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Full-Text Articles in Engineering

Geotechnical Properties Of Ballast And The Role Of Geosynthetics In Rail Track Stabilisation, Buddhima Indraratna, H. Khabbaz, Wadud Salim, D. Christie Dec 2015

Geotechnical Properties Of Ballast And The Role Of Geosynthetics In Rail Track Stabilisation, Buddhima Indraratna, H. Khabbaz, Wadud Salim, D. Christie

Buddhima Indraratna

The ballast and its engineering behaviour have a key role in governing the stability and performance of railway tracks. The deformation and degradation behaviour of ballast under static and dynamic loads was studied based on large-scale triaxial testing. The possible use of different types of geosynthetics to improve the performance of fresh and recycled ballast was also investigated. The research findings showed that the inclusion of geosynthetics improves the performance of ballasted tracks.


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.


Coupled Hydro-Geochemical Modelling Of A Permeable Reactive Barrier For Treating Acidic Groundwater, Buddhima Indraratna, Punyama Pathirage, Kerry Rowe, Laura Banasiak Mar 2014

Coupled Hydro-Geochemical Modelling Of A Permeable Reactive Barrier For Treating Acidic Groundwater, Buddhima Indraratna, Punyama Pathirage, Kerry Rowe, Laura Banasiak

Buddhima Indraratna

This study focuses on coupling geochemistry with geo-hydraulics to enable time-dependent modelling of the remediation of acidic groundwater using an alkaline permeable reactive barrier (PRB). Chemical clogging due to secondary mineral precipitates reduces the porosity and hydraulic conductivity of the reactive medium. The governing equations are incorporated into commercial numerical codes, MODFLOW and RT3D. An original algorithm was developed for RT3D to simulate geochemical reactions occurring in the PRB. The results and the model predictions are in agreement, confirming that the hydraulic conductivity reduction due to mineral precipitation occurs at the start of permeation and continues until halfway through the …


Shear Behaviour Of Rock Joints Under Cyclic Loading, Buddhima Indraratna, Ali Mirzaghorbanali, David Oliveira, Wuditha N. Premadasa Mar 2014

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 Mar 2014

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 …


Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga Mar 2014

Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga

Buddhima Indraratna

During the past decade, the application of vacuum preloading for stabilising soft coastal clay and other low-lying estuarine soils has become popular in Australia. The cost-effectiveness isa major factor in most projects in view of the significantly reduced time for achieving high degree of consolidation. Due to an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235 ha) adjacent to the existing port facilities via land reclamation. A vacuum assited surcharge load and conventional surcharge scheme in conjunction with …


Conceptual Model Describing Smear Zone Caused By Mandrel Action, Cholachat Rujikiatkamjorn, Made Ardana, Buddhima Indraratna, S Leroueil Mar 2014

Conceptual Model Describing Smear Zone Caused By Mandrel Action, Cholachat Rujikiatkamjorn, Made Ardana, Buddhima Indraratna, S Leroueil

Buddhima Indraratna

In this study the characteristics and extent of the smear zone are investigated using a large, undisturbed sample. The aim of using such a sample is to capture the realistic characteristics of the smear zone in relation to the in situ soil structure during the installation of prefabricated vertical drains (PVDs) using a mandrel. The extent of the smear zone for Bulli clay (New South Wales, Australia) is determined on the basis of normalised permeability (k(h)/k(hu)) and the reduction in the water content upon consolidation. The permeability and compressibility of the soil are investigated to determine the extent to which …


Performance And Prediction Of Vacuum Combined Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, Jayantha Ameratunga, Cholachat Rujikiatkamjorn, Harry G. Poulos, A S. Balasublamaniam Mar 2014

Performance And Prediction Of Vacuum Combined Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, Jayantha Ameratunga, Cholachat Rujikiatkamjorn, Harry G. Poulos, A S. Balasublamaniam

Buddhima Indraratna

During the past decade, the application of vacuum pressure for stabilising soft coastal clay and other low-lying estuarine soils has become increasingly popular in Australia, mainly due to the proven costeffectiveness in view of the significantly reduced time for achieving a high degree of consolidation and enhanced shear strength. Due to an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235ha) adjacent to the existing port facilities via land reclamation. A scheme of vacuum assisted surcharge load in conjunction …


Permeable Reactive Barrier (Prb) Technology: An Innovative Solution For The Remediation Of Acidic Groundwater From Acid Sulphate Soil (Ass) Terrain, Laura Banasiak, Buddhima Indraratna Mar 2014

Permeable Reactive Barrier (Prb) Technology: An Innovative Solution For The Remediation Of Acidic Groundwater From Acid Sulphate Soil (Ass) Terrain, Laura Banasiak, Buddhima Indraratna

