the university of western...

THE UNIVERSITY OF WESTERN AUSTRALIA

SCHOOL OF CIVIL AND RESOURCE ENGINEERING

FINAL YEAR PROJECTS 2010 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. By the end of the third week of 1st Semester (by the end of the third week of 2nd Semester if a Mid Year enrolment) it is essential that each student shall have agreed on a topic with a supervisor and have submitted the title to the Head of School.

2. 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.

3. 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.

4. 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.

5. 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: • a 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.

Liang Cheng Head of School 3 March 2010

List of Supervisors

(Updated 30 June 2010)

Liang Cheng 1

Britta Bienen (COFS) 3

Christophe Gaudin (COFS) 4

Dave White (COFS) 6

Hong Hao 7

Yuxia Hu 8

Arcady Dyskin 11

Ming Zhao 19

Andy Fourie 20

Mehrdad Kimiaei (COFS) 22

Hang Thu Vu 24

Richard Durham 25

Tongming Zhou 26

Barry Lehane 28

Chari Pattiaratchi (SESE and UWA Oceans Institute) 29

Greg Ivey 31

Melinda Hodkiewicz 32

School of Civil & Resource Engineering 1

Supervisor: Professor Liang Cheng [email protected]

1. Onset of scour below a partially embedded pipeline When a partially embedded pipeline is subjected to an environmental flow (induced by waves or tidal currents), the flow over the pipeline produces a large pressure difference between the upstream and downstream sides of the pipeline. The pressure difference over the pipeline then induces a seepage flow in the soil underlying the pipeline. The onset condition for scour is considered to occur when the seepage flow pressure gradient at any point on the seabed exceeds the floatation gradient of the soil.

This project aims to investigate onset of scour below a partially embedded pipeline under combined wave and current conditions. An existing numerical model that was developed at UWA will be used to carry out this work. The critical embedment depth for onset of scour under different wave and current combinations will be quantified.

2. Seabed morphology around a partially buried pipeline Subsea pipelines laid directly on erodible seabed are subjected to natural burial through a number of physical processes such as installation stresses and local scour. Burial of pipelines is beneficial for the stability of the pipelines. However pipeline burial depth may undergo significant changes during the passage of a storm event. The burial depth change during a storm affects pipeline stability. Since such changes often occur during storm period, it is very difficult to monitor such changes in-situ.

This project aims to simulate seabed morphology around a partially buried pipeline using a state of art scour package developed at UWA. The effect of initial burial depth on seabed morphology change and hydrodynamic forces will be investigated under a range of flow conditions. It is expected that improved understanding gained through this project will benefit pipeline design practice.

3. Local scour around gravity anchors In recent years, gravity anchors (GAs) have become a preferred option as secondary stabilization of large diameter pipelines installed in Australian waters. Gas are typically arch-shaped concrete blocks. They are often fabricated from pre-cast concrete. GAs are installed astride a pipeline or a pipeline bundle as shown in Figure 1. Typical dimensions of a GA are approximately 3.5 m in depth (along pipeline direction), 6 m in width (perpendicular to pipeline) and 3 m in height. They weigh around 40 to 50 tonnes in air or 25 to 35 tonnes in water. Under normal operating conditions, GAs are separated from the pipeline. GAs are engaged to provide additional resistance to pipeline movements only if the pipeline moves sideways under extreme loading. Pipelines are not designed to carry any load directly or indirectly from GAs.

mailto:[email protected]


The presence of a GA over a pipeline disturbs flow patterns in the immediate neighbourhood of the combined anchor-pipeline system. This leads to an increase in local sediment transport capacity of the flow and consequently scour of sediments around the

GA. Scour can undermine the stability of GAs. Once a gravity anchor losses its stability, it posses significant risk to the safety of the pipeline. For example, the pipeline can be damaged by excessive loading exerted by the weight of the gravity anchor if the gravity anchor settled on to the pipeline. To prevent this from happening, scour protection measures around GAs are almost inevitable. The choice of a different scour protection system around the GA-pipeline system can have significant impacts on the engineering costs of the project.

Figure 1 A Typical GA-Pipeline

The overall objectives of this project are to investigate cost-effective scour protection measures and to develop practical scour protection design guidelines, based on the understanding of scour and flow mechanisms around GA-pipeline systems. Specifically we will

1. carry out physical model tests to investigate the dependence of local scour depths, scour extents and scour rates on various flow and sediment parameters under steady currents , waves and combined waves and currents conditions;

2. Investigate the effectiveness and costs of various scour protection measures for GA-pipeline systems;

The tests will be carried out in the only O-tube facility in the world located at UWA. Two motivated students are required to carry out the project. One student will focus on local scour mechanisms and the other student will investigate cost-effective scour protection measures.


Supervisor: Dr. Britta Bienen

[email protected]

1. Rate effects and set-up during installation of jack-up footings in soft clay

(suitable for BE) Co-supervisors: Christophe Gaudin, Mark Cassidy

The installation of self-elevating jack-up platforms is a load-controlled process. In consequence, the rate of penetration of the rig’s footings varies. For instance, the penetration slows down once full preload is achieved. This additional penetration can be of the order of several meters. Further, installation is rarely a continuous process. Periods of delay allow (partial) consolidation around the footing, which may lead to the risk of rapid leg penetration when the installation process is re-commenced. Depending on the severity of such a ‘leg run’, damage of the platform may occur. This project will investigate these time-dependent effects through experiments in the geotechnical centrifuge. 2. Extraction of jack-up spudcans from soft clay locations (suitable for BE)

Co-supervisors: Christophe Gaudin, Mark Cassidy Jack-up drilling rigs are not custom-designed for a particular location offshore, but move from site to site. Before each rig move, the legs and footings need to be ‘pulled’ from the seabed. In soft clays, the footings penetrate deeply into the soil before adequate bearing capacity is met. This can pose significant difficulties for the leg extraction, as the soil resistance may exceed the uplift capacity that can be provided by the buoyancy of the rig. In this project, strategies for successful leg extraction will be explored through model tests in the geotechnical centrifuge. 3. Comparative numerical study of the push-over capacity of jack-up platforms

with spudcan or caisson footings (suitable for BE) Mobile jack-up drilling rigs typically rest on conical ‘spudcan’ footings. Caisson footings have recently received research attention in the context of offshore wind farm developments. This project investigates the ultimate capacity of a jack-up platform, considering the two foundation options. The numerical program SOS_3D will be used for this project as it allows integrated fluid-structure-soil interaction analysis to be performed.



