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Faculty of Engineering - Papers (Archive)

Soil

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Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn Jan 2012

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

Faculty of Engineering - Papers (Archive)

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 …


Permeable Reactive Barrier (Prb) Technology For The Remediation Of Acidic Groundwater From Acid Sulphate Soil Floodplain In South East New South Wales, L J. Banasiak, B Indraratna, A. Golab Jan 2012

Permeable Reactive Barrier (Prb) Technology For The Remediation Of Acidic Groundwater From Acid Sulphate Soil Floodplain In South East New South Wales, L J. Banasiak, B Indraratna, A. Golab

Faculty of Engineering - Papers (Archive)

The release of acidic water contaminated with toxic metals such as aluminium (Al) and iron (Fe) resulting from pyrite oxidation within acid sulphate soils (ASSs) is a major environmental issue in Australia. Groundwater manipulation using weirs and modified floodgates is not effective in low-lying floodplains due to the high risk of flooding and their inability to prevent pyrite oxidation. Permeable reactive barrier (PRB) technology has been looked at as an alternative remediation technique in ASS terrain. Batch and short-term column tests were used to choose a suitable reactive material for the remediation of acidic water and the removal of Al …


Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna Jan 2012

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

Faculty of Engineering - Papers (Archive)

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 …


Characterising Compacted Soil Using Shear Wave Velocity And Matric Suction, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn Jan 2012

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

Faculty of Engineering - Papers (Archive)

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 …


Key Strategies For Managing Acid Sulphate Soil (Ass) Problems On The Southeastern Coast Of New South Wales, Australia, L J. Banasiak, B Indraratna Jan 2012

Key Strategies For Managing Acid Sulphate Soil (Ass) Problems On The Southeastern Coast Of New South Wales, Australia, L J. Banasiak, B Indraratna

Faculty of Engineering - Papers (Archive)

The acidification of Australian coastal waterways as a result of the oxidation of acid sulphate soil (ASS) containing appreciable quantities of sulphidic material (e.g. pyrite) has well recognised environmental, economic and social effects including the loss of fish, biodiversity and agricultural productivity as well as the corrosion of concrete and steel infrastructure by acidic drainage. Largescale artificial drainage and one-way floodgates in low-lying coastal floodplains has lowered the groundwater table, thus enhancing pyritic oxidation and increasing the distribution, magnitude and frequency of acid generation and release of toxic metals such as aluminium (Al3+) and iron (total Fe) from ASS. Engineering …


The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn Jan 2012

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

Faculty of Engineering - Papers (Archive)

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 …


Permeable Reactive Barrier (Prb) Technology: An Innovative Solution For The Remediation Of Acidic Groundwater From Acid Sulphate Soil (Ass) Terrain, Laura Banasiak, Buddhima Indraratna Jan 2012

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

Faculty of Engineering - Papers (Archive)

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 …


Introduction To The Sydney Soil Model, Martin D. Liu, John P. Carter, David W. Airey Jan 2012

Introduction To The Sydney Soil Model, Martin D. Liu, John P. Carter, David W. Airey

Faculty of Engineering - Papers (Archive)

In this paper a new constitutive model recently suggested by the authors, referred to as the Sydney Soil model, is introduced. The Sydney Soil Model is formulated within the framework of Critical State Soil Mechanics and is suitable for describing the behaviour of structured soils including both clays and sands. In the proposed model, the mechanical behaviour of soil is divided into two parts, that at a reference state and that attributed to the influence of soil structure. The reference state behaviour is formulated according to the soil properties at the critical state of deformation, based on the concept of …


Use Of The Soil Modulus For Compaction Control Of Compacted Soils, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn Jan 2012

Use Of The Soil Modulus For Compaction Control Of Compacted Soils, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering - Papers (Archive)

Insufficient compaction conditions can cause significant roadway infrastructure maintenance costs. Conventional compaction control, using nuclear methods, is based on the discrete in situ determination of the dry density and moisture content. Recently, there has been an increase interest in alternative methods for compaction control using intelligent compaction technologies. This method enables the continuous measurement of the soil modulus and the degree of compaction on the layer that is being compacted. Thus, the efficiency of the compaction process can be maximized. Although the adoption of this method is very promising, it constitutes a change of project specification for the contractors (i.e. …


Consolidation Behavior Of Soil-Cement Column Improved Ground, Suksun Horpibulsuk, Avirut Chinkulkitniwat, Arnon Cholphatsorn, Jirayut Suebsuk, Martin D. Liu Jan 2012

