Four journal papers have been selected from the candidate's published research output, to represent his work in developing analytical methods for use in geotechnical engineering design and analysis. Two of the papers contribute to significant advances in the understanding of the behaviour of dry-stone retaining walls, which will lead to greater confidence in the assessment of existing walls and the design of new walls. The other two papers develop optimisation and analysis routines with the aim of supporting the assessment of slope stability, and the design of new cut and built slopes and stabilisation works.

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In this thesis I examine how the shear-waveform changes when it propagates through media with different crack strikes and how this affects our ability to interpret the shear-waveform in terms of rock properties. It is found that the polarization of the leading split shear-wave is dependent on the anisotropic structure of the last medium it passed through. However, if the anisotropy is weak, or the raypath short, visual interpretation of the polarization diagrams will be difficult. Data collected in reflection surveys are harder to interpret than those collected in vertical seismic profiles as the signal is not recorded in the layer of interest. The presence of changing crack orientations with depth will mean that the results of rotation type anisotropic estimation techniques will no longer give accurate estimates of crack strike and time delay. Field data from a vertical seismic profile in a region where changing crack strike with depth is suspected are examined as a case study. The amplitudes of shear-waves reflected from anisotropic interfaces are investigated to see if they contain useful information about the anisotropic properties of a reflecting layer. The relative amplitudes of reflected shear-waves polarized parallel and perpendicular to the strike of vertical cracks give information about the crack density. Field data are modelled to explain the significance of this effect. For thin cracks, the amplitudes of offset reflections can give information about crack content which maybe useful in crosshole work. Our ability to interpret offset reflected data is considerably reduced if the near-surface layers are also anisotropic or the acquisition line is not parallel or perpendicular to the crack strike. In the final part of this thesis vertical seismic profile data from three sites along the Austin Chalk trend in Texas are examined. Two of the data sets have multi-offset data which allows the anisotropic structure to be modelled. The anisotropic parameters of time delay and polarization angle are extracted from the data using a selection of currently available techniques. Most of the observed anisotropy is in the near-surface and polarization directions follow regional stress patterns. The anisotropic parameters are modelled and a combination of crack and thin layer anisotropy, giving an orthorhombic symmetry, is required to get a good fit.

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This thesis presents an investigation of the influence of elevated temperatures, defined in this thesis as within the range of 70°C-200°C, on the thermal-hydraulic-mechanical response of unsaturated soils. At elevated temperatures, high pore gas pressures develop due to an increase in both dry air pressure and vapour pressure. This gas pressure drives the flow of both gas and vapour, therefore advective flow of vapour dominates over diffusion flow. Moreover, elevated temperatures impact standard thermal/physical parameters of the various phases in the soil-water system. Based on Luikov's approach to thermal-hydraulic behaviour of capillary porous bodies, and an existing thermal-hydraulic-mechanical model, a new thermalhydraulic- mechanical formulation is developed within a mechanistic framework for unsaturated soils, applicable for elevated temperatures. Key advances carried out include the development of a new pore gas transfer equation as opposed to dry air transfer, changes to velocity of pore gas expression to account for elevated temperatures and the inclusion of thermo-osmotic flow of liquid due to temperature gradient. Also temperature sensitive parameters in the energy conservation equation have been considered as a function of temperature. A numerical solution is used to solve the theoretical formulation. A finite element method is presented to achieve spatial discretisation and temporal discretisation is achieved through the use of a finite difference technique. The performance of the model is explored via the simulation of two laboratory based experiments subjected to elevated thermal loads to cover the range of 70°C-200°C. Firstly, thermal and thermal-hydraulic experiments have been simulated to study the thermal-hydraulic response for a temperature boundary condition of 85°C. The new model shows a significant rise in pore gas pressure due to the elevated temperature. Consequently pore gas pressure gradients dominate the vapour flow. The advantages of the new model over an alternative model where elevated temperature effects are not considered are demonstrated via comparison of moisture distribution results. The new model shows much improved accuracy. A second simulation is carried out with an applied boundary temperature to a value of 150°C. The new model's performance again shows a significant increase in pore gas pressure due to the elevated temperature. Again the results yield a much improved solution compared to the alternative model.