Supervisor: Prof. Christophe Gaudin

[email protected] 1. Feasibility and performance of an hybrid foundation system for Jack-up rig in

deep water (Experimental)

Co-supervised with Prof. M. Cassidy and Dr B. Bienen

Mobile jack-up rigs play a critical role in developing offshore oil and gas reserves. However, the current shallow foundations and installation procedure limit their operational water depth to 120 m. Pivotal to the use of jack-ups in deeper water is a novel foundation system that self-installs but eliminates the application of large ballast loads during installation. Such a concept is proposed here: The “hybrid” foundation combines suction caissons for preload application with skirted mats to provide stability under the combined loading of offshore storms. This project will address the key geotechnical uncertainties and use innovative physical modelling and analytical methods to develop design tools for engineering application.

Skirted mat

Caisson unit

Jack-up rig

Jack-up leg

The project involves an experimental parametric study in the drum centrifuge to investigate the respective contribution of the skirted mat and suction caisson on the V,H,M capacity of the hybrid foundation. The student will be expected to design the hybrid foundation model, establish the experimental programme, perform the centrifuge tests and report and interpret the results, in order to establish recommendations to optimize the geometry of the hybrid foundation.

2. Improving recovery of manifold foundations (Experimental)

Co-supervised with Prof. M. Cassidy

Manifold foundations are Subsea structures, resting on the seabed and connecting together



flowlines, jumpers, etc. They must be optimised to allow installation and recovery from moderate-sized vessels, while still being able to withstand the significant moment and torsional loading from the variety of connected flowlines, pipelines and jumpers. The project aims to develop strategies for controlled recovery of deep water seabed infrastructure. This is required for maintenance or re-use on other fields.

The project will be mainly experimental, involving centrifuge tests on foundation models. The tests will be investigating the performance of the foundation under various combinations of loading and potential technical solutions to facilitate recovery, by notably reducing the suction developing at the foundation invert.


Supervisor: Dr. David White

[email protected]

1. The interface shear strength of soils at very low effective stresses There will be more than 2000 km of pipeline installed on the seabed offshore Australia in the next 5 years. The axial resistance between the pipeline and the seabed controls the thermal expansion of the pipeline, and its stability against external loads. This is an experimental project aimed at measuring the interface shear strength of soil relevant to low effective stress applications such as pipelines. At very low stresses the friction angle of soil is higher than at the stress levels relevant to conventional geotechnical problems. There is also a transition in behaviour as the response at the interface changes from drained to undrained conditions as the velocity of movement increases. These two simple phenomena are poorly understood, and have not been quantified for soils found offshore Australia. A modified shear box has been fabricated and the project would involve tests using this device and investigating the strength of seabed soils at very low stress levels, beyond the range of previous experience. Measurements of the low-stress strength and the undrained-drained transition will be made, and distilled into a simple model. This model will be input into a simple analysis for the expansion of a pipeline, to illustrate the impact of the observed behaviour. The outcome of this project would be a better understanding of the axial pipe-soil response for Australian offshore soils.



Supervisor: Professor Hong Hao

[email protected]

1. Theoretical and experimental study of the accuracy of engineering strain in dynamic tests

(Suitable for undergraduate student only) Strain is defined as the ratio of deformation in an infinitesimal length of a material. In practice it is obtained by measuring the deformation in a given length of a structure specimen. Under static loading conditions, this approach gives accurate strain measurement because deformation and stress in the specimen is uniform. Under dynamic loading condition, however, this measurement may not be able to give reliable strain measurement because strain and stress in the specimen are not uniform owing to wave propagation. In theory the true dynamic strain can only be obtained by using a strain gauge of infinitesimal length. In this project, both theoretical and experimental study will be carried out to investigate the errors that might be introduced in dynamic tests to measure the dynamic strains by using various strain gauges. The theoretical study will be based on 1D wave propagation theory. Experimental study will be performed on concrete specimens tested statically and dynamically with different loading rates, and using strain gauges of different sizes.



Supervisor: Professor Yuxia Hu

[email protected] 1. Compaction vibration effect on underground conduits (taken) This project will look at the vibration effect on underground gas pipelines. The vibration is generated by compaction roller during road construction. The underground pipelines are buried in subgrade soils. The scope of the project may involve in situ testing with pressurized pipes. The vibration effect on the separation of pipe protection cover can be studied by laboratory tests. 2. Centrifuge or Numerical study (as two separate projects) on offshore

foundation on layered soils Offshore foundations are used to support jack-up structures in offshore oil/gas explorations. When layered soil appears between, the foundation capacity can’t be designed based on the top layer. This project is to investigate the soft layer effect on foundation capacity. 3. Centrifuge or Numerical investigations (as two separate projects) on mitigation

of foundation punch-through failure on sand over clay soils using skirted foundation (centrifuge testing is taken)

When a spudcan foundation installed on a soil with sand overlaying clay, a punch-through failure may occur. This means that when the spudcan reaches its maximum capacity, it will have a sudden penetration into the lower layer due to the lower capacity of the soft clay layer. Skirted foundation is seen to have the potential to avoid the punch-through failure. This project is to investigate the potential of skirted foundation to mitigate the punch-through failure on stiff clay over soft clay.

4. Numerical study on strain softening effect on stiffeners on offshore caissons

Suction caissons have attracted more and more attention from offshore foundation design engineers, since the caissons have potential to provide large pullout capacity for offshore foundations. As the caisson aspect ratio increases, the stiffeners are designed to strengthen the caisson stability. This project is to study the soil failure mechanisms around stiffeners during caisson penetration and pullout when soil has strain-softening character.



