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Selected Works

2011

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The Behaviour Of Ballasted Track Foundations: Track Drainage And Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Nayoma Chulani Tennakoon Dec 2011

The Behaviour Of Ballasted Track Foundations: Track Drainage And Geosynthetic Reinforcement, Buddhima Indraratna, Sanjay Nimbalkar, Nayoma Chulani Tennakoon

Buddhima Indraratna

Ballasted Rail tracks are widely used throughout the world due to its resiliency to the repeated wheel loads, low construction cost and ease of maintenance. However, the ballast layer needs periodic maintenance due to its deformation and degradation associated with particle breakage and fouling. A proper understanding of the contamination due to various types of fines and its implications on track drainage is a pre-requisite for effective implementation of track maintenance operations. A new parameter Void Contaminant Index (VCI) can accurately assess the contamination as it includes the effect of void ratio, specific gravity and gradation of ballast and fouling …

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Critical Review On Shear Strength Models For Soil-Infilled Joints, David Oliveira, Buddhima Indraratna, Jan Anton Nemcik Dec 2011

Critical Review On Shear Strength Models For Soil-Infilled Joints, David Oliveira, Buddhima Indraratna, Jan Anton Nemcik

Buddhima Indraratna

An infilled rock joint is likely to be the weakest plane in a rock mass. The presence of infill material within the joint significantly reduces the friction of the discontinuity boundaries (i.e. rock to rock contact of the joint walls). The thicker the infill, the smaller the shear strength of the rock joint. Once the infill reaches a critical thickness, the infill material governs the overall shear strength, and the joint walls (rock) play no significant role. Several models have been proposed to predict the peak shear strength of soil-infilled joints under both constant normal load (CNL) and constant normal …

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Occurrence And Consequences Of Acid Sulphate Soils And Methods Of Site Remediation, Alexandra N. Golab, Buddhima Indraratna Dec 2011

Occurrence And Consequences Of Acid Sulphate Soils And Methods Of Site Remediation, Alexandra N. Golab, Buddhima Indraratna

Buddhima Indraratna

The oxidation of sulphides in acid sulphate soils (ASS) causes the acidification of many Australian coastal river systems. The acidity negatively impacts upon coastal ecosystems, aquaculture, agriculture and concrete and steel infrastructure. In the low-lying floodplains, relatively deep surface drains fitted with one-way floodgates lower the watertable, thereby exposing the sulphidic minerals to oxidation. On the Broughton Creek floodplain in SE Australia, four distinct remediation strategies have been developed to tackle the issue of acidification by ASS: (i) simple V-notch weirs that raise the level of the watertable surrounding the drains thereby submerging the pyrite and preventing the further formation …

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Modeling Of Acid Generation In Pyritic Estuarine Soils, Buddhima Indraratna, Bruce G Blunden Dec 2011

Modeling Of Acid Generation In Pyritic Estuarine Soils, Buddhima Indraratna, Bruce G Blunden

Buddhima Indraratna

The effective management of acid sulfate or pyritic soils is a major issue for many coastal regions in Australia. Drainage and subsequent aeration of potential acid sulfate soils often leads to pyrite oxidation and the acidification of the soil and groundwater. A numerical model has been developed to calculate the rate and magnitude of pyrite oxidation in acid sulfate soils, and the distribution of oxidation products such as H+, SO4 2- and Fe3+ within the soil profile. The pyrite oxidation model includes vertical diffusion of oxygen from the atmosphere through soil macropores, lateral diffusion of dissolved oxygen from the macropores …

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Development Of Sediment-Infilled Rock Joint Models And Implications On Rockmass Stability, Buddhima Indraratna, Wuditha N. Premadasa, David Oliveira, H S. Welideniya Dec 2011

Development Of Sediment-Infilled Rock Joint Models And Implications On Rockmass Stability, Buddhima Indraratna, Wuditha N. Premadasa, David Oliveira, H S. Welideniya

Buddhima Indraratna

Soil-infi lled discontinuities adversely infl uence the stability of rockmass, because, the infi ll materials especially when saturated, drastically reduce the shear strength. The angle of shearing resistance of a discontinuity decreases signifi cantly for increasing infi ll thickness. Once it reaches a critical thickness, the shear strength of the discontinuity will be governed only by the infi ll material and the rock-walls effect becomes negligible. Owing to the lack of research on the shear behavior of infi lled rock joints, it has been common practice to assume that the shear strength of the joint is that of the infi …

