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Full-Text Articles in Engineering

Improved Performance Of Ballasted Tracks Under Impact Loading By Recycled Rubber Mats, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn Jan 2019

Improved Performance Of Ballasted Tracks Under Impact Loading By Recycled Rubber Mats, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part B

Ballasted tracks at transition locations such as approaches to bridges and road crossings experience increasing degradation and deformation due to dynamic and high impact forces, a key factor that decreases the stability and longevity of railroads. One solution to minimise ballast degradation at the transition zones is using rubber energy absorbing drainage sheets (READS) manufactured from recycled tyres. When placed beneath the ballast layer, READS distributes the load over wider area and attenuate of the load over a longer duration thus decreasing maximum stress, apart from reducing the energy transferred to the ballast and other substructure components. Subsequently, the track …


Improved Performance Of Ballasted Tracks At Transition Zones: A Review Of Experimental And Modelling Approaches, Buddhima Indraratna, Muhammad Babar Sajjad, Ngoc Trung Ngo, A Correia, Richard B. Kelly Jan 2019

Improved Performance Of Ballasted Tracks At Transition Zones: A Review Of Experimental And Modelling Approaches, Buddhima Indraratna, Muhammad Babar Sajjad, Ngoc Trung Ngo, A Correia, Richard B. Kelly

Faculty of Engineering and Information Sciences - Papers: Part B

Track transitionssuch as bridge approaches, road crossings and shifts from slab track to ballasted track are common locations wheretrack degradation accelerates due to dynamic and high impact forces; as a consequence there is higher differential settlement. Thesetypes of discontinuities cause an abrupt change in the structural responseof the track due mainly tovariations in stiffness and track damping. Track transitionzones are prone to an accelerated deterioration of track material and geometrythat leads to increased maintenance costs.Track deteriorationalso leads to vehicle degradation due to enhanced acceleration, low frequency oscillation, and high frequency vibrations. While ballastdeterioration is amajor factor affecting thestability and longevity …


Ground Improvement For Transport Infrastructure: Geosynthetic Inclusions For Enhanced Ballasted Rail Tracks, Buddhima Indraratna, Ngoc Trung Ngo, Fernanda Bessa Ferreira, Cholachat Rujikiatkamjorn Jan 2017

Ground Improvement For Transport Infrastructure: Geosynthetic Inclusions For Enhanced Ballasted Rail Tracks, Buddhima Indraratna, Ngoc Trung Ngo, Fernanda Bessa Ferreira, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part B

Given the increasing demand for trains to carry heavier loads, current Australian ballasted rail networks require a significant amount of upgrading. Railroad ballast is an unbounded granular material that displaces laterally when subjected to repeated train loading. During track operations, ballast deteriorates due to progressive breakage and the infiltration of fine particles or mud-pumping from the underneath layers (e.g., capping, subgrade), which decreases the shear strength, impedes track drainage and increases the deformation of ballasted tracks. Rail track substructures can be reinforced by geosynthetics to reduce lateral displacements and optimise overall track performance. This paper presents the current state-of-the-art knowledge …


Coupled Dem-Fem Analysis For Simulating Ballasted Rail Tracks, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn Jan 2017

Coupled Dem-Fem Analysis For Simulating Ballasted Rail Tracks, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part B

Ballasted tracks play an essential role in its economy through transporting freight and bulk commodities between major cities and ports, and carrying passengers, particularly in urban areas. Ballast usually consists of hard and strong angular particles, which are derived from high strength unweathered rocks. Ballast aggregates undergo gradual and continuing degradation under cyclic train loadings. In this study, the load-deformation responses of ballasted rail tracks subjected to cyclic loading are studied experimentally using a large-scale Track Process Simulation Apparatus (TPSA), and numerically through a coupled discrete-continuum approach, namely, coupled DEM-FEM. Laboratory tests are carried out to examine the deformation and …


Improved Performance Of Ballasted Rail Track Using Geosynthetics And Rubber Shockmat, Sanjay Nimbalkar, Buddhima Indraratna Jan 2016

Improved Performance Of Ballasted Rail Track Using Geosynthetics And Rubber Shockmat, Sanjay Nimbalkar, Buddhima Indraratna

Faculty of Engineering and Information Sciences - Papers: Part A

Large repetitive wheel loads from heavy haul and passenger trains can cause significant track deformation that leads to poor track geometry and safety issues. The inclusion of geosynthetics and rubber mats (i.e., shockmat) in critical sections in the track for reducing these adverse effects was further examined through an extensive field trial in the town of Singleton, New South Wales (NSW), Australia. Four types of geosynthetics and a shockmat were installed below the ballast layer in selected sections of track constructed on three different subgrades (soft alluvial clay, hard rock, and concrete bridge), and the performance of the instrumented track …


Field Assessment Of Ballasted Railroads Using Geosynthetics And Shock Mats, Sanjay Nimbalkar, Buddhima Indraratna Jan 2016