Pavement Design Projects

(These projects are proposed by by Colin Leek from City of Canning)

PD1: AN INVESTIGATION INTO THE SUBGRADE CBR VALUE AND TEST METHODS TO DETERMINE CBR VALUES OF SAND SUBGRADES AFTER TRAFFICKING. (taken)

It has been recognised after many instu investigations that the upper layers of a sand subgrade consolidate with trafficking, and that testing with a PSP will give blow counts of typically in excess of 20 blows/150mm. This would indicate that for rehabilitation design, either some part of the subgrade may be modelled as an existing pavement layer, or as a very stiff upper subgrade layer. This may be as a result of consolidation which would imply high insitu density, or it may be some other factor that is not immediately apparent The investigation should consider: − Methods of determining insitu CBR o Cone or sand penetrometer o Estimation from deflection testing o Insitu CBR testing o Static cone penetrometer o Clegg impact hammer and compare these results to: − Methods of laboratory determination of CBR o Undisturbed CBR on cores o Laboratory remoulded CBR Soaked At insitu MC

The relationships between CBR and modulus as determined by RLT should also be examined, and an attempt at least to remould samples to an equivalent density as that existing and determination of RLT modulus at insitu conditions. The investigation would need to consider the variation of CBR (or modulus) with depth, and consider the pavement modelling procedure, either as a layered subgrade, or a effective CBR based on combining layers eg Japan method. PD2: AS A FOLLOW ON FROM THE ABOVE, A SECOND STUDY MAY LOOK AT THE EFFECTS OF SAND GRADING, CLAY AND ORGANIC CONTENT, AND THE EFFECTS ON IN SERVICE CBR.


PD3: AN INVESTIGATION TO DETERMINE ENERGY INPUTS OF VARIOUS PAVEMENT MATERIALS IN WESTERN AUSTRALIA. Environmental issues are becoming increasingly important in life cycle costing, but many studies are related to overseas or interstate studies where differing proportions of primary energy are used. The study should consider material source, energy input required to manufacture materials, including cement, flyash, bitumen and should include clearing, loss of vegetation and habitat, loss of energy stored and recycled in vegetation, recycling, processing, pavement life etc. The relative transport distance and mode of transport should be considered, as should the onsite energy to place and compact.


Supervisor: Professor Arcady Dyskin [email protected]

All projects are suitable as Masters Projects

1. Structures based on interlocking blocks (a group of projects) The projects from this group form a part of a large ongoing project focused at developing novel methods in Structural Engineering. This is based on interlocking building blocks/bricks which are the blocks that due to the specifics of their geometry can form self-holding assemblies. Different smooth block shapes have been discovered that allow the interlocking without the aid of keys or connectors. Thus the blocks are produced that can hold together without adhesive, which leads to a range of possible civil engineering applications from demountable structures and pavements (e.g. for air fields) to seismic-proof foundations and can cast a light on the astonishing longevity of ancient dry stone structures.

1.1 FE simulation of heavy duty vehicle tyre loading on OB segmental paver system (with David Yong)

Based on work carried out by Deanna Bramwell in 2009, it was found that the traffic load distribution performance of conventional and interlocking concrete block pavement (ICBP) varies with underlying sub-base stiffness. This would probably explain for why certain ICBP design guidelines, particularly the UK Interpave code, indicated that segmental block paving only serves as a surfacing layer with no structural capability to improve wheel load distribution. In contrast, research carried out in South America, Australia, and Japan indicated otherwise. Deformation observations by port authorities worldwide also indicated that the way segmental block paving is being constructed is crucial to its deformation response. In terms of conventional paving technology, it is widely understood that one of the main load distribution mechanism is through the wedging effect, which effectively locks blocks together to form an interlocked matrix that readily re-distributes wheel loading. However, this mechanism requires certain degree of block rotation to mobilise; the stiffer the underlying material, the less rotation and thus wedging is less likely to occur. This project will involve numerical modelling through ABAQUS/Explicit for the following objectives: • Assess varying sub-base stiffness on conventional ICBP performances; and • Determine if sub-base stiffness affects the load distribution capabilities of vertically interlocking blocks (not limited to osteomorphic blocks). Prior experience on ABAQUS is not a required, but will greatly help.

1.2 FE simulation of eccentrically loaded OB assembly as a column structure (with David Yong) Research carried out by Shuai Li and Guo Peiran in 2009 highlighted the following numerical observations with regards to the utilisation of osteomorphic blocks for construction of load-bearing structures: • Eccentric loading of osteomorphic block assemblies achieve similar response to that of dry-stacked rectangular block assemblies whereby a certain threshold interface friction is applied; and • Even with adequate threshold interface friction to maximise the eccentric load capacity of osteomorphic block assemblies, the introduction of slenderness effect introduces



progressive delamination across the assembly, subsequently leading to much lower bending moment capacity as compared to monolithic assemblies by as much as 30%. The previous research focused on solid osteomorphic blocks. However in real life construction, such blocks are bound to have holes within to facilitate the insertion of reinforcement bars. The question now is: how will such holes affect the eccentric load capacity of OB assemblies, and also with regards to slenderness effects? This will project will follow on from the aforementioned past research procedures using ABAQUS/Explicit.

1.3 Bending stiffness of interlocking structures (Numerical, 3 projects) – 1 taken The ultimate load bearing capacity of interlocking structures as well at their vibration and sound properties are controlled by bending rigidity. As the blocks in the interlocking structures, as well as in fragmented structures are not connected, in the process of bending they can delaminate. The delamination affects the bending rigidity, differently for different types of interlocking blocks. On top of that, the delamination depends upon the magnitude of confining pressure. There are two projects which aim to study the change of bending rigidity and associated mechanical behaviour of fragmented structures due to delamination. The projects are continuation of the last year project on bending of the beam for different types of constraint. Project Buckling of interlocking and fragmented beams involves analysis and computer simulation of buckling and the determination the buckling loads and modes as functions of the beam length. Project Wave propagation in interlocking and fragmented beams involves studying the dynamics and flexure wave propagation in a fragmented beam. Project Bending of interlocking plates involves analysis and computer simulation of bending rigidity and static deformation of fragmented plates. The results will be compared to available experimental data.

1.4 Modelling of in-plane oscillations in interlocking structures In-plane oscillations in interlocking structures are controlled by the specific property of their interface which has different stiffness in tension and compression. This produces new resonances not present in traditional structures. This affects the ability of the structure to dump vibrations and attenuate noise which is a very important property in buildings and foundations. Another feature of interlocking structures is the presence of constraining force. If the compressive force is much larger than the amplitude of the driving force the block separation will not occur and the structure will behave as a traditional linear system. There should be a threshold (or a transition zone) where the structural behaviour is a mixture of both. The project aims at investigating the transition zone, both in terms of the ability to transmit or dissipate the energy of vibrations. This project is based on numerical modelling and is a continuation of a 2009 project.

