Infrastructure Engineering - Theses
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ItemManufacture and properties of prepacked aggregate concrete( 1984)The properties of prepacked concrete have long been studied and compared with those of normal concrete, although very little is known about its strength and deformation behaviour. Either by experiment or theory these aspects have been described in different ways. This thesis describes some experimental programmes on prepacked concrete that include its manufacture and a study of its strength, deformation and failure mechanism. To compare these aspects, normal concretes having the same water-cement and aggregate-cement ratios were made and tested under the same condition. The experimental work investigates the use of different types of admixture in grout in order to improve the strength of prepacked concrete. Among them the expanding admixture was found to be most suitable. Data are presented on some properties of grout using different types of admixture at various sand-cement ratios. Along with the strength investigation, investigation on modulus of elasticity, creep and shrinkage were also carried out. Tests of creep and shrinkage reveal that the magnitudes of both in prepacked concrete were much lower than in normal concrete. Different aspects of the failure mechanism of prepacked concrete are also presented and discussed.
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ItemEvaporation from an agricultural catchment: a field and theoretical study of evaporation( 1983-05)This is a field and theoretical study of the evaporation component of the hydrology of an agricultural catchment. The aim of the study was to improve the evaporation section of the Australian Representative Basis Model, ARBM. ARBM is a physically based computer model of catchment hydrology. It was developed for use in conjunction with the representative Basins Project. The catchment selected for this study was the Warrambine Creek Representative Basin, No. 2.15. A major part of the study was the development of equipment to directly measure evaporation in the field. Two sets of equipment were developed. One system was based on the energy balance method of evaporation measurement. The other system was based on the eddy correlation method. In its final form, the energy balance equipment proved most satisfactory. At the study site over 100 days of complete data was collected. However this data was discontinuous due to instrument and data recording faults. The data collected was used in the testing of various components of the evaporation model. A detailed analysis was undertaken to estimate the likely errors in the computer values of evaporation. This analysis showed that little error could be expected when evaporation was measured over a wet surface. For a dry surface, the analysis predicted that erratic results could occur. This prediction was confirmed with experimental evidence. The development of the eddy correlation system was less successful. This occurred because of the late start to this section of the work and because of the innovative nature of the equipment which was developed. A microprocessor system was designed to replace the eddy correlation analogue computers. This system offers many advantages over conventional equipment. Unfortunately it was only developed to the laboratory testing stage. Also an infrared hygrometer was designed. This too was only tested in the laboratory. Although no field measurements of evaporation were made with this equipment, additional theory and insight into this method was obtained. The performance of any hydrological model depends on the reliability and representativeness of its input data. This data is supplied by a Bureau of Meteorology climate station situated only 3 km from the study site. The location of the climate station appears to be non-representative of the catchment in general. Thus climatic data from the two sites was compared. Little difference was noted in dry bulb temperature and rainfall data. Wet bulb depressions were slightly different. A poor correlation of pan evaporation was found. It was also found that the global radiation data collected at the climate station was worthless due to an instrument fault. The evaporation model of ARBM was examined in detail. In particular, the parameter known as potential evaporation, PE, was examined from first principles. It was found that PE is poorly defined. PE was re-defined and prediction formulae were derived. These formulae were used in a new PE model for ARBM. The model which predicts the diurnal variation of evaporation was examined and found to be satisfactory. Particular improvements to the equipment and topics of further study were recommended.
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ItemThe stability of wedges of granular materials( 1956)The design of embankments usually involves a stability analysis by one or more of the various slip surface methods. A common feature of these methods is the assumption that a state of limiting plastic equilibrium exists over the surface of failure. The shape of the potential failure surface is, however, determined empirically. In recent years various refinements have been introduced in the most generally used method (the Swedish slip-circle); but these refinements have been superficial and the underlying assumptions of the method continue to be accepted, to a greater or lesser degree. (For complete introduction open document)
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ItemRapid drawdown in earth dams( 1971)It would appear that the most rational method of obtaining the rapid drawdown pore pressure response is to apply the field stress path to laboratory samples of the embankment material. However this approach has not been very successful and stability analyses indicate that a detailed understanding of rapid drawdown response is necessary for safe and economic design. Therefore controlled drawdown tests were carried out in the laboratory and the results were compared with various methods of prediction. The drawdown behaviour could be predicted by a refined analysis but the results cannot be applied directly to field situations. The drawdown stress changes were studied for prototype structures and the variables that govern the undrained pore pressure response were also studied. On the basis of these investigations the reported field measurements can be understood and a conservative design estimate of the drawdown pore pressure response is given.
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ItemFree surface flow in a circular conduit: a theoretical and experimental investigation of the influence of velocity distributions on flow behaviour( 1963)General Introduction: Since Chezy first proposed his well known equation for uniform flow in open channels, many other formulae have been suggested, either to replace the Chezy expression or form determining the value of the coefficient C. Perhaps the major objection to the use of these formulae is that no account is taken of the variation of the boundary effects with Reynolds number — although in some cases this is done indirectly by relating Chezy’s C to the hydraulic mean radius. Following more recent work, notably by Prandtl, there have been attempts to produce relationships between Chezy’s C, Reynolds number and a roughness parameter, (similar to those which exist for pipe flow) but these habe not been generally applied as the effects of the free surface and unsymmetrical flow conditions have not yet been fully evaluated.
