Foundations constructed by the deep mixing method have been used to successfully support embankments, structures, and excavations in Japan, Scandinavia, the U.S., and other countries. The current state of practice is that design is based on deterministic analyses of settlement and stability, even though deep mixed materials are highly variable. Conservative deterministic design procedures have evolved to limit failures. Disadvantages of this approach include (1) designs with an unknown degree of conservatism and (2) contract administration problems resulting from unrealistic specifications for deep mixed materials. This dissertation describes research conducted to develop reliability-based design procedures for foundations constructed using the deep mixing method. The emphasis of the research and the included examples are for embankment support applications, but the principles are applicable to foundations constructed for other purposes. Reliability analyses for foundations created by the deep mixing method are described and illustrated using an example embankment. The deterministic stability analyses for the example embankment were performed using two methods: limit equilibrium analyses and numerical stress-strain analyses. An important finding from the research is that both numerical analyses and reliability analyses are needed to properly design embankments supported on deep mixed columns. Numerical analyses are necessary to address failure modes, such as column bending and tilting, that are not addressed by limit equilibrium analyses, which only cover composite shearing. Reliability analyses are necessary to address the impacts of variability of the deep mixed materials and other system components. Reliability analyses also provide a rational basis for establishing statistical specifications for deep mixed materials. Such specifications will simplify administration of construction contracts and reduce claims while still providing assurance that the design intent is satisfied. It is recommended that reliability-based design and statistically-based specifications be implemented in practice now. / Ph. D.

Thesis regarding the application of the Kinematic Element Method to slope stability analysis in geotechnical engineering. / In this thesis, the effectiveness of the Kinematic Element Method (KEM), developed by Dr. Gussmann at the University of Stuttgart, was evaluated by comparing the solutions with the Limit Equilibrium Method (LEM), specifically the Morgenstern-Price method. The KEM was evaluated using a variety of problems, ranging from homogeneous slopes to retaining walls. The KEM was shown to predict similar potential failure mechanisms and values for the factor of safety (FS) as the Morgenstern-Price method. The FS were generally within the ±6% which is the range of variance for rigorous limit equilibrium methods. A simplified version of KEM (KEMv) was developed based on limit equilibrium formulations. In KEMv, an alternate iterative scheme to determine the FS is proposed, in which boundaries between elements are vertical. The KEMv provided similar values for the factor of safety and interelement forces as Gussmann’s KEM for vertical interelement boundaries given similar element locations. The KEM was assumed by Gussmann to be an upper bound solution. However, given the similarities in the solutions between KEM and KEMv, it may be a limit equilibrium method. The interelement forces from the KEM and KEMv were found to be sensitive to the location of the elements. Elements in the upper part of the slope often had small normal forces relative to shear forces, possibly being negative as well. Sensitivity analysis regarding the number of elements showed that a 5-element solution predicts the appropriate failure mechanism and provides a reasonably accurate FS. In a parametric study, slope geometry and soil properties were varied and comparisons were made between KEM and the Morgenstern-Price method. The KEMv displayed similar trends in factor of safety as the Morgenstern-Price method but predicted slightly larger values. The change in KEM critical slip surfaces with soil properties was consistent with trends predicted by Janbu’s dimensionless parameter. / Thesis / Master of Applied Science (MASc) / The stability of slopes is a challenging subject in geotechnical engineering. Geotechnical engineers are often interested in the factor of safety (FS), which is a quantitative measure of the stability of a slope. In this thesis, the effectiveness of the Kinematic Element Method (KEM) is evaluated by comparing its solutions to the Limit Equilibrium Method (LEM). The KEM was shown to predict similar potential failure mechanisms and values for the factor of safety. A simplified version of the KEM (KEMv) was developed based on LEM formulations. In KEMv, an alternate iterative scheme to determine the FS is proposed, in which the boundaries between elements are vertical. The KEMv provided similar values for the factor of safety and element forces as Gussmann’s KEM for vertical interelement boundaries. In a parametric study, KEM displayed similar trends in the change in FS and critical slip surface as the LEM.