1.5 Dynamics of bilinear engineering systems (Numerical with Prof. Elena Pasternak) The project deals with engineering structures that contain links or parts with different stiffness in tension and compression. Examples of such systems include: • Structures made of interlocking bricks which interfaces have no stiffness in tension or any mortar-less structures • Mooring lines • Links between train carriages


Another group of examples is constituted by • Concrete, rock and rock mass as they usually have different moduli in tension and compression • Granular materials • Materials with thin cracks Characteristic features of such systems are the presence of resonance frequencies which have no correspondence in traditional linear approximation, in particular sub-harmonics, and the ability of the system to be excited by random forces. In many cases the subsequent behaviour becomes chaotic. It is believed that these features can be responsible for catastrophic failures in traditional structures (such as breakage long trains), liquefaction in sands and the extraordinary hight energy absorption and self-healing in potentially unbreakable structures made of interlocking bricks. In concretes and rocks these features could potentially be used for non-destructive control. The project aims to investigate these resonances using one-dimensional system of masses connected by bilinear springs. The numerical analysis will be based on standard procedures of solving systems of differential equations that can be found in any package (e.g. Matlab, Mathcad, Mathematica) with subsequent spectral analysis. Two parallel programs for Matlab and Mathcad have already been produced and tested for the cases of 1 and 2 masses. One of these programs will have to be upgraded to a general case of arbitrary number of masses. 2. Risk assessment of excavation instability and borehole breakouts in

homogeneous rocks Instability of excavations and borehole breakouts caused by failure of rocks leads to the breakage of equipment with considerable financial loss and, in the worst case scenario, loss of life. At large scale instability of excavation can trigger natural disasters like earthquakes. There are therefore serious social and economic needs to improve the stability of excavations and boreholes. In order to achieve this, computer models capable of predicting rock failure for different cases are required. Two issues need to be resolved for such models to be adequate for the needs of mining and petroleum industries are: (1) each element of the model representing the rock should accurately model the realistic rock behaviour. These can be achieved using the information from high quality laboratory tests; (2) the choice of the element size is crucial for the model to be successful. This second issue can be resolved based on the new concept of scalability developed at the School. The aim of the project is to develop the simplest realistic model of rock failure at the openings in rock mass that resolves the above issues. The model will be used to determine the failure extent and provide the means for risk assessment. The project will consist of a number of computer simulations using ABAQUS with realistic rock behaviour specified for the finite element. 3. Modelling of crack growth in compression (computer modelling) Catastrophic collapse of underground excavations and rock masses as well as heavy loaded concrete structures is often caused by sudden crack propagation under the action of high compressive load. Proper understanding of crack growth in compression is therefore of paramount importance for the prediction of failure and the development of the methods of preserving the structures. Extensive experimental studies of this failure mechanism have cast some light on its basics but failed to provide comprehensive understanding because of


significant difficulties in conducting precise fracture tests in such heterogeneous materials as rocks and concrete. With the advance of computer technologies, computer simulation and modelling is become a viable and cheap alternative to experimentation. The research aims at computer simulation of crack growth in compression using a Finite Element model. This project is a continuation of a 2008 project 4. 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. 5. Risk assessment of excavation collapse due to catastrophic pillar failure (with

Prof. Phil Dight) The project, being a continuation of 2007 and 2009 final year projects deals with stability of large slot-like opening whose roof is supported by many pillars (parts of rock mass left unmined) – so-called room and pillar mining method. Typically the height of the opening is 5 m, the area - hundreds of metres. When a pillar is broken its load is transferred to the neighbouring pillars increasing the probability of their failure. The strengths of separate pillars can vary a lot, so initially failure of few weakest pillars does not yet pose a problem. However, when a certain number of pillars are broken, the breakage of the next one can trigger an avalanche-type failure of the rest of pillars and, eventually, the collapse of the excavation. The situation is further complicated when the pillars are deliberately removed to utilise the resources left in them. The project will use computer simulation to model the catastrophic pillar collapse. With the aid of this simulation the design for determining the stability of the excavation and the failure risk chart will be refined. An @Risk model will be created to simulate the variability of pillar strength from the known variability of rock strength and pillar width. The information on the distributions of rock strengths and pillar widths will be found in the literature. 6. 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.

6.1 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.

6.2 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 the 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. 7. 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.


8. Smart ultrasonic dust for monitoring of underground water flow (Two projects.

Computer modelling. Jointly with Prof. Elena Pasternak and Prof. Rachel Cardell-Oliver)

A wide range of geotechnical applications ranging from extraction of geothermal energy to tracing the pollution transport require understanding of water flow which happens at various depths underground. Our ability of monitoring of water flow is currently limited to relatively shallow depths. It is therefore important to develop novel monitoring methods applicable to high depths (up to 10 km in the case of extraction of geothermal energy). A new monitoring system has recently been proposed based on tracing the stress waves induced to the rock by large groups of miniature floating ultrasonic actuators. As the actuators are small the bulk of the energy they emit concentrate in very high frequency (short) waves, which get attenuated by rock heterogeneity to the level undetectable from the ground. We however showed that if the actuators (we call them ‘screamers’) are synchronised to emit pulses (‘scream’) in a tight succession, they interfere in such a way that a considerable portion of their energy pumps into the low frequency spectrum producing waves which can be detected. The development of this idea requires two projects: The first project will develop a simulator to test the algorithms of synchronisation of the screamers and the investigation of the robustness of the algorisms to the adverse environmental factors leading to various delays in the pulse emitting and loss of the screamers. This project would involve considerable amount of programming using Matlab. Objective of the second project is to create a computational model that adequately represents the interference of screamers in the influence of their special locations as well as the locations of the wave detectors. The project will involve modelling of wave propagation in the Earth’s crust and would require the understanding of the corresponding mathematical theories and numerical methods. 9. Modelling crack growth in concrete (Numerical, Matlab, 2 projects) – 1 taken Crack propagation is a major cause of failure of brittle materials such as concrete and rock. Increase of the life time of structures and failure prediction require accurate modelling of crack growth. Concrete and rock are highly heterogeneous materials, which imposes specific conditions of crack growth. A main feature is the development of so-called process zone at the crack tip – a narrow zone where the non-linear processes of deformation and fracture are concentrated. The aim of the projects is to simulate the process zone based on so-called fibre-bundle model whereby material in the process zone is replaced with a layer of parallel elastic fibres with random strengths. When the load exceeds the strength of a fibre it breaks. The load increase continues until sufficient number of fibres breaks enabling a step of crack propagation. There are two ways this model can be implemented. Both ways will be tried and the results compared. The first way is a direct Monte-Carlo simulation of breakage of the fibres situated in the process zone. This is the scope of project Simulation of crack growth in concrete. The project will be heavily based on statistical simulation and analysis. The second way is to apply homogenisation technique whereby the stress-strain relationship of a uniformly loaded fibre bundle is obtained first and then it is incorporated in the process zone when the crack is modelled. This is the scope of project Homogenised modelling of crack growth in concrete. The project will involve solving the crack equation using the method of collocation. The method will involve the use of complex numbers.


