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- Vertical drains (4)
- Numerical modeling (3)
- Case histories (2)
- Consolidation (2)
- Remediation (2)
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- Soft clays (2)
- Soft soils (2)
- Vertical drain (2)
- Vertical Drains. (1)
- vertical drains. (1)
- 3D Numverical modeling (1)
- Acid sulphate soil (1)
- Acid sulphate soils (1)
- Analystical modeling (1)
- Clay (1)
- Clays; consolidation; laboratory tests; pore pressures; rocks; shear strength (1)
- Clays; laboratory tests; pore pressure; rocks/rock mechanics; shear strength (1)
- Deformation; friction; laboratory tests; shear strength; soft rocks; stiffness (1)
- Deformation; gravels; laboratory tests; particle crushing/crushability; repeated loading (1)
- Finite element analysis (1)
- Finite element modelling (1)
- Geosynthetics vertical drain (1)
- Geosynthetics; large-scale triaxial testing; railway ballast (1)
- Ground Improvement (1)
- Groundwater contamination (1)
- Grouting (1)
- Hydraulic conductivity (1)
- Hydromechanics (1)
- Joint rocks (1)
- Numerical analysis (1)
Articles 1 - 30 of 47
Full-Text Articles in Engineering
Radial Consolidation Of Clay Using Compressibility Indices And Varying Horizontal Permeability, B. Indraratna, C. Rujikiatkamjorn, I. Sathananthan
Radial Consolidation Of Clay Using Compressibility Indices And Varying Horizontal Permeability, B. Indraratna, C. Rujikiatkamjorn, I. Sathananthan
Buddhima Indraratna
A system of vertical drains with surcharge load to accelerate consolidation by shortening the drainage path is one of the most popular methods of soft ground improvement. The conventional radial consolidation theory (including smear and well resistance) have been commonly employed to predict the behaviour of vertical drains in soft clay. Its mathematical formulation is based on the small strain theory, and for a given stress range, a constant volume compressibility (mv) and a constant coefficient of lateral permeability (kh) are assumed. However, the value of mv varies along the consolidation curve over a wide range of applied pressure (Dp). …
Soft Clay Foundation Improvement With Drainage And Geo-Inclusions, With Special Reference To The Performance Of Embankments And Transportation Systems, Buddhima Indraratna, Cholachat Rujikiatkamjorn, V. Wijeyakulasuriya, A. S. Balasubramaniam
Soft Clay Foundation Improvement With Drainage And Geo-Inclusions, With Special Reference To The Performance Of Embankments And Transportation Systems, Buddhima Indraratna, Cholachat Rujikiatkamjorn, V. Wijeyakulasuriya, A. S. Balasubramaniam
Buddhima Indraratna
In this paper, the geotechnical aspects of soft clay improvement using prefabricated vertical drains (PVDs) with special reference to embankments will be demonstrated. The Cavity Expansion Theory is employed to predict the smear zone caused by the installation of mandrel driven vertical drains. Analytical and Numerical analyses adopting the equivalent plane strain solution are conducted to predict the excess pore pressures, lateral and vertical displacements. The advantages and limitations of vacuum application through vertical drains avoiding the need for high surcharge embankments are discussed using the proposed solutions. A few selected case histories are discussed and analyzed, including the site …
A Shear Strength Model For Idealised Infilled Joints Under Constant Normal Stiffness, Buddhima Indraratna, S. Welideniya, T. Brown
A Shear Strength Model For Idealised Infilled Joints Under Constant Normal Stiffness, Buddhima Indraratna, S. Welideniya, T. Brown
Buddhima Indraratna
Infill materials found in natural rock joints may cause a reduction in joint shear strength, influencing rock mass stability. This paper reports a study aimed at developing a semi-empirical methodology for predicting the shear strength of infilled joints, taking into account joint surface characteristics and the properties of the joint and infill materials. A new model for predicting the shear strength of infilled joints is presented, on the basis of a series of tests carried out on two types of model joint surface having asperity angles of 9.5° and 18.5°, with graphite and bentonite used as infill materials. All tests …
Numerical Analysis Of Matric Suction Effects Of Tree Roots, Buddhima Indraratna, Behzad Fatahi, H. Khabbaz
Numerical Analysis Of Matric Suction Effects Of Tree Roots, Buddhima Indraratna, Behzad Fatahi, H. Khabbaz
Buddhima Indraratna