Failure of slopes adjacent to the UK transport infrastructure causes delays and these are expensive assets to repair and maintain. Understanding the processes that lead to failure will assist asset managers both now and in the future in the context of a changing climate. The EPSRC-funded multidisciplinary FUTURENET project investigated the effect of climate change on the resilience of the UK transport network and this thesis is a part of that project considering the weather patterns leading to slope failures along transport infrastructure slopes within the UK. To that end a series of slope failure case studies were investigated to understand the processes leading to failure. These were compiled using nationally held datasets as well as news reports. This research used data from the FUTURENET partners that hold national data sets and asset management information. This shows the wide reaching remit of a multidisciplinary collaborative project such as FUTURENET, but also highlights the limitations of datasets collected and used for very specific purposes and not necessarily suited to wider research. From these case studies a suite of slope failure weather thresholds were developed. These thresholds consider the antecedent period, water content within the slope through the soil moisture deficit and triggering rainfall through comparison to the long term average rainfall. Consideration was given to possible future weather using weather event sequences (WESQs), possible weather patterns for 2050 derived from the UKCP09 climate projection data. By considering these possible weather patterns with the slope failure thresholds a picture of a possible future was evaluated.

Σκοπός αυτής της Διπλωματικής εργασίας είναι η αποτύπωση της κατάστασης της κατολισθαίνουσας ζώνης στην επαρχιακή οδό Παλαιοχωρίου - Χρυσοχωρίου, στα δύο σημεία που παρατηρήθηκαν αστοχίες. Στην περιοχή αυτή πραγματοποιήθηκε αποτύπωση και χαρτογράφηση της κατολισθαίνουσας ζώνης, παρουσιάζονται τα αποτελέσματα της τεχνικογεωλογικής - γεωτεχνικής έρευνας που παρατηρήθηκαν στις δύο θέσεις αστοχίας, μετά από την μεγάλη κατολίσθηση που εκδηλώθηκε το Φεβρουάριο του 2010 από έντονες βροχοπτώσεις, καθώς και τον σχεδιασμό των μέτρων προστασίας της επαρχιακής οδού Παλαιοχωρίου -Χρυσοχωρίου. / The purpose of this essay is to capture the situation of landslide zone on provincial road Palaiochorioy - Chrysochorioy, at two failures were observed.In this area was done survey and maps of landslide zone which presents the results of geotechnical - geotechnical investigation, observed in both locations of failure, after major landslide that occurred in February 2010 after heavy rains, and the design of measures to protect the provincial road Palaiochorio-Chrysochorioy.

Seismic slope stability is often evaluated via permanent displacement analyses, which quantify the cumulative, downslope displacement of a sliding mass subjected to earthquake loading. Seismic sliding block displacements provide a useful index as to the seismic performance of a slope. Seismic sliding block displacements can be computed for a suite of acceleration-time histories selected to fit a design event. This thesis explores the effect of ground motion selection on computed seismic sliding block displacements through two approaches. First, rigid sliding block displacements were computed for ground motion suites developed to fit uniform hazard spectra (UHS), conditional mean spectra (CMS), and conditional probability distributions for peak ground velocity (PGV) and Arias Intensity (Ia). Evaluation of the suites in terms of their PGV and Ia distributions provided useful insight into the relative displacements computed for the suites. The PGV and Ia distributions of the suite selected to fit the UHS exceed the theoretical distributions of these ground motion parameters. In fact, the scaled Ia values of motions in the UHS suite are greater than the largest Ia values in the Next Generation Attenuation (NGA) ground motion database. As such, the displacements computed for the UHS suite exceed the displacements computed for any other suite. If only two ground motion parameters are to be considered in ground motion selection we recommend those parameters be PGA and PGV. However, it is important to consider PGA, PGV, and Ia when developing ground motion suites for permanent displacement analyses. Next, the use of simulated ground motions for permanent displacement analyses was addressed by comparing displacements computed for simulated ground motions to displacements computed for the corresponding recorded ground motion. Simulated ground motions generated via four seismological models were considered: the deterministic Composite Source Model (CSM), the stochastic model EXSIM, the deterministic-stochastic hybrid model by Graves and Pitarka (GP), and the deterministic-stochastic hybrid model developed at San Deigo State University (SDSU). The displacements computed for the SDSU simulations were the most similar to those computed using the recorded motions, with the average displacement of the SDSU simulations exceeding that of the corresponding recorded ground motion by about 6%. Additionally, the displacements from the SDSU simulations provided the smallest variability about the displacements computed for the recorded motions. / text