Consolidation Behavior Of Soil-Cement Column Improved Ground, Suksun Horpibulsuk, Avirut Chinkulkitniwat, Arnon Cholphatsorn, Jirayut Suebsuk, Martin D. Liu

Faculty of Engineering - Papers (Archive)

Columnar inclusion is one of the effective and widely used methods for improving the engineering properties of soft clay ground. This article investigates the consolidation behavior of composite soft clay ground using both physical model tests under an axial-symmetry condition and finite element simulations using the PLAXIS 2D program. It was determined that the final settlement and the rate of consolidation of the composite ground depended on the stress state. For an applied stress that is much lower than the failure stress, the final settlement of the composite ground was lower, and the consolidation was rapid. When the soil–cement column …


Geo-Environmental Approaches For The Remediation Of Acid Sulphate Soil In Low-Lying Floodplains, Buddhima Indraratna, Gyanendra Regmi, Long Nghiem, Alexandra N. Golab Jan 2011

Geo-Environmental Approaches For The Remediation Of Acid Sulphate Soil In Low-Lying Floodplains, Buddhima Indraratna, Gyanendra Regmi, Long Nghiem, Alexandra N. Golab

Faculty of Engineering - Papers (Archive)

Acidity generated from the oxidation of pyrite and other sulphidic compounds that exist at shallow depths in acid sulphate soils (ASS) presents a challenging environmental problem in coastal Australia. The generated acidic groundwater can adversely impact coastal ecosystems, aquaculture and agriculture. Groundwater manipulation using weirs and modified floodgates in creeks and flood mitigation drains in ASS-affected farmland, which has been practiced for over a decade for preventing pyrite oxidation, is not effective in low-lying floodplains due to the high risk of flooding. In this paper, the authors present an overview of their experience in coastal Australia, a critical evaluation of …


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 Jan 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

Faculty of Engineering - Papers (Archive)

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. …


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

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

Faculty of Engineering - Papers (Archive)

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 …


Cyclic Behaviour Of Soft Soil Subgrade Improved By Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jing Ni Jan 2011

Cyclic Behaviour Of Soft Soil Subgrade Improved By Prefabricated Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jing Ni

Faculty of Engineering - Papers (Archive)

The behaviour of saturated soft clays subjected to cyclic loading is of considerable importance in the design of railway subgrades. Soft clays can be extensively found in many coastal regions of Australia up to significant depths, including the coastal belt and the central part of NSW. These soft clay deposits are characterised by very low bearing capacity and excessive settlement. The increase in generated excess pore pressures due to heavy freight trains significantly reduces the bearing capacity and causes serious damage to the rail infrastructure such as clay pumping underneath railway tracks and excessive subsidence. The use of prefabricated vertical …


Seismic History Analysis Of Asymmetrical Adjacent Buildings With Soil-Structure Interaction Consideration, Mehmet Uz, Muhammad N. S Hadi Jan 2011

Seismic History Analysis Of Asymmetrical Adjacent Buildings With Soil-Structure Interaction Consideration, Mehmet Uz, Muhammad N. S Hadi

Faculty of Engineering - Papers (Archive)

The seismic response history analysis of multi-storey asymmetric adjacent buildings with soil-structure interaction (SSI) during impact is investigated in this study. The coupled multi-degree of freedom modal differential equations of motion for the two way asymmetric shear buildings are derived and solved using a step by step solution by the fourth-order Runge-Kutta method with impact and without impact. The SSI forces are modelled in the form of the frequencyindependent soil springs and dashpots. A numerical example of two-way asymmetric four-storey adjacent buildings under the variation of the important SSI system parameters such as the large and small SSI effects is …


Flac3d Analysis On Soil Moving Through Piles, E H. Ghee, W D. Guo Jan 2011

Flac3d Analysis On Soil Moving Through Piles, E H. Ghee, W D. Guo

Faculty of Engineering - Papers (Archive)

Piles may be utilized as deep foundations or employed to support offshore structures, which may be subjected to passive loading due to lateral soil movements. The safety of the piled foundations depends on the additional stresses induced. This issue has been investigated recently by conducting model tests on single piles and on pile groups with a new apparatus developed by the authors. Typical test results were analysed and reported previously. In this paper three-dimensional finite difference analyses are reported: (1) to predict the results of two model tests (with and without axial load); and (2) to investigate the effect of …


Nonlinear Analysis For A Single Vertical Drain Including The Effects Of Preloading Considering The Compressibility And Permeability Of The Soil, Buddhima Indraratna, Xueyu Geng, Cholachat Rujikiatkamjorn Jan 2010