Field Assessment Of Ballasted Railroads Using Geosynthetics And Shock Mats, Sanjay Nimbalkar, Buddhima Indraratna

Faculty of Engineering and Information Sciences - Papers: Part A

The ballasted railroads form an integral part of the modern transportation infrastructure in Australia. However, they are subjected to large stresses especially on mixed traffic lines, where heavy freight trains are operated. Under such adverse operational conditions, ballast progressively degrades contributing to overall track deformations and frequent maintenance. Maintaining geometry of ballast embankments is necessary to improve safety and efficiency of railway operations. The use of artificial inclusions (geosynthetics and shock mats) as well as recycled (discarded) ballast in track can be economically viable options. In order to gain more insight, the CGRE has conducted extensive field trials on two …


State-Of-The-Art Design Aspects Of Ballasted Rail Tracks Incorporating Particle Breakage, Fouling, And The Benefits Of Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Michael Martin, Tim Neville, Cholachat Rujikiatkamjorn Mar 2014

State-Of-The-Art Design Aspects Of Ballasted Rail Tracks Incorporating Particle Breakage, Fouling, And The Benefits Of Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Michael Martin, Tim Neville, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

No abstract provided.


Effects Of Geosynthetic Reinforcement On Performance Of Ballasted Rail Track, Pongpipat Anantanasakul, Buddhima Indraratna, Sanjay S. Nimbalkar, Tim Neville Mar 2014

Effects Of Geosynthetic Reinforcement On Performance Of Ballasted Rail Track, Pongpipat Anantanasakul, Buddhima Indraratna, Sanjay S. Nimbalkar, Tim Neville

Buddhima Indraratna

The 'field' performance of different geosynthetics to reinforce ballasted rail tracks was investigated. An extensive monitoring program was undertaken on fully instrumented track sections constructed near Singleton, New South Wales. Four types of geosynthetics were installed at the ballast-subballast interface of track sections located on subgrades with three distinctly different values of stiffness. It was found that geogrids could decrease vertical settlements of the ballast layer with obvious benefits of improved track stability and decreased maintenance cost. It was also found that the effectiveness of reinforcing geogrids increased when the subgrade stiffness decreased. Keywords: Geosynthetic, Reinforcement, Rail track, Ballast.


Field Monitoring Of Performance Of Ballasted Rail Track With Geosynthetic Reinforcement, P Anantanasakul, B Indraratna, S S. Nimbalkar, T Neville Mar 2014

Field Monitoring Of Performance Of Ballasted Rail Track With Geosynthetic Reinforcement, P Anantanasakul, B Indraratna, S S. Nimbalkar, T Neville

Buddhima Indraratna

Large cyclic stresses induced from heavy traffic can cause significant degradation of rail tracks, leading to poor track geometry and safety. Inclusion of resilient materials such as geosynthetics to reinforce the track substructure has been observed in the laboratory to be viable at reducing the impact of such adverse effects. Despite this, the ‘field’ performance of different geosynthetics to reinforce ballasted tracks has not been investigated in a systematic manner. An extensive field study was therefore undertaken on experimental track sections near Singleton, New South Wales. Four types of geosynthetics were installed at the ballast-subballast interface of track sections constructed …


State-Of-The-Art Design Aspects Of Ballasted Rail Tracks Incorporating Particle Breakage, Fouling, And The Benefits Of Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Michael Martin, Tim Neville, Cholachat Rujikiatkamjorn Mar 2014

State-Of-The-Art Design Aspects Of Ballasted Rail Tracks Incorporating Particle Breakage, Fouling, And The Benefits Of Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Michael Martin, Tim Neville, Cholachat Rujikiatkamjorn

Buddhima Indraratna

No abstract provided.


The Role Of Geosynthetics In Improving The Behaviour Of Ballasted Rail Tracks, Buddhima Indraratna, Sanjay Shrawan Nimbalkar Jan 2013

The Role Of Geosynthetics In Improving The Behaviour Of Ballasted Rail Tracks, Buddhima Indraratna, Sanjay Shrawan Nimbalkar

Faculty of Engineering and Information Sciences - Papers: Part A

This chapter contains a laboratory assessment of the role of geosynthetics in the performance of railway ballast. The main objectives of this testing were to examine the actual potential of selected geosynthetic products for ballast stabilisation. A series of cyclic drained tests were carried out using a large scale prismoidal triaxial apparatus that was designed and built at the University of Wollongong, and is the most innovative cyclic process simulation testing equipment available in the world today. The effects of different types of geosynthetics, including bi-axial geogrid, non-woven geotextile and geocomposite (a combination of bi-axial geogrid and non-woven geotextile) have …


Effects Of Geosynthetic Reinforcement On Performance Of Ballasted Rail Track, Pongpipat Anantanasakul, Buddhima Indraratna, Sanjay S. Nimbalkar, Tim Neville Jan 2013

