Title from PDF of title page (University of Missouri--Columbia, viewed on March 2, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. William Likos, Thesis Supervisor. Vita. Includes bibliographical references.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 101-106). Also available in electronic version.

Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 132-134). Also available via the World Wide Web.

The Arabian plate is classified as medium sized. It is surrounded by the Nubian, Somalian, Eurasian and Indian plates. Previous investigations of present-day kinematics of the Arabian plate using GPS measurements were primarily obtained from stations located on surrounding plates, with few stations actually located on the Arabian plate itself. Due to the inhomogeneous distribution of these GPS stations and the fact that some of these were actually located in the plate boundary zone, the motion of Arabia was only sensed in a few locations of the rigid plate interior. Through the establishment of GPS networks in Saudi Arabia, the aim of this study was to compute an updated estimate for the absolute and relative motion of the Arabian plate Euler pole and rotation rate. Then to investigate, at the regional scale, the strain rate accumulation within the Arabian plate. Then, to investigate, at a local scale, the strain rate accumulation in the tectonically active south-western part of Saudi Arabia. The results of this study are on absolute motion model for the Arabian plate which is significantly different from those obtained in previous studies, as a result of the number of stations used and their distribution. This does not mean that the previous studies were in error, but that they suffered from a lack of evenly distributed geodetic data for Arabia. Hence, this study result is a new contribution to the knowledge of Arabian plate motion. The results of this study for the relative motion model of the Arabian plate with respect to the Eurasian, Nubian and Somalian plates confirms the results from previous studies, and confirms that the Arabian plate motion is slowing down. This study has also shown that, in general, the strain values are low in most of the Arabian plate, where there is a compression in the north-east to south-west directions and an extension in the north-west to south-east direction, except in two areas, the north-west, close to the Aqaba Gulf and the Dead Sea fault, and the southwest where there are high strain values and variable directions for the principle strain. Furthermore, this study agrees with geologic studies in that there is a compression north-east to south-west and extension north-west to south-east between Farasan Island and the coast of the Red Sea.

One of the greatest breakthroughs in soil mechanics was the development of Critical State Soil Mechanics (CSSM) in the 1950s and 1960s and the derivation of a continuum elasto-plastic constitutive model, namely Cam clay, which was the foundation for other continuum models for clays, and much later for sands. However, as yet there has been no micro mechanical analysis which explains the existence of such continuum models; such a micro perspective must take into account the discontinuous nature of soil. Without such insight, the engineer cannot understand which micro parameters affect soil behaviour. This work uses the discrete element method (DEM) to model a silica sand as a sample of discrete particles, with properties which have been calibrated against experimental data in previous work, to build up a micro mechanical picture of the behaviour of sand under different loading conditions. The simplest of loading conditions is the one dimensional or oedometer test and has been modelled to check whether this agrees with previously published research. The simulated sample has then been subjected to isotropic compression to establish a normal compression line in log voids ratio – log stress space, and which turns out to be parallel to the one-dimensional normal compression line, in agreement with CSSM. The evolution of the isotropic normal compression line is due to local shear stresses within the sample, and the origin of the existence of both lines lies in the evolution of a fractal distribution of particles with a fractal dimension of 2.5. The effect of boundary particles has then been minimised by choosing an appropriate aspect ratio and a smaller number of particles in the sample to give a computational time which is acceptable for subsequent shearing to critical states. Isotropically normally compressed samples have been unloaded to different stress levels and sheared to critical states. A unique critical state line (CSL) exists at high stress levels, which is parallel to the normal compression lines, in agreement with CSSM. At low stress levels, the CSL is not linear and is non-unique; that is to say it is a function of preconsolidation pressure because the fractal distribution of sizes has not fully evolved. Samples sheared on the dense side of critical dilate and have a peak strength whilst loose samples exhibit ductile contraction, in agreement with CSSM. At a critical state, the work shows that crushing continues in the formation of ‘fines’, small particles with smaller than 0.1mm dimensions, which plays no part in the mechanical behaviour, which is reflected in the average mechanical co-ordination number and which means that plastic hardening can be assumed to have ceased at a critical state. For the isotropically overconsolidated samples sheared to critical states, a number of different definitions of yield have been used to establish a yield surface in stress space. The work shows that a previously published yield surface for sand (Yu, 1998; McDowell, 2002) gives a good representation of the behaviour, and it has therefore been shown that the sample of discrete particles has been shown to give rise to observed continuum behaviour. The work is, to the author’s knowledge, the first that has shown a DEM soil to show many of the desirable features of sand, in that the sample qualitatively gives normal compression lines and a CSL of the correct slope, which obeys CSSM and which gives a Cam Clay type yield surface in stress space. The work means that the established model can be used in the study of other micro mechanics problems such as particle shape and time effects and the application of DEM to boundary value problems directly.