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Dem Simulation Of Effect Of Confining Pressure On Ballast Behaviour, P K. Thakur, Buddhima Indraratna, Jayan Sylaja J S Vinod Dec 2011

Dem Simulation Of Effect Of Confining Pressure On Ballast Behaviour, P K. Thakur, Buddhima Indraratna, Jayan Sylaja J S Vinod

Buddhima Indraratna

In this paper, an attempt has been made to investigate the influence of confining pressure on deformation and degradation behaviourof railway ballast using the Discrete Element Method (DEM). A novel approach has been employed to model the two dimensionalprojection of field size ballast particles as cluster of bonded particles. Bonded particles are held together by a bond, and debonding isconsidered as particle breakage. A series of cyclic loading simulations using DEM were carried out on an assembly of angular ballast particles at different confining pressures (10 kPa to 240 kPa). The results highlight that the development of axial strain during …

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State Of The Art Large Scale Testing Of Ballast, Buddhima Indraratna, D J Ionescu Dec 2011

State Of The Art Large Scale Testing Of Ballast, Buddhima Indraratna, D J Ionescu

Buddhima Indraratna

Poor performance of rail roads is often associated with the loss of cross level, track profile and track alignment. The initial as placed condition of ballast and its engineering behaviour govern the stability and the performance of a railway track. The load bearing capacity of ballast and its short and long term degradation characteristics can only be studied using large scale testing equipment, because the conventional geotechnical equipment cannot accommodate the relatively large aggregates. Large-scale testing provides specific geotechnical knowledge on the shear strength and particle degradation of ballast, in relation to the particle size distribution. The influence of principal …

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Modeling Of Bolted Joint Behaviour Under Constant Normal Stiffness Conditions - Laboratory Study, Buddhima Indraratna, Najdat I. Aziz, A Dey Dec 2011

Modeling Of Bolted Joint Behaviour Under Constant Normal Stiffness Conditions - Laboratory Study, Buddhima Indraratna, Najdat I. Aziz, A Dey

Buddhima Indraratna

The shear behaviour of grouted joints has been studied in the recent past using the conventional direct shear apparatus, where the normal load on the joint plane is kept constant during testing. The Constant Normal Stiffness (CNS) condition is adopted in this study of shear behaviour of bolted joints, as the CNS condition represents a better approximation of the deformation behaviour of grouted joints in underground excavations as compared to the conventional Constant Normal Load (CNL) condition. A series of tests were conducted to study the behaviour of these stabilised joints under constant normal stiffness condition at an initial normal …

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Treatment Of Acidic Groundwater In Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, A. Golab, B Guru Prasad Dec 2011

Treatment Of Acidic Groundwater In Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, A. Golab, B Guru Prasad

Buddhima Indraratna

Acidic groundwater generated from pyrite oxidation in acid sulfate (AS) soil is a major geoenvironmental problem in Australia. This study aims to evaluate recycled concrete as a reactive material in permeable reactive barriers (PRBs) for the remediation of acidic groundwater in low-lying AS soil floodplains. Laboratory experiments were systematically conducted to investigate the acid neutralization behavior of recycled concrete and its potential to remove dissolved Al and Fe. The results confirmed that recycled concrete could effectively treat acidic groundwater from an AS soil terrain, resulting in near neutral effluent over a long period with complete removal of Al and Fe. …

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Numerical Prediction Of Vadose Zone Behaviour Influenced By Vegetation, Buddhima Indraratna, Behzad Fatahi, Mohammad Hadi Khabbaz Dec 2011

Numerical Prediction Of Vadose Zone Behaviour Influenced By Vegetation, Buddhima Indraratna, Behzad Fatahi, Mohammad Hadi Khabbaz