The use of native vegetation in the coastal regions of Australia has become increasingly popular for stabilising railway corridors built over expansive clays and compressive soft soils. The tree roots provide three stabilising functions: (a) they reinforce the soil; (b) they dissipate excess pore pressures; and (c) they establish sufficient matric suction to increase the shear strength. The matric suction generated within the tree root zone propagates radially into the soil matrix, as a function of the moisture content change. Considering soil conditions, the type of vegetation and atmospheric conditions, a mathematical model for the rate of root water uptake …
Effect Of Stress Change On Water Inflows To Underground Excavations, Buddhima Indraratna, J Wang
Effect Of Stress Change On Water Inflows To Underground Excavations, Buddhima Indraratna, J Wang
Buddhima Indraratna
The change in ground stresses in a rock mass has a significant influence on the aperture of rock joints, and therefore, on the water inflow to mining excavations. In this . paper, the distinct element code UDEC (Itasca Consulting Group, 1993) has been applied to simulate water flow through simplified joint geometries, considering appropriate joint apertures and in-situ stress ratios. For a rectangular excavation, a fully coupled hydro-mechanical analysis has been conducted. where joint conductivity is dependent on the change in apertures under applied stress, and conversely, the domain water pressures affect the deformation behaviour of the rock mass around …
Shear Behaviour Of Railway Ballast Based On Large Scale Triaxial Testing, Buddhima Indraratna, D. Ionescu, H. D. Christie
Shear Behaviour Of Railway Ballast Based On Large Scale Triaxial Testing, Buddhima Indraratna, D. Ionescu, H. D. Christie
Buddhima Indraratna
Quarried rock fragments (ballast) constitute one of the most commonly used construction matierals in railway engineering. Ballast is subjected to high stress levels as well as being always exposed to environmental changes. Unsatisfactory performance of railway tracks is often associated with the loss of cross level, track profile and track alignment.
Radial Consolidation Theories And Numerical Analysis Of Soft Soil Stabilisation Via Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Rohan T. Walker
Radial Consolidation Theories And Numerical Analysis Of Soft Soil Stabilisation Via Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Rohan T. Walker
Buddhima Indraratna
In this paper, an analytical solution based on actual radial soil permeability and compressibility is proposed considering the impact of parabolic variation of permeability in smear zone. The use of the spectral method for multilayered soil consolidation is introduced and verified. The Cavity Expansion Theory is employed to predict the extent of soil disturbance (smear zone) caused by the installation of mandrel driven vertical drains. The smear zone prediction is then compared to the data obtained from large-scale radial consolidation tests. Furthermore, the advantages and limitations of vacuum application through vertical drains are discussed using the proposed solutions. The applied …
A New Model For The Behaviour Of Granular Filters, M. Locke, Buddhima Indraratna
A New Model For The Behaviour Of Granular Filters, M. Locke, Buddhima Indraratna
Buddhima Indraratna
Filters are used in geotechnical engineering to control seepage and to prevent erosion of soil due to the drag forces of seeping water. Filters act as barriers to retain the base soil while allowing seepage flows to exit without causing high hydraulic gradients or pore pressures which may damage the structure. This paper describes a new anyalytical model of filtration. The model is based on a three dimensional network model of filter pores, and the equations of conservatioln of mass and momentum which govern the rate of particle transport. The model has application in the design of granular filters for …
Three-Dimensional Analysis Of Soft Soil Consolidation Improved By Prefabricated Vertical Drains, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Three-Dimensional Analysis Of Soft Soil Consolidation Improved By Prefabricated Vertical Drains, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Buddhima Indraratna
A system of prefabricated vertical drains (PVDs) with a surcharge load is an effective method for accelerating soil consolidation by promoting radial flow. This study presents a three-dimensional (3D) finite element model for soft soil improved by a single drain. In the finite element analysis, the actual rectangular PVD cross-section is considered, and the equivalent drain diameter is then back calculated based on the consolidation curves. The numerical predictions are then compared to previous studies. The settlements observed in the laboratory are subsequently compared with the three-dimensional finite element analysis incorporating the modified Cam-Clay model and Hansbo’s theory.