Current needs for infrastructure and services in urban areas often require the construction of tunnels that may affect existing surface and buried structures. In general, the construction of new tunnels in the proximity of deep foundations raises concerns related to pile failure and associated structural damage (in both the superstructure and the foundation). Despite its practical importance, few studies have investigated the global tunnel-pile-structure interaction (TPSI) and, thus, engineers generally compensate for the lack of understanding with an overly conservative design approach. To provide insights into the interaction mechanisms of TPSI, this research used geotechnical centrifuge testing as the main investigation method to acquire data related to both greenfield tunnelling in sands and tunnel excavations beneath piles and piled buildings. In particular, a novel method was developed to study TPSI problems through the real-time coupling of numerical and centrifuge modelling, enhancing centrifuge modelling capabilities. Furthermore, empirical and closed-form solutions were used to study the tunnelling-induced displacement fields and simplified elastic analyses were used to provide insights into the global TPSI mechanisms. Results from the greenfield tests illustrate that ground movement prediction in sands is very complex because of soil arching effects and changes that occur as tunnels transition from relatively shallow to deep depths, resulting in highly non-linear displacement mechanisms. Results also illustrate the correlation between vertical and horizontal displacement mechanisms. In particular, the influence of soil relative density and volume loss on deformation patterns is highly dependent on the tunnel relative depth. To provide simple tools for engineering practice, empirical and closed-form solutions are proposed. Predicted ground movements provide sufficient accuracy for preliminary assessments, though limitations of these methods should be considered. The centrifuge tests on TPSI provide experimental evidence that tunnelling-induced pile displacements are affected by [i] pile installation method (displacement versus non-displacement piles), which affects the pre-tunnelling soil state and the distribution of loads between pile shaft and base, [ii] initial safety factor of the pile foundation, which is related to pile bearing capacity and superstructure self-weight, and [iii] superstructure stiffness and configuration, which results in pile load redistribution while minimising structural distortions. In addition, results show that potential for pile failure is a critical aspect for piles with relatively low initial safety factors and that pile failure may be prevented by a limited relative reduction in the pile load due to the superstructure. Finally, the importance of superstructure stiffness and self-weight on tunnelling-induced structural distortions is confirmed. Piled buildings respond critically to tunnelling beneath the pile tip depth in terms of flexural deformations. In general, it is shown that [iv] piles increase structural distortions compared to shallow foundations and that [v] the superstructure stiffness and self-weight decrease and increase the superstructure distortions resulting from tunnelling, respectively. Results are also evaluated within the modification factor approach; parametric analyses of elastic soil-pile-structure interaction are used to develop simple design charts that can be used to estimate horizontal strains and deflection ratio modification factors based on newly defined relative axial and bending stiffness parameters. The envelopes compare well with deflection ratio modification factors measured from centrifuge tests. Further research is needed to include the effects of soil plasticity, building self-weight, superstructure configuration and tunnel-structure eccentricity in these design charts. This dissertation highlights the improvements in the design of underground constructions that can be achieved by combining ground and structural engineering.