Buddhima Indraratna

Bioengineering aspects of native vegetation are currently, and rapidly, being evolved to improve soil stiffness, slope stabilisation, and erosion control. Apart from the reinforcement effect, tree roots establish sufficient matric suction to increase the shear strength and stiffness of the soil. This paper looks at the way, vegetation influences soil matric suction, shrinkage, and ground settlement. A mathematical model for the rate of root water uptake that considers ground conditions, type of vegetation and climatic parameters, has been developed. Based on this proposed model, the distribution of moisture and the matric suction profile adjacent to the tree are numerically analysed. …

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Design Procedure For Vertical Drains Considering A Linear Variation Of Lateral Permeability Within The Smear Zone, Cholachat Rujikiatkamjorn, Buddhima Indraratna Dec 2011

Design Procedure For Vertical Drains Considering A Linear Variation Of Lateral Permeability Within The Smear Zone, Cholachat Rujikiatkamjorn, Buddhima Indraratna

Buddhima Indraratna

A system of vertical drains with surcharge preloading is an effective method for promoting radial drainage and accelerated soil consolidation. This study presents a procedure for the design of vertical drains that significantly extends the previous technique proposed by the authors to include: (i) a linear reduction of lateral permeability in the smear zone, (ii) the effect of overlapping smear zones in a closely spaced drain network, and (iii) the gain in undrained shear strength due to consolidation. Design examples are provided for both single stage and multi-stage embankment construction demonstrating the convenient use of the proposed solutions in practical …

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Modelling Of Soft Ground Consolidation Via Combined Surcharge And Vacuum Preloading, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Ali Ghandeharioon Dec 2011

Modelling Of Soft Ground Consolidation Via Combined Surcharge And Vacuum Preloading, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Ali Ghandeharioon

Buddhima Indraratna

A system of vertical drains combined with vacuum and surcharge preloading is an effective approach for promoting radial flow to accelerate soil consolidation. When a higher load is required to meet the desired rate of settlement and the cost of surcharge is also significant, the application of vacuum pressure with reduced surcharge loading can be used. The equivalent 2-D plane strain solution for multi-drain analysis is described with the inclusion of the effects of vacuum pressure and smear zone caused by mandrel driven vertical drains. A large-scale radial consolidometer is employed to determine the extent of the smear zone and …

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Physical And Chemical Ground Improvement For Sustainable Transportation Infrastructure Under Cyclic Loads, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jayan S. Vinod, Sanjay Nimbalkar Dec 2011

Physical And Chemical Ground Improvement For Sustainable Transportation Infrastructure Under Cyclic Loads, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jayan S. Vinod, Sanjay Nimbalkar

Buddhima Indraratna

Railways form one of the major worldwide transportation networks and they continue to provide quick and safe public and freight transportation. In order to compete with other modes of transportation and to meet the ever growing demand of public and freight transport, railway industries face challenges to improve their efficiency and decrease the costs of maintenance and infrastructure. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly …

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Evaluating Waste Concrete For The Treatment Of Acid Sulphate Soil Groundwater From Coastal Floodplains, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, Laura Banasiak Dec 2011

Evaluating Waste Concrete For The Treatment Of Acid Sulphate Soil Groundwater From Coastal Floodplains, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem, Laura Banasiak

Buddhima Indraratna

The treatment of acidic groundwater generated from acid sulphate soil (ASS) terrain is a challenging environmental issue in coastal floodplains of Australia. In this study, a laboratory column experiment was conducted to assess the performance of waste concrete for treating the acidic groundwater leachate from ASS terrain of the Shoalhaven region of NSW. The groundwater was highly acidic (pH of 2.5–3.5) and contained elevated concentrations of iron (10–90 mg/L) and aluminium (30–45 mg/L). Passage of the acidic groundwater through the column filled with waste concrete resulted in a significant improvement in water quality. Reduction in the concentration of iron and …

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Effect Of Particle Breakage On Cyclic Densification Of Ballast: A Dem Approach, P K. Thakur, Jayan S. Vinod, Buddhima Indraratna Dec 2011

Effect Of Particle Breakage On Cyclic Densification Of Ballast: A Dem Approach, P K. Thakur, Jayan S. Vinod, Buddhima Indraratna