Vacuum Consolidation Effects On Lateral Yield Of Soft Clays As Applied To Road And Railway Embankment, Buddhima Indraratna, Cholachat Rujikiatkamjorn, G. Mcintosh, A. Balasubramaniam
Vacuum Consolidation Effects On Lateral Yield Of Soft Clays As Applied To Road And Railway Embankment, Buddhima Indraratna, Cholachat Rujikiatkamjorn, G. Mcintosh, A. Balasubramaniam
Buddhima Indraratna
The use of vertical drains with vacuum preloading is considered as the most effective and economical method for improving soft clays (normally consolidated to lightly over-consolidated) to eliminate settlements of the permanent infrastructure. Application of vacuum pressure via prefabricated vertical drains promotes radial flow consolidation enhancing the shear strength of the compressed ground. In this paper, the mechanisms of the vacuum preloading system based on current practices are described through the selection of the important design parameters. The equivalent plane strain solution for both Darcian and non-Dracian flow are presented to predict the excess pore pressures, lateral and vertical displacements. …
Analytical And Numerical Modeling Of Soft Soil Stabilized By Prefabricated Vertical Drains Incorporating Vacuum Reloading, Buddhima Indraratna, I. Sathananthan, Cholachat Rujikiatkamjorn, A. S. Balasubramaniam
Analytical And Numerical Modeling Of Soft Soil Stabilized By Prefabricated Vertical Drains Incorporating Vacuum Reloading, Buddhima Indraratna, I. Sathananthan, Cholachat Rujikiatkamjorn, A. S. Balasubramaniam
Buddhima Indraratna
This paper describes the analytical formulation of a modified consolidation theory incorporating vacuum pressure, and numerical modeling of soft clay stabilized by prefabricated vertical drains, with a linearly distributed ~trapezoidal! vacuum pressure for both axisymmetric and plane strain conditions. The effects of the magnitude and distribution of vacuum pressure on soft clay consolidation are examined through average time-dependent excess pore pressure and consolidation settlement analyses. The plane strain analysis was executed by transforming the actual vertical drains into a system of equivalent parallel drain walls by adjusting the coefficient of permeability of the soil and the applied vacuum pressure. The …
Measurement Of Pore Water Pressure Of Clay-Infilled Rock Joints During Triaxial Shearing, Buddhima Indraratna, J. Mylvaganam
Measurement Of Pore Water Pressure Of Clay-Infilled Rock Joints During Triaxial Shearing, Buddhima Indraratna, J. Mylvaganam
Buddhima Indraratna
Joints existing within a rock mass are normally filled with fine materials such as clay and silt, which decrease its ultimate strength and make it easier to deform. The shear behaviour of infilled rock joints is controlled by several parameters, such as infill thickness, joint roughness and drainage conditions (Ladanyi & Archambault, 1977; Lama, 1978; de Toledo & de Freitas, 1993; Indraratna et al., 2005). If the infill material is saturated and drainage is impeded, pore water pressure within the infilled joint will build up and change during shear displacement. The importance of pore water pressure in the hydromechanical stability …
Theoretical And Numerical Perspectives And Field Observations For The Design And Performance Evaluation Of Embankments Constructed On Soft Marine Clay, Buddhima Indraratna, Iyathurai Sathananthan, C. Bamunawita, A. S. Balasubramaniam
Theoretical And Numerical Perspectives And Field Observations For The Design And Performance Evaluation Of Embankments Constructed On Soft Marine Clay, Buddhima Indraratna, Iyathurai Sathananthan, C. Bamunawita, A. S. Balasubramaniam
Buddhima Indraratna
In this chapter, a two-demensional plane strain solution is adopted for the embankment analysis, which includes the effects of smear zone caused by mandrel driven vertical drains. The equivalent (transformed) permeability coefficients are incorporated in finite element codes, employing modified Cam-clay theory. Selected numerical studies have been carried out to study the effect of embankment slope, construction rate, and drain spacing on the failure of the soft clay foundation. Finally, the observed and predicted performances of well-instrumented full-scale trial embankments built on soft Malaysian marine clay have been discussed in detail. The predicted results agree with the field measurements.
