final year projects for students starting semester 2 … · 6. at the start of 1. st. semester, a...
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THE UNIVERSITY OF WESTERN AUSTRALIA
SCHOOL OF CIVIL AND RESOURCE ENGINEERING
FINAL YEAR PROJECTS FOR STUDENTS STARTING SEMESTER 2 2013
1. Attached is a list of projects that are being offered by staff members in the School, the Centre for Offshore Foundation Systems (COFS) and the Australian Centre for Geomechanics (ACG). Students may propose other topics (for example with an external company or government agency), in consultation with any staff member.
2. It is essential that each student shall have agreed on a topic with a supervisor and have submitted the title on a Project Allocation Form to the Head of School by Friday 16th August 2013.
3. Each Project unit will have a 12 point weighting out of about 48 points for the year. Since this is a unit equivalent to a quarter of the total year’s work, each student is expected to devote at least the equivalent amount of time to the project throughout the whole year. You cannot expect to get a high grade in your Project unless you put the appropriate effort (and time commitment) into this unit.
4. Each project will be broad enough to be completed at a high enough level that can justify the award of Honours. Project reports (theses) will be graded on a continuous scale. At the end of the year, the performance in the Project, combined with the performance in the coursework component over the four years of the degree will be used to assign results on a continuous scale, from 1st Class Honours, through 2A and 2B Honours, to Pass. Students should refer to the Final Year Handbook for details.
5. Students are encouraged to choose projects that are consistent with their goals for employment and the general thrust of their choice of other options in final year. The Head of School, or other supervisors, should be consulted about the wisdom of the choice being made, particularly with regard to appropriateness of the choice in relation to the other final year options chosen.
6. At the start of 1st semester, a Project Booklet, giving details of various aspects of the projects, will be distributed. Briefly, the assessable components of the project are:
• progress report, submitted during 1st semester;
• a short summary paper submitted prior to the “Final Year Project Symposium”, held in 2nd semester;
• an oral presentation of your project made at the above Symposium in front of fellow students, staff, and industry representatives; and
• the final Project Report (Thesis), submitted at the end of 2nd semester.
Winthrop Professor Andy Fourie
Head of School
List of Supervisors and Projects (Updated 28th May 2013)
Hongwei An: Supervisor/Research Associate (4 Projects) .................................................... 1
Dr. Kaiming Bi: Supervisor (5 Projects) ................................................................................... 2
Asst/Prof Nathalie Boukpeti: Supervisor (2 Projects) ............................................................ 3
Professor Antonio Carraro: Supervisor (4 Projects) ............................................................... 4
Winthrop Professor Liang Cheng: Supervisor (1 Project) ..................................................... 6
Assistant Professor Daniela Cianccio: Supervisor (1 Project) .............................................. 7
Asst. Prof. James Doherty: Supervisor (6 Projects) ............................................................... 8
Professor Richard Durham: Supervisor ..................................................................................... 9
Professor Arcady Dyskin: Supervisor (8 Projects) ................................................................ 10
Winthrop Professor Andy Fourie: Supervisor (11 Projects) ................................................ 14
Winthrop Professor Hong Hao: Supervisor: (8 Projects) ..................................................... 17
Associate Professor Shazzad Hossain: Supervisor (2 Projects) ......................................... 20
Professor Yuxia Hu: Supervisor (3 Projects) .......................................................................... 22
Assoc/Prof Ali Karrech: Supervisor (4 Projects) .................................................................... 23
Asst. Prof. Mehrdad Kimiaei: Supervisor (2 Projects) .......................................................... 24
Winthrop Professor Barry Lehane: Supervisor ...................................................................... 25
Professor Guowei Ma: Supervisor (5 Projects) ...................................................................... 26
Dr. Yinghui Tian: Supervisor (1 Project) ................................................................................ 27
Professor David White: Supervisor (4 Projects) .................................................................... 28
Professor Tongming Zhou: Supervisor (3 Projects) ............................................................. 29
Hongwei An: Supervisor/Research Associate (4 Projects)
1. Numerical simulations about a circular cylinder subject to ramping-up currents.
In this study the force components and vortex shedding frequency of a pipe exposed to a ramping-up flow will be investigated numerically in terms of the drag coefficient, lift coefficient and Strouhal number. The effects of these mentioned parameters, particularly their influence on vortex shedding conditions will be studied.
2. Local scour around submerged caisson type of structures.
This project aims to determine the maximum equilibrium scour depth and the location of the maximum scour depth for caisson dimensions. The tests will determine how the scour is influence by the combination of scour and waves, it will also investigate how the caisson dimensions and flow attack angle influence the scour profile. The tests will be conducted in the Large O-tube Facility.
3. Local scour around a truncated pile group.
This project aims to determine the maximum equilibrium scour depth and the location of the maximum scour depth for various pile arrangements. The tests will determine how the scour is influence by the combination of scour and waves, it will also investigate how the gap to pile diameter ratio influences the scour for a single configuration of the waves to current ratio. The tests will be conducted in the Large O-tube Facility.
4. Experimental investigation about pressure distribution in a horseshoe vortex around a cylinder-wall junction.
A horseshoe vortex exists at a cylinder-plane junction due to the boundary layer induced pressure gradient on the cylinder surface. In this project, pressure sensors will be installed on the cylinder surface to measure pressure distribution in the horseshoe vortex. The pressure information will be used to calculated force on the cylinder. The testing results will improve the understanding about horseshoe vortex and its effect on aerodynamic force. The tests will be conducted in the wind tunnel.
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Dr. Kaiming Bi: Supervisor (5 Projects)
1. Progressive collapse of multi-span simply supported bridge structures
Hongqi Bridge was a multi-span simply-supported bridge in Zhuzhou, China. It collapsed during the mechanical demolish of the bridge in May 2009. It is a typical Domino type progressive collapse. This study tends to carry out numerical simulation of the accident by using finite element code LS-DYNA.
2. Seismic analysis and assessment of a skew highway bridge
Foothill Boulevard Undercrossing suffered serious damage during the 1971 San Fernando earthquake. This study tends to carry out numerical simulation of the seismic responses of this bridge by using finite element code Seismostruct. Various parameters will be discussed.
3. Numerical simulation of abutment excitation on bridge pounding
Bridge damage due to pounding at joints of girders and abutments has been observed in many major earthquakes. However, most of previous studies rarely considered the influence of abutment excitation. This paper tends to carried out numerical simulation of abutment excitation on bridge pounding by using LS-DYNA.
4. Effect of CFRP on the bridge column seismic retrofitting
Carbon Fiber Reinforced Plastic (CFRP) is usually used in the seismic retrofitting of bridge columns. This study tends to investigate the effect of CFRP on the bridge column seismic retrofitting. The finite element code LS-DYNA will be used and various parameters will be discussed.
5. Analytical investigation on Novel Friction Hinge Restrainers for Mitigating Pounding and Unseating Damages on Highway bridges
This study proposes using Rotational Friction Hinge Restrainers to mitigate the joint opening and pounding between the adjacent structures. The objective of this research is to conduct numerical analyses on the effectiveness of the device subjected to the uniform and non-uniform ground motions through extensive parametrical analysis. Finite element code Seismostruct will be used.