Buddhima Indraratna

In this paper, an attempt has been made to investigate the effect of particle breakage on densification behaviour of ballast under cyclic loading using Discrete Element Method (DEM). Numerical simulations using PFC2D have been carried out on an assembly of angular particles with and without incorporation of particle breakage. Two-dimensional projection of angular ballast particles were simulated using clusters of bonded circular particles. Degradation of the bonds within a cluster was considered to represent particle breakage. Clump logic was used to make the cluster of particles unbreakable. DEM simulation results highlight that the particle breakage has a profound influence on …

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Consolidation Of Ground With Partially Penetrated Pvds Combined With Vacuum Preloading, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn Dec 2011

Consolidation Of Ground With Partially Penetrated Pvds Combined With Vacuum Preloading, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Partially penetrating prefabricated vertical drain (PVDs) with a combined surcharge and vacuum preloading are considered in this paper. The analysis results can be used in cases where the soft soil clay is too deep and not economical to be penetrated to full depth, or the surcharge preloading is too small to justify full penetration of soft clay layer or the vacuum pressure can be lost, which is caused by the permeability of the bottom of the clay for the fully penetrated drain etc.. In this model, a virtual vertical drain is assumed to reflect the real three-dimensional seepage in the …

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Stress Analysis In Failed Roof At A Longwall Face, Jan Anton Nemcik, Ian Porter, Buddhima Indraratna Dec 2011

Stress Analysis In Failed Roof At A Longwall Face, Jan Anton Nemcik, Ian Porter, Buddhima Indraratna

Buddhima Indraratna

This paper presents a conceptual work on roof failure mechanisms at a longwall coal mining face based on a multiple sliding block model. Underground observations of the caved roof strata at the longwall face indicate that many types of fracture exist and that two are dominant. In response to roof convergence close to the goaf, the stratified ground flexes resulting in shear failure along the weak bedding planes that are present in sedimentary strata, while sub-vertical fractures form just ahead of the longwall face in response to the mining induced stress state. . These mining induced fractures usually occur at …

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Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith Dec 2011

Coupled Air-Water Flow Through Fractured Sandstones, Buddhima Indraratna, P Ranjith

Buddhima Indraratna

In two-phase flow within a rock mass, where both air and water phases flow together, the accurate flow measurement of each individual phase is important in numerical analyses. The increased quantity of water phase decreases the relative permeability of the air phase, and vice versa. The relative permeability is important to analyse the risk of groundwater inundation and gas outbursts particularly in underground excavations. Two-phase flow (i.e., water and air) behaviour through naturally and artificially fractured standard rock cores is investigated using the high-pressure triaxial equipment developed by the authors. Findings of this study show that the individual flow rate …

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Analytical Solutions For A Single Vertical Drain With Time-Dependent Vacuum Combined Surcharge Preloading In Membrane And Membraneless Systems, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn Dec 2011

Analytical Solutions For A Single Vertical Drain With Time-Dependent Vacuum Combined Surcharge Preloading In Membrane And Membraneless Systems, Xueyu Geng, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Buddhima Indraratna

Vertical drains combined with vacuum pressure and surcharge preloading are widely used to accelerate the consolidation process of soft clay in order to decrease the pore pressure as well as to increase the effective stress. Currently there are two types of vacuum preloading systems commercially available; (a) membrane system with an airtight membrane over the drainage layer and, (b) membraneless system where a vacuum system is connected to individual drain. Their effectiveness varies from site to site depending on the type of soil treated and the characteristics of the drain-vacuum system. This study presents the analytical solutions of vertical drains …

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Experimental And Numerical Modeling Of Shear Behaviour Of Rock Joints, Buddhima Indraratna, A Haque Dec 2011

Experimental And Numerical Modeling Of Shear Behaviour Of Rock Joints, Buddhima Indraratna, A Haque

Buddhima Indraratna

The shear behaviour of soft rock joints is investigated in laboratory under both Constant Normal Load (CNL) and Constant Normal Stiffness (CNS) conditions. The laboratory behaviour is modelled numerically using the Universal Distinct Element Code (UDEC). The predicted shear stress, normal stress and dilation behaviour with shear displacements are compared with the laboratory results. It is observed that UDEC can predict the peak shear stress of unfilled joints under CNS, however, it overestimates the joint dilation as well as the normal stress. The maximum peak shear stress in UDEC is attained at a greater shear displacement in contrast to the …

