Documents disponibles écrits par cet auteur

Field assessment of the performance of a ballasted rail track with and without geosynthetics / Buddhima Indraratna in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 907-917 Titre : Field assessment of the performance of a ballasted rail track with and without geosynthetics Type de document : texte imprimé Auteurs : Buddhima Indraratna, Auteur ; Sanjay Nimbalkar, Auteur ; David Christie, Auteur Année de publication : 2010 Article en page(s) : pp. 907-917 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Railroad  tracks  Ballast  Cyclic  loads  Deformation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Understanding the complex mechanisms of stress transfer and strain accumulation in layers of track substructure under repeated wheel loading is essential to predict the desirable track maintenance cycle as well as the design of the new track. Various finite element and analytical techniques have been developed in the past to understand the behavior of composite track layers subjected to repeated wheel loads. The mechanical behavior of ballast is influenced by several factors, including the track confining pressure, type of aggregates, and the number of loading cycles. A field trial was conducted on an instrumented track at Bulli, New South Wales, Australia, with the specific aims of studying the benefits of a geocomposite installed at the ballast-capping interface, and to evaluate the performance of moderately graded recycled ballast in comparison to traditionally very uniform fresh ballast. It was found that recycled ballast can be effectively reused if reinforced with a geocomposite. It was also found that geocomposite can effectively reduce vertical and lateral strains of the ballast with obvious implications for improved track stability and reduced maintenance costs. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p907_s1?isAuthorized=no [article] Field assessment of the performance of a ballasted rail track with and without geosynthetics [texte imprimé] / Buddhima Indraratna, Auteur ; Sanjay Nimbalkar, Auteur ; David Christie, Auteur . - 2010 . - pp. 907-917. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 907-917 Mots-clés : Railroad  tracks  Ballast  Cyclic  loads  Deformation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Understanding the complex mechanisms of stress transfer and strain accumulation in layers of track substructure under repeated wheel loading is essential to predict the desirable track maintenance cycle as well as the design of the new track. Various finite element and analytical techniques have been developed in the past to understand the behavior of composite track layers subjected to repeated wheel loads. The mechanical behavior of ballast is influenced by several factors, including the track confining pressure, type of aggregates, and the number of loading cycles. A field trial was conducted on an instrumented track at Bulli, New South Wales, Australia, with the specific aims of studying the benefits of a geocomposite installed at the ballast-capping interface, and to evaluate the performance of moderately graded recycled ballast in comparison to traditionally very uniform fresh ballast. It was found that recycled ballast can be effectively reused if reinforced with a geocomposite. It was also found that geocomposite can effectively reduce vertical and lateral strains of the ballast with obvious implications for improved track stability and reduced maintenance costs. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p907_s1?isAuthorized=no

Improved performance of railway ballast under impact loads using shock mats / Sanjay Nimbalkar in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 3 (Mars 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 281-294 Titre : Improved performance of railway ballast under impact loads using shock mats Type de document : texte imprimé Auteurs : Sanjay Nimbalkar, Auteur ; Buddhima Indraratna, Auteur ; David Christie, Auteur Année de publication : 2012 Article en page(s) : pp. 281-294 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Railroad  tracks  Railroad  ballast  Impact  forces  Deformation  Degradation  Geotechnical  models Résumé : Impact loads generated because of wheel and rail defects cause accelerated ballast breakage leading to adverse performance of ballasted rail tracks. In the present study, experimental and numerical investigations have been carried out to develop an understanding of the performance of shock mats in the attenuation of dynamic impact loads and subsequent mitigation of ballast degradation. The investigations include different locations of shock mats considering stiff and weak subgrade conditions. With the provision of shock mats, the magnitude of impact forces decreases, and the time duration of impact ges prolonged. In the case of stiff subgrade, the efficiency of the shock mat in reducing the impact forces is greater when it is located at the bottom of ballast rather than at the top, whereas the reverse is true for weak subgrade. However, the provision of shock mats both at the top and bottom of the ballast bed, irrespective of the subgrade condition, is the best solution for minimising the impact force. The shock mats can bring down the impact-induced strains in the ballast bed by as much as 50%, apart from substantially reducing the ballast breakage. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i3/p281_s1?isAuthorized=no [article] Improved performance of railway ballast under impact loads using shock mats [texte imprimé] / Sanjay Nimbalkar, Auteur ; Buddhima Indraratna, Auteur ; David Christie, Auteur . - 2012 . - pp. 281-294. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 281-294 Mots-clés : Railroad  tracks  Railroad  ballast  Impact  forces  Deformation  Degradation  Geotechnical  models Résumé : Impact loads generated because of wheel and rail defects cause accelerated ballast breakage leading to adverse performance of ballasted rail tracks. In the present study, experimental and numerical investigations have been carried out to develop an understanding of the performance of shock mats in the attenuation of dynamic impact loads and subsequent mitigation of ballast degradation. The investigations include different locations of shock mats considering stiff and weak subgrade conditions. With the provision of shock mats, the magnitude of impact forces decreases, and the time duration of impact ges prolonged. In the case of stiff subgrade, the efficiency of the shock mat in reducing the impact forces is greater when it is located at the bottom of ballast rather than at the top, whereas the reverse is true for weak subgrade. However, the provision of shock mats both at the top and bottom of the ballast bed, irrespective of the subgrade condition, is the best solution for minimising the impact force. The shock mats can bring down the impact-induced strains in the ballast bed by as much as 50%, apart from substantially reducing the ballast breakage. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i3/p281_s1?isAuthorized=no