Acid Sulphate Soil Remediation Techniques On The Shoalhaven River Floodplain, Australia, Buddhima Indraratna, A. N. Golab, W. Glamore, B. Blunden
Acid Sulphate Soil Remediation Techniques On The Shoalhaven River Floodplain, Australia, Buddhima Indraratna, A. N. Golab, W. Glamore, B. Blunden
Buddhima Indraratna
A commonly used flood mitigation technique in coastal areas of Australia during the late 1960’s was the installation of one-way floodgates on flood mitigation drains. In regions affected by acid sulphate soils (the oxidation of pyrite in the soil forms sulphuric acid), the floodgates prevent tidal carbonate/bicarbonate buffering of the drains and thereby create reservoirs of acidic water (pH < 4.5) that discharge during low tide. Several acid sulphate soil remediation techniques have been used in coastal lowland in southeastern NSW, Australia. Following extensive monitoring and finite element modelling of groundwater conditions and quality, fixed level v-notch weirs were installed at three elevations to maintain elevated groundwater levels. The weirs successfully maintained the groundwater level above the acid sulphate soils, preventing additional pyrite oxidation, and reduced the rate of discharge of acid to the drain. Following further monitoring, investigation into anaerobic acid sources, and finite element based geochemical modelling, modified two-way floodgates that allow tidal ingress were installed. The modified floodgates were successful in buffering the drain water pH before discharging the drain water into adjacent waterways. Numerical analysis based on FEM was extended to illustrate that saline intrusion into the surrounding soil (as a result of tidal ingress and acid buffering in the drains) was not a major concern for the pastureland or other agricultural activities
Nature And Properties Of Acid Sulphate Soils In Drained Coastal Lowlands In New South Wales, Buddhima Indraratna, B. Blunden, A. Nethery
Nature And Properties Of Acid Sulphate Soils In Drained Coastal Lowlands In New South Wales, Buddhima Indraratna, B. Blunden, A. Nethery
Buddhima Indraratna
Acid sulphate soils pose severe constraints to the protection of engineering infrastructure, sustainable agriculture and environmental quality in coastal estuarine systems in many parts of Australia. The nature and properties of acid sulphate soils are described with reference to data collected from intensively drained coastal lowlands located on the South Coast of New South Wales.
Performance Of Embankment Stabilized With Vertical Drains On Soft Clay, Buddhima Indraratna, A. S. Balasubramaniam, P. Ratnayake
Performance Of Embankment Stabilized With Vertical Drains On Soft Clay, Buddhima Indraratna, A. S. Balasubramaniam, P. Ratnayake
Buddhima Indraratna
This study describes the performance of a fldl-scale embankment raised on a soft marine clay, stabilized with vertical band drains in Malaysia. The finite element code CRISP, which is based on critical-state soil mechanics, has been employed to investigate the performance of the embankment and the underlying soft clay. Predictions of the excess pore pressures and both vertical and lateral displacements are made and compared with field observations. The limited use of closed-form solutions for the prediction of settlements at the line of symmetry of the embankment is also discussed. The effectiveness of the prefabricated drains has been evaluated according …
Stabilisation Of Rail Tracks And Underlying Soft Soil Formations, Buddhima Indraratna, Mohamed A. Shahin, Cholachat Rujikiatkamjorn
Stabilisation Of Rail Tracks And Underlying Soft Soil Formations, Buddhima Indraratna, Mohamed A. Shahin, Cholachat Rujikiatkamjorn
Buddhima Indraratna
Construction of rail tracks requires appropriate improvement techniques for ballast and underlying soft formation soil, both of which deform and degrade progressively under heavy train loads. This paper aims to demonstrate and discuss some major aspects in relation to stabilisation of ballasted rail tracks overlaying soft formation soils. The use of geocomposites (i.e. bonded geogrid-geotextile layers) for enhancing the performance of rail tracks is described, with the aim of achieving reduced track settlement, increased resilient modulus and decreased ballast degradation. The effects of increasing the confining pressure on rail tracks in regard to particle breakage are studied using laboratory tests. …
Vacuum Preloading Techniques - Recent Developments And Applications, J. Chu, S. Yan, Buddhima Indraratna
Vacuum Preloading Techniques - Recent Developments And Applications, J. Chu, S. Yan, Buddhima Indraratna
Buddhima Indraratna
In this paper, an overview on the mechanisms, techniques and applications of the vacuum preloading method are presented. Some recent developments in the vacuum preloading techniques, including the use of new materials, the expansion of the method, and new analysis or numerical modeling methods are briefly summarized.