Buddhima Indraratna

The remediation of acidic groundwater contaminated with potentially toxic metals such as aluminium (Al) and iron (Fe) resulting from the oxidation of sulphidic materials in acid sulphate soils (ASSs) is a challenging geo-environmental problem that requires innovative engineering solutions. In low-lying coastal floodplains, the remediation strategies of groundwater manipulation (e.g. fixed-level weirs) and tidal buffering (e.g. two-way modified floodgates) are not feasible due to the risk of flooding during heavy rainfall events and their inability to prevent pyritic oxidation. In view of this in 2006, the first pilot subsurface permeable reactive barrier (PRB) using recycled concrete for the remediation of …


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 …


Rail Track Infrastructure For Enhanced Speed - Analysis Design And Construction Challenges, Buddhima Indraratna, Sanjay Shrawan Nimbalkar, Jayan Sylaja J S Vinod Mar 2014

Rail Track Infrastructure For Enhanced Speed - Analysis Design And Construction Challenges, Buddhima Indraratna, Sanjay Shrawan Nimbalkar, Jayan Sylaja J S Vinod

Buddhima Indraratna

Rail is one of the largest transportation modes offering freight and passenger traffic in rapidly developing nations, including India. Conscious efforts to improve productivity, modernization and technology upgrading have led to an impressive growth in railways. Large-scale physical modeling, sophisticated numerical modeling and full-scale field monitoring often provide significant knowledge to better understand track performance and to extend the current state-of-the-art in design. A series of large-scale laboratory tests were conducted to establish relationships between (i) ballast breakage and train speed, (ii) ballast fouling and strength and (iii) interface strength and geogrids. Comprehensive field trials were carried out on instrumented …


Elastic Modules Of Soils Treated With Lignosulfonate, J S. Vinod, M A. A Mahamud, B Indraratna Mar 2014

Elastic Modules Of Soils Treated With Lignosulfonate, J S. Vinod, M A. A Mahamud, B Indraratna

Buddhima Indraratna

This paper presents the variation of modulus, in terms of E/qu, with strain for clay soils stabilised by a non-traditional admixture, lignosulfonate. The E/qu has been computed from the stress-strain curves obtained from unconfined compressive strength tests. Lignosulfonate (LS) treated soil shows an increase in the value of E/qu with the addition of LS, especially for soil containing the reactive clay mineral, montmorillonite. The observed variation of E/qu with strain was compared with cement treated soils, and it was found that soils treated with more than 1.0% cement exhibited a decreasing E/qu. Moreover, micro-chemical changes in the soils due to …


Performance Assessment Of Reinforced Ballasted Rail Track, Buddhima Indraratna, Sanjay Nimbalkar, Tim Neville Mar 2014

Performance Assessment Of Reinforced Ballasted Rail Track, Buddhima Indraratna, Sanjay Nimbalkar, Tim Neville

Buddhima Indraratna

In coastal Australia, high population density and increased traffic volumes have promoted rapid expansion of urban transportation infrastructure including railways. Coastal soft clays pose significant construction challenges. Therefore, the search for innovative ground improvement techniques imperative for more resilient and sustainable transport infrastructure has become an obvious priority in research and development. Use of artificial inclusions such as polymeric geosynthetics and energy-absorbing shock mats is described in this paper as a suitable alternative for reducing unacceptable track degradation and for ensuring sustainable track alignment. An extensive monitoring programme was undertaken on fully instrumented track sections constructed near Singleton, New South …


Characterising Compacted Soil Using Shear Wave Velocity And Matric Suction, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn Mar 2014

Characterising Compacted Soil Using Shear Wave Velocity And Matric Suction, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Buddhima Indraratna

The manner in which soil compacts governs the practical and reliable criteria in controlling compaction in the field. A nuclear density meter, based on radioactive isotopes, is the method most commonly used for field compaction, and while it performs well for controlling placement, its localised natnre is not suitable for deeper fills or for assessing larger surface areas. In those types of conditions, alternative non-destrnctive methods should be considered. Numerous resea,:ch studies have focused on the characteristics of compacted soil at its optimum moisture content under saturated conditions, but only a few have evaluated compacted soil under unsaturated conditions using …


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 …


Vertical Drains, Vacuum Consolidation & Preloading, Buddhima Indraratna Mar 2014

Vertical Drains, Vacuum Consolidation & Preloading, Buddhima Indraratna

Buddhima Indraratna

Due to the rapid increase in population, and the subsequent industrial and construction boom, especially in the urban and coastal regions, many countries have intensified the inevitable need for developing infrastructure on problematic soils, including soft compressible clays and deposits with low bearing capacities. Moreover, good quality geological materials for construction are also becoming scarce, a problem exacerbated by the numerous environmental constraints imposed in various countries. Because of these reasons, and environmental restrictions on certain public works, ground improvement has now become an integrated and essential component of infrastructure development. Consequently, civil engineers are forced to utilise even the …