Nonlinear Analysis For A Single Vertical Drain Including The Effects Of Preloading Considering The Compressibility And Permeability Of The Soil, Buddhima Indraratna, Xueyu Geng, Cholachat Rujikiatkamjorn

Faculty of Engineering - Papers (Archive)

In this paper, the free strain radial consolidation theory incorporating the changes of compressibility and permeability of the soil with the change in effective stress via time dependent surcharge preloading is presented. In contrast to the conventional analysis, the current study highlights the nonlinear characteristics of the soil during the consolidation process. A comparison of the nonlinear radial consolidation model, with the conventional theory and the equal strain theory i.e. constant volume compressibility, mv and constant coefficient of horizontal permeability, kh is presented. Finally, a case history at Muar coastal plain, Malaysia is analysed on the basis of the current …


Recent Advances In The Application Of Vertical Drains And Vacuum Preloading In Soft Soil Stabilisation, Buddhima Indraratna Jan 2010

Recent Advances In The Application Of Vertical Drains And Vacuum Preloading In Soft Soil Stabilisation, Buddhima Indraratna

Faculty of Engineering - Papers (Archive)

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 all 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. Pre-construction consolidation of soft soils through the application of a surcharge load alone often takes too long, apart from which, the load required …


Performance Of A Prb For The Remediation Of Acidic Groundwater In Acid Sulfate Soil Terrain, Buddhima Indraratna, Gyanendra Regmi, Long Nghiem, A. Golab Jan 2010

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

Faculty of Engineering - Papers (Archive)

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 …


Detection Of Biochar Components For Soil Fertility Using Thz-Tds, E M. Pogson, J Horvat, Roger A. Lewis, S D. Joseph Jan 2010

Detection Of Biochar Components For Soil Fertility Using Thz-Tds, E M. Pogson, J Horvat, Roger A. Lewis, S D. Joseph

Faculty of Engineering - Papers (Archive)

Different forms of biochar can have greatly different properties as fertilisers, yet there is no effective screening method to distinguish them. Terahertz Time Domain Spectroscopy has been used to distinguish various biochars, including Sawdust char, BMC5 with lime char and Saligna char.


Stabilization Of An Erodible Soil Using A Chemical Admixtures, Buddhima Indraratna, M.A.A Mahamud, J S. Vinod, Vasantha Wijeyakulasuriya Jan 2010

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

Faculty of Engineering - Papers (Archive)

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 …


Scrap-Tyre Soil Mixture For Seismic Protection, M S. Mashiri, M Neaz Sheikh, J S. Vinod, Hing Ho Tsang Jan 2010

Scrap-Tyre Soil Mixture For Seismic Protection, M S. Mashiri, M Neaz Sheikh, J S. Vinod, Hing Ho Tsang

Faculty of Engineering - Papers (Archive)

Scrap tyre stockpile has been a significant disposal problem around the world. Significant research attention has been devoted in recent years to find new beneficial ways to recycle and reuse the huge stockpile. This paper proposes a new method of utilizing scrap tyres for infrastructure protection. The method involves mixing scrap tyres with soil materials and placing the mixtures around foundations for vibration absorption. This method provides two major benefits: (i) the low-cost would make it accessible to developing countries and rural areas of developed countries where resources and technology are not adequate for earthquake mitigation with welldeveloped, expensive, techniques …


Effective Remediation Of Groundwater In Acid Sulphate Soil Terrain, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem Jan 2009

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

Faculty of Engineering - Papers (Archive)

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 …


Long-Term Performance Of A Permeable Reactive Barrier In Acid Sulphate Soil Terrain, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem Jan 2009

Long-Term Performance Of A Permeable Reactive Barrier In Acid Sulphate Soil Terrain, Gyanendra Regmi, Buddhima Indraratna, Long Nghiem

Faculty of Engineering - Papers (Archive)

Deep drainage technique utilised for flood mitigation in low-land coastal areas of Australia during the late 1960s has resulted in the generation of sulphuric acid in soil by the oxidation of pyritic materials. Further degradation of the subsurface environment with widespread contamination of the underlying soil and groundwater presents a major and challenging environmental issue in acid sulphate soil (ASS) terrains. Although several ASS remediation techniques recently implemented in the floodplain of Southeast Australia including operation of gates, tidal buffering and lime injections could significantly control the pyrite oxidation, they could not improve the long-term water quality. More recently, permeable …


Protecting Low-To-Medium-Rise Buildings By Scrap Tyre-Soil Mixtures, Hing Ho Tsang, Nelson Lam, Saman Yaghmaei-Sabegh, M Neaz Sheikh, Wei Xiong, Shou-Ping Shang Jan 2009