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Asst/Prof Nathalie Boukpeti: Supervisor (2 Projects) [email protected]
1. Cyclic behaviour of offshore sediments
This project aims at exploring modelling approaches to represent strain accumulation and volumetric tendency in offshore sediments subjected to cyclic loading. Existing constitutive models will be reviewed, and available data from previous testing campaigns conducted in the Soils Laboratory will be analysed, with the aim of identifying key aspects of cyclic behaviour of sediments from offshore Australia. Suitable models will be tested and refined through a series of tests in the laboratory (e.g., cyclic triaxial tests, cyclic simple shear tests).
Co-Supervisor: W/Prof Barry Lehane
2. Influence of Sample Disturbance on Intermediate Soils Characterisation
The assessment of sample disturbance of soil specimens is critical for determining whether parameters obtained in the laboratory are suitable for a particular design to meet the required level of safety. Disturbance of soil during sampling may result in parameters that lead to excessive deformation or possibly failure of infrastructure in operation. Disturbance is often assessed using criteria based on the reconsolidation to in-situ stresses and analysis of the stress-strain behaviour during shearing/loading. For assessment of disturbance through reconsolidation behaviour, criteria developed for soft onshore clays are often used, irrespective of the soil type.
Offshore Australia, fine grained soils are often much coarser than soft onshore clays and are composed of radically different particles. These soils may not behave in a fully undrained manner during sampling and are susceptible to particle breakage. The applicability of current sample disturbance criteria to these types of soils is not clear at present. This project will examine through well controlled laboratory tests (e.g. triaxial tests), the effect of different degrees of damage on the reconsolidation and shearing behaviour of intermediate soils from offshore Australia. The project aim is to show the effects of sample disturbance on the soil behaviour and examine different methods that may be used to assess the degree of disturbance in practice.
Co-Supervisor: Professor Antonio Carraro
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Professor Antonio Carraro: Supervisor (4 Projects) [email protected]
1. Particle breakage of a soil with crushable grains in one-dimensional compression
Geomaterials with relatively weak grains may not be properly modelled using classical constitutive relationships relying upon friction and dilatancy only. Examples of such materials include (but are not limited to) some types of offshore sediments, railway track foundations and weathered mine waste rock used to construct tailings dams. Thus, while it may not be well understood, the phenomenon of particle breakage impacts both offshore and onshore geotechnical analyses and adds a challenging component to otherwise conventional geotechnical designs. In this final year thesis project, the student will conduct exciting research and become knowledgeable on the poorly understood but critical effect of particle breakage on the one dimensional compression response of a crushable geomaterial. The well-known effects of factors such as stress and density on geomaterial behaviour will be systematically assessed using a modern consolidometer apparatus as well as how these factors might impact the (unknown) amount of particle breakage during one-dimensional compression.
Co-Supervisor: Research Assistant Prof. Nathalie Boukpeti
2. Critical-state strength degradation of a crushable geomaterial Critical-state strength is a classical yet rigorous feature of the mechanical behaviour of geomaterials. The critical-state friction angle, perhaps a more practical representative of critical-state strength, is accordingly a widely used parameter required in modern geotechnical analyses. While critical states would theoretically define a unique relationship between density and stress for a given soil, the concept might not be directly applicable to geomaterials undergoing a substantial amount of particle breakage upon shearing. Such materials are relatively common in foundation layers for offshore structures, railways or as the main constituent of embankment tailings dams. In this final year thesis project, the student will carry out exciting research and become knowledgeable on the relatively poorly understood effect of particle breakage on this important design parameter (i.e., critical state friction angle) that is commonly required by consulting geotechnical engineers in both offshore and onshore projects. Due to its convenience in assessing strength characteristics at very large strains, a ring shear apparatus will be employed in this study to systematically characterize the amount of particle breakage induced to a soil with relatively weak grains.
Co-Supervisor: Research Assistant Prof. Nathalie Boukpeti
3. Boundary conditions imposed by simple shear tests Various types of simple shear devices are used in geotechnical practice leading to testing procedures and boundary conditions that are not necessarily consistent across the spectrum of devices available. This can have a profound impact on any geotechnical design or analysis that relies on results from simple shear tests. In turn, analysis of simple shear test results requires careful examination (and understanding) of the exact boundary conditions imposed by any of the existing testing protocols available. The purpose of this final year project is to conduct a rigorous analysis of simple shear test results and corresponding boundary conditions imposed by various types of simple shear testing protocols commonly used in practice. Results will be interpreted using a rigorous mechanistic framework and will assist with the design of the new generation of simple shear apparatus that is currently underway at UWA.
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4. Effect of partial drainage on intermediate soil behaviour
The mechanical behaviour of intermediate soils is particularly affected by strain/ loading rate, as the actual behaviour of such soils may not be categorised into typical drainage boundary conditions (drained or undrained) in a very straightforward way. The purpose of this final year project is to contribute to the state-of-the-art on intermediate soil behaviour by unlocking the fundamental mechanisms and processes that lead to the development of partial drainage conditions in intermediate soils. The study will involve a combination of high-quality element testing procedures and analyses to assess the influence of factors such as strain rate, fabric, density and stress on soil response.
Co-Supervisor: Research Assistant Prof. Shiaouhuey Chow
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CEEDS
Winthrop Professor Liang Cheng: Supervisor (1 Project) [email protected]
1. 3D CFD investigation of UWA large O-tube facility
The objective of this project is to undertake 3D CFD modelling of the test section of the UWA large O-tube facility to improve understanding of flow behaviour around the model pipe. Of particular interest are:
• Hydrodynamic forces on the model pipe, especially variation on the forces along the model pipe and benchmarking against published and LOT experimental test results for standard flow conditions;
• Flow non- uniformity through the LOT test section, especially the presence of any systematic flow features such as longitudinal vortices;
• Mapping of seabed shear stresses around the pipe looking for non- uniformity.
Motivation: UWA has undertaken a number of phases of research testing in the recently developed Large O-Tube Facility based at UWA's Shenton Park campus. The results show in some instances that the hydrodynamic forces measured on the mid-pipe bracelet of pressure transduces differ noticeably to published industry models. In order to improve understanding of the causes of these differences, numerical modeling of the LOT test section is proposed.
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Assistant Professor Daniela Cianccio: Supervisor (1 Project) [email protected]
Suitable for Bachelor and Master students
1. Investigation of erodibility of rammed earth flooring systems
Project co-supervised by
Project description: the student will investigate the erosion rate and other material properties of cement-stabilised and traditional rammed earth slabs. The results of the experimental study will be used in a real project supervised by architect Adam Lusby for the construction of the floor of two pavilions in Mandurah.
Co-Supervisor: Architect Adam Lusby
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Asst. Prof. James Doherty: Supervisor (6 Projects) [email protected]
1. Soil Parameter Selection using Numerical Optimisation
This project will explore the use of mathematical optimisation techniques to calibrate soil constitutive models based on the stress-strain/load-displacement response measured from both laboratory and in-situ tests, including triaxial, pressuremeter and foundation load tests. Finite element models representing each test will used to generate model data. This data is then compared with measured tests data. Direct search methods are then employed to change the constitutive model parameters between specified upper and lower bounds, in order to minimise the difference. The project will involve programming in MATLAB, as well as using Abaqus finite element software.
