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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Návrh sanace sesuvu / Design of Landslide Remediation

Poruba, Michal January 2015 (has links)
Main goal of thesis entitled "Landslide remediation design" is - based on acquired knowledge and submitted documents about the problematic of landslides - to determine the causes of the landslides on II. class road between villages Koryčany and Jestřabice and to propose optimal redevelopment.
182

Posouzení stability skalní stěny a návrh sanačních opatření / Assessment of the stability of rock walls and design of remedial measures

Nevřalová, Jana January 2015 (has links)
The work aims to evaluate rock slope including static assessment and to estimate the financial cost. Static analysis is done manually and the program GEO 5. The proposal remediation is performed in 6 combinations of which one is selected and processed into project documentation.
183

Analyse des processus de glissements gravitaires sous-marins par une approche géophysique, géotechnique et expérimentale : cas de la pente continentale de Nice / Analysis of submarine mass-movements processes through a geophysical, geotechnical and experimental approach : case study of the Nice continental slope

Kelner, Maëlle 21 December 2018 (has links)
Les glissements de terrains sous-marins, même de petite taille, représentent un risque majeur d’érosion littorale et de submersion marine lorsqu’ils sont déclenchés à proximité des côtes. Ce fut le cas à Nice (France) avec l’effondrement en mer d’une partie de la plateforme aéroportuaire, suivit d’un tsunami du fait d’un glissement sous-marin en octobre 1979. Du fait que la pente continentale niçoise soit abrupte, à proximité des côtes et soumise à une activité sismique modérée, elle constitue un véritable laboratoire naturel pour l’étude des glissements sous-marins de petite échelle. Ce travail repose sur une approche multidisciplinaire permettant une étude globale des processus de glissement dans la zone proximale. Il intègre des données issues de la géophysique marine, de la sédimentologie de la géotechnique et une phase préliminaire de modélisation numérique. Pour la première fois, la morphologie ainsi que l’architecture des dépôts du delta du Var ont été investigués à partir de données de très haute résolution. Elles ont permis d’identifier la signature de nombreux processus gravitaires de petite taille en surface (morphologie / taille / répartition spatiale) ainsi que leur imbrication en profondeur. Dans le cas du glissement de 1979, des éléments encore inconnus ont été identifiés tels que : 1) ses cicatrices Est et Ouest ; 2) des blocs et paquets glissés non évacués ; 3) la surface de glissement en profondeur ; 4) l’estimation d’un volume total déplacé différent du volume de sédiments évacués. Les carottes sédimentaires ont ensuite permis de discuter de la répartition en zone proximale des dépôts/érosion et de l’enregistrement de paléoglissement à partir de l’état de surconsolidation des dépôts. L’activité des glissements a été estimée dans le temps. Les plus grands glissements (V > 106 m3) ont des fréquences estimées ~50 ans, les glissements de taille moyenne (105 < V < 106 m3) autour de 3 à 25 ans, et les nombreux petits glissements (V < 105 m3) tous les 1-2 mois à 5 ans au cours des périodes actives des 50 dernières années. Ces glissements sont enregistrés dès la zone proximale à des fréquences de 3-7 ans au cours des périodes de plus forte activité depuis 400 ans. L’évolution de la morphologie suit des cycles successifs de déclenchement/quiescence/rechargement. À l’échelle de temps humaine deux cycles s’étendent de 1967-1999 et de 1999-2011 ; les ruptures se regroupent en cluster de 5-10 ans. À l’échelle pluriséculaire, les clusters de turbidites durent 20-40 ans et les périodes de quiescence ~100 ans. Enfin, cette étude apporte de nouvelles contraintes à propos des facteurs déclenchants ou préconditionnants agissant sur le delta du Var. L’état de stabilité de la zone semble être fortement préconditionné par la complexité de la topographie, l’état de consolidation des sédiments et l’importance des apports sédimentaires du Var. L’architecture des dépôts semble principalement contraindre la profondeur des instabilités. Parmi les forçages externes connus sur la zone, nous avons cartographié l’extension de la zone riche en gaz ainsi que des panaches de fluides dans la colonne d’eau. Notre analyse montre que l’amplitude des précipitations, des crues et du niveau de la nappe alluviale seraient trop faibles au cours des 50 dernières années pour agir en tant que facteur déclenchant de manière isolée. Afin de déstabiliser les pentes, ces forçages semblent devoir être couplés entre eux ou associés à l’action de séismes. Les analyses des bases de données en lien avec l’activité des glissements ainsi que les tests numériques permettent de suggérer que la sismicité régionale et que les séismes historiques sont soit 1) de magnitude trop faible, soit 2) à de trop grandes distances des zones de déclenchement, pour générer des PGA assez fort (0,2 g) et avoir individuellement un impact sur les pentes du Delta. / Small submarine landslides, when triggered near the coast represent a major coastal hazard due to erosion of the coastline and marine submersion. In October 1979, a submarine landslide generated a part of the airport platform of Nice (France) to collapse at sea and provoked a tsunami. Because the continental slope off this region is abrupt, close to the coast and subject to moderate seismic activity it is a natural laboratory to study small-scale submarine mass movements processes. This work is based on a multidisciplinary approach allowing a global study of landslide processes in the source area. It integrates data from marine geophysics, sedimentology, geotechnics and numerical modelling. For the first time morphology and architecture of the Var delta deposits are investigated using very high resolution data. It allows identification of numerous small-size gravitational processes signatures as well as their embedding at depth. In the case of the 1979 landslide previously unknown features are identified: 1) eastern and western scars, 2) in-situ blocks and lateral spreading’s traces, 3) in-depth sliding surface, 4) estimation of a total displaced volume, which is different from the evacuated sediment volume. The sedimentary cores are then used to discuss the proximal distribution of deposits, erosion and paleo-landslides records from the deposits overconsolidation. The landslide activity has been estimated over time in terms of return frequencies. The largest landslides (>106 m3) have return frequencies nearing 50 years; the medium-size landslides (105 > V > 106 m3) between 3 and 25 years; and the numerous small landslides (<105 m3) every 1-2 months to 5 years during the most active periods in the last 50 years. Landslides deposits recorded in the source area show return frequencies of 3-7 years during periods of greater activity over the last 400 years. The morphology’s evolution follows successive cycles of sliding/quiescence/reloading. In recent times, two main cycles can be observed (from 1967 to 1999 and from 1999 to 2011) during which triggering are clustered in 5-10 years. On a longer time scale, the turbidites clusters span 20-40 years and quiescence periods ~100 years. Finally, this study brings new constraints on preconditioning and triggering factors acting on the Var delta. The stability of the area seems to be strongly conditioned by the complexity of the topography, the sediments consolidation and the quantity of sediments brought by the Var river. The deposits architecture mainly constrains the depth of the instabilities. Among the external drivers known in the area the extension of the gas-rich zone as well as fluids plumes in the water column have been considered and mapped. Looking at other external drivers, the analysis shows that the magnitude of rainfall and floods, and the alluvial water level would be too low over the past 50 years to act as an isolated triggering factor. In order to destabilize slopes, these external drivers need to be tackled together or associated to earthquakes. Relationships between databases analyses, landslides activity and numerical tests suggest that regional seismicity and historical earthquakes are either too small or too distant from the source areas to generate sufficient peak ground acceleration (0.2 g) and to have an individual impact on the delta slopes.
184