Let (L,h) → (X,ω) be a compact toric polarized Kahler manifold of complex dimension n. For each k ε N, the fibre-wise Hermitian metric hk on Lk induces a natural inner product on the vector space C∞(X,Lk) of smooth global sections of Lk by integration with respect to the volume form ωn /n! . The orthogonal projection Pk : C∞(X,Lk) → H0(X,Lk) onto the space H0(X,Lk) of global holomorphic sections of Lk is represented by an integral kernel Bk which is called the Bergman kernel (with parameter k ε N). The restriction ρk : X → R of the norm of Bk to the diagonal in X × X is called the density function of Bk. On a dense subset of X, we describe a method for computing the coefficients of the asymptotic expansion of ρk as k → ∞ in this toric setting. We also provide a direct proof of a result which illuminates the off-diagonal decay behaviour of toric Bergman kernels. We fix a parameter l ε N and consider the projection Pl,k from C∞(X,Lk) onto those global holomorphic sections of Lk that vanish to order at least lk along some toric submanifold of X. There exists an associated toric partial Bergman kernel Bl,k giving rise to a toric partial density function ρl,k : X → R. For such toric partial density functions, we determine new asymptotic expansions over certain subsets of X as k → ∞. Euler-Maclaurin sums and Laplace’s method are utilized as important tools for this. We discuss the case of a polarization of CPn in detail and also investigate the non-compact Bargmann-Fock model with imposed vanishing at the origin. We then discuss the relationship between the slope inequality and the asymptotics of Bergman kernels with vanishing and study how a version of Song and Zelditch’s toric localization of sums result generalizes to arbitrary polarized Kahler manifolds. Finally, we construct families of induced metrics on blow-ups of polarized Kahler manifolds. We relate those metrics to partial density functions and study their properties for a specific blow-up of Cn and CPn in more detail.

[pt] Movimentos de terra em encostas frequentemente causam grandes prejuízos econômicos, ambientais, sociais e, com freqüência, perda de vidas humanas. O mecanismo que desencadeia o processo de movimentação geralmente ocorre em períodos de chuvas intensas, principalmente nas encostas com pouca cobertura vegetal ou naquelas que sofreram mudanças recentes na topografia, geralmente pela execução de cortes. Neste trabalho foram realizadas análises de estabilidade da um trecho da encosta da BR-376, que liga as cidades de Curitiba a Joinville no km 55+800 do oleoduto OSPAR da Transpetro. Em 1995, cortes executados para duplicação da rodovia provocaram instabilidade em certa área da encosta. Em janeiro de 1997, durante um período de fortes chuvas, um novo escorregamento da porção inferior do talude provocou a ruptura do muro existente e uma série de escorregamentos sucessivos, que chegaram a atingir a faixa dos oleodutos. Diante desse cenário, utilizou-se primeiramente o programa de elementos finitos PLAXIS para as análises de estabilidade e posteriormente, a fim de comparação, o programa Slope/W e Sigma/W. Para as análises no PLAXIS foi utilizado o hardening soil model para o solo, com os parâmetros sendo determinados através de ensaios triaxiais com amostras obtidas de dois blocos de solo coletados das encosta. Os efeitos da movimentação da encosta no oleoduto OSPAR foram analisados por programa 3D de elementos finitos, dando-se ênfase às tensões e deformações para se a fim de verificar a integridade do duto. / [en] In densely populated urban areas, landslides generally cause large economic, social and environmental damages as well as, quite frequently, the loss of human lives. The main triggering factor for soil slope failures is the occurrence of heavy rainfalls and the most affected slopes are those with little vegetal covering or that had suffered recent changes in topography, generally due to the execution of cuts and excavations. In this work, stability analyses of a soil slope located at km 55+800 of the Transpetro’s OSPAR oil pipeline were carried out In 1995, the works for the duplication of the BR-376 highway, connecting the cities of Curitiba and Joinville, caused some instability in certain area of the soil slope. Later, in January 1997, during a period of heavy rainfall, a new landslide near the slope toe provoked the failure of the existing retaining wall and triggered a series of successive slides that reached the protected area were the oil pipeline was buried. In order to better understand the mechanics involved in this process, numerical analyses were carried out using the computational programs Slope/W, Sigma/W and Plaxis v.8. The soil behavior was simulated considering the hard soil model, whose constitutive parameters were estimated from triaxial tests. The influence of soil movements on the OSPAR oil pipeline were investigated through a 3D finite element analysis, with emphasis on stress and strain distributions in order to check the pile line structural integrity.