From Theory To Practice In Rail Geotechnology, B Indraratna, Sanjay Nimbalkar, N Tennakoon, Q D. Sun Mar 2014

From Theory To Practice In Rail Geotechnology, B Indraratna, Sanjay Nimbalkar, N Tennakoon, Q D. Sun

Buddhima Indraratna

In recent times the increase in axle loads and train speeds have posed serious geotechnical issues with ballasted railway tracks, both in Australia and the world. The large deformations and degradation of ballast under cyclic and impact loads, and the low bearing capacity of compacted ballast and impaired drainage often exacerbate track maintenance. In recent times in Australia, geosynthetics have been trialed in ballasted tracks constructed on soft and saturated formations to help improve stability and longevity. Comprehensive field studies on instrumented tracks at Bulli (near Wollongong) and Singleton (near Newcastle) supported by RailCorp and ARTC, were carried out to …


Characterising Compacted Fills At Penrith Lakes Development Site Using Shear Wave Velocity And Matric Suction, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn, R Golaszewski Mar 2014

Characterising Compacted Fills At Penrith Lakes Development Site Using Shear Wave Velocity And Matric Suction, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn, R Golaszewski

Buddhima Indraratna

Conventional quality control of compaction during construction is currently based on an in-situ determination of dry unit weight and moisture content via nuclear procedures, but because this is a localised procedure, poor compaction can often occur. Moreover, with older compacted embankments where few or no records of the control done during construction are available, there is no existing methodology that can help practising engineers assess their post-construction condition. This means that the scope of the nuclear method renders it as inadequate and alternative methods should be considered. The use of shear wave velocity (Vs) surveys (i.e. MASW) to assess the …


Current State Of The Art In Vacuum Preloading For Stabilising Soft Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Current State Of The Art In Vacuum Preloading For Stabilising Soft Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Buddhima Indraratna

In this paper the analytical solutions for radial consolidation that include time dependent surcharge loading and vacuum pressure are proposed, whilst also considering the impact of the parabolic variation of permeability in the smear zone. The use of the spectral method for multilayered soil consolidation is introduced and verified. The Elliptical Cavity Expansion Theory is used to predict the extent of soil disturbance (smear zone) caused by the installation of mandrel driven vertical drains. The predicted smear zone is then compared to the data obtained from large-scale radial consolidation tests. Furthermore, the advantages and limitations of applying a vacuum through …


Ground Improvement At The Port Of Brisbane, Australia Using Vertical Drains And Vacuum Assisted Preloading, Buddhima Indraratna, Cholachat Rujikiatkamjorn, A S. Balasubramaniam Mar 2014

Ground Improvement At The Port Of Brisbane, Australia Using Vertical Drains And Vacuum Assisted Preloading, Buddhima Indraratna, Cholachat Rujikiatkamjorn, A S. Balasubramaniam

Buddhima Indraratna

Soft clays in coastal areas have low shear strength and high compressibility. Thus construction activities for infrastructure developments in these deposits often pose geotechnical problems due to large time dependent settlements and lateral movements. Ground improvement techniques are adopted to reduce the water content of the soft clays by preloading techniques with vertical drains. Depending on the magnitude of the surcharge used substantial immediate settlement with lateral movements can takes place during preloading. This in tum causes stability problems in the loaded areas. The use of vacuum assisted preloading has now become a popular method in Australia where substantial loads …


Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn Mar 2014

Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn

Buddhima Indraratna

This study was focused on the effects of compaction energy on the dynamic properties of a silty sand in its as-compacted state in relation to the measured values of matric suction. The influence of the imparted energy on the shear wave velocity and the small-strain shear modulus of the compacted soil was studied for three different energy levels that correspond to the standard Proctor as well as reduced and enhanced. The specimens were prepared with moisture contents ranging from the dry to wet of optimum, and subsequently compacted to known dry unit weights for which the corresponding matric suction and …


Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Buddhima Indraratna

A system of vertical drains (PVDs) with preloading is a successful method for promoting horizontal drainage and accelerating soil consolidation. A piecewise technique is used to capture the radial consolidation in the multi-layer soil system to incorporate (a) the effect of soil downdrag and (b) smear zone where soil permeability varying linearly. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of required time for consolidation. It can be seen that the consolidation of the multi layer soil depends on the interaction between 2 adjacent layer, penetration depth, and …


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 …


Numerical Prediction Of Unsaturated Ground Behavior Influenced By Vegetation And Vacuum Consolidation, Cholachat Rujikiatkamjorn, Buddhima Indraratna, B Fatahi Mar 2014