10. Modelling of domino effect in instability of shear ruptures and faults (with Prof.

Boris Tarasov and Prof. Elena Pasternak) Catastrophic propagation of shear fractures and sliding over a fault are major dynamic effects causing excavation collapse. The correct understanding of the physical processes taking place at this phase is extremely important for failure prediction. A recently identified mechanism of this type of instability suggests that during shear crack propagation slender rock blocks are formed and then rotate. The block rotation causes domino effect which is accompanied by high velocity of propagation of the front of rotating blocks and sudden release of large amount of elastic energy. The project aims at investigating this mechanism by considering a simplified models consisting of a set of levers on hinges connected by springs. This system is modelled by a system of differential equations which is to be solved numerically (using Matlab). The numerical results will be compared with results of experiments with a physical model. 11. Modelling drill bit – rock/concrete interaction (with Prof. Elena Pasternak) Drilling and cutting using mechanical tools is one of the main methods of rock fragmentation in mining and petroleum industries and concrete machining in construction industry. An important feature of the interaction is the induced vibrations of the drill bit. The vibrations depending on the parameters can have both positive effect, by assisting the fragmentation, and negative effect due to the dissipation of mechanical energy. The aim of the project is to develop mathematical model of vibrations which takes into account the different stiffnesses of the drill bit suspension and the material being fragmented. The project will involve numerical modelling using MatLab. 12. The effect of borehole on stress determination based on rock memory

(numerical with W/Prof. Phil Dight) The methods of stress determination based on rock memory (The Kaiser effect method and the Deformation Rate Analysis DRA) involve extracting the rock cores from the part of rock mass of interest, subcoring them in different directions and then loading the subcores to determine the stress they were subjected in situ. The main problem is that the borehole drilled to extract the cores changes the stress field producing stress concentration. It is this stress concentration which is actually being recovered by the rock memory methods. The aim of the project is to quantify the borehole-induced stress concentrations and to develop a procedure of recovering the true stress from the rock memory measurements. 13. Finite Element Modelling of Rate-Dependent Ratcheting in Granular Materials

(with A/Prof Ali Karrech) Granular materials such as sand or fragmented rocks are commonly used in Civil Engineering. In particular, ballast used in railway tracks or similar agglomerates used in road pavements represent key materials for the transport industry. Understanding the behaviour of these materials especially under cyclic loading represents a challenging subject requiring a lot of research efforts. Cyclic loading of ballast leads to ratcheting (unidirectional deformation),


rate-dependency, and non associated flow, which should be taken into account in any practically important modelling. Both experimental and numerical results show that granular materials exhibit a gradual decrease of the volume of voids resulting in a nonlinear permanent deformation with respect to the number of cycles. The purpose of this project is to describe the ratcheting phenomenon associated with rate-dependency using a continuum approach. Existing models including rate and pressure dependencies will be extended to describe ratcheting as a kinematic hardening phenomenon. The project will utilise the Finite Element package ABAQUS which is currently an industry standard. 14. Modelling of Coupled geomechanical and chemical processes (with A/Prof. Ali

Karrech) Many energy and mineral extraction technologies, such as geothermal energy, petroleum and coal mining as well as in-situ leaching involve geomechanical processes coupled with chemical reactions. Optimising the outcomes and reducing environmental impact require proper modelling of the coupling. The purpose of this work is to (i) extend an existing stand-alone numerical model (written in python) to include the effect of advective transport (ii) improve the numerical solver by including existing libraries of linear systems inversion or direct implementation of the skyline method. Thermodynamics will be used a unified framework to describe several mechanical and chemical processes which can exhibit complex coupling aspects.


Supervisor: Dr. Ming Zhao [email protected]

1. Numerical investigation of passive flow control of vortex-induced-vibration (VIV) (co-supervisor Prof. Liang Cheng)

If the natural frequency of a sub-sea structure is close to the frequency of vortex shedding, resonance will happen and the structure may be damaged. Vortex-induced vibration is a hazard for sub-sea structures. Measures should be taken to reduce vortex-induced vibrations of structures in engineering practice. In this project passive control of VIV will be investigated numerically. The passive control will be realized by attaching a device such a spoiler or another small control cylinder to the cylinder. The aim of the project will be to study the effectiveness of passive control devices. 2. Numerical Simulation of vortex-indued Vibration of a subsea pipeline in

oscillatory flow Subsea pipelines are important facilities in the offshore engineering for transporting oil and gas products. If a subsea pipeline is laid in shallow water zone, wave-induced oscillatory fluid velocity will have significant impact on the pipeline stability. Wave motion are usually modeled by oscillatory flow when the wave action on the pipeline is investigated. Vortex-induced vibration (VIV) may happens if the pipeline-to-seabed gap occurs due to local scour or uneaven seabed. The existance of the seabed will make the pipeline vibration different from the VIV of a circular in an unbounded domain. In this project, the VIV of a subsea pipeline will be modeled by VIV of a circular cylinder close to a plane boundary. The influence of the plane boundary on the VIV will be studied numerically . 3. Numerical Simulation of Vortex-Induced Vibration of a subsea pipeline in an

scoured seabed in steady current. If a subsea pipeline is laid on sandy sea-bed and local scour happens, scour hole beneath the pipeline will lead to Vortex-Induced Vibration (VIV) of the pipeline. VIV of a pipeline on a scoured hole is different from the VIV on a plane boundary because of the uneven seabed. In this project, VIV of a subsea pipeline on an scour hole will be studied by two-dimensional numerical simulation. The effect of the sour depth beneath the pipeline will be studied by numerical method.