Soft Ground Improvement By Vacuum-Assisted Preloading, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Soft Ground Improvement By Vacuum-Assisted Preloading, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Buddhima Indraratna
This paper describes the behaviour of soft soil foundation stabilized with vacuum-assisted preloading at the New Bangkok International Airport, Thailand. An analytical solution considering the variation of soil permeability and compressibility and a finite element analysis based on an equivalent plane strain model developed by the authors are employed to investigate the performance of the test embankment. The converted equivalent plane strain parameters are incorporated in the finite element code ABAQUS. The associated settlement, excess pore pressure and lateral movement are predicted and compared with the available field measurement. The data indicate that the efficiency of the prefabricated vertical drains …
Analytical And Numerical Solutions For Soft Clay Consolidation Using Geosynthetic Vertical Drains With Special Reference To Embankments, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Iyathurai Sathananthan, Mohamed A. Shahin, Hadi Khabbaz
Analytical And Numerical Solutions For Soft Clay Consolidation Using Geosynthetic Vertical Drains With Special Reference To Embankments, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Iyathurai Sathananthan, Mohamed A. Shahin, Hadi Khabbaz
Buddhima Indraratna
Good quality geologic materials for construction are also becoming scarce. Due to these reasons and because of the environmental restrictions on certain public works, ground improvement is becoming an essential part of infrastructure development. As a result, Civil Engineers are forced to utilise even the poorest soft clay foundations for buildings, highways and railway tracks. Therefore, the application of prefabricated vertical drains with preloading has now become common practice and one of the most effective ground improvement techniques. The classical solution for vertical drains (single drain analysis) has been well documented in the literature, where there are many vertical drains, …
Developments In Geotechnical And Geo-Environmental Research In Relation To Low-Lying Floodplain Improvement, With Special Reference To Acidic Soil Improvement, Buddhima Indraratna, A. Golab, Mohamed A. Shahin, Cholachat Rujikiatkamjorn
Developments In Geotechnical And Geo-Environmental Research In Relation To Low-Lying Floodplain Improvement, With Special Reference To Acidic Soil Improvement, Buddhima Indraratna, A. Golab, Mohamed A. Shahin, Cholachat Rujikiatkamjorn
Buddhima Indraratna
In many countries, the ever-growing demand for housing and tourism in coastal regions has forced the development of low-lying estuarine floodplains and wetlands for major infrastructure including highways, railways, hotels and high rise apartments, and commercial buildings. The estuarine clays, often with high organic content, are usually characterised by very high settlement upon loading affecting the stability of all forms of infrastructure. In addition, pyrites and other sulphidic compounds that exist at shallow depths in these soils can oxidise to form sulphuric acid presenting a challenging environmental issue, which if not controlled can cause catastrophic damage to coastal aquaculture and …
Two-Phase (Air And Water) Flow Through Rock Joints: Analytical And Experimental Study, Buddhima Indraratna, P. G. Ranjith, J. R. Price, W. Gale
Two-Phase (Air And Water) Flow Through Rock Joints: Analytical And Experimental Study, Buddhima Indraratna, P. G. Ranjith, J. R. Price, W. Gale
Buddhima Indraratna
This research study deals with the characterization of two-phase flow in a fractured rock mass. A comprehensive mathematical model with which to predict the quantity of each flow component in a single joint is developed. A joint with two parallel walls filled with layers of water and air (stratified) is analyzed. The effects of mechanical deformation of the joint, the compressibility of fluids, the solubility of air in water, and the phase change between fluids have been taken into account to develop analytical expressions which describe the behavior at the air–water interface. The model was calibrated using a newly designed …
Filtration Of Broadly Graded Soils: The Reduced Psd Method, M. Locke, Buddhima Indraratna
Filtration Of Broadly Graded Soils: The Reduced Psd Method, M. Locke, Buddhima Indraratna
Buddhima Indraratna
Granular filters are used in earth structures, such as embankment dams, to protect fine soils from erosion due to seepage forces. Successful filtration requires that the filter voids are fine enough to capture some of the coarse fraction of the base soil. These retained particles are then able to capture progressively finer base soil particles, and eventually a filter interface forms that is able to prevent any further erosion. This process is called self-filtration. Lafleur et al. (1989) examined self-filtration in cohesionless, broadly graded base soils. It was found that the extent of mass loss before selffiltration occurs was greater …
Geotechnical Properties Of Ballast And The Role Of Geosynthetics In Rail Track Stabilisation, Buddhima Indraratna, H. Khabbaz, Wadud Salim, D. Christie
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.
