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A Field Survey and mapping was conducted after photo interpretation at a scale of 1:11,000 in an area of Northeast Scotland having varying geological features, physical conditions and land use. Mineralogical and Micromorphological analysis of modal pedo-units samples were carried out. Two Transects were marked out for land cover classification and soil mapping using the following remote sensing techniques: Aerial Photo-Interpretation (API), Landsat MSS and Airborne Thematic Mapper (ATM). MSS bands 4, 5, 7 and the corresponding ATM bands 3, 5, 6 were used in order to highlight the effects of spatial resolution. Five image classification techniques, Density Slicing (DS), Unsupervised Cluster Analysis (CL), Box Classification (BX), Maximum Likelihood (ML) and Visual Interpretation (VS) were used to separate six major land classes (urban, forest, agricultural land, moorland, bare soil and water). For soil survey and mapping the land cover classifications were compared with the various soil units in the study area. There is a weak correlation between the mineralogy and the soil types but the micromorphology correlated well with the soil types. Accuracy test for MSS August shows that ML has the highest classification accuracy having 70.0-75.6%. For MSS April computer aided VS having 72.1-77.6% is the most accurate. For the ATM the Unsupervised algorithm cluster analysis is the most effective having accuracy range of 86.6-90.6%. The comparison of the three remote sensing techniques shows that for land cover classification API is the most accurate having 93.3% followed by ATM bands (3, 5 and 6) CL having 86.6-90.1%. Landsat MSS had only 72.1-72.6%. The lower than expected value for the ATM is probably due to inappropriate and inadequate waveband selection (3 out of 11 bands). For soil survey the ATM CL analysis is the most effective. Accuracy for API and ATM are 70.6-76.2% and 86.9-90.9% respectively. It is expected that higher classification accuracy can be obtained from the ATM data by adequate waveband selection. Those suggested are bands 2, 3, 4, 5, 7, 10 and 11.

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In 1979, the volcanic island of Dominica was severely affected by Hurricanes David and Frederic. Together they devastated vegetation and buildings and resulted in innumerable landslides on the predominantly very steep slopes of the deeply dissected landscape. This thesis examines the major medium to long term effects of these hurricanes and in particular assesses their role in initiating rapid mass movements. Despite the massive disturbance caused by the 1979 hurricanes, and also by a third, Allen (in 1980), evidence suggests the landscape is rapidly reverting to its pre-hurricane state. Variations in the frequency of tropical cyclones will clearly have great effect on the denudation characteristics of the Dominican (or similar) environments. The thesis, therefore, first examines the changing frequency of West Indian tropical cyclones. Cyclone frequencies were particularly high in the periods 1780-1840, 1880-1910 and 1930-1959. Large troughs in the frequency of cyclones are noted in the mid 17th century and since 1960. Superimposed upon these peaks and troughs have been marked variations in favoured tracks. During the 20th century there has been a definite shift in mean tracks, northwards and eastwards. The unusual physical, geotechnical and hydrological characteristics of the island's residual clay soils are investigated and the considerable problems which arose in the measurement and geomorphological interpretation of soil properties are stressed. A detailed understanding of soil formation and runoff processes, notably depth of soil, zones of percolation impedence, throughflow, and positive pore water pressure development is found to be essential to explanations of slope failure patterns. Although only a small increase in positive pore water pressure would be necessary to initiate failure in the deeper soil horizons, the amount of additional water necessary to achieve this is large. It is suggested that such an increase could only occur in the type of exceptionally prolonged and high intensity rainfalls associated with tropical cyclones.

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A set of finite element computer programs has been written for the settlement analysis of structures founded on normally consolidated and lightly overconsolidated soft clays. The programs take into account nonlinear material stress-strain behaviour and creep. Analyses may assume 'undrained' and 'drained' conditions and fully coupled consolidation analyses are also possible. The 'modified' Cam clay model has been used with some modification to model nonlinear material stress-strain behaviour and a phenomenological creep relationship to model creep behaviour. The author's programs have been-tested against another, fully tested, finite element package and also against closed form solutions where they exist. Sensitivity of the results of creep analyses in response to possible variations in the determination of the values of the creep parameters has also been studied. Results of a combined creep and consolidation analysis of a flexible strip footing. indicate the relative importance of creep displacements with respect to the consolidation settlements which are difficult to separate in practice. A review is made of the main nonlinear models of soil behaviour available to the practising engineer. The main techniques within the finite element method that are used to implement such nonlinear soil models are also reviewed and the 'initial strain' method chosen for use in the computer programs developed. The author's programs have been used to calculate displacements and excess pore pressures resulting from the construction of a trial embankment built at Cubzac-les-Ponts in France and compared to the measured in-situ values. In the conclusions an appraisal is made of the soil model developed by the author and the nonlinear finite element solution technique used. Also, the results of analyses using the computer programs and the accuracy of the results of the analyses of the trial embankment are summarised. The author's computer programs are explained and listed in the form of appendices.

Theoretical models for the prediction of the performance of wide cutting blades have been in existence for some time. These models characterise the soil as a rigid-plastic Mohr-Coulomb material and depend on advanced mathematical techniques developed for the solution of the complex equations of equilibrium of soil elements in two-dimensional plane-strain failure. Less rigorous techniques have been employed for developing mathematical models for the behaviour of deep narrow tines. In both cases the soil-implement contact boundary is assumed to be a plane surface of simple geometrical shape. The extension of these methods to deal with three-dimensional failure generated by curved loading boundaries is of comparatively recent origin. The soil failure patterns associated with disc soil cutting implements fall into this category. The thesis describes the development of a mathematical model for predicting the performance of such implements. The method employed follows the technique used by Godwin et al for reducing three-dimensional failure into two-dimensional components. The present analysis caters for discs implements having both inclination and disc angles. Soil contact in such implements takes place on complex curved surfaces and the geometry of these were analysed. These surfaces were approximated by plane elements which were then assumed to generate two-dimensional failure in planes parallel to the direction of translation of the disc. The rupture geometry and the forces acting on these elements are then computed using the Newcastle adaptation of Sokolovski's rigorous solution to soil failure. The force acting on the soil contact surface is then obtained by a version of the method of slices used for analysing slip surfaces. The model developed can predict the quasi-static soil reactions on disc implements from a knowledge of the disc geometry, soil properites and depth of cut. The computer programme was used to investigate the sensitivity of the input parameters to the final predicted results and this information was used to develop a set of non-dimensional force coefficients which can be used in a simple additive algebraic equation to predict the three orthogonal force components acting on the disc. Empirical correction factors have been devised to cater for deviations between these and computed valus and prediction to within 5 percent of the computer prediction are possible by this relatively simple method. In order to check the performance of this theoretical model a special dynamometer rig was designed and built to assess all three orthogonal force components acting on a disc tool. A single plough disc was tested in a loam soil and the computer prediction was in good agrement with experimental values. The model was also used to check other published experimental results and once again the prediction was good.

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