Numerical Prediction Of Unsaturated Ground Behavior Influenced By Vegetation And Vacuum Consolidation, Cholachat Rujikiatkamjorn, Buddhima Indraratna, B Fatahi

Buddhima Indraratna

Bioengineering including native vegetation is an ancient method of improving the stability of slopes. In modern railway engineering, this technique is re-captured for increasing the soil stiffness and shear strength of subgrade beneath rail tracks. Currently this practice has become increasingly popular in Australia for stabilising railway corridors built over expansive clays and compressive soft soils. This paper looks at the stabilisation role by suction generated by both the natural vegetation and the artificial vacuum application using the numerical analysis. For demonstrating the role of native vegetation, a mathematical model for the rate of root water uptake was incorporated in …


Stabilising Railway Embankments With Geosynthetic Grids And Drains And A Class A Prediction Of Track Behaviour, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

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 …


Frontier Technologies In Design And Construction For Sustainable Transport Infrastructure, Buddhima Indraratna, Sanjay Shrawan Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

Frontier Technologies In Design And Construction For Sustainable Transport Infrastructure, Buddhima Indraratna, Sanjay Shrawan Nimbalkar, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Railways are expected to be one of the main modes of future transport in rapidly developing countries with high population densities, including Sri Lanka. In spite of recent advances in rail track geotechnology, ballasted tracks progressively degrade under heavy cyclic and impact loading. Field studies often provide significant knowledge to better understand track performance and to extend the current state-of-the-art in design. Therefore, comprehensive field trials were carried out on two instrumented rail tracks in Bulli and in Singleton, New South Wales, Australia. In these studies, several track sections were reinforced with different types of geosynthetics placed beneath the ballast …


Vertical And Radial Consolidation Analysis Of Multilayered Soil Using The Spectral Method, Rohan T. Walker, Buddhima Indraratna, Nagaratnam Sivakugan Mar 2014

Vertical And Radial Consolidation Analysis Of Multilayered Soil Using The Spectral Method, Rohan T. Walker, Buddhima Indraratna, Nagaratnam Sivakugan

Buddhima Indraratna

A new, easy to implement, solution to the consolidation of multilayered soil based on the spectral method is presented. Combined vertical and radial drainage under instantaneous or single ramp loading is considered, ignoring well resistance. Flow in the vertical direction is based on the average hydraulic gradient at a particular depth which allows smear effects to be included. The excess pore-water pressure profile across all soil layers is described by a single expression calculated with common matrix operations. Average excess pore pressures within or across any number of layers are easily calculated from the single expression. The new model is …


Compaction Of Coal Wash As Reclamation Fill, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Gabriele Chiaro Mar 2014

Compaction Of Coal Wash As Reclamation Fill, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Gabriele Chiaro

Buddhima Indraratna

In this paper, detailed laboratory investigations were conducted on coal wash produced at coal mine, Wollongong, New South Wales, Australia. Geotechnical tests were conducted to determine the particle size distribution, compaction characteristics, shear resistance and collapse potential. The compaction tests were conducted under dry and submerged condition to examine the compactability and the strength of the coal wash. The laboratory tests show that compacted coal wash has good potential as effective fill for embankments, and land reclamation. Although coal wash is compacted under submerged condition, increased level of compaction has minimal effect.


Experimental Study On The Effectiveness Of Prefabricated Vertical Drains Under Cyclic Loading, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Guanghui Meng Mar 2014

Experimental Study On The Effectiveness Of Prefabricated Vertical Drains Under Cyclic Loading, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Guanghui Meng

Buddhima Indraratna

This study is an attempt to investigate the effectiveness of a prefabricated vertical drain (PVD) installed in remoulded soft clay, where a large-scale cyclic triaxial process simulation rig was employed to simulate cyclic loading representing a track environment. The experimental data show that PVD successfully prevents excessive accumulation of pore water pressure during cyclic loading, and their dissipation continues to occur after the load is removed. The findings of this study have direct significance to rail track environments, e.g. in coastal Australia, where PVD installation beneath rail tracks constructed on low-lying estuarine soils has been recently adopted.


Future Of Australian Rail Tracks Capturing Higher Speeds With Heavier Freight, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

Future Of Australian Rail Tracks Capturing Higher Speeds With Heavier Freight, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn

Buddhima Indraratna

In Australia, quicker and more cost effective commuter and freight transports are essential to cater for the needs of travel demand and supply chains in the mining and agriculture sectors. Such development in coastal areas would necessitate the use of ground improvement techniques in response to environmental legislation and requirements for improved performance and sustainability. In coastal Australia the high cost of track maintenance is the main issue due to poor drainage of soft coastal soils, ballast degradation, fouling (e.g. coal and subgrade soil), differential settlement of track, pumping of subgrade soils and track misalignment due to excessive lateral movements. …