Supervisor: Professor Andy Fourie [email protected]

1. The bearing capacity of soft clays beneath a sand layer and the relationship to access time on a mineral sands mine

(Suitable for Vacation Work Project) In many mineral sands mining operations in Western Australia, the mined void is filled with a low strength mixture of sand and fine clay material, as soon as possible after mining has been completed. As part of the re-instatement process, the objective is to cover this backfilled material as soon as possible with topsoil and then to begin revegetation procedures. Problems are frequently encountered with earthmoving machinery becoming bogged, or worse still, completely submerged in the soft backfill. This project will develop guidelines on safe access to the backfill surface, with the objective of minimising risk to machinery operators, but improving access time. The project will require modelling of a two-layer system – the soft backfill overlain by a thin layer of sand – with earthmoving equipment working on the sand surface. The modelling will involve use of a finite element package, plus other analytical techniques such as the method of characteristics. Finally, the project will develop a detailed plan for an experiment in the geotechnical centrifuge which, time permitting, will also be carried out as part of the project. 2. Developing a mandatory system for reporting Mine Closure financial

provisioning and activities The Australasian Joint Ore Reserves Committee (JORC) code was established to set minimum standards for public reporting (in Australia and New Zealand) of exploration results, mineral resources and ore reserves. It ensures that disclosures on the stock exchange are as accurate as possible, providing potential investors with the security of knowing the information is correct. This project will investigate the establishment of a similar code for reporting financial provisions a mining company has made for future Mine Closure, and what activities (if any) have been taken to ensure closure is carried out responsibly. With the increasing penetration of many mining companies from countries with relatively little regulation of mining activities into Australia (and into many developing countries that have no regulatory framework in place), there is the risk of both environmental devastation occurring, plus Australian mining companies being unfairly penalised when working abroad because they adhere to Australian standards whereas others may adhere to no standards whatsoever. If successful, the proposed Mine Closure code will be presented to the Australian Institute of Mining for consideration for future adoption. 3. Wall steepening at KCGM There are plans for both a significant cutback at the KCGM superpit, and some degree of wall steepening, with a view to reducing unit mining costs. There are a number of problematic geological features within the pit, and this project will investigate the potential for future instabilities due to these features if the proposed expansions proceed. Use will need to be made of programs such as Map3D and FLAC, and it will be necessary to work with geotechnical engineers from the site to develop appropriate geological and mining models.



4. An improved design approach for lining systems beneath waste disposal sites Most waste disposal sites include provision for an impermeable lining system, to minimise the potential for groundwater contamination. These lining systems usually include one or more layers of geosynthetic material. The primary layer is a geomembrane or geosynthetic clay liner, which is often protected with a layer of geotextile and perhaps includes a synthetic drainage material such as a geonet. There have been a number of failures of lining systems on the slopes of landfills, the best known of which is the Kettleman Hills landfill in the USA. The failures are usually caused by slippage between the various layers of geosynthetics. Current design approaches focus on limit equilibrium analyses of these lining systems, ignoring the importance of strain compatibility between the layers. This project will develop a design methodology that includes provision for strain compatibility, using a spreadsheet or other relatively simple approach to modelling the problem. 5. Geotechnical characteristics of flocculated sediments One of the ways to improve the consolidation characteristics of very fine grained soils is to add a flocculant. The flocculant causes individual particles to agglomerate, forming floc aggregates that then settle relatively rapidly. Little is known about the changes in strength and consolidation behaviour of soils that have been altered in this way. For example, how does it respond to applied stresses compared to the same soils that have not been artificially flocculated? This project will test two different soils, kaolin and mineral sands tailings. Tests will be carried out on both flocculated and unflocculated (i.e. untreated) material and a range of conventional tests will be carried out on these materials, including index tests, consolidation and triaxial tests. Once the basic geotechnical engineering properties have been characterised and any significant differences between flocculated and unflocculated material identified, more detailed testing will be carried out using the Rowe consolidation cell, stress path triaxial tests and centrifuge tests.


Supervisor: Dr Mehrdad Kimiaei [email protected]

1. Numerical modelling of Jacket launch analysis Fixed offshore platforms are the most reasonable alternative in shallow to moderate water depths. Usually two sets of different in-service and pre-service analyses are needed to confirm the integrity of fixed offshore platforms during their operation life and installation phase respectively. In installation phase of the jackets, when the jacket weight and dimensions become large, or even in case of restrictions in crane lifting capacities, a launching technique can be used. In jacket launching operation, in summary, the cargo barge will be ballasted in a trimmed manner and after applying an initial push-pull force on the jacket, it will start moving on the barge and then finally it will dive into seawater at the end of the cargo barge. This operation is the most critical operation in the entire installation procedure. The failure could result in damage to local members, defects to the barge, overturning of the unit and even total loss of the structure. Main objective of this research is to develop a proper model for launching the jackets (using Orcaflex software) and to study the effects of main operational parameters, including environmental conditions, launch barge specification, ballast, trim angle, friction coefficient, etc on overall response and stability of the jacket and the barge during launch operation. The effects of input parameters will be closely examined by numerical modellings in a series of sensitivity analyses. For postgraduate students, this study can be extended into implementation of this model in the first step of deployment of subsea platforms using pendulous installation method (already conducted in COFS). This project will suit Bachelor and Master students with interests in offshore installation engineering concepts and backgrounds in civil or mechanical engineering. Knowledge of fluid mechanics and hydrodynamic loading is a bonus, but not essential. 2. Structural configuration effects on reliability of fixed offshore platforms More than 6000 fixed steel jacket platforms in continental shelves have been set up all around the world for over the past 50 years. Almost a third of these platforms need to be reassessed for various reasons such as damaged members, installation of new equipment on decks, or the possibility that some of the installations’ or members’ design life are due. To assess the conditions of existing platforms or in design of new platforms, reliability of the structures must be studied. Reserve Strength Ratio (RSR) is a parameter which will be used in determination of reliability of offshore platforms. In structural reliability analysis, Target RSR (showing the relationship between annual probability of failure and the environmental loads) will be compared with Configured RSR (showing the maximum strength which can be achieved by a platform). Target RSR and Configured RSR are both dependent on structural configuration of the platforms (ie geometry, bracing configuration, member sizes, foundation modelling, etc).