2. Development and Documentation of a MATLAB Finite Element Library
A “Library” of MATLAB functions is being developed to perform non-linear finite element analysis for geotechnical problem. Students should have a strong interest in programming and numerical methods.
3. Effective Stress versus Total stress analysis of undrained problems in geotechnical engineering (excavations)
Several different options are available for modelling undrained behaviour in finite element analysis. If they are not properly understood, results may be grossly incorrect, leading to catastrophic collapse. This was highlighted by the recent collapse of a major excavation in Singapore. The aim of this project is to simulate undrained excavations in several different ways, compare the results and make recommendations regarding the suitability of each approach.
4. Effective Stress versus Total stress analysis of undrained problems in geotechnical engineering (offshore foundations)
Several different options are available for modelling undrained behaviour in finite element analysis. If they are not properly understood, results may be grossly incorrect, leading to catastrophic collapse. This was highlighted by the recent collapse of a major excavation in Singapore. The aim of this project is to simulate undrained loading of offshore foundations in several different ways, compare the results and make recommendations regarding the suitability of each approach.
5. Three dimensional finite element analysis of the simple shear test
This project will involve a finite element study of the UWA and Cambridge type simple shear test, carried out using the Abaqus finite element software. The results will be used to show the strengths and limitations of the simple shear test and determine which design performs best and how the test results should be interpreted.
6. Testing and interpretation of the UWA centrifuge scale pressuremeter
A miniature soil pressuremeter has recently been developed at UWA for use in the geotechnical centrifuge. This project will involve conducting tests with the device in a pressure chamber and interpreting the results of the tests using conventional cavity expansion theory as well as back analysis using finite element software packages.
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Professor Richard Durham: Supervisor [email protected]
Professor Richard Durham has reached his quota and will be unable to supervise any more students for Semester 2.
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Professor Arcady Dyskin: Supervisor (8 Projects) [email protected]
1. Modelling vibrations and energy dissipation in interlocking structures (with Prof. Elena Pasternak)
A very important property in buildings and foundations is the ability of structural members to dump vibrations and attenuate noise. This property has a number of applications, from noise reduction (both industrial and domestic) to seismic-proof construction. The principle of interlocking offers new opportunities to design structures with very efficient vibration and noise reduction since preliminary experiments have revealed considerable vibration damping and sound absorption (up to 95% on a specific frequency).
The project aims at investigating the vibrations in a one-dimensional interlocking structure. The structure is modelled as an assembly of rigid blocks whose interfaces are represented by springs with different stiffnesses in tension and compression. The energy dissipation is controlled by the coefficient of viscous friction and the coefficient of restitution. The project comprises numerical modelling using Matlab and the analysis of results.
2. Investigation of pattern formation in granular materials (experimental) (with Prof. Elena Pasternak)
The abundance of granular materials (sand, aggregates, fragmented rock, etc.) used in Civil Engineering warrants comprehensive investigation of mechanics of their deformation and failure. It is well known that large deformation starts with the formation of shear bands and with the subsequent deformation and failure concentrating along the bands. What our recent research has shown that in the process of deformation the shear bands appear then disappear and reappear again. It was observed that smaller scale patterns could be formed in between the instances of the shear band generation.
The aim of the project is to investigate the shear band formation and patterning in a 2D physical model of granular material as a function of inter-grain friction and grain size distribution. The project involves experimentation using the apparatus built in the course of a last year final year project.
3. Mechanism of post-peak softening in concrete and rock (computer simulation) Post-peak softening – stress reduction with increasing strain after the peak load (strength) is passed – is a very important characteristic of brittle materials such as concrete, masonry and many types of rock and cemented soil which controls the long term survival of the structures. While being routinely measured in the lab and refereed to, the mechanism of post-peck softening is still far from being understood. Furthermore, there is evidence that the post-peak softening depends upon subtle details of the loading frame, in particular its ability to prevent or otherwise the rotation of the loading platens.
The project is aimed at investigating the mechanism of post peak softening and the effect of axial and rotational stiffnesses of the loading frame. The analysis will be based on the fibre model whereby the sample is represented as a set of many parallel elastic fibres with randomly assigned strength, while the loading frame is modelled as two rigid blocks connected by a link with given axial and rotational stiffnesses. The project involves computer simulation of subsequent breakage of the fibres as the blocks are pulled apart with a constant rate.
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4. Methods of stress determination in rocks (2 projects) (with Prof. Phil Dight))
Rocks at depth are subjected to high in-situ stress produced by the weight of overburden and tectonic movement. This stress is the main cause of rock falls in mining industry and borehole breakouts in petroleum industry. Stress also effects petroleum production and flooding of excavations. Currently there are a number of methods used in stress measurements. The following projects will look into some of from.
4.1 Hollow inclusion cell method
The stress determination using this method is based on the interpretation of strain measurements utilising a model of rock deformation. Conventionally, the method assumes that the rock is isotropic, i.e. its response to loading is the same in all directions. However, rocks are rarely isotropic. Moreover, in some cases the elastic module can vary more than 10 times when the loading direction changes. The aim of this project is to conduct computer simulation to analyse the effect of rock anisotropy on the accuracy of stress determination with the Hollow inclusion cell method and, if necessary, modify the method. The project will use computer simulation using a Finite Element or Boundary Element package.
4.2 Rock memory methods
The information of the stress distribution in rock man is often limited due to the restricted access to the places of stress measurement and due to high cost of the existing methods of in situ stress determination. Recently, a new approach to stress measurements emerged based on the rock stress memory effect. The man advantage of the method is that it can use the abundance of the rock cores left form the exploration boreholes and potentially having the memory of the stresses they were subjected at the time of extraction.
Currently, there exist two methods of stress Measurements based on rock memory: the acoustic emission method (Kaiser effect method) and the Deformation Rate Analysis (DRA). The aim of this experimental project is to calibrate these methods using samples of rock or rock-type materials subjected to known stress and develop recommendations for the stress measurements based on the combined use of these methods. In the course of the project the student will master the techniques of rock testing, acoustic emission measurements and wave velocity determination.
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5. Scale effect in determination of rock deformability (Numerical) (with Prof. Phil Dight))
In situ rock deformability is currently measured by testing rock samples. Rock in the rock mass can be anisotropic with difference in deformability in different directions reaching 2-3 times. In this case one needs to test a lot of samples cut out in a number of different directions. The only economically viable technology currently available is sub-sampling of a core. This method however produces samples of relatively small sizes, which leads to very high variability of the deformability measurements and, subsequently, the necessity to test large numbers of samples. This translates into high cost associated with this stage of the rock mass characterisation. The aim of the project is to investigate a mechanism of variability in deformation measurements in anisotropic foliated rock and quantify it. The project will consist of finite element modelling of layered and foliated rocks and simulating subsampling in different directions. It is anticipated that a new sequential method of subsampling will be designed whereby the location and orientation of the next sub sample is determined on the basis of the results of the testing of previous subsamples.
