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Full-Text Articles in Engineering
Shear Behaviour Of Rock Joints Under Cyclic Loading, Buddhima Indraratna, Ali Mirzaghorbanali, David Oliveira, Wuditha N. Premadasa
Shear Behaviour Of Rock Joints Under Cyclic Loading, Buddhima Indraratna, Ali Mirzaghorbanali, David Oliveira, Wuditha N. Premadasa
Buddhima Indraratna
For the design of civil and mining engineering geo-structures, it is often necessary to investigate the behaviour and the role of discontinuities on the rock mass performance. In many cases, failure is governed by the shear behaviour of discontinuities in excavations. In this context, evaluation of the effects of small repetitive earthquakes on the shear strength parameters of rock joints especially in tunnels and dam foundations is also important. This paper presents the results of a systematic study carried out on the cyclic shear behaviour of artificial rock joints under constant normal stiffness (CNS) conditions, as many of the previous …
A Laboratory Study Of Railway Ballast Behaviour Under Various Fouling Degree, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Ngoc Trung Ngo, Matthew Coop
A Laboratory Study Of Railway Ballast Behaviour Under Various Fouling Degree, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Ngoc Trung Ngo, Matthew Coop
Buddhima Indraratna
This paper presents a laboratory study of interface behavior between ballast and geogrid under various degree of fouling by coal fines. The stress-displacement behaviour of fresh and fouled ballast with geogrid was investigated through a series of large-scale direct shear tests where the fouling degree varied from 0% to 95% Void Contamination Index (VCI), at normal stresses ranging from 15kPa to 75kPa. The results showed that geogrid enhances the shear strength and increases apparent angle of shearing resistance, while only slightly reduces the vertical displacement of the composite geogrid-ballast system. However, when ballast was contaminated by coal fines, the influences …
Behaviour Of Clay-Fouled Ballast Under Drained Triaxial Testing, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Shrawan Nimbalkar, Cholachat Rujikiatkamjorn
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
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 …
Stabilising Railway Embankments With Geosynthetic Grids And Drains And A Class A Prediction Of Track Behaviour, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn
Stabilising Railway Embankments With Geosynthetic Grids And Drains And A Class A Prediction Of Track Behaviour, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn
Buddhima Indraratna
The ballast layer is intended to provide a free draining base and sufficient bearing capacity to maintain a proper track alignment. Due to the growth in commuter and industrial traffic, the railway industry needs to fulfil the demands for faster, heavier, and longer trains. However, these high traffic loads often result in a large plastic deformations and degradation of ballast, which in turn, leads to a significant loss of track stability and high maintenance costs. The deformation and degradation of ballast are influenced by factors such as the amplitude and frequency of loading, the number of load cycles, track confining …
Cyclic Behaviour Of Soft Soil Subgrade Improved By Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jing Ni
Cyclic Behaviour Of Soft Soil Subgrade Improved By Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jing Ni
Buddhima Indraratna
The behaviour of saturated soft clays subjected to cyclic loading is of considerable importance in the design of railway subgrades. Soft clays can be extensively found in many coastal regions of Australia up to significant depths, including the coastal belt and the central part of NSW. These soft clay deposits are characterised by very low bearing capacity and excessive settlement. The increase in generated excess pore pressures due to heavy freight trains significantly reduces the bearing capacity and causes serious damage to the rail infrastructure such as clay pumping underneath railway tracks and excessive subsidence. The use of prefabricated vertical …
Effects Of Fouling On The Stress-Strain-Degradation Behaviour Of Rail Ballast, Buddhima Indraratna, Nayoma C. Tennakoon, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn
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 …
Shear Behaviour Of Rock Joints With Unsaturated Infill, B Indraratna, Wuditha N. Premadasa, E. T. Brown
Shear Behaviour Of Rock Joints With Unsaturated Infill, B Indraratna, Wuditha N. Premadasa, E. T. Brown
Buddhima Indraratna
Behaviour of soil-infilled rock joints has significant importance with respect to the strength of fractured rock mass. The presence of even a small amount of fine-grained infill material within a joint can reduce its shear strength considerably, depending on the degree of saturation of infill. Therefore, it is crucial to examine how the infill material can adversely affect the joint shear strength. Previous studies of infilled joints have mainly been focused on idealised regular joint patterns owing to the simplicity and reproducibility in laboratory testing. Current literature on infilled rock joints has also neglected the effect of the degree of …