Main objective of this research is to investigate the main parameters affecting Target and Configured RSRs of fixed platforms. In a series of numerical analysis, using USFOS software, effects of platform configuration on overall reliability of fixed platforms will be studied. Traditional quasi static and new dynamic methods will be used for pushover analysis in determination of structural reserve strength ratios. Collapse modes of different platforms will also be studied in this research. For postgraduate studies, this study can be extended into comparing the results of different approaches for reliability analysis of fixed platforms, looking at wave on deck effects, and implementation of modal and incremental techniques for dynamic pushover analysis. This project will suit Bachelor and Master students with interests in offshore structural engineering concepts and backgrounds in analysis of structural systems. Knowledge of non-linear behaviour of structural systems is a bonus, but not essential. 3. Fatigue analysis of SCRs considering nonlinear pipe-soil-interaction effects

(Co-supervisor: Prof. Mark Randolph)

As the offshore industry continues to progress developments in deep waters, the preferred riser solutions are still SCRs (Steel Catenary Risers). SCRs can offer the cheapest riser solution depending on specific field, environmental and load constraints. In riser engineering, nonlinear behaviour of SCRs at the vessel hang-off and in the touch down area (TDA) have 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 the cyclic loading. Current design approaches are based on linear solutions to these nonlinear problems, partly due to lack of appropriate nonlinear models for the interaction involved and partly because linear solutions simplify the fatigue study. These approaches appear to lead to very conservative fatigue design of SCRs for typical values of linear soil stiffness assumed. This research will be in continuation of the studies already started at COFS on fatigue design of SCRs . Main objective of this numerical research is to get a better understanding of fatigue design of SCRs at TDA using a robust nonlinear soil-interaction model recently developed in UWA and implemented in Orcaflex software. In a series of analyses using Orcaflex software, sensitivity of the fatigue life of the risers to linear or nonlinear soil models, static or dynamic analyses, soil parameters and dynamic motions of the vessel will be studied in this dissertation. This project will suit Bachelor students with interests in offshore engineering concepts and backgrounds in analysis of structural systems. Knowledge of fatigue analysis is a bonus, but not essential.


Supervisor: Asst. Professor Hang Thu Vu [email protected]

1. p adaptive procedure in 3D for the scaled boundary finite element method

(Suitability: Master Degree only) Abstract: The scaled boundary finite element method is a novel semi-analytical technique, whose versatility, accuracy and efficiency are not only equal to, but potentially better than the finite element method and the boundary element method for certain problems. In previous works, it was shown that higher rates of convergence can be obtained using p-refinement instead of h-refinement. This stimulated the development of various p-hierarchical adaptive strategies. Numerical studies were performed on various bounded domain and unbounded domain 2D problems. The results indicate these strategies works efficiently. This project extends the past study to examine performance of one proposed p-adaptive technique towards 3D problems. The p- hierarchical adaptivity approach based on a conventional energy norm will be considered. This project is suitable for either undergraduate or master student.



Supervisor: Professor Richard Durham [email protected]

Please note that usually at least 50% of Mining Engineering students get their thesis topics from industry whilst on vacation work over

summer

1. Shotcrete markers

One of the critical issues with the application of shotcrete is the quality control and in particular ensuring the specified thickness has been applied. This thesis would continue work done in the previous years into simple markers that let the operator see the thickness of the shotcrete as it is being applied. 2. Modelling caving using discrete particle analysis Modelling the drawdown behaviour of a caving operation as a particulate process, using EDEM software (http://www.dem-solutions.com)

3. The golden rule of drilling re inclined holes

One of the “rules of thumb” for exploration is that for a vertical deposit inclined drillholes give more information. A paper has been written recently that disputes this. The project would involve simulating various deposits (using Excel or Datamine) and then comparing the costs vs information obtained of various drilling strategies

4. Effectiveness of surface miners

Continuous surface miners have been used effectively for many years in road making, tunnelling and mining of “soft” rocks (e.g. coal). Their application in harder rock mining is being investigated by several parties in the iron ore industry. The challenge is to find a theoretical and/or empirical model of predicting how productive they will be in any given rock environment.


http://www.dem-solutions.com/


Supervisor: Dr. Tongming Zhou [email protected]

1. Dynamic forces on an inclined bluff body and its dependence on Reynolds

numbers (2 students) – 1 taken Vortex shedding is a well known phenomenon that occurs when a flow passes a bluff body. The vortices shed from the bluff body can induce vibration, which, at resonance, will result in excessive motion and possible structural failure. There are extensive studies on vortex shedding from single cylinders in a cross-flow (i.e. the incoming flow is perpendicular to the axis of the structure). 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 a wind tunnel to study the wake flows of bluff structure (either a circular cylinder or a square cylinder) at different inclination angles between the cylinder axis and the flow. Dependents of the drag coefficients, vortex shedding frequency and Strouhal number on Reynolds number and inclination angles will be studied and compared with that obtained in wakes of cross-flows. The experiments will be conducted in the wind tunnel of School of Civil and Resource Engineering of UWA. 2. Comparison on the effect for suppressing vortex-induced vibration using

helical strakes of different geometries (3 students) – 1 taken 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 the helical strakes, which are attached to the surface of the cylinder. The objective of the project is to compare the effectiveness of the helical strakes of different dimensions on VIV suppression. The experiments will be conducted in the wind tunnel of School of Civil and Resource Engineering of UWA. 3. Measurements of forces on two particles of various arrangements in terms of

particle separations and inclination angles (2 students) – 1 taken

(Co-supervisor Professor Liang Cheng) When particles are put in a moving fluid, forces will be formed on them. The force in the



streamwise direction is called drag and in the cross-flow direction is called lift. In the present project, you are required to measure the drag and lift forces on the two particles. The two particles can be arranged at various relative locations in terms of their separation and inclination angles. The experiments will be conducted in the wind tunnel of School of Civil and Resource Engineering of UWA. Vacation Research Project Title: Flow characteristics and forces of a piggyback pipeline Pipelines in offshore engineering are sometimes arranged in piggyback format with the bigger one for production and the smaller one for accommodating cables and water injection etc. When fluid flows over a bluff body, vortex will be shed if Reynolds number Re exceeds about 49. The Re is defined as ν/Re UD= , where U is the velocity in the free stream, D is the diameter of the cylinder and ν is the kinematic viscosity of the fluid. In this project, the fluid is air with ν = 1.5×10-5 m2/s and density of 1.23 kg/m3. The diameters of the cylinders are D = 8 cm and d = 4 cm, respectively. The gap η/D between the two pipes is varied, namely 0, 0.1, 0.2 0.3, 0.4 and 0.5. The air has a velocity U = 5.5 m/s. There are five arrangements for the pipes with α = 0°, 45°, 90°, 135° and 180°, i.e. there are totally 30 cases of arrangement in this project. You are required to use FLUENT to calculate the forces on the structures for all the cases and compare them with the experimental results provided.

