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Full-Text Articles in Engineering

Performance And Prediction Of Surcharge And Vacuum Consolidation Via Prefabricated Vertical Drains With Special Reference To Highways, Railways And Ports, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Xueyu Geng Mar 2014

Performance And Prediction Of Surcharge And Vacuum Consolidation Via Prefabricated Vertical Drains With Special Reference To Highways, Railways And Ports, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Xueyu Geng

Cholachat Rujikiatkamjorn

Much of the world’s essential infrastructure is built along congested coastal belts that are composed of highly compressible and weak soils up to significant depths. Soft alluvial and marine clay deposits have very low bearing capacity and excessive settlement characteristics, with obvious design and maintenance implications on tall structures and large commercial buildings, as well as port and transport infrastructure. Stabilising these soft soils before commencing construction is essential for both long term and short term stability. A system of vertical drains combined with vacuum pressure and surcharge preloading has become an attractive ground improvement alternative in terms of both …


Numerical Analysis Of Bearing Reinforcement Earth (Bre) Wall, Cherdsak Suksiripattanapong, Avirut Chinkulkijniwat, Suksun Horpibulsuk, Cholachat Rujikiatkamjorn, Theerasak Tanhsutthinon Mar 2014

Numerical Analysis Of Bearing Reinforcement Earth (Bre) Wall, Cherdsak Suksiripattanapong, Avirut Chinkulkijniwat, Suksun Horpibulsuk, Cholachat Rujikiatkamjorn, Theerasak Tanhsutthinon

Cholachat Rujikiatkamjorn

This paper presents a numerical simulation of the bearing reinforcement earth wall by PLAXIS 2D. The bearing reinforcement was regarded as a cost-effective earth reinforcement. The model parameters for the simulation were obtained from the conventional laboratory tests and back analyses from the laboratory pullout tests of the bearing reinforcement. The simplified method for modeling the bearing reinforcement, which converts the contribution of friction and bearing resistance to the equivalent friction resistance, is introduced. This method is considered to be acceptable and practical in working state with sufficient factor of safety and small pullout displacement. The bearing reinforcement is modeled …


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

Cholachat Rujikiatkamjorn

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 …


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

Cholachat Rujikiatkamjorn

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 …


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

Cholachat Rujikiatkamjorn

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 …


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

Cholachat Rujikiatkamjorn

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

Cholachat Rujikiatkamjorn

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 …


Analytical Solutions For Filtration Process Based On Constriction Size Concept, Vo Trong Nguyen, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Analytical Solutions For Filtration Process Based On Constriction Size Concept, Vo Trong Nguyen, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Cholachat Rujikiatkamjorn

An analytical model is proposed to describe the filtration process applicable to a base soil-filter system. The Navier-Stokes equations for porous media are used to capture the hydrodynamic behavior, whereas, numerically, a new algorithm is proposed to solve the Navier-Stokes equation in a nonlinear form. The various mixtures of base soil particles eroded and water flow within the system are computed using the workenergy principle incorporating the constriction size of the filter.The model can assess the filtration process through the flowrate and the accumulation and redistribution of fine particles within the filter. By discretizing the base soil and filter domains …


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

Cholachat Rujikiatkamjorn

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

Cholachat Rujikiatkamjorn

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

Cholachat Rujikiatkamjorn

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

Cholachat Rujikiatkamjorn

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 …


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

Cholachat Rujikiatkamjorn

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 …


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

Cholachat Rujikiatkamjorn

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 …


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

Cholachat Rujikiatkamjorn

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 …


The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn Mar 2014

The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

In this paper, cyclic triaxial loading tests were conducted on specimens of soft clay with varying cyclic stresses and frequencies to investigate the performance of soft soil subgrade subjected to cyclic loading. The laboratory results indicate that given the same level of cyclic stress, the stability of clay subgrade is primarily dependent on the loading time with no consistent frequency/train speed effect. There exists a critical level of cyclic stress between 60 and 80% of the monotonic shear strength, above which failure may occur regardless of the loading frequency. The nature that soils behave dependently on cyclic stress level rather …


Deformation And Degradation Of Clay Fouled Ballast Subjected To Monotonic Loading, Nayoma Tennakoon, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

Deformation And Degradation Of Clay Fouled Ballast Subjected To Monotonic Loading, Nayoma Tennakoon, Buddhima Indraratna, Sanjay Nimbalkar, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

Railways offer an efficient and economic transport mode in many countries including Australia, China and USA. Conventionally, rail tracks are positioned on ballast due to several potential benefits, including economy (availability and abundance), rapid drainage and high load bearing capacity. However, the ballast becomes contaminated due to intrusion of pumped subgrade material (e.g. clay and silt). This is one of the primary reasons for rapid track deterioration. In severe circumstances, fouled ballast needs to be cleaned or replaced to maintain the desired track resiliency, load bearing capacity and the track alignment, all of which influence the level of safety. In …


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

Cholachat Rujikiatkamjorn

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.