Investigating Erosional Behaviour Of Chemically Stabilised Erodible Soils, Buddhima Indraratna, Thevaragavan Muttuvel, Hadi Khabbaz
Investigating Erosional Behaviour Of Chemically Stabilised Erodible Soils, Buddhima Indraratna, Thevaragavan Muttuvel, Hadi Khabbaz
Buddhima Indraratna
Chemical stabilisation is a popular technique to improve the erosion resistance of the soils. In this study, two chemical stabilisers, namely lignosulfonate and general purpose Portland cement were tested on two different soils, a silty sand and a dispersive clay. A series of erosion tests were performed to study the effectiveness of the stabilisation in increasing the erosion resistance. Results showed that the increase in the critical shear stress of the silty sand with only 0.6% lignosulfonate treatment was equivalent to that with around 2.5% cement treatment. However, the stabilisation of the dispersive clay with 0.6% cement was more effective …
Analysis Of Radial Vacuum-Assisted Consolidation Using 3d Finite Element Method, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Analysis Of Radial Vacuum-Assisted Consolidation Using 3d Finite Element Method, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Buddhima Indraratna
In this study, a 3D numerical modelling of a single vertical drains consolidation incorporating vacuum preloading considering both vertical and horizontal drainage is presented. The effects of nonlinear soil compressibility, varying permeability and vacuum pressure distribution along the drain are examined through the dissipation of average excess pore pressure and associated settlement. A selected case history, using 3D finite element method, is employed to analyse two embankments constructed at the Second Bangkok International Airport, Thailand stabilised with prefabricated vertical drains and vacuum preloading. The behaviour of this embankment including settlements and excess pore pressures is then compared with the numerical …
Recent Advancements In The Use Of Prefabricated Vertical Drains In Soft Soils., Buddhima Indraratna
Recent Advancements In The Use Of Prefabricated Vertical Drains In Soft Soils., Buddhima Indraratna
Buddhima Indraratna
A system of prefabricated vertical drains with surcharge load to accelerate consolidation by shortening the drainage path is one of the most popular methods of soft ground improvement. An analytical solution is proposed based on radial (lateral) soil permeability while considering variations in vacuum pressure. The predicted smear zone and effects of drain unsaturation are compared with laboratory data obtained from large-scale radial consolidation tests. When a higher load is required to meet the desired rate of settlement and the cost of raising a surcharge embankment is also significant, the application of vacuum pressure with a reduced surcharge load can …
Enhanced Criterion For Base Soil Retention In Embankment Dam Filters, Buddhima Indraratna, A. K. Raut
Enhanced Criterion For Base Soil Retention In Embankment Dam Filters, Buddhima Indraratna, A. K. Raut
Buddhima Indraratna
In effective filters, potentially erodible base particles are transported to the filter and retained to form a stable self-filtration layer. At any given time, the mass proportion of the filter and the base materials in this layer depends on the initial porosity of the filter and the subsequent porosity of the self-filtration layer. In this paper, an analytical procedure is given to obtain the particle size distribution (PSD) of the self-filtration layer by combining the PSDs of the filter and the base soil modified by Dc95, where 95% of filter constrictions are finer than the size denoted by Dc95. The …
Effectiveness Of Vertical Drains In Dissipating Excess Pore Pressures Induced By Cyclic Loads In Clays, A. Attya, Buddhima Indraratna, Cholachat Rujikiatkamjorn
Effectiveness Of Vertical Drains In Dissipating Excess Pore Pressures Induced By Cyclic Loads In Clays, A. Attya, Buddhima Indraratna, Cholachat Rujikiatkamjorn
Buddhima Indraratna
The purpose of this paper is to investigate the effectiveness of Prefabricated Vertical Drains (PVDs) in dissipating the excess pore water pressures induced by cyclic loading in soft clays. Cyclic triaxial testing on soft clay samples with vertical drains has been carried out using a large scale cyclic triaxial apparatus designed and built at the University of Wollongong. The samples used were 300 mm in diameter and 600 mm in height. The samples were anisotropically consolidated under ko condition to simulate the in-situ stress history of the field. Stress-controlled cycles were then applied to the soil samples with different loading …
Effect Of Confining Pressure On Ballast Degradation And Deformation Under Cyclic Triaxial Loading, J. Lackenby, Buddhima Indraratna, G. Mcdowell, D. Christie
Effect Of Confining Pressure On Ballast Degradation And Deformation Under Cyclic Triaxial Loading, J. Lackenby, Buddhima Indraratna, G. Mcdowell, D. Christie
Buddhima Indraratna
Traditional railway foundations or substructures have become increasingly overloaded in recent years, owing to the introduction of faster and heavier trains. A lack of substructure re-engineering has resulted in maintenance cycles becoming more frequent and increasingly expensive. Two significant problems arising from increasing axle loads are differential track settlement and ballast degradation. One potential method of enhancing the substructure is to manipulate the level of ballast confinement. To investigate this possibility, a series of high-frequency cyclic triaxial tests has been conducted to examine the effects of confining pressure and deviator stress magnitude on ballast deformation (permanent and resilient) and degradation. …