U incomingflow velocity D

Pipe 1

αd

η/D

α = 45°

α = 90°

α = 135°

α = 180°α = 0°

Pipe 2

U incomingflow velocity D

Pipe 1

αd

η/D

α = 45°

α = 90°

α = 135°

α = 180°α = 0°

Pipe 2


Supervisor: Professor Barry Lehane [email protected]

1. Soil-structure interaction for offshore pipelines (with Prof. David White)

This project will involve extension of experimental laboratory work undertaken in 2009 to determine the static and cyclic shear strength at the very low effective stresses operating at soil-pipeline interfaces. These results will then be incorporated in a numerical model for soil-pipeline interaction which can be used to assist design for lateral buckling and “walking” of pipelines. 2. Settlement of piled footings on sand This project will involve experimentation with instrumented piled footings at the UWA sand test bed site at Shenton Park. This experimentation, combined with findings from previous load tests on shallow footings and piles at Shenton Park and with numerical analyses, will be used to formulate a design approach for piled footings on sand. 3. Effects of pre-loading on capacities of shallow foundations The re-use of foundations is a key issue in sustainable urban development. There is, however, little information available regarding the effects of pre-loading on the performance of shallow foundations in clay. This project will extend previous UWA research in this area and involve a series of centrifuge tests on footings in clay as well as parallel FE (Plaxis) analyses. 4. The bearing capacity of soft clays beneath a sand layer and the relationship to

access time on a mineral sands mine. (with Prof. Andy Fourie) In many mineral sands mining operations in Western Australia, the mined void is filled with a low strength mixture of sand and fine clay, directly after mining has been completed. As part of the re-instatement process, the objective is to cover this backfilled material as soon as possible with topsoil and then to begin re-vegetation. Problems are frequently encountered with earthmoving machinery becoming bogged, or worse still, completely submerged in the soft backfill. This project will develop guidelines on safe access to the backfill surface, with the objective of minimising risk to machinery operators, but improving access time. The project will require modelling of the two-layer system (soft backfill overlain by a thin layer of sand) with earthmoving equipment working on the sand surface. The modelling will involve use of a finite element package, plus other analytical techniques such as the method of characteristics. Finally, the project will develop a detailed plan for an experiment in the geotechnical centrifuge which, time permitting, will also be carried out as part of the project.



Supervisor: Professor Chari Pattiaratchi [email protected]

There are a few environmental projects available as shown below: 1. Synthesis of the wave climate between Jurien Bay and Fremantle

(supervisors: Chari Pattiaratchi and Ivan Haigh) As part of the Integrated Marine Observation System (IMOS) several HF radar installations between Lancelin and Fremantle will provide high resolution direction wave data at hourly intervals to a distance 200km of the coast. This is a unique opportunity for a student to examine the variability in the wave adjacent to the WA coast at unprecedented spatial and temporal scales. The radars are already deployed so the data will be available for analysis immediately. 2. Tsunami risk for north west Australia

(supervisors: Chari Pattiaratchi) In this project we will examine the tsunami behavior along the WA coast (Scott Reef, Kimberley, Geraldton, Jurien Bay, Fremantle etc) using a high resolution numerical model already developed. The availability of high resolution data sets along the south-west provide a unique opportunity to examine these effects. Another feature of interest is the role of tsunamis inside ports and harbours. There are many harbours being built in the north-west but even small tsunamis can have a significant effects through the generation of currents, particularly at the port entrances. Another topic could be the effect if tsunamis in regions of oil&gas regions where they may have a influence on offshore installations (such as submarine pipelines, particularly in shallow water). 3. Effects of coastal sea level rise on beaches

(supervisors: Chari Pattiaratchi and Ivan Haigh) Lidar is a technique for obtaining bathymetry and topographic data using a laser technique yielding high spatial resolution data. This type of data has not been available in WA previously. Lidar data from the coastline of southwest Australia, from Two Rocks to Cape Naturaliste is now available. This data provide a unique data set which can be used to identify regions which may be at risk due to climate change (eg coastal erosion, coastal flooding). 4. Modelling of wave dynamics in the vicinity of reef structures

(supervisors: Chari Pattiaratchi and Ivan Haigh)

Offshore reef systems play a significant role in the wave attenuation along the WA coast. This project will apply a wave refraction/diffraction model to investigate the shoreline configurations and bottom habitat distribution to the wave shoaling coefficients.



5. Coastal Flooding in the Swan river/Peel Harvey Estuary (supervisors: Chari Pattiaratchi and Ivan Haigh)

Increasing sea levels, due to global warming, will increase the number of coastal flood events (note coastal flooding is flooding due to combinations of storm surges and tides rather than river flood events). The student will undertake a numerical model study of the study regions to predict changes to the coastal flood frequency.


Supervisor: Professor Greg Ivey [email protected]

1. Convective flushing of the North-West Shelf

(Supervisors: Greg Ivey and Nicole Jones)

Buoyancy driven currents on continental shelves provide a mechanism for the exchange of water between, shallow coastal regions, the adjacent shelf, and the deep ocean. In mid-latitudes, freshwater input and surface heating often provide a source of lighter fluid on continental shelves, while surface cooling and evaporation lead to the formation of dense water in shallow coastal regions. The proposed project will quantify the role of buoyancy driven currents in flushing the Australian North-West Shelf. This will be achieved by examining the output of two numerical models: the BLUELink Reanalysis global ocean model and the Regional Ocean Modeling System. 2. Boundary layer dynamics on the North-West Shelf

(Supervisors: Greg Ivey, Nicole Jones and Cynthia Bluteau) When using numerical models to reproduce hydrodynamics in aquatic environments, one ultimately selects a turbulence closure scheme. Many closure schemes exist, each of them with their assumptions, limitations, and applicability to the physical question at hand. This choice can have significant consequences on mixing and circulation predictions. Furthermore, the dynamics of the bottom boundary layer, which are usually of smaller scale than a model's grid resolution, must be properly parameterized to accurately simulate ocean circulation. For this project, field measurements taken in the boundary layer will be compared to the output obtained from the numerical model: Regional Ocean Modeling System (ROMS). The model has been run using different closure schemes, and the main objective is to establish if any of them can reproduce the features seen in the field observations.


Supervisor: Assoc Prof Melinda Hodkiewicz

[email protected]

1. Analysis of asset decay profiles in wharves Using historical condition inspection reports and Fremantle Ports’ new quantitative asset condition assessment framework, generate a timeseries of historical condition date for wharves within the Port of Fremantle to then be analysed for a relationship between wharf age/usage and condition, and hence remaining useful life. Special request: Requires confidentiality agreement.


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