As one of the most versatile and reliable in-situ devices, cone penetrometers have been extensively used in soil exploration (e.g. soil classification, soil profiling, back-calculation of soil properties etc.) both experimentally and theoretically over the past 80 years. To improve its site accessibility, reduce the required sample size with minimal boundary effects, or model soil penetration by plant roots or earthworms, cone penetrometers with various sizes are often employed both in the field and laboratory. Consequently, size-dependent performance may appear, and this is one of the subjects of this research. A series of cone penetration tests with three sized cone penetrometer (12mm, 6mm, 3mm) on the Leighton Buzzard sand with two fractions (E and C) was performed at the 1g condition. Evident size effects were observed both in the cone tip resistance and shaft friction. To account for the observed size-dependent behaviour, theoretical methods based on the cavity expansion theory were developed in addition to the available experimental findings. Firstly, a size-dependent quasi-static cavity expansion solution was developed by improving the conventional cavity expansion theory incorporating with a strain gradient theory of plasticity. A stiffer response is modelled for a smaller cylindrical/ spherical cavity with this solution. Based on the analogy of cone penetration and quasi-static cavity expansion, the developed size-dependent expansion solution for spherical cavities was employed to quantify the size effect in the cone tip resistance, and fair good agreements were achieved between the theoretical prediction and experimental results. Subsequently, the scale effect observed in shaft friction resistance was explained in terms of the interface frictional strength and mobilised lateral soil stress. The size-dependent interface frictional strength was discussed based on the available experimental data of other researchers, and an improved solution based on the elastic cylindrical cavity expansion solution was derived to quantify the size dependency of the mobilised lateral stress on the shaft. In the light of above discussions, dominating factors influencing the size-dependent behaviours in the cone penetration test are summarised. The other objective of the present research was to model the mechanical interaction between a growing root tip and the surrounding soil. Two elastic solutions for computing the stress and displacement fields around a displacement-controlled ellipse were developed based on the complex variable theory of elasticity and Fourier series method. By assuming the axial cross section of a root tip as a half-ellipse, the two-dimensional soil response to a short-term growing root tip was discussed with the derived elastic solutions. Benefits of radial swelling of the root tip to its axial penetration were summarised, and an approximate analytical method to estimate the soil resistance mobilised by a short-term root growth was suggested and employed in the present root tip-soil interaction analyses. In addition, influences of the additional shear stress in the process of static and quasi-static cavity expansion were analysed with an elastic-perfectly-plastic model. For Tresca materials, a non-equal initial stress field was considered in the static stress solution, and a quasi-static expansion solution was then derived for a cavity deforming in a hydrostatic stress field considering the material compressibility. The static stress solution is capable of calculating the stress redistribution around a circular rotating probe, and the large-strain quasi-static solution may be useful in theoretical predictions of the tip resistance of a rotating penetrometer (or pile) which has been often utilised in needle cone penetration tests for modelling the root tip elongation. Then the introduced methods in above solutions were applied to the static stress analysis of a circular cavity surrounded by the Mohr-Coulomb material under a non-equal stress field. Based on the conformal mapping function proposed by Detournay and Fairhurst (1987), both a loading and unloading analysis were carried out with the derived analytical solution. It can provide a simple method to predict the plastic failure zone and calculate the stress redistribution around a circular excavation (e.g. tunnel, pipeline) either under loading or unloading.

Made available in DSpace on 2016-01-13T13:27:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-04-16. Added 1 bitstream(s) on 2016-01-13T13:33:10Z : No. of bitstreams: 1 000855531.pdf: 22155177 bytes, checksum: 4266696e47f9f52d9c0df84c015e88b1 (MD5) / A análise do meio físico feita através da avaliação de terrenos tem grande importância nos estudos da sua suscetibilidade a processos naturais, como os movimentos de massas. Este trabalho teve como objetivo avaliar duas formas de obtenção da suscetibilidade a escorregamentos aplicadas em imagens de alta resolução espacial (0,5 m) do sistema sensor GeoEye. A Análise Integrada analisa conjuntamente os elementos do terreno por meio da compartimentação fisiográfica da área. A Análise Paramétrica utiliza vários mapas temáticos, com mesma escala, para posterior sobreposição destes com aplicação de pesos definidos pelo Método AHP. A área de estudo possui 108,6 km², é um trecho da faixa de dutos ORBEL localizado no município de Duque de Caxias, e porções dos municípios de Nova Iguaçu e Belford Roxo, no estado do Rio de Janeiro. Essa região é atravessada por oleodutos e gasodutos e possui grande importância econômica. As etapas de trabalho envolveram: a caracterização da área com levantamento de dados bibliográficos; a confecção de mapas auxiliares através do Modelo Digital de Elevação, são estes os mapas