Effect Of Coal Fines On The Shear Strength And Deformation Characteristics Of Ballast, S S. Nimbalkar, Buddhima Indraratna, Cholachat Rujikiatkamjorn, M Martin Mar 2014

Effect Of Coal Fines On The Shear Strength And Deformation Characteristics Of Ballast, S S. Nimbalkar, Buddhima Indraratna, Cholachat Rujikiatkamjorn, M Martin

Cholachat Rujikiatkamjorn

Ballast is the most common material supporting the rail track structure due to its large shear strength, high load bearing capacity and free-drainage. However, the fouling of ballast effects deterioration of track performance, and eventually demands track cleaning. Fouling refers to the progressive intrusion of fines into the ballast layer and subsequently filling the voids. Coal spilling from wagons during transport, sleeper and ballast degradation and soil pumping from soft subgrade are the major factors contributing to ballast fouling. Queensland rail network suffers mainly due to ballast breakdown and intrusion of coal fines. The maintenance costs of ballasted tracks can …


Behavior Of Fresh And Fouled Railway Ballast Subjected To Direct Shear Testing: Discrete Element Simulation, B Indraratna, N T Ngo, C Rujikiatkamjorn, J S. Vinod Mar 2014

Behavior Of Fresh And Fouled Railway Ballast Subjected To Direct Shear Testing: Discrete Element Simulation, B Indraratna, N T Ngo, C Rujikiatkamjorn, J S. Vinod

Cholachat Rujikiatkamjorn

This paper presents the three-dimensional discrete element method (DEM) that was used to study the shear behaviour of fresh and coal fouled ballast in direct shear testing. The volumetric changes and stress-strain behaviour of fresh and fouled ballast were simulated and compared with the experimental results. 'Clump logic' in Particle Flow Code (PFC3D) incorporated in a MATLAB Code was used to simulate irregular shaped particles in which groups of ten to twenty spherical balls were clumped together in appropriate sizes to simulate ballast particles. Fouled ballast with various Void Contaminant Index (VCI), ranging from 20%VCI to 70%VCI, were modelled by …


3d Numerical Modelling Of Hexagonal Wire Mesh Reinforced Embankment On Soft Bangkok Clay, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Dennes T. Bergado Mar 2014

3d Numerical Modelling Of Hexagonal Wire Mesh Reinforced Embankment On Soft Bangkok Clay, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Dennes T. Bergado

Cholachat Rujikiatkamjorn

The numerical modeling of the full scale test embankment reinforced with hexagonal wire mesh was analyzed using finite difference method under three dimensional (3D) conditions to reflect the actual embankment dimensions. In the analysis, the 3D finite difference simulation using 5 times of vertical laboratory permeability can reasonably predict its behavior on soft foundation. In comparison with the field measurements, the predicted results from 3D analysis reasonably agreed with measured data including vertical settlement, excess pore pressures and lateral displacements. Thus, the actual embankment geometry and the selected permeability influenced the behavior of the reinforced embankment constructed on soft ground …


Numerical Solution Of Stone Column Improved Soft Soil Considering Arching, Clogging And Smear Effects, Buddhima Indraratna, Sudip Basack, Cholachat Rujikiatkamjorn Mar 2014

Numerical Solution Of Stone Column Improved Soft Soil Considering Arching, Clogging And Smear Effects, Buddhima Indraratna, Sudip Basack, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

Improvement of soft clay deposits by the installation of stone columns is one of the most popular techniques followed worldwide. The stone columns not only act as reinforcingmaterial increasing the overall strength and stiffness of the compressible soft soil, but they also promote consolidation through effective drainage. The analytical and numerical solutions available for ascertaining the response of column-reinforced soil have been developed on the basis of the equal strain hypothesis. For typical surcharge (embankment) loading, the free strain analysis appears to give more realistic results comparable to field data. The paper presents a novel numericalmodel (finite-differencemethod) to analyze the …


Track Stabilisation With Geosynthetics And Geodrains, And Performance Verification Through Field Monitoring And Numerical Modelling, Buddhima Indraratna, S Nimbalkar, Cholachat Rujikiatkamjorn Mar 2014

Track Stabilisation With Geosynthetics And Geodrains, And Performance Verification Through Field Monitoring And Numerical Modelling, Buddhima Indraratna, S Nimbalkar, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

All over the world, ballasted railway tracks form one of the major transportation networks designed to provide heavy haul freight and passenger traffic. However, large cyclic loading from heavy axle trains operating at high speeds often causes excessive deformation and degradation of ballast, as well as unacceptable differential settlement of compressible foundation and, or pumping of the soft subgrade soils. The problem becomes more severe under high impact loads due to rail or wheel imperfections, causing accelerated ballast breakage. A proper understanding of load transfer mechanisms and their effects on track deformations are essential prerequisites for minimising maintenance costs. The …


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.