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Performance Of A Prb For The Remediation Of Acidic Groundwater In Acid Sulfate Soil Terrain, Buddhima Indraratna, Gyanendra Regmi, Long Nghiem, A. Golab Dec 2011

Performance Of A Prb For The Remediation Of Acidic Groundwater In Acid Sulfate Soil Terrain, Buddhima Indraratna, Gyanendra Regmi, Long Nghiem, A. Golab

Buddhima Indraratna

Contaminated groundwater resulting from pyrite oxidation of acid sulfate soils (ASSs) is a major environmental problem in coastal Australia. A column test was carried out for an extended period with recycled concrete to study the efficiency of the reactive materials for neutralizing acidic groundwater. Results show that the actual acid neutralization capacity of the recycled concrete could decrease to less than 50% of the theoretical value due to armoring effects. Nevertheless, the performance is good as a spot treatment in ASS Terrain using a near-zero cost waste product. Based on the test results and site characterization, a permeable reactive barrier …

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Use Of Geosynthetics In Railways Including Geocomposites And Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar Dec 2011

Use Of Geosynthetics In Railways Including Geocomposites And Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar

Buddhima Indraratna

Australia relies heavily on rail for the transportation of bulk commodities and passenger services, and has introduced faster and heavier trains in recent years due to a growing demand. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly track maintenance works. A proper understanding of load transfer mechanisms and their effects on track deformations are essential prerequisites for minimising maintenance costs. The reinforcement of the track by …

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Effective Remediation Of Groundwater In Acid Sulphate Soil Terrain, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem Dec 2011

Effective Remediation Of Groundwater In Acid Sulphate Soil Terrain, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem

Buddhima Indraratna

Acidic groundwater, generated from acid sulphate soil (ASS) is a major geo-environmental problem in Australia. Manipulation of groundwater through the use of weirs and gates in the nearby creeks and drains of ASS, which is being practised right now for preventing pyrite oxidation, are not effective in low land floodplains due to the risk of flooding. The application of permeable reactive barrier (PRB) can be a novel alternative for remediation of acidic groundwater in such floodplains. Laboratory column experiments were carried out prior to installation of the PRB for examining the efficiency of the material. Results of these experiments have …

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Stabilization Of An Erodible Soil Using A Chemical Admixtures, Buddhima Indraratna, M.A.A Mahamud, J S. Vinod, Vasantha Wijeyakulasuriya Dec 2011

Stabilization Of An Erodible Soil Using A Chemical Admixtures, Buddhima Indraratna, M.A.A Mahamud, J S. Vinod, Vasantha Wijeyakulasuriya

Buddhima Indraratna

This paper presents internal erosion behaviour of an erodible soil stabilized by chemical admixtures using a novel Process Simulation Apparatus for Internal Crack Erosion (PSAICE), designed and built at University of Wollongong. Laboratory tests were carried out on typical erodible soils (collected from Wombeyan caves, Australia) stabilised using chemical admixtures such as lignosulfonate and cement. Test results reveal that the erosion parameters such as critical shear stress and coefficient of soil erosion were improved with the increase in the amount of chemicals. It has been seen that lignosulfonate exhibits better performance in stabilizing the erodible soil compared to cement. Based …

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Ground Improvement/Grouting/Dredging, Buddhima Indraratna Dec 2011

Ground Improvement/Grouting/Dredging, Buddhima Indraratna

Buddhima Indraratna

Due to the rapid increase in population, industrial and construction boom especially in the urban as well as coastal regions of many countries have considerably intensified the inevitable need for infrastructure development on problematic soils including soft compressible clays, deposits with low bearing capacities, soils prone to erosion and collapse upon wetting, highly fractured and jointed rock mass among other geological deposits. Good quality geologic materials for construction are also becoming scarce, exacerbated by numerous environmental constraints in various countries. Due to these reasons and environmental restrictions on certain public works, ground improvement has now become an integrated and essential …

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Deformation And Degradation Mechanics Of Recycled Ballast Stabilised With Geosynthetics, Buddhima Indraratna, Wadud Salim Dec 2011

Deformation And Degradation Mechanics Of Recycled Ballast Stabilised With Geosynthetics, Buddhima Indraratna, Wadud Salim