6. Utilisation of pressure sensitive mixtures in remote stress measurements (Numerical) (with Prof. Elena Pasternak)
It has recently been found that liquids and jellies filled with hollow plastic microspheres can considerably alter the velocities of wave propagation even for minute concentrations of spheres. As the wave velocities can be measured remotely, this effect calls for applications in distant stress measurements, especially in Mining and Petroleum Industries. The aim of the project is to study the effect further and investigate a potential for utilising it for stress measurements. The project consists of modelling and conceptual parts.
The computer modelling part involves calculating the wave velocity reduction with pressure for mixtures of different concentrations of spheres.
The conceptual part will review the existing methods of in-situ stress and wave velocity measurements, investigate the ways the mixtures can be injected in the ground and develop recommendations for the use of the proposed techniques for the stress determination.
7. Wedge Failure in Open Pits (Numerical, with Prof. P. Dight)
Sliding of wedges in open pits can be assisted or in some cases triggered by external vibrations. The vibrations are regularly produced by production blasting and by seismic events (e.g. earthquakes, rock bursts in adjacent excavations) when they occur. It is hypothesised that the mechanism of this form of slope instability is in temporary friction reduction caused by high amplitude vibrations, mostly when the system wedge-rock mass is in resonance. The aim of this project is to check this hypothesis. To this end a simple model of the contact vibration under applied pressure will be developed using Matlab or any suitable computer language. This will be used to gain initial insight before a move complex Finial Element Model of a rock slope with wedges is set up. The stability of the wedges will be checked under applied vibrations of different frequencies. Different types of wedge/slope interfaces will have to be tried. A computer package ABAQUS will be used for the final element modelling.
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8. Simulations of frictional sliding in granular materials (with Prof. Elena Pasternak)
Granular materials such as sand, some soils and rock debris are often used as construction material. They also form foundations and fault gouge. Plastic deformation of granular material is usually localised over slip lines where sliding is characterised by friction. In order to ensure efficient performance of this type of structural materials as well as to be able to predict failure accurate models are required. Currently, the modelling is based on the assumption that the grains are spherical. The real grains are not. Furthermore, it has been recently discovered that a non-spherical grain produces a specific shape effect that is akin to negative friction. The aim of the project is to study a collective behaviour of grains of non-spherical shape and their effect on frictional sliding. The project involves Monte-Carlo style computer modelling using Matlab or a similar computer language.
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Winthrop Professor Andy Fourie: Supervisor (11 Projects)
1. Electrokinetic strengthening of soft clays
It is now well established that the undrained shear strength of soft clays can be increased through the process of electrokinetic dewatering. The process through which the strength increases is not well understood, as the strength gain is greater than that due to a reduction in water content alone. Some form of particle alteration appears to be taking place. This project will investigate the effect of electrokinetic dewatering on the development of an apparent preconsolidation pressure, an effect that renders the soft clay extremely stiff, even though it has not undergone a preconsolidation process. Based on the conclusions from a study completed in 2009, the laboratory test will be modified to utilise a switching system based on maintaining a constant current, rather than on water level. The project will also require some scanning electron microscopy work to establish the nature of the changes to the particle structure that explain the observed pseudo-preconsolidation pressure.
2. Liquefaction of silt-sand mixtures
In order to test the susceptibility of various silt-sand mixtures, such as mine tailings, it is necessary to carry out laboratory tests, such as triaxial and shear box tests. There is a difficulty in preparing samples for testing at the required void ratio; in order to produce the required contractive behaviour, samples must be prepared as loose as possible. These low densities cannot be achieved using conventional techniques. This project will investigate the potential improvements obtained by sedimenting into ‘dirty’ water. By adding very small quantities of clay such as kaolinite or bentonite, it appears to be possible to produce looser specimens. This will be the focus of the project, and once a suitable technique has been developed, shear strength testing on these specimens will be carried out.
3. Changes to geotechnical properties of clays and silts due to addition of flocculants
Some industries, such as mine tailings management and dredge spoil management, are experimenting with the addition of synthetic flocculants to these materials. The objective is to accelerate the rate of consolidation and strength gain of these materials, which start out as dilute slurry suspensions. However, there is very little information available on the resulting geotechnical properties such as compressibility and shear strength. Various blends of either tailings or dredge spoil will be mixed with varying proportions of a polymeric flocculant, then consolidated to a small effective stress value before transferring the samples to shear boxes for testing. Tests will be carried out on unflocculated samples, to provide a comparison with the flocculated behaviour.
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4. Planning for backfilling of open pits: getting the right balance between fine and coarse particles.
The addition of relatively small amounts of fine grained material, such as clay, to a sandy soil can dramatically change the geotechnical characteristics. This is important when scheduling backfilling of open pits, as is done in many mineral sands operations. The project will investigate changes in compressibility of a sand due to incremental changes in fines content. The nature of the fines will be varied, and include kaolin clay and mica. Careful testing will be required to determine a transition void ratio, should it exist, as well as whether the consolidation lines eventually converge. All these issues are important for mine planning purposes. Modelling of the results will be carried out using discrete element software.
5. Changes in shear strength of sand in the presence of saline water
There is some evidence in the literature that salty water changes the shear strength of certain soils. While this is especially apparent for clays, the effect on sands is more contentious. This project will include shear strength tests on various silty sand mixtures that have been prepared with different concentrations of salty water. Hypersaline water from the Goldfields will be used in the study. Shear tests will include saturated samples, as well as tests on partially saturated specimens. Depending on the results, some samples will be evaluated using SEM techniques to help explain differences in behaviour that are observed. The results will be of particular interest to designers of tailings storage facilities, particularly those in WA, where hypersaline groundwater is common.
6. Changes in sensitivity of soils due to breakdown of flocculants
Polymeric flocculants are often added to soils to accelerate consolidation and water release. Very little is known about the changes in behaviour of these soils as the flocculants disintegrate with time. There is the potential for significant changes in shear strength if a loose, sensitive structure is produced by the flocculants. The project will test both fresh (recently flocculated) soils and those where some degree of aging has occurred, and compare results. Clearly we cannot wait for twenty years to test the effect of aging, so some form of accelerated testing will be required, such as subjecting the flocculated samples to elevated temperatures for a certain time before shearing them. The results could be of critical importance for designers of facilities that are built to retain these materials. If possible, a range of flocculants, such as anionic and cationic, will be tested.
7. Investigation of non-performance of soil suction sensors
An instrument that is used to measure negative pore water pressures (suction) in soil is a ‘gypsum block’. It is relatively inexpensive, and therefore attractive for use in the field. However, recent experience at UWA of their use in underground mine backfill applications has not been satisfactory. One possible explanation is that these instruments change behaviour when subjected to high total stress values, as they are generally installed at shallow depth (they are, for example, used to schedule irrigation activities). The project will develop a suitable testing procedure and then test a range of gypsum blocks at various confining total stresses. It will be necessary to prepare test samples at various degrees of suction and to monitor the gypsum blocks as confining stresses are increased.