Deslizamentos em solos tropicais são frequentemente resultados do avanço de uma frente de umedecimento devido às águas das chuvas. O avanço desta frente de umedecimento provoca elevação da poro-pressão de água ou redução da sucção, e consequentemente, perda de resistência do solo. Este trabalho apresenta um estudo sobre a resistência ao cisalhamento dos solos não saturados, abrangendo uma fase experimental envolvendo ensaios de caracterização, resistência e obtenção das propriedades hidráulicas dos solos e um estudo numérico, com o objetivo de verificar o comportamento da poro-pressão no interior de um talude e a influência na sua estabilidade. Os ensaios de resistência foram realizados no aparato de cisalhamento direto, para a condição inundada, e no aparato de compressão simples com medida direta de sucção, por meio do tensiômetro de alta capacidade (TAC), para a condição não saturada. O equipamento TRIFLEX 2 foi utilizado para se determinar os coeficientes de permeabilidade na condição saturada, e as curvas de retenção foram obtidas utilizando-se a placa de sucção, o TAC e o método do papel filtro. A partir dos resultados obtidos na fase experimental, avaliou-se a influência das características das precipitações (duração e intensidade), condições inicias de sucção no talude e das propriedades hidráulicas dos solos na variação da poro-pressão de água, no interior do talude, ao longo do tempo. Paralelamente à variação da poro-pressão de água, foi obtida a variação do fator de segurança durante e após a precipitação. / Landslides in tropical soils are often the result of advance of the wetting due to rainfall. This advance results from an increase in pore water pressure, reduction in present soil matric suction, reduction in the shear strength of the soil. This work will present a study related to the shear strength of unsaturated soils, including an experimental study, involving characterization, shear strength tests and obtaining hydraulic characteristics of the soils. There is also a numeric study with the aim to analyze the pore water pressure behavior in slopes and its influence in the slope stability. The shear strength tests were carried out in the direct shear test device, for the flooded condition, and concerning the unconfined compression with direct measured matric suction using a high capacity tensiometer (HCT) placed at the base of the sample, for the unsaturated condition. The permeability tests were carried out with TRIFLEX 2 device, and the retention curves were determined using suction plate, HCT and filtered paper. The experimental data permitted the evaluation of the influence of the characteristics of the rainfall (duration and intensity), initial conditions of the slope and of the hydraulic characteristics of the soils in the pore-pressure change of water in the slope, during the test time. In parallel to the pore pressure change of water, the variations of the safety factors during and after the rainfall were obtained.

Taludes formados por solos na condição não saturada são muito comuns no Brasil. Nestes casos a poro-pressão de água contribui para a estabilidade desses taludes. Este trabalho pretende avaliar o efeito do tipo de revestimento superficial na alteração do perfil de poro-pressão de água provocado por fluxos gerados a partir de precipitações, evaporação e evapo-transpiração, e conseqüentemente na estabilidade de talude experimental. São apresentadas aqui as características geológico-geotécnica, geomorfológica, climática e pluviométrica de campo experimental implantado na zona leste de São Paulo/SP, onde foram instalados e monitorados tensiômetros, pluviômetro e medidor de nível dágua por um período oito meses. Resultados de ensaios de caracterização, resistência e obtenção das propriedades hidráulicas dos solos que compõem o maciço estudado são analisados, assim como ensaios realizados com a argamassa de revestimento do talude, ensaios para a análise do funcionamento dos tensímetros e tubos tensiométricos utilizados no monitoramento, e outros ensaios realizados in situ. O monitoramento realizado indicou coerência entre precipitações e variação da poropressão de água, e variação do nível dágua do terreno, em ambos os tipos de revestimento superficial, vegetação natural e argamassa, nos dois tipos de solo presentes no maciço. Análises de estabilidade do talude indicaram o efeito do tipo de revestimento superficial e das variações sazonais de poro-pressão de água no fator de segurança ao escorregamento do talude. / Slopes formed by unsaturated soils are very common in Brazil. In these cases porewater pressure contribute for the slope stability behavior. This work aims at evaluating the effects of types of superficial coating on the profile of pore-water pressure changes, due to flow generated by precipitation, evaporation and evapotranspiration, and consequently on the stability of a experimental slope. It is presented here the geological-geotechnical, geomorfological, climatic and pluvial characterizations of the experimental field located in the east zone of São Paulo/SP, where have been installed and monitored tensiometers, pluviometer and groundwater level measurer during eight months. Results of tests of characterization, shear strength, and for obtaining the hydraulic properties of the in situ soils are analyzed, as well as the tests carried out with de mortar applied over the slope, as well as the functionality tests for the tensimeters and tensiometric tubes used on the monitoring, as well as other in situ tests. Monitoring indicated coherence between precipitation and change in pore-water pressure profile, and groundwater level, in both types of superficial coatings, natural vegetation and mortar, and in both types of in situ soils. Stability analyzes indicated the effect of the type of superficial coating and of the variation of pore-water pressure profile, during the experiment, on the factor of safety of the experimental slope.