Buddhima Indraratna

Railway ballast deforms and degrades progressively under heavy train (cyclic) loading. Ballast degradation is influenced by several factors including the amplitude and number of load cycles, density of aggregates, track confining pressure, angularity, and most importantly, the fracture strength of individual grains. The degraded ballast is usually cleaned on track, otherwise fully or partially replaced by fresh ballast, depending on the track settlement and current density. The disposed waste ballast may be cleaned, sieved and re-used in the track. However, due to the breakage of the sharp edges and the development of micro-cracks during the previous loading cycles, recycled ballast …

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Investigation On Effectiveness Of A Prefabricated Vertical Drain During Cyclic Loading, Buddhima Indraratna, Jing Ni, Cholachat Rujikiatkamjorn Dec 2011

Investigation On Effectiveness Of A Prefabricated Vertical Drain During Cyclic Loading, Buddhima Indraratna, Jing Ni, Cholachat Rujikiatkamjorn

Buddhima Indraratna

The effectiveness of prefabricated vertical drains (PVDs) in enhancing the stability of soft soils during cyclic loading was investigated using triaxial cyclic loading tests. Both undrained and with PVD tests were employed to study the associated excess pore pressure and accumulated strain under the repeated loading condition. The loading frequency and cyclic stress ratio have been chosen to be the variables which influence the performance of soft clays. The experimental results illustrate that with PVDs, the excess pore water pressure generation during cyclic loading decreases significantly. It is found that the excess pore water pressure build up depends on both …

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Internal Erosional Behaviour Of Lignosulfonate Treated Dispersive Clay, J S. Vinod, Buddhima Indraratna, M A. A Mahamud Dec 2011

Internal Erosional Behaviour Of Lignosulfonate Treated Dispersive Clay, J S. Vinod, Buddhima Indraratna, M A. A Mahamud

Buddhima Indraratna

Internal erosional behaviour of lignosulfonate treated dispersive clay has been studied using the Process Simulation Apparatus for Internal Crack Erosion (PSAICE) designed and built at UOW. Effectiveness of lignosulfonate treated dispersive clay on the erosion resistance has been investigated and its advantage over traditional admixtures is presented. Test results show that the hydraulic shear stress increases with increase in the amount of lignosulfonate. In addition, the micro-chemical analysis has been carried out using FTIR. Based on the Fourier Transform Infrared (FTIR) Spectroscopy results a stabilization mechanism has been proposed for lignosulfonate treated dispersive soil.

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A Multi-Staged Management Strategy For Restoring Tidal Flushing, William Glamore, Buddhima Indraratna Dec 2011

A Multi-Staged Management Strategy For Restoring Tidal Flushing, William Glamore, Buddhima Indraratna

Buddhima Indraratna

Tidal restoration/wetland rehabilitation projects are being undertallimitations, this paper presents a tidal restoration/floodgate manipulation strategy that was developed from a four-year field study undertaken in southeastern NSW and subsequently applied at multiple field sites. An eight stage methodology is proposed to incorporate water quality, hydraulics, groundwater/saline intrusion, hydrology, field monitoring and flood design criteria. The strategy begins with a quantification of perceived outcomes for the study. Using these goals, the potential improvement in water quality are calculated using ion association models and field sampling techniques. The third stage quantifies the spatial flooding extent using GIS spatial analysis methods. The risks …

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Finite Element Simulation Of Mandrel Penetration In A Normally Consolidated Soil, Cholachat Rujikiatkamjorn, Ali Ghandeharioon, Buddhima Indraratna Dec 2011

Finite Element Simulation Of Mandrel Penetration In A Normally Consolidated Soil, Cholachat Rujikiatkamjorn, Ali Ghandeharioon, Buddhima Indraratna

Buddhima Indraratna

In this paper, a finite element simulation of the mandrel penetration in normally consolidated soils is presented using a commercial finite element code (ABAQUS). A coupled analysis with large-strain frictional contact is used to simulate the soil-mandrel interface during mandrel penetration. The modified Cam clay model is used to represent the soft soil. The numerical predictions are then compared with the results obtained from the large scale laboratory tests to predict the extent of the smear zone. A large scale consolidation test was conducted with the rate-controlled device used to install the mandrel. The associated excess pore pressures at various …

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