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8. Measuring the tensile strength of Cemented Paste Backfill (CPB) and implementation in simple design procedures
Increasing use is being made of CPB in WA underground mines. Sometimes the mining schedule requires that the backfilled stope is undermined. Under these conditions the true tensile strength of the CPB is critically important. Relatively simple tensile tests, such as the Brazilian tensile test and the two-point bending test will be carried out on various blends of CPB, with different initial solids contents. Tests will also be carried out on CPB reinforced with short polymeric fibres, and the possible improvements in tensile strength quantified. The results will be implemented in simple design calculations for undercut backfilled stopes and the potential improvements provided by the reinforcing elements will be quantified.
9. Measuring true stress changes in granular material using smart aggregates
When testing coarse, granular material such as road base or cemented rockfill, it is common to assume the applied stress is carried uniformly across a specimen – the continuum idealisation. However, recent work using the discrete element method has shown that ‘force chains’ develop, where some zones of the material being loaded carry most of the applied load, and other zones carry very little load. This project will investigate the use of ‘smart aggregates’ to measure true loads within aggregates. These smart aggregates are still under development, and this project aims to do initial characterisation of the material, under simple loading conditions, with a minimum number of aggregate pieces. This will require the design of the experimental equipment, which could consist of a simple cylinder in which aggregates can be packed at varying densities.
10. Quantifying The Porosity of Cemented Paste Backfill at Different Curing Time using 3D Synchrotron X-ray Computed Microtomography Technique
Cemented Paste Backfill is a material used to backfill underground mined-out voids (stopes). It is a mixture of tailings, cement and water. The project will analyse sub-micron resolution 3D images of the CPB. The images were obtained from the New Australian Synchrotron Facility. The image datasets consist of CPB samples at different curing time. The images show solids and voids inside the CPB samples. You will use image analysis software including Avizo Fire at Ivec supercomputing facility at UWA to visualize and analyse the porosity evolution at different curing times. A second component of the project will analyse sub-micron resolution 3D images of tailings from different mine site. The datasets consist of dry tailing samples. The images show tailing particles inside the samples. You will again use image analysis software to visualize and analyse micro properties of the tailings.
11. Predicting Strength Properties of Tailings using Discrete Element Method (PFC3D)
Discrete Element Method (DEM) is a relatively new computational method in Geomechanics. It uses a discrete mechanics approach as opposed to continuum mechanics approach (i.e., finite elements). The soils are modelled in particulate geometry such as spheres, ellipsoids, etc. It provides a more realistic approach for modelling soil behaviour. This project will use DEM (using commercial software PFC3D) to simulate triaxial compression tests on mine tailings. Predictions will be compared against laboratory test results (already available) and finite element predictions (to be done as part of this project).
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Winthrop Professor Hong Hao: Supervisor: (8 Projects) [email protected]
1. Numerical simulation of effectiveness of porous blast wall on mitigating blast loads Suitable for postgraduate and undergraduate students)
Blast walls/barriers are commonly used to protect personnel, important structures and facilities. Many types of blast walls exist. These include simple earth berm, sand bag, sand filled defence cell, concrete block gabion, concrete wall, FRP strengthened concrete wall, water-filled blast barrier, sandwich panels, foam wall, and profiled wall, etc. Each of these walls has its own merits and shortcomings. Depending on the strength, ductility and dimension, they have applications in different situations and provide different levels of protections. One thing in common is that all these walls are solid. They are designed with sufficient strength and ductility to resist blast loads and to block and reflect the shock waves for protection of personnel and structure behind the wall. In acoustic area, it has been understood long time ago that presence of obstacles modifies the wave flow field owing to wave reflection, refraction and interaction that generate new waves, vortex and turbulence in which wave energy dissipates. These wave-structure interaction characteristics have been applied in acoustic and optical engineering to dissipate unwanted noise and lights, however, have not been used to design blast walls for effective structure and personnel protections. A recent experimental study of the effectiveness of using porous panel with tapered holes revealed that depending on the porosity, i.e., the open area to the entire area of the panel, the panel could reduce the peak blast pressure behind the panel by 80% and impulse by 30%. In this project, this novel design concept will be explored by performing intensive numerical simulations. Computer code AUTODYN will be used to simulate shock wave propagation and interaction with obstacles of different shape, dimension, and arrangement. The numerical results of peak pressure and impulse in front and behind the obstacles will be compared. The effectiveness of using porous walls as blast barriers will be investigated.
2. Laboratory tests of frame structures installed with non-buckling segmented brace members
Suitable for postgraduate and undergraduate students)
Brace members are usually applied to frame structures to resist earthquake loads. They enhance structural lateral stiffness and provide significant lateral resistance. Under seismic ground excitation, a brace member experiences both tensile and compressive loading. Under compressive force, buckling of brace members often occurs, which makes the brace members ineffective in resisting cyclic seismic loads. Recently an innovative segmented brace member to prevent buckling and to resist seismic ground motions in frame structures has been proposed. A single segmented brace member had been tested in UWA. In this project, a small scaled frame model with the segmented brace members will be fabricated and tested to further examine its capacity in resisting cyclic loading.
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3. Laboratory Tests of Dynamic FRP Material Properties Suitable for postgraduate and undergraduate students)
Intensive studies of static FRP material properties have been conducted by many researchers. Owing to its high tensile strength, light weight and easy in application, FRP is now commonly used to strengthen and retrofit concrete and masonry structures. Various design guides of FRP strengthening of structures to resist static loads have been published. Studies of using FRP strengthening of structures to resist dynamic loads have also been reported. However, because of a lack of testing data, FRP dynamic material properties are not well understood. In studies of FRP strengthening of structures to resist dynamic loads, usually static FRP material properties are used. Since dynamic material properties such as stiffness and strength are usually different from its static counterparts, using FRP static material properties might lead to inaccurate predictions of responses of FRP strengthened structures under dynamic loadings. This project will conduct a comprehensive literature review of commonly used FRP materials and their available static and dynamic properties. Common FRP materials will be selected and tested in laboratory to determine their static and dynamic material properties. Based on testing data, dynamic FRP material models will be developed.
4. Laboratory Tests of Dynamic Material Properties of PVB and SGP Suitable for postgraduate and undergraduate students)
Because of their very high ductility, PVB and SGP are commonly used in laminated glass to prevent glass shattering under dynamic and impact loads. They are commonly used in window and glazing structures that are subjected to possible dynamic and impact loads. A recent project on modeling laminated glass window response to windborne debris impact revealed that in current design practice, usually static PVB and SGP material properties are used because there are very limited numbers of dynamic testing data and no dynamic material model. As dynamic material properties are usually different from their static counterparts, using static material properties in the analysis and design of glass structures under dynamic loading may not lead to accurate assessment of glass structure capacities in resisting dynamic loadings. This project will perform laboratory tests of static and dynamic PVB and SGP material properties. Based on testing data, dynamic material models will be developed for PVB and SGP materials.