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ItemPneumatic separation of grain from straw and chaff in the combine harvester( 1970)The riddle mechanism, used to clean threshed grain in harvesting machinery, has remained basically unchanged for over a century. The desired function and throughput of the cleaning mechanism in a harvester is discussed, together with the effectiveness of the conventional system. The published work on a combined harvester is reviewed; the history and development of the various components leading to their present configurations is examined together with work done on developing alternatives to the usual components in a harvester. Pneumatic separation in a vertical air stream, proposed as an alternative to the riddle system of cleaning the efflux from the threshing system of a harvester, is examined in depth. Theoretical prediction of the performance of a vertical air stream, as a separator, is shown to be intractable while predictions of separation based on terminal velocities of all the types of particles present in the mixture (which were measured fully) are shown to provide only a fair indication of likely performance. A small pneumatic separator was designed and built; the performance of this unit was investigated in detail; the effects of air velocity, feed rate, and of material composition are discussed. Likely ways of improving separation, together with the lines along which further investigations should be conducted, are discussed using the results obtained from the separation tests.
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ItemState of Victoria: a description of the Loch Garry Flood Protection Scheme: Goulburn River levees( 1924)In dealing with the subject of the Loch Garry Flood Protection Scheme, no attempt will be made to describe in detail all Flood Protective works carried out along the Goulburn River, but, in order to explain clearly the present position in regard to such works, the more important geographical and physical characteristics of the Goulburn River will be described and a brief outline will be given of the steps leading up to the adoption of the present scheme.
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ItemA rational approach to the thermodynamic behaviour of air chambers( 1967)In the past, studies of air pockets as well as air chambers utilized the polytropic relationship; p Vn = constant, to represent the thermodynamic behaviour of the air. Since this simple equation specifies the properties of the air without regard to the accompanying physical transients, it cannot truly satisfy the thermodynamic requirements. The main aim of the present project is to indicate a rational approach which is in accordance with the condition for thermodynamic behaviour. Controlled laboratory experiments verify the general trend of the proposed theory and illustrate how erroneous the adoption of a constant value of the polytropic index, n, can be. The concept developed is further applied to a typical air chamber installation to emphasize how the pressure-volume relationships differ from other methods.
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ItemSoil moisture and hydrology of the basalt plains of Western Victoria: a field and computer study of surface hydrology( 1979)This is a field and digital model study of surface hydrology. An attempt is made to relate field measurements to the assumptions of a physically-based deterministic rainfall-runoff model that has been proposed for widespread use in Australia. A major part of the field study was the measurement and interpretation of soil moisture contents obtained with a neutron moisture meter, and two methods were developed and used to provide calibrations appropriate to both locally variable soils and the large (55 km2) study area. Independent estimates of each of the major components of the water balance were made, utilizing data collected on the study by other authorities. Further measurements of field parameters were made to provide independent estimates of the appropriate parameter values for the digital model. A single year of data was used for development of the model and final selection of the parameter values. The prediction of the observed streamflow was used as the basis for this testing, and the hydrological validity of the assumptions upon which the model is based was then tested by a comparison of the internal prediction and the independent measurements of soil moisture contents. The model was found to behave reasonably well, but deficiencies in some of the algorithms were identified. A sensitivity analysis showed that the concept of an infiltration capacity is not important for runoff generation on this catchment, and that the spatial variability of the moisture holding capacity of the soil makes it virtually impossible to estimate this model parameter from field measurements alone. It was found that a simple approximation to this spatial variability provided a more realistic annual hydrograph, and reduced the accuracy required to determine the mean value of this moisture storage capacity from field measurements. The main conclusions are that deterministic models offer a useful approach to the understanding of surface hydrology, although further development is required before the parameter values for such a model can be determined solely from field measurements. The use of the field measurements and the model showed that the hydrology of this catchment is dominated by a nearly impermeable B horizon, that the concept of an infiltration capacity is irrelevant to the generation of storm runoff, and that the spatial variation of the moisture holding capacity of the soil is important. Particular topics for further study include the acceptance of spatial variability in the other algorithms of the model, and the hydrological validation of this and other models on other catchments.
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ItemThe control of thermal and shrinkage cracking in reinforced concrete( 1977)Wide, randomly spaced cracks in lightly reinforced concrete members result from restrained reductions in the volume of the member. Extensive research in the past has identified the causes of these volume changes (e.g. thermal contraction, creep and drying shrinkage) but comparatively little research effort has been directed specifically towards controlling the cracks induced by these movements. This thesis examines the control of thermal and shrinkage cracking in reinforced concrete members. A survey of the literature discusses the causes of this type of cracking and identifies the critically important role played by the bond of reinforcing to the surrounding concrete; the majority of current crack width prediction formulae are shown to be unsatisfactory. A review follows of recent structures in which thermal and shrinkage cracks were causing concern, and indicates that present design recommendations and criteria are inadequate. Simple and comprehensive theoretical models of restrained concrete members are developed and equations are derived enabling the prediction of the behaviour of cracks. Experimental work determined the mechanisms by which different types of reinforcing act to control the width and shape of cracks in reinforced concrete walls. Amounts of conventional reinforcing up to four times greater than presently recommended values are shown to be necessary to achieve a controlled pattern of cracks, and fundamental differences identified between the control exercised by deformed bar and fabric reinforcement.