Effects Of Geosynthetic Reinforcement On Performance Of Ballasted Rail Track, Pongpipat Anantanasakul, Buddhima Indraratna, Sanjay S. Nimbalkar, Tim Neville

Faculty of Engineering and Information Sciences - Papers: Part A

The 'field' performance of different geosynthetics to reinforce ballasted rail tracks was investigated. An extensive monitoring program was undertaken on fully instrumented track sections constructed near Singleton, New South Wales. Four types of geosynthetics were installed at the ballast-subballast interface of track sections located on subgrades with three distinctly different values of stiffness. It was found that geogrids could decrease vertical settlements of the ballast layer with obvious benefits of improved track stability and decreased maintenance cost. It was also found that the effectiveness of reinforcing geogrids increased when the subgrade stiffness decreased. Keywords: Geosynthetic, Reinforcement, Rail track, Ballast.


Field Monitoring Of Performance Of Ballasted Rail Track With Geosynthetic Reinforcement, P Anantanasakul, B Indraratna, S S. Nimbalkar, T Neville Jan 2012

Field Monitoring Of Performance Of Ballasted Rail Track With Geosynthetic Reinforcement, P Anantanasakul, B Indraratna, S S. Nimbalkar, T Neville

Faculty of Engineering - Papers (Archive)

Large cyclic stresses induced from heavy traffic can cause significant degradation of rail tracks, leading to poor track geometry and safety. Inclusion of resilient materials such as geosynthetics to reinforce the track substructure has been observed in the laboratory to be viable at reducing the impact of such adverse effects. Despite this, the ‘field’ performance of different geosynthetics to reinforce ballasted tracks has not been investigated in a systematic manner. An extensive field study was therefore undertaken on experimental track sections near Singleton, New South Wales. Four types of geosynthetics were installed at the ballast-subballast interface of track sections constructed …


State-Of-The-Art Design Aspects Of Ballasted Rail Tracks Incorporating Particle Breakage, Fouling, And The Benefits Of Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Michael Martin, Tim Neville, Cholachat Rujikiatkamjorn Jan 2012

State-Of-The-Art Design Aspects Of Ballasted Rail Tracks Incorporating Particle Breakage, Fouling, And The Benefits Of Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Michael Martin, Tim Neville, Cholachat Rujikiatkamjorn

Faculty of Engineering - Papers (Archive)

No abstract provided.


The Behaviour Of Ballasted Track Foundations: Track Drainage And Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Nayoma Chulani Tennakoon Dec 2011

The Behaviour Of Ballasted Track Foundations: Track Drainage And Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Nayoma Chulani Tennakoon

Buddhima Indraratna

Ballasted Rail tracks are widely used throughout the world due to its resiliency to the repeated wheel loads, low construction cost and ease of maintenance. However, the ballast layer needs periodic maintenance due to its deformation and degradation associated with particle breakage and fouling. A proper understanding of the contamination due to various types of fines and its implications on track drainage is a pre-requisite for effective implementation of track maintenance operations. A new parameter Void Contaminant Index (VCI) can accurately assess the contamination as it includes the effect of void ratio, specific gravity and gradation of ballast and fouling …


Implications Of Ballast Breakage On Ballasted Railway Track Based On Numerical Modelling, Buddhima Indraratna, S Nimbalkar Jan 2011

Implications Of Ballast Breakage On Ballasted Railway Track Based On Numerical Modelling, Buddhima Indraratna, S Nimbalkar

Faculty of Engineering - Papers (Archive)

Large and frequent cyclic train loading from heavy haul and passenger trains often leads to progressive track deterioration. The excessive deformation and degradation of ballast and unacceptable differential settlement of track and/or pumping of underlying soft subgrade soils necessitate frequent and costly track maintenance. A proper understanding of load transfer mechanisms and subsequent deformations in track layers is the key element for safe and economical track design and optimum maintenance procedures. Many simplifi ed analytical and empirical design methods have been used to estimate the settlement and stress-transfer between the track layers. However, these design methods are based on the …


The Behaviour Of Ballasted Track Foundations: Track Drainage And Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Nayoma Chulani Tennakoon Jan 2010

The Behaviour Of Ballasted Track Foundations: Track Drainage And Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Nayoma Chulani Tennakoon

Faculty of Engineering - Papers (Archive)

Ballasted Rail tracks are widely used throughout the world due to its resiliency to the repeated wheel loads, low construction cost and ease of maintenance. However, the ballast layer needs periodic maintenance due to its deformation and degradation associated with particle breakage and fouling. A proper understanding of the contamination due to various types of fines and its implications on track drainage is a pre-requisite for effective implementation of track maintenance operations. A new parameter Void Contaminant Index (VCI) can accurately assess the contamination as it includes the effect of void ratio, specific gravity and gradation of ballast and fouling …