5. Numerical Simulation of Structural Panel Response to Windborne Debris Impact Suitable for postgraduate and undergraduate students)
The 2011 version of Australian Wind Loading Code increased the requirement of structural panel capacity to resist windborne debris impact. In particular the debris impact velocity is increased from 15 m/s to 40% of the wind speed, which in extreme situations could be 40 m/s. while this substantial increment imposes challenges in designing new impact resistant panels, the safety of existing panels also needs be evaluated. This project will perform numerical simulations of structural panels under windborne debris impact. Common structural panels used in Australia construction industry will be modeled. Commercial code LS-DYNA will be used in the analysis. Influences of various parameters such as debris impact velocity, impact angle, impact location, debris mass, geometry and dimension, as well as panel material, dimension and boundary condition on panel performance under debris impact will be analyzed.
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6. Static and Dynamic Properties of EPS Foam Materials Used in Sandwich Structural Panels Suitable for postgraduate and undergraduate students)
Insulated structural panels are commonly used in Australia building industry to cope with extreme climate conditions. Usually these panels are made of Extended Poly Stryrene (EPS) core sandwiched between steel or timber boards. They provide certain load carrying capacities, are light weight and have excellent insulation properties. Although some static testing of EPS material properties has been reported, no dynamic EPS material properties can be found in the literature. In practice, usually the performance of a prototype EPS sandwich panel under static and dynamic loadings is tested, instead of testing the material properties of the EPS. This lack of material properties makes numerical modeling and prediction of EPS sandwich panel responses to static and dynamic loads very difficult. This project will perform static and dynamic tests to determine the EPS material properties.
7. Investigation of Efficient Methods to Mix Steel Fibres in Concrete Suitable for postgraduate and undergraduate students)
Concrete material has rather low tensile strength and is very brittle under tensile loading. To increase concrete material tensile strength and ductility, various fibres have been mixed into concrete. Compared to natural and synthetic fibres, steel fibres are found effective in enhancing concrete strength and ductility. However, the ductility enhancement very much depends on the bonding strength between concrete and steel fibres. In fact debonding failure is one of the primary problems that prevent steel fibre reinforced concrete material to achieve its maximum capacity. Despite various forms of fibres having been made, such as the hooked end fibres to increase its anchorage and bonding strength to the concrete matrix, debonding failure still remains one of the primary problems. Recently a spiral shaped fibre has been proposed to increase the anchorage of the fibre with concrete matrix, as well as the deformation capacity of the fibre. It was found that spiral fibre reinforced concrete outperformed other types of fibres reinforced concrete material in terms of strength, toughness, ductility, and crack stopping capacity. However, the main drawback of using spiral fibres is that it is very difficult to distribute and mix them in the concrete matrix. This makes the use of fibres to reinforce concrete material rather expensive, and sometimes prevent the application of fibres in the concrete despite their demonstrated excellent properties. This project will investigate the current methods used to mix fibres, and possibly propose a new mixing method that can be applied in construction practice to efficiently mix spiral and other types of fibres in concrete matrix.
8. Further Laboratory Tests of SFRC Materials with Spiral Fibres of Different Geometries and Dimensions
Suitable for postgraduate and undergraduate students)
Both laboratory tests and numerical simulations have demonstrated that the recently proposed spiral shaped fibres provide better anchorage in the concrete matrix and larger deformation capacity than other types of steel fibres. The spiral fibre reinforced concrete material has higher strength, larger ductility, higher toughness, better impact resistance and better crack stopping capacity than other fibre reinforced concrete. As the performance of fibre reinforced concrete material depends on the fibre dimension, geometry and aspect ratio, to find the optimal spiral fibre configurations, this project will conduct further laboratory tests to investigate the performance of concrete materials reinforced with spiral fibres of different dimensions, geometry and aspect ratio. The test data will be analyzed to identify the best spiral fibre configurations.
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Associate Professor Shazzad Hossain: Supervisor (2 Projects)
1. Bearing behaviour of spudcan foundations on sand-over-sand deposits
Most offshore drilling in shallow to moderate water depths (up to around 150 m) is performed from self-elevating jack-up rigs due to their proven flexibility, mobility and cost-effectiveness. Today’s jack-ups typically consist of three independent truss legs, each attached to a large 10 to 20 m diameter inverted conical footing colloquially known as a spudcan.
Depletion of known reserves in the shallow waters of traditional hydrocarbon regions is resulting in exploration in deeper, unexplored and undeveloped environments. These are exhibiting more complex soil conditions at the seabed. In emerging provinces and fields, highly layered soils are prevalent. For instance, over 75 % of the case study data sets forming the basis for the InSafeJIP involved stratified seabed profiles, with interbedded layers of clay and sand displaying strong variations in shear strength. The Sunda Shelf, offshore Malaysia, Australia’s Bass Strait and North-West Shelf, Gulf of Thailand, South China Sea, offshore India and Arabian Gulf are particularly problematic in terms of stratigraphy and soil types. Layered deposits are also encountered in the Gulf of Mexico. The seabed deposits offshore Australia, Arabian Gulf, South China Sea and (in some regions of) the Gulf of Mexico comprise problematic calcareous sediments, often layered, that range from relatively permeable calcareous sands to fine grained muds, and with varying degrees of intergranular cementation.
In this project, a series of tests will be undertaken at 1g to investigate the bearing behaviour of conventional and skirted spudcans in loose sand-over-dense sand and the reverse. Both commercially available silica sand and calcareous sand dredged directly from Australian seabed will be used. Finally, a series of tests will be conducted on three-layer deposits including a mud layer (of kaolin clay) above silica sand-over-sand deposits and a mud layer (of calcareous silt/clay) above calcareous sand-over-sand sediments.
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2. A new technique to reconstitute crust layers for model testing in layered sediments
(Co-supervisors: Associate Professor Conleth O’Loughlin and Professor Christophe Gaudin)
Depletion of known reserves in the shallow waters of traditional hydrocarbon regions is resulting in exploration in deeper, unexplored and undeveloped environments. These are exhibiting more complex soil conditions at the seabed. In emerging provinces and fields, highly layered soils are prevalent. For instance, over 75 % of the case study data sets forming the basis for the InSafeJIP involved stratified seabed profiles, with interbedded layers of clay and sand displaying strong variations in shear strength. The Sunda Shelf, offshore Malaysia, Australia’s Bass Strait and North-West Shelf, Gulf of Thailand, South China Sea, offshore India and Arabian Gulf are particularly problematic in terms of stratigraphy and soil types. Layered deposits are also encountered in the Gulf of Mexico. The seabed deposits offshore Australia, Arabian Gulf, South China Sea and (in some regions of) the Gulf of Mexico comprise problematic calcareous sediments, often layered, that range from relatively permeable calcareous sands to fine grained muds, and with varying degrees of intergranular cementation.
