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Science and Technology Studies

Buddhima Indraratna

Ballast

Articles 1 - 5 of 5

Full-Text Articles in Social and Behavioral Sciences

Behaviour Of Clay-Fouled Ballast Under Drained Triaxial Testing, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Shrawan Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

Behaviour Of Clay-Fouled Ballast Under Drained Triaxial Testing, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Shrawan Nimbalkar, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Contamination or fouling of rail ballast with external fines, including slurried and pumped subgrade material (e.g. clay and silt), is one of the primary reasons for track deterioration. Fouling causes differential settlement of the track, and also decreases the load-bearing capacity, owing to the reduction in the friction angle of the granular assembly. In certain circumstances, fouled ballast needs to be cleaned or replaced to maintain the desired track stiffness, load-bearing capacity and track alignment, all of which influence safety. This paper presents and discusses the results of a series of large-scale triaxial tests conducted on latite basalt, a rail …


Dem Simulation Of The Behaviour Of Geogrid Stabilised Ballast Fouled With Coal, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn Mar 2014

Dem Simulation Of The Behaviour Of Geogrid Stabilised Ballast Fouled With Coal, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Geogrids are commonly used in railway construction for reinforcement and stabilisation. When railway ballast becomes fouled due to ballast breakage, infiltration of coal fines, dust and subgrade soil pumping, the reinforcement effect of geogrids decreases significantly. This paper presents results obtained from Discrete Element Method (DEM) to study the interface behaviour of coal-fouled ballast reinforced by geogrid subjected to direct shear testing. In this study, irregularly-shaped aggregates (ballast) were modelled by clumping together 10-20 spheres in appropriate sizes and positions. The geogrid was modelled by bonding a large number of small spheres together to form the desired grid geometry and …


Stress-Strain Degradation Response Of Railway Ballast Stabilized With Geosynthetics, Buddhima Indraratna, Sanjay Nimbalkar Mar 2014

Stress-Strain Degradation Response Of Railway Ballast Stabilized With Geosynthetics, Buddhima Indraratna, Sanjay Nimbalkar

Buddhima Indraratna

Large cyclic loading on ballasted railroad tracks is now inevitable owing to an increased demand for freight and public transport. This leads to a progressive deterioration and densification of railroad ballast and consequently to the loss of track geometry and differential settlement. Understanding these complex stress-strain and degradation mechanisms is essential to predict the desirable track maintenance cycle, as well as the design of new track. This paper presents the results of cyclic drained tests and numerical studies carried out on a segment of model railway track supported on geosynthetically reinforced railroad ballast bed. The relative performance and effectiveness of …


Deformation Of Coal Fouled Ballast Stabilized With Geogrid Under Cyclic Load, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn Mar 2014

Deformation Of Coal Fouled Ballast Stabilized With Geogrid Under Cyclic Load, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn

Buddhima Indraratna

This paper presents the results of laboratory investigations into the deformation of coal fouled ballast stabilized with geogrid at various degrees of fouling. A novel track process simulation apparatus was used to simulate realistic rail track conditions subjected to cyclic loading, and the void contamination index (VCI) was used to evaluate the level of ballast fouling. The experimental results show that coal fines act as a lubricant, causing grains of ballast to displace and rotate, and as a result, accelerate its deformation. However, coal fines also reduce ballast breakage because of a cushioning effect, that is, by reducing interparticle attrition. …


Effects Of Fouling On The Stress-Strain-Degradation Behaviour Of Rail Ballast, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

Effects Of Fouling On The Stress-Strain-Degradation Behaviour Of Rail Ballast, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Ballast is most commonly used as a structural component of rail track due to its high load bearing capacity, resiliency and rapid drainage. However, ballast along coal freight corridors often becomes fouled due to spilling of coal from moving wagons, in addition to further track deterioration attributed to particle breakage and pumping of soft subgrade. Highly fouled ballast needs to be cleaned or replaced to maintain the desired track resiliency, load bearing capacity and the track alignment. In order to identify the risk associated with fouling, it is important to accurately assess the amount of fouling. In this paper, the …