Assessment Of Ballast Fouling And Its Implications On Track Drainage, Nayoma Tennakoon, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar Mar 2014

Assessment Of Ballast Fouling And Its Implications On Track Drainage, Nayoma Tennakoon, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar

Cholachat Rujikiatkamjorn

Australian railways offer an efficient and economic mode for transporting freight and passengers across all States. Conventionally, rail tracks are positioned on ballast for reasons including economy (availability and abundance), rapid drainage, and high load bearing capacity. However, the ballast becomes fouled due to the intrusion of fines either from the subgrade or surface which impairs track drainage. In order to maintain serviceability, it is necessary to maintain adequate drainage capacity in the track. To identify the risk associated with fouling, it is important to understand the effects of the amount of fouling on drainage conditions. In this present study …


Application Of Vacuum Consolidation For Sustainable Transport Infrastructure, Cholachat Rujikiatkamjorn, Buddhima Indraratna Mar 2014

Application Of Vacuum Consolidation For Sustainable Transport Infrastructure, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Cholachat Rujikiatkamjorn

A system of vertical drains combined with vacuum preloading to accelerate soil consolidation by promoting radial flow is an effective method. In this paper, the analytical modelling of vertical drains incorporating vacuum preloading in an axisymmetric condition is proposed. The distribution of vacuum pressure along the drain and variations in volume compressibility, and permeability of soil based on large scale laboratory observations are included in the proposed solutions. These analytical predictions are compared with a case history taken from Thailand where the entire embankment was stabilised with vertical drains and subjected to vacuum preloading. This analysis employing the writer’s model …


The Role Of Ballast Fouling Characteristics On The Drainage Capacity Of Rail Substructure, Nayoma Tennakoon, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar, Tim Neville Mar 2014

The Role Of Ballast Fouling Characteristics On The Drainage Capacity Of Rail Substructure, Nayoma Tennakoon, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar, Tim Neville

Cholachat Rujikiatkamjorn

The ballast layer is designed to be free draining, but when the voids of the granular medium are wholly or partially filled due to the intrusion of fine particles, the ballast is considered to be “fouled”. In order to ensure acceptable track performance, it is necessary to maintain good drainage within the ballast layer. This paper critically examines the current methods commonly used for evaluating the degree of ballast fouling and, due to their limitations, a new parameter, Void Contaminant Index is introduced. A series of large-scale constant head hydraulic conductivity tests were conducted with different levels of fouling to …


Compaction And Strength Testing Of Industrial Waste Blends As Potential Port Reclamation Fill, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Gabriele Chiaro, S Naeeni, S M. A Tasalloti Mar 2014

Compaction And Strength Testing Of Industrial Waste Blends As Potential Port Reclamation Fill, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Gabriele Chiaro, S Naeeni, S M. A Tasalloti

Cholachat Rujikiatkamjorn

This paper reports on preliminary laboratory geotechnical investigations conducted to explore the compaction and unconfined compression strength (qu) behaviour of granular waste mixtures of coal wash (CW) and steel furnace slag (SFS). Compaction was conducted under relatively dry and submerged conditions. Proctor compaction test results show that the higher the SFS content, the greater the maximum dry density of mixtures, while the optimum moisture content (OMC) is rather constant. However, for mixtures compacted at their OMC, qu decreases with increasing SFS content. In contrast, for mixtures compacted under submergence and cured in seawater for up to 28 days, qu increases …


Laboratory Study Of Small-Strain Behavior Of A Compacted Silty Sand, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn Mar 2014

Laboratory Study Of Small-Strain Behavior Of A Compacted Silty Sand, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Cholachat Rujikiatkamjorn

Small-strain behavior is a key indicator for assessing the performance of compacted fills. Compaction conditions, i.e., initial moisture content and applied energy, govern compaction effectiveness and thus, the structure and matric suction of compacted soil. This paper presents an experimental study of the small-strain behavior of compacted silty sand prepared with different compaction conditions. Specimens with varying initial moisture contents and compaction energies were tested with bender elements to determine the small-strain shear modulus (G0), while the post-compaction matric suction was measured using the filter paper method and tensiometer. The experimental data suggest a pronounced relationship between G0 and the …


Non-Linear Analysis Of Soft Ground Consolidation At The Ballina By-Pass, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly Mar 2014

Non-Linear Analysis Of Soft Ground Consolidation At The Ballina By-Pass, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Richard Kelly

Cholachat Rujikiatkamjorn

This study presents a numerical assessment of consolidation under vacuum preloading with a system of vertical drains and membrane, considering the non-linear properties of the soil This membrane system, already widely used in Australia, is where an airtight membrane is placed over the drainage layer to allow a vacuum to be distributed within the sand platform, along the surface of the soil, and down the vertical drains. To date, there have only been a few fundamental investigations and field studies that have tried to assess the way in which the vacuum can propagate in soft clay, both laterally and vertically. …