) were installed to a depth of less than 8 m to swiftly consolidate the soft upper clay stratum thereby helping resist long term track settlement while increasing the bearing capacity and shear strength. A sophisticated finite element program was developed to capture the behaviour of ballast, subballast and subgrade under cyclic loading via a coupled flow-deformation analysis capable of predicting the vertical and lateral displacement of the tracks, as well as the build-up of excess porewater pressure in the soft estuarine clay. The field data provided by the track owner (one year after the initial design and FEM predictions) proved that PVDs improved track stability by reducing the lateral movements of the subgrade while increasing its load bearing capacity.
ARTC 2006a, RCP-01: Standard for Earthworks Construction Procedures, Australian Rail Track Corporation, Newcastle, Australia.
ARTC 2006b, TDS-12: Standard for Formation Capping Material, Australian Rail Track Corporation, Newcastle, Australia.
ARTC 2007a, ETA-04–01: Ballast Specifications, Australian Rail Track Corporation, Newcastle, Australia.
ARTC 2007b, TDS-08: General Standards for Formation and Earthworks, Australian Rail Track Corporation, Newcastle, Australia.
Brinkgreve, RBJ 2002, PLAXIS (version 8) User’s Manual, Delft University of Technology and PLAXIS B.V., Netherlands.
Brown, SF, Kwan, J & Thom, NH 2007, 'Identifying the key parameters that influence geogrid reinforcement of railway ballast', Geotextiles and Geomembranes, vol. 25, no. 6, pp. 326-335.
Hansbo, S 1981, 'Consolidation of fine-grained soils by prefabricated drains', Proceedings of 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, vol. 3, pp. 677-682.
Holtz, R 1987, 'Preloading with prefabricated vertical strip drains', Geotextiles and Geomembranes, vol. 6, no. 1, pp. 109-131.
Hunter Valley Region 2005, Geotechnical information report for the Sandgate Rail Grade Separation, prepared by K Chan, Report no. 21/12890//AV572.
Indraratna, B & Nimbalkar, S 2013, 'Stress-strain degradation response of railway ballast stabilized with geosynthetics', Journal of Geotechnical and Geoenvironmental Engineering, vol. 139, no. 5, pp. 684-700.
Indraratna, B & Salim, W 2003, 'Deformation and degradation mechanics of recycled ballast stabilised with geosynthetics', Soils and foundations, vol. 43, no. 4, pp. 35-46.
Indraratna, B, Balasubramaniam, A & Ratnayake, P 1994, 'Performance of embankment stabilized with vertical drains on soft clay', Journal of Geotechnical Engineering, vol. 120, no. 2, pp. 257-273.
Indraratna, B, Karimullah Hussaini, SK & Vinod, J 2012, 'On the shear behavior of ballast-geosynthetic interfaces', ASTM geotechnical testing journal, vol. 35, no. 2, pp. 305-312.
Indraratna, B, Navaratnarajah, SK, Nimbalkar, S & Rujikiatkamjorn, C 2014a, 'Use of shock mats for enhanced stability of railroad track foundation', Australian Geomechanics Journal, Special Edition: ARC Centre of Excellence for Geotechnical Science and Engineering, vol. 49, no. 4, pp. 101-111.
Indraratna, B, Nimbalkar, S & Neville, T 2013, 'Performance assessment of reinforced ballasted rail track', Proceedings of the
ICE-Ground Improvement, vol. 167, no. 1, pp. 24-34.
Indraratna, B, Nimbalkar, S & Rujikiatkamjorn, C 2014b, 'From theory to practice in track geomechanics – Australian perspective for synthetic inclusions', Transportation Geotechnics, vol. 1, no. 4, pp. 171-187.
Indraratna, B, Nimbalkar, S & Rujikiatkamjorn, C 2014c, 'Enhancement of rail track performance through utilisation of geosynthetic inclusions', Geotechnical Engineering Journal of the SEAGS & AGSSEA, vol. 45, no. 1, pp. 17-27.
Indraratna, B, Nimbalkar, S & Tennakoon, NC 2010b, 'The behaviour of ballasted track foundations: track drainage and geosynthetic reinforcement', in DO Fratta, AJ Puppala & B Muhunthan (eds), Proceedings of the ASCE Annual GI Conference (GeoFlorida 2010), American Society of Civil Engineers, Reston, VA, pp. 2378-2387.
Indraratna, B, Nimbalkar, S, Christie, D, Rujikiatkamjorn, C & Vinod, J 2010a, 'Field assessment of the performance of a ballasted rail track with and without geosynthetics', Journal of Geotechnical and Geoenvironmental Engineering, vol. 136, no. 7,
Indraratna, B, Rujikiatkamjorn, C, Ewers, B & Adams, M 2010c, 'Class A prediction of the behavior of soft estuarine soil foundation stabilized by short vertical drains beneath a rail track', Journal of Geotechnical and Geoenvironmental Engineering, vol. 136, no. 5, pp. 686-696.
Indraratna, B, Salim, W & Rujikiatkamjorn, C 2011, Advanced rail geotechnology: ballasted track, CRC Press, Boca Raton, FL.
Indraratna, B, Shahin, MA & Salim, W 2007, 'Stabilisation of granular media and formation soil using geosynthetics with special reference to railway engineering', Journal of Ground Improvement, vol. 11, pp. 27-43.
Jeffs, T & Marich, S 1987, 'Ballast characteristics in the laboratory', Proceedings of the 4th Conference on Railway Engineering, Institute of Engineers, Barton, Australia, pp. 141-147.
Johnson, SJ 1970, 'Precompression for improving foundation soils', Journal of the Soil Mechanics and Foundations Division, vol. 96, no. 1, pp. 111-114.
Lackenby, J, Indraratna, B, McDowell, G & Christie, D 2007, 'Effect of confining pressure on ballast degradation and deformation under cyclic triaxial loading', Geotechnique, vol. 57, pp. 527-536.
Lambe, T 1973, 'Predictions in soil engineering', Geotechnique, vol. 23, no. 2, pp. 151-202.
Li, AL & Rowe, RK 2001, 'Combined effects of reinforcement and prefabricated vertical drains on embankment performance', Canadian Geotechnical Journal, vol. 38, no. 6, pp. 1266-1282.
Newcastle Geotech2011, Geotechnical investigation of specific areas of track formation concern for Minimbah Bank Stage 1 Third Track, prepared by M Delaney, NSW, Australia, Report no. 138-4.
Nimbalkar, S, Indraratna, B, Dash, S & Christie, D 2012, 'Improved performance of railway ballast under impact loads using shock mats', Journal of Geotechnical and Geoenvironmental Engineering, vol. 138, no. 3, pp. 281-294.
Raymond, GP 2002, 'Reinforced ballast behaviour subjected to repeated load', Geotextiles and Geomembranes, vol. 20, no. 1, pp. 39-61.
Robertson, PK 1990, 'Soil classification using the cone penetration test', Canadian Geotechnical Journal, vol. 27, no. 1, pp. 151-158.
Selig, ET & Waters, JM 1994, Track geotechnology and substructure management, Thomas Telford, London.