This research project considers the development of numerical simulation processes of the production and management of leachate from landfill sites. The existing landfill leachate management models are reviewed and analysed on the basis of their applicability and effectiveness, identifying a number of important deficiencies in these models. These models simplify the actual flow process in the waste matrix and assume the same density throughout the simulation period. Moisture flow through waste material is investigated through experiments, and as a result different mathematical models were developed. These models represent the effect of density on the hydraulic properties of waste material such as: moisture capacities, drainage rates and saturated hydraulic conductivity. The effect of density is identified as the fundamental parameter governing the flow phenomena in waste material. A large database of information obtained provides a better interpretation of statistical analyses, in fitting statistical distributions to parameters and to cover the variability of waste material. A basic applied numerical model named NUMMOL (NUMerical MOdelling of Leachate) is developed based on the water balance approach, which simulates the leachate production, movement and distribution within landfill sites. NUMMOL incorporates the most appropriate mathematical models representing the various landfill hydrological processes. The moisture flow through waste layers is modelled using the models derived through experimental investigation. The model's limitations and assumptions are discussed with suggestions for future work that is necessary to enhance further its applicability. Sensitivity analysis and evaluation of the simulation capabilities of the NUMMOL model are included. It was found that correct identification of the hydraulic properties of the landfill material is very important. To investigate model usefulness and efficiency as an environmental planning tool, the individual components of the model are evaluated. It was found that the model iterative scheme is very effective in simulating leachate movement in a cell and leachate distribution within cells. The model was applied to the landfill site in order to compare the effect of layers on leachate distribution.

The main objective of this thesis has been to research the non-linear dynamic behaviour of fluid saturated porous media based on the Biot's formulation. Amongst several numerical methods the irreducible compressible form, and the irreducible incompressible (penalty) form are applied for this purpose. For numerical analysis the standard Galerkin method was applied. Relevant numerical solution techniques to this two phase problem are surveyed and emphasis was placed on a stability analysis of a staggered method for n-p formulation (displacement - pore pressure formulation) which has been given up to use on the middle of our research. The u-p formulation may be efficiently adopted with an explicit method for the solid and an implicit method the for fluid in the time integration scheme. As one of the problems for the application throughout 'during-' and 'post-' earthquake response were considered and in order to solve this type of problem efficiently, a variable step scheme was developed and applied to earthquake and consolidation problems. It is reported through experimental surveys that the high concentration of pore pressure built up by earthquake motion may induce liquefaction phenomena. New elasto-plastic models were implemented and investigated for their capability and performance to simulate the liquefaction phenomenon. Several numerical solutions were presented to discuss the physical nature of fluid saturated porous media and the behaviour of the numerical algorithm. Computational and programming aspects were also discussed and brief explanations of the computer program DIANA used here was presented.

This thesis comprises 28 papers which illustrate the nature and direction of development work and associated research undertaken between 1965 and 1993 on soil and rock anchorage systems. The research was performed in order to obtain a basic understanding of the behaviour of newly developed anchorage systems in a variety of ground types and conditions, in order to improve anchorage designs, construction methods and testing procedures, and thereby encourage the safe and economic application of ground anchorages worldwide. Field development of anchorage construction methods in gravels, sand, clays, marls and chalk using cement grout injection techniques is described together with equations evolved to estimate the ultimate resistance to withdrawal for each ground type, based on systematic testing of full scale anchorages. A new design method for single and multi tied stiff retaining walls installed in any soil is detailed and validated by large scale tests and closely monitored case histories. The interactions between wall, anchorage and soil are illustrated, coupled with the refinement of overall stability analyses in cohesionless soils using wedge and log spiral based mechanics of failure. For the rapid installation of anchorages in granular soils, vibratory driving is investigated in the laboratory and two distinct types of motion are found to exist. Theoretical equations of motion are developed to define the penetration processes and facilitate the design of vibrodrivers and vibrohammers. World practice in relation to the design, construction, testing and behaviour of rock anchorages is appraised, and field studies permit an improved understanding of uplift capacity by general shear failure, load transfer mechanisms, bond at rock/grout and grout/tendon interfaces, debonding, service performance and post-failure behaviour.