This project focuses on a new technique for reconstituting a crust layer for model testing on layered deposits. The technique will primarily be used in model testing on two-layer sediments with a thin crust layer overlying normally consolidated calcareous silt and Angola clay, reconstituting conditions encountered in some locations of Australia’s North-West Shelf and Offshore Africa. Commercially available Plaster of Paris (PoP) will be mixed in various proportions with silt (or clay) slurry, and will be placed above the deposited silt or clay layer varying the thickness, in an attempt to achieve various strength ratios (between the peak strength in the crust layer and the strength intercept of the underlying silt or clay deposit at the layer interface). A suite of supplemented characterisation test data will be allowed for making a direct comparison, in terms of various characteristics, with those of silt or clay. These will include penetrometer (e.g. T-bar) tests, fall cone tests and (LL, PL, Gs) tests. In addition, and importantly, images through SEM (scanning electron microscope) and XRD (X-ray diffraction) will be captured for both crust layers (of various mixing ratios) and bottom silt and clay layers and will be compared in the context of the relevant effect on the bearing behaviour of a foundation.
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Professor Yuxia Hu: Supervisor (3 Projects) [email protected]
Cone, T-bar and Ball penetrometers are the three commonly used site investigation tools for soil characterisation. Especially in offshore engineering, when cored soil sample for laboratory characterisation becomes more difficult and costly, the in situ testing tools become more attractive. The continuous penetration resistance profiles from the various penetrometers can provide continuous soil strength profiles. This can be more beneficial when layered soil profiles are often encountered in deep water oil/gas field. The following three projects are based on numerical analysis using Large Deformation Finite Element (LDFE) analysis with Remeshing and Interpolation Technique with Small Strain model (RITSS). The LDFE/RITSS has been developed and coded at UWA.
1. LDFE analysis of cone penetrometer into sand over clay soils
2. LDFE analysis of T-bar penetrometer into sand over clay soils
3. LDFE analysis of ball penetrometer into sand over clay soils
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Assoc/Prof Ali Karrech: Supervisor (4 Projects) [email protected]
Professor Karrech is keen to supervise mining engineering students, who have interesting ideas that they would like assistance in developing.
1. Instabilities due to mine water discharge and flooding
Description of the project:
Dewatering and flooding of mines can alter the stress states within the crust and cause significant instabilities. Worldwide studies show that human-induced activities can cause pre-existing faults reactivation and trigger earthquakes with seismic moment magnitude of up to 7 on the Richter scale. The purpose of this project is to study the mechanisms of instability triggering based on numerical approaches.
Profile of the candidate: A final year Mining (or Civil) Engineering student
2. Fault reactivation in geo-materials
Description of the project: The purpose of this project is to study faults reactivation within resource reservoirs. Based on existing approaches of continuum damage mechanics, computational geo-mechanics and homogenisation, this project aims at studying hydraulic damage nucleation and propagation.
Profile of the candidate: A final year Civil Engineering student
3. Seismic events due to coupled multi-physics processes
Description of the project: Effective stresses within geological porous media are dependent on pore pressures, temperature, and other state variables. Perturbations of those state variables can produce instabilities, which are undesirable for economical and environmental reasons. In particular, perturbations due to industrial activities, which require fluid injection and/or extraction such as geothermal energy harnessing, induce systematic change in effective stresses. The purpose of this project is study particular scenarios of instabilities’ triggering due to geo-infiltration in natural reservoirs.
Profile of the candidate: A final year Civil Engineering student
4. Chemical damage of civil engineering structures due to weathering conditions
Description of the project: Durability of construction materials is often sensitive to the environment in which they evolve. Within salty and humid regions, those materials can exhibit accelerated degradation, which jeopardise their strength. Chemical damage is one of the possible causes of such behaviour. The purpose of this project is to investigate the effect of weathering on construction materials. A literature review on crystallisation in porous media will be conducted and a simple micro-mechanical model will be developed to enlighten the complex underpinning processes.
Profile of the candidate: A final year Civil Engineering student
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Asst. Prof. Mehrdad Kimiaei: Supervisor (2 Projects) [email protected]
1. Dynamic response and fatigue design of steel catenary risers in the touch down area
Steel Catenary Risers (SCRs) are one of the most popular and cost effective types of risers for development of offshore fields in shallow to medium water depths. There are many engineering challenges for design of SCRs but their fatigue design in the touch down area (TDA) has always been among the major design challenges.
The riser-seabed interaction in the TDA is highly nonlinear because of the nonlinear behaviour of the soil and the random nature of cyclic motion of the riser too. Traditional design approaches, based on linear solutions to these nonlinear problems, usually lead to very conservative fatigue design of SCRs.
Main objective of this numerical research is to get a better understanding of dynamic response and fatigue design of SCRs at TDA. This study will be in continuation of the previous studies carried out at COFS on fatigue design of SCRs. In a series of sensitivity studies, using Orcaflex software, effects of main input parameters (environmental loading, soil behaviour, etc) which will influence fatigue life the system will be investigated.
This project will suit both bachelor and master students who are interested in deep water offshore engineering concepts and strong backgrounds in analysis of structural systems. Knowledge of fatigue analysis is a bonus, but not essential.
2. Nonlinear dynamic analysis of offshore platforms under randomly generated waves
Wave loads are usually the most important environmental loads that should be taken into account for structural design of offshore platforms. Regular wave theories are used widely for estimation of wave loads on offshore platforms but waves are irregular and random in shape and in height by nature.
Dynamic analysis of offshore platforms under irregular random waves can provide the most accurate results for the platform responses under wave loads but it needs excessive computational efforts. Constrained NewWave is a new approach for generation of random waves that allows for robust evaluation of the response statistics.
In this study nonlinear dynamic response of offshore platforms, using USFOS software, under extreme waves will be investigated. Previous works carried out at COFS on dynamic pushover analysis of offshore platforms using deterministic or probabilistic waves will be continued in this study. Main objective of this numerical study is to get a better understanding of ultimate strength of offshore platforms under randomly generated waves.
This project will suit bachelor students with interests in offshore structural engineering concepts and strong backgrounds in analysis of structural systems. Knowledge of nonlinear structural analysis is a bonus, but not essential.
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Winthrop Professor Barry Lehane: Supervisor [email protected]
Professor Barry Lehane has reached his quota and will be unable to supervise any more students for Semester 2.
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Professor Guowei Ma: Supervisor (5 Projects) [email protected]
1. Fluid flow in discrete fracture networks (Suitable for undergraduate and postgraduate students)
Fluid flow in discontinuous fractured rock mass is an important issue in underground engineering. The objective of this project is to simulate and find out the outstanding pathways of fluid in fracture networks. A computational model will be created by considering the fracture connectivity and conductivity. Different geological models will be used based on statistical data from site survey.
2. Underground oil and gas storage in rock cavern and related scientific issues (Suitable for undergraduate and postgraduate students)
Oil and gas can be stored underground by different means. Conventional methods for underground oil and gas storage include the uses of aquifers, depleted reservoirs in oil and gas field and in rock salt caverns. The objective of the present project is to investigate the major scientific issues related to underground oil and gas storage, especially on the leakage control including permeability control and hydrodynamic containment. Environmental impact and cost in constructing and maintenance of the storage cravens will be preliminarily assessed.