Hipsométrico, de Declividade e de Formas de Vertentes, na escala 1:50.000; a elaboração do Mapa de Inventário a Escorregamentos por meio da extração das cicatrizes na imagem de Janeiro de 2010, onde foram identificadas 165 cicatrizes ao todo; o Mapa de Suscetibilidade a Escorregamento - Compartimentação Fisiográfica elaborado a partir da fotoleitura seguida da fotoanálise e fotointerpretação nas imagens GeoEye que resultou na divisão em quatro unidades fisiográficas. O Mapa de Suscetibilidade a Escorregamento - Método AHP foi gerado pela sobreposição com ponderação dos mapas auxiliares, foi utilizado o método de hierarquização pareada para a atribuição dos pesos e foram obtidas também quatro classes de suscetibilidade. A comparação dos mapas de suscetibilidade foi realizada de... / The analysis of the environment through the terrain evaluation has a great significance in the study of its susceptibility to natural processes, such as mass movements. This research aimed the comparison between two different approaches to landslide susceptibility mapping, using GeoEye high resolution images (0.5 m). In the Integrated Analysis, the terrain elements were analyzed together through the physiographic compartmentalization. In the Parametric Analysis several thematic maps in the same scale, were combined using weights, defined by the AHP Method. The study area has 108,6 km², is a stretch of the ORBEL pipeline located in the municipality of Duque de Caxias, and portions of the municipalities of Nova Iguaçu and Belford Roxo, Rio de Janeiro State. This region is crossed by several gas and oil pipelines and has a considerable economic significance. The research steps involved: characterization of the area with the support of bibliographic data; elaboration of auxiliary maps through the Digital Elevation Model, such as the Hipsometric, Declivity and Slope Form maps, scale 1:50,000; Landslide Inventory Map, through the extraction of landslide features in the image from January 2010, with a total of 165 identified features; Landslide Susceptibility Map - Physiographic Compartmentalization elaborated from the photo-reading, photo-analysis and photointerpretation in the GeoEye images that resulted in the division into four physiographic units. The Landslide Susceptibility Map - AHP Method generated through the weighted combination of several thematic maps, it used the pairwise hierarchy method for the allocation of weights and were also obtained four susceptibility classes. The comparison between the susceptibility maps was carried out using both quantitative and descriptive analysis. It is concluded that the two approaches reached the purpose of rating the landslide susceptibility, but the Parametric Analysis showed a greater level ...

Made available in DSpace on 2014-06-11T19:26:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-04-25Bitstream added on 2014-06-13T20:33:58Z : No. of bitstreams: 1 maia_mso_me_rcla.pdf: 2213372 bytes, checksum: 66c98972c27a86921f43056d7c86a3cc (MD5) / As características geotécnicas do solo, na maioria dos casos, não são consideradas nas intervenções feitas na estrutura urbana, pôr conseguinte também não as são nas expansões urbanas. Como conseqüência disso, verificam-se freqüentemente problemas como movimentos de massa, inundações, assoreamento de rios e igarapés, e erosões. O mapeamento geotécnico surge então como uma ferramenta indispensável para auxiliar o planejamento das intervenções necessárias para acompanhar o rápido crescimento urbano. Na obtenção do zoneamento geotécnico de uso geral, através da utilização do Sensoriamento Remoto, de nossa área de estudo-Sítio urbano do Município de Rio Branco/Ac e seus arredores, foram desenvolvidas três etapas. A primeira etapa consistiu na realização da compartimentação fisiográfica da área com base na análise de elementos texturais de relevo e drenagem e de suas estruturas em imagens fotográficas, obtendo-se assim as unidades básicas de compartimentação (UBC's). Na segunda etapa, estas unidades foram caracterizadas em função de cinco fatores geotécnicos (alterabilidade, permeabilidade, declividade, tipo do material do manto de alteração e espessura do manto de alteração) considerados básicos para subsidiar a avaliação das unidades quanto ao seu potencial de uso. Na terceira etapa as unidades básicas de compartimentação são classificadas quanto ao grau relativo de aptidões /restrições para fins de expansão urbana. / Geotechnical characteristics of the soil are rarely taken into consideration when interventions are made in the urban structure, nor, consequently, in urban expansions. As a consequence, there are often problems with landslides, floods, silt accumulation in rivers and sand bars and erosion. Geotechnical mapping has emerged as an indispensable tool to help plan the interventions needed to keep up with rapid urban growth. In this study, three stages were developed to obtain geotechnical zoning for general use in the study area, urban area of the Municipality of Rio Branco, in the state of Acre, using remote sensing. The first stage involved carrying out physiographic subdivision of the area based on analysis of textural elements of the relief and drainage system, and of their structures in photographic images, thus obtaining basic units of sub-division . In the second stage, these units were characterized according to five geotechnical factors (alterability, permeability, slope, type of material of the mantle of alteration, and thickness of the mantle of alteration) considered to be basic for the evaluation of the units with respect to their potential use. In the third stage, the basic units of sub-division were classified according to their relative degree of suitability/restrictions for urban expansion.