Protecting Low-To-Medium-Rise Buildings By Scrap Tyre-Soil Mixtures, Hing Ho Tsang, Nelson Lam, Saman Yaghmaei-Sabegh, M Neaz Sheikh, Wei Xiong, Shou-Ping Shang

Faculty of Engineering - Papers (Archive)

The stockpiling of scrap tyres is a significant threat to our environment and has been a hot topic amongst the engineering community which has been looking for long term viable solutions to the recycling and reuse of rubber. This paper proposes a new method of utilizing scrap tyres for applications in infrastructure protection forming part of the solution strategy. The method involves mixing scrap tyres with soil materials and placing the mixtures around building foundations, for vibration absorption. The potential of the proposed method will be demonstrated by numerical modelling to show its effectiveness and robustness as a means of …


Consolidation Analysis Of A Stratified Soil With Vertical And Horizontal Drainage Using The Spectral Method, Rohan Walker, Buddhima Indraratna Jan 2009

Consolidation Analysis Of A Stratified Soil With Vertical And Horizontal Drainage Using The Spectral Method, Rohan Walker, Buddhima Indraratna

Faculty of Engineering - Papers (Archive)

A novel use of the spectral method to determine excess pore water pressure during vertical consolidation of multi-layered soil with time constant material properties is presented, considering a unit cell with combined vertical and radial drainage. Equal strain conditions are assumed in the analysis. The novel adoption of material properties that vary in a linear fashion with depth allows arbitrary distributions of properties to be modelled. By incorporating surcharge and vacuum loading that vary with both depth and time, a wide range of consolidation problems can be analysed. The spectral method is a meshless approach producing a series solution to …


Finite Element Simulation Of Mandrel Penetration In A Normally Consolidated Soil, Cholachat Rujikiatkamjorn, Ali Ghandeharioon, Buddhima Indraratna Jan 2008

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

Faculty of Engineering - Papers (Archive)

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 …


Non-Linear Consolidation Of Soil With Vertical And Horizontal Drainage Under Time-Dependent Loading, Xueyu Geng Jan 2008

Non-Linear Consolidation Of Soil With Vertical And Horizontal Drainage Under Time-Dependent Loading, Xueyu Geng

Faculty of Engineering - Papers (Archive)

This paper presents a nonlinear theory for sand drain consolidation of clayey soils under time dependent loading. The solution is obtained using the method of separation of variables. Using the solutions obtained, some diagrams are prepared and the relevant consolidation behavior of soil with vertical and horizontal drainage under time-loadings is discussed. For nonlinear material properties, average degree of consolidation can be defined either in terms of settlement or in terms of effective stress. And consolidation will be slower when compared to the cases with constant material properties. And the difference depends on the external loading pressure N, and the …


Qushion: Earthquake Protection By Rubber-Soil Mixtures, Hing H. Tsang, M Neaz Sheikh, S H. Lo, Nelson Lam Jan 2008

Qushion: Earthquake Protection By Rubber-Soil Mixtures, Hing H. Tsang, M Neaz Sheikh, S H. Lo, Nelson Lam

Faculty of Engineering - Papers (Archive)

This paper presents a promising earthquake protection method by placing rubber-soil mixtures (RSM) around the foundation of structures for absorbing seismic energy and exerting a function similar to that of an earthQuake cUSHION, named hereafter as "QUSHION". The validity of the method has been demonstrated by numerical simulations. A parametric study was carried out to evaluate the effectiveness and robustness of this method. The use of scrap tires as the rubber material can provide an alternative way of consuming huge stockpiles of scrap tires from all over the world. Moreover, the low cost of this proposed seismic isolation methods can …


Effects Of Vertical Heterogeneity Of Soil Sediments On Seismic Soil Response, Srikanth Venkatesan, M Neaz Sheikh, Hing Ho Tsang, Nelson Lam Jan 2007

Effects Of Vertical Heterogeneity Of Soil Sediments On Seismic Soil Response, Srikanth Venkatesan, M Neaz Sheikh, Hing Ho Tsang, Nelson Lam

Faculty of Engineering - Papers (Archive)

Site effects are resulted from the non-linear filtering mechanisms within the soil sedimentary layers overlying bedrock. In contemporary design codes, site effects are taken into account by introducing different site factors for different site classes. The prescribed site classification systems are based on averaging shear wave velocity in the soil sediments. However, significant amplification of the seismic displacement demand may be developed from mechanisms which can result in resonance behaviour. In such situations, soil amplification cannot be determined accurately by considering the average shear wave velocity of the sediments alone. The effects of vertical heterogeneity in the soil sediments have …