3. Fragmentation analysis of window glass under blast load (Suitable for undergraduate and postgraduate students)
Glass is a typical brittle material and vulnerable to impact and blast loads. The present project aims to simulate glass failure under blast load. Fragmentation of window glass will be simulated by using LS-DYNA. Parametric analysis of glass failure with respect to stand-off distance, window size and glass properties will be carried out. This project is joined with Prof Hong Hao.
4. Vulnerability mapping of hazards and economic loss assessment of offshore oil and gas platforms subject to accidental explosion and fires (Suitable for undergraduate and postgraduate students)
The aims of this proposal are to assess the impact of explosion and fires on offshore oil and gas fixed platforms; to evaluate explosion induced offshore platform damage by using advanced analytical and numerical modelling; to generate a set of vulnerability maps suitable for typical offshore platforms with equipment layouts, by consideration of explosion occurrence probabilities at different platform parts; and to carry out economic loss assessment in terms of structural engineering, social and environmental aspects.
5. Simulation of natural gas decompression in high pressure pipelines
Decompression of natural gas through the crack opening or the open end of the pipeline may cause high stress, thus, the catastrophic rupture of the pipeline. Numerical simulation of fluid-structure interaction to derive the decompression curve against internal high pipeline pressure and the pipeline structural configuration will cast light on the optimization of the structural configuration and the pipeline pressure. CFD/Abaqus will be applied to carry out the numerical simulation. The objectivity of the respective failure criteria will be discussed. The burst test in open literature will be modeled as a benchmark for the numerical modeling and simulation procedure.
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Dr. Yinghui Tian: Supervisor (1 Project)
1. Study on the plate anchor
With the depletion of oil and gas reservoir, offshore engineering is going into deep water, where the
traditional fixed platforms are no longer suitable. One principal challenge for offshore oil and gas
development in deep water is to seek an efficient and economic foundation type to moor the floating
facilities. Plate Anchors, increasingly utilised in recent years, are proven to be a promising deep
water anchoring solution. This project will carry out numerical study of plate anchor in clay to
investigate the failure mechanism and optimise the anchor design.
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Professor David White: Supervisor (4 Projects) [email protected]
1. Pipeline integrity in cold regions
Three projects are available under this broad heading. The overarching aim is to develop improved methods to assess the integrity of pipelines buried on the seabed in cold regions, where icebergs are found. Icebergs create scour tracks across the sea floor, and can damage pipelines that are laid on the seabed or buried within a trench. The three projects involve (i) holistic assessment of ice-pipeline interaction risks, using a probabilistic risk-based approach, (ii) theoretical analysis of ice-pipeline interaction by developing theoretical solutions for the seabed deformation caused by an iceberg keel and (iii) physical modelling in UWA’s lab, to investigate the soil deformation mechanisms beneath a pipeline, to validate theoretical solutions. Projects are available in each of these three areas, and will involve interaction with the oil and gas firm Shell.
2. Friction on hot pipelines
The friction between a pipeline and the seabed provides stability against axial movements caused by slopes or thermal expansions. However, the surface temperature of a pipeline can rise significantly, due to the heat of the contents. This heat transfer into the surrounding soil may raise the local pore water pressure and reduce the available friction. A physical modelling setup has been developed at UWA to examine thermo-mechanical coupling around pipelines. This project will use the apparatus to examine whether this effect should be considered in pipeline design, as a potentially-overlooked source of unconservatism.
3. Suction anchor performance in the Gulf of Mexico
This project will use field records of suction anchor performance to investigate the variation of capacity with time. Through an industry partner, Shell, we have access to field records from the installation and extraction of suction anchors used to moor mobile offshore drilling units (MODUs). During your project you will collate a database of the available field records, and interpret them to determine the soil resistance on the suction anchor during each installation and extraction. Back-analysis of these records will provide insight into time-dependent ‘set-up’ effects such as consolidation. The overall aim is to provide more reliable predictions of suction anchor performance, both for short term applications such as MODUs and also for long-term mooring of floating production units.
4. The hemiball penetrometer
This project will explore the performance of a new type of penetrometer for characterisation of the seabed. A previous project has developed a prototype version of the hemiball penetrometer, which is designed to measure the engineering properties of the shallowest ∼3m of the seabed, which is relevant for pipeline design. This project will involve tests in the UWA labs using the prototype hemiball, to mimic use of the tool in the field. The aim is to demonstrate the relative performance of the hemiball compared to other methods of seabed characterisation.
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Professor Tongming Zhou: Supervisor (3 Projects) [email protected]
1. Suppression of vortex-induced vibration of a pipeline using porous shroud (2 students)
Vortex shedding is a phenomenon which occurs when a flow passes a bluff body (e.g. a single or a group of tall chimneys, tall buildings, marine risers for oil production, mooring lines, deepwater structures such as the pipelines). It is well known in the offshore community that the cylindrical bluff structures suffer from vortex-induced vibration (VIV) in strong current conditions. The marine risers, for example, also induce the flow around them to separate and initiate vortex shedding. These vortices cause extra dynamic forces and vibration to the risers. VIV should be avoided in engineering applications. This is because: (1) VIV will increase the fluid dynamic loading to the structures, (2) it will also influence the stability of the structures, (3) the vibration of the structures will accelerate the fatigue failure etc. The above factors will influence both the capital investment of the structures and the expenses for maintenance. Therefore, great effort has been devoted to the control of vortex shedding from a bluff body, both using active methods and passive methods.
In the present project, vortex shedding will be suppressed using a porous shroud. The objective of the project is to examine the effectiveness and mechanism of porous shroud on VIV suppression. The experiments will be conducted in the wind tunnel of School of Civil and Resource Engineering of UWA.
2. Suppression of vortex from a wavy cylinder (1 student) Vortex shedding is a phenomenon which occurs when a flow passes a bluff body (e.g. a single or a group of tall chimneys, tall buildings, marine risers for oil production, mooring lines, deepwater structures such as the pipelines). It is well known in the offshore community that the cylindrical bluff structures suffer from vortex-induced vibration (VIV) in strong current conditions. The marine risers, for example, induce the flow around them to separate and initiate vortex shedding. These vortices cause extra dynamic forces and vibration to the risers. VIV should be avoided in engineering applications.
In the present project, vortex shedding will be suppressed using a wavy cylinder. The objective of the project is to examine the effectiveness and mechanism of wavy cylinder on vortex shedding suppression. The experiments will be conducted in the wind tunnel of School of Mechanical Engineering of UWA.
3. Hydrodynamic forces on an inclined bluff body in oscillatory flows (2 students) For the design of offshore structures, it is important to evaluate the hydrodynamic forces on the structures in waves and steady current. In many engineering applications, the structures are not necessarily perpendicular to the incoming flow, and yet the flow structures and vortex shedding characteristics of the inclined cylinder wakes are not studied extensively.
In the present project, experiments will be conducted in an oscillatory flow to study the hydrodynamic forces on the structures at different inclination angles, KC numbers and Reynolds numbers. Dependents of the drag coefficients, vortex shedding frequency and Strouhal number on Reynolds number and inclination angles will be examined and compared with that obtained in wakes of cross-flows. The experiments will be conducted in the towing tank in the Hydraulics Lab of UWA.
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