Made available in DSpace on 2015-07-13T12:10:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-08-29. Added 1 bitstream(s) on 2015-07-13T12:24:12Z : No. of bitstreams: 1 000836425_20180318.pdf: 302119 bytes, checksum: 884e33a7eff6f6538f9d09592eb55634 (MD5) Bitstreams deleted on 2018-03-23T14:17:27Z: 000836425_20180318.pdf,. Added 1 bitstream(s) on 2018-03-23T14:18:12Z : No. of bitstreams: 1 000836425.pdf: 1693868 bytes, checksum: f9f42c391dd2ffdabbcea05c83aef47f (MD5) / O Penetrômetro Dinâmico Leve, conhecido por DPL (Dynamic Probing Light) é um equipamento portátil de sondagem geotécnica e surgiu como uma alternativa para auxiliar o ensaio SPT (Standard Penetration Test). Este é hoje um dos equipamentos de sondagem mais utilizados no mundo. Embora o DPL tenha potencial para substituir o SPT nos ensaios em solos com baixa resistência à penetração, onde o N NSP <5. Na prática é ainda pouco conhecido na área da engenharia, com aplicação de pouco destaque nas obras da construção civil. A proposta deste trabalho é instrumentar um DPL com sistema eletrônico que possa em ensaio dinâmico, medir a resistência do solo à penetração. Essa medida se deve ao trabalho da energia efetiva que impulsiona o cone do equipamento para baixo cravando-o no solo. Constatou-se que o sistema eletrônico implantado no equipamento ficou mais barato que o seu similar, os resultados dos ensaios foram gerados em menor espaço de tempo, podem ser utilizados como dados de projetos de fundações. Os sinais de força e velocidade foram produzidos nas células de carga e acelerômetro. Para obtenção desses resultados, o sistema indicou automaticamente a penetração do cone no solo, motivada pela energia envolvida no processo, que por sua vez, é resultado da integração do produto da força atuante e da velocidade das partículas (no domínio do tempo). O objetivo do trabalho foi alcançado, visto que, a instrumentação do DPL, com um sistema eletrônico, possibilitou avaliar a resistência do solo à penetração. Constatou-se que essa medida está condicionada à qualidade do sinal de força e aceleração. Esta por sua vez depende de fatores como: qualidade técnica dos sensores de deformação, construção da célula de carga, qualidade do adesivo e corretos procedimentos nos ajustes e nos ensaios com o equipamento DPL instrumentado / The Dynamic Penetrometer Lightweight, known as, Dynamic Probing Light (DPL) is a portable geotechnical survey device, which came out, as an alternative tool to assist the Standard Penetration Test (SPT). Currently, it is one of the most used equipment all over the world. Although, the DPL has the potential for replacing the SPT in testing on soils with low penetration resistance, where the NNSP <5, it has not been known in the engineering field, applying little attention in the civil construction works. The purpose of this study is to instrument a DPL with electronics system intended to measure soil penetration resistance in dynamic test. This measure is due to the work of the effective energy that drives down the cone of the equipment, nailing it on the ground. It was found that the electronic system implemented in the equipment was cheaper than its similar, the results of the tests were generated in a shorter time and these findings can be used as data for foundation projects. The force and speed signals were produced on the load cells and accelerometer. In order to obtain these results, the system automatically indicated the penetration of the cone into the soil, caused by the energy involved in the process, which in turn, results from the integration of the active power output and speed of the particles (in the time domain). The objective of the study was reached, since the instrumentation of the DPL with an electronic system, enabled to evaluate the soil penetration resistance. It was found that this measure is subject to the quality of the force and the acceleration signal. This, in turn, depends on factors such as technical quality of strain sensors, load cell construction, quality of the adhesive and correct procedures on the adjustments, as well as, on the tests with the DPL instrumented equipment