Métodos de estudo de estabilidade de taludes são diversificados e estão bastante desenvolvidos e consolidados na Geologia de Engenharia. Paralelamente, a aplicação de ferramentas de geoprocessamento tem se intensificado bastante em todos os campos de conhecimento técnico científico, demonstrando ser uma ferramenta de grande importância e auxiliando a tomada de decisão, sendo inclusive utilizado no estudo de escorregamentos e processos correlatos a instabilização de taludes. Dentro deste contexto, este trabalho objetivou desenvolver uma abordagem de estudo para caracterizar a estabilidade de taludes de mineração combinando técnicas e métodos usuais de investigação e análise geológico-geotécnica. A pesquisa foi aplicada nas minas de ferro do complexo Fazendão, localizadas no município de Catas Altas (MG) e são de propriedade da companhia VALE S/A. O trabalho está dividido essencialmente em duas etapas de estudo: primeiramente um foco semi-regional, seguido de um estudo de detalhe em uma mina em particular. Para a análise semi-regional foi utilizando Sistema de Informação Geográfica - SIG para geração de mapas temáticos, abrangendo todas as minas do complexo. Já no estudo de detalhe, foram realizados levantamentos sistemáticos em campo na mina de São Luís, sendo posteriormente realizado um levantamento específico de seções dentro da mina. A partir dos mapas temáticos foram identificadas as principais drenagens e bacias hidrográficas da área de estudo. Estes mapas juntamente com os mapas de declividade, curvatura, direção de vertente e mapa geológico, forneceram informações importantes sobre a região onde as minas estão inseridas, o que possibilita um melhor planejamento das intervenções que vierem a serem feitas. As análises por estereogramas indicaram várias situações de instabilidade frente às direções de fraturas e bandamento, com relação à direção e ângulo de mergulho de alguns taludes, sendo várias destas feições identificadas em campo. Por outro lado, a análise por equilíbrio limite apontam fatores de segurança muito altos, desde que não ocorra a influência do nível de água. Por fim, a abordagem utilizada foi bastante útil na caracterização da região. O estudo semi-regional em conjunto com uma análise de detalhe permitiu identificar feições que comprometem a segurança dentro da mina. A partir do resultado deste estudo, espera-se auxiliar a programação do avanço da mina de forma otimizar sua exploração, sem comprometer a segurança. / Methods of study of slope stability are diverse and are well developed and consolidated in Engineering Geology. In addition, the application of GIS tools has intensified greatly in all fields of scientific expertise, proven to be an important tool aiding in the decision making, including being used in the study of landslides and processes related to slope instability. Within this context, this study aimed to develop a approach to characterize the stability of slopes mining combining geoprocessing techniques and the usual methods of investigation and analysis of geological-geotechnical. The research was applied to the iron mines of Fazendão complex, located in the municipality of Catas Altas (MG) and are the property of the company VALE S/A. The research is divided into two main stages of the study: first a semi-regional focus followed by a study in detail of a particular mine. For the semi-regional analysis has been using GIS for thematic maps, covering all the mines the complex. In the study of detail, systematic surveys were conducted in the field for geological and geotechnical parameters in the mine of São Luís, and later conducted a survey within specific sections of the mine. From the thematic maps were identified the major drainage and hydrographic basins of the study area. Those maps, analyzed together with the slope map, curvature, direction of slope and geologic map provided important information about the area which the mines are located, allowing better planning of interventions that were to be made. The stereograms analyzes indicated various situations of instability depending of the fractures and banding directions, according to direction and dip angle of some slopes, some of it identified in the field. Moreover, the limit equilibrium analysis safety factors showed very high, since there was no influence of the water levels. Finally, the used approach was useful in characterizing the region. The semi-regional study combined with a detail analysis allowed to identify features that compromise the safety inside the mine. From the results of this study is expected to help advance the schedule of the mine in order to optimize their operations, without compromising security.