Análisis de la influencia de la succión del suelo en la resistencia al corte dentro de la estabilidad de taludes / Influence analysis of soil suction on shear resistance within slope stability

Bermudez Lopez, Javier Antonio, Castañeda Mora, Alvaro Cesar 02 December 2020 (has links)
En la actualidad, dentro del ámbito nacional, la succión matricial es un parámetro que no se toma en cuenta dentro de los estudios de mecánica de suelos. Este motivo junto con la constante amenaza de deslizamientos de masa en el país generó la necesidad de llevar acabo un análisis para verificar los efectos del parámetro de succión dentro de un análisis de estabilidad de taludes de manera específica en tres sectores de la carretera Lima – Canta – Huayllay, Región Lima; y confirmar si los estudios sobre su relación con la resistencia al corte siguen el mismo principio. En el presente trabajo se realizan tres exploraciones geotécnicas directas (calicatas) dentro de la carretera en mención para la recuperación de muestras de suelo, realizar las respectivas caracterizaciones físicas y mecánicas como también efectuar un análisis de estabilidad de taludes para cada sector estudiado. Para la obtención de la succión matricial se utilizan curvas características suelo - agua para cada tipo de suelo muestreado; asimismo, se utiliza el software SLIDE para el análisis de estabilidad de talud estático y pseudoestático. / Nowadays, within the national scope, the matrix suction parameter is not taken into consideration within the soil mechanics studies. This reason, in conjunction with the constant threat of mass landslides in the country, generated the need to carry out an analysis to verify the effects of matrix suction within a slope stability analysis specifically in three sectors of the Lima - Canta highway. - Huayllay, Lima Region; and confirm whether studies on its relationship with shear strength follow the same principle. In the present work, three direct geotechnical explorations (pits) are performed within the mentioned road for the recovery of soil samples, to conduct the respective physical and mechanical characterizations as well as to conclude with a slope stability analysis for each studied sector. To obtain the matrix suction, soil-water characteristic curves were used for each type of soil sampled; likewise, SLIDE software is used for static and pseudostatic slope stability analysis. / Trabajo de investigación
185

Flexible culverts in sloping terrain : Research advances and application

Wadi, Amer January 2015 (has links)
Although the construction of flexible culverts involves simplicity in comparison to similar concrete structures, the complexity of the beneficial interaction between soil and steel materials requires good understanding for their composite action and performance. Current design methods have certain validity limitations with regard to applicable slopes above the structures. Given the short construction time of flexible culverts, there is an urge to explore the feasibility and the constructability of such as cost-effective structures in sloping terrain, where they may function as an avalanche protection structure for a given road, a culvert under a ski slope, or even as a protection canopy for tunnel entrances. This report compiles the efforts carried out toward gaining knowledge about the different factors that may affect the behaviour of flexible culverts in sloping environment. The report includes an extended summary of the investigation, which is mainly presented in two appended papers. The study involved numerical simulation of three case studies to investigate their performances with regard to soil loading and avalanche loads as well. The height of cover, surface slope intensity, slope stability, soil support conditions, and avalanche proximity, were studied and discussed. The study results allowed realizing the susceptibility of flexible culverts to low heights of soil cover when built in sloping terrain, which is reflected in the deformation response and the incremental change in sectional forces, especially the bending moments. It is also found that increasing the depth of soil cover may feasibly improve the structural performance under asymmetrical soil loading and avalanche loads, where it subsequently help in reducing the bending moments in the wall conduit. The presence of a flexible culvert may affect adversely the soil stability in sloping terrain and thus need to be addressed in design. Furthermore, the flexural response of a flexible culvert is directly influenced by the soil support configuration at the downhill side of the structure. In addition, the report also attempts to highlight some general guidelines about the design aspects of flexible culverts in sloping terrain, and seeks to reflect some of the findings on the design methodology for flexible culverts used in Sweden. / <p>QC 20151130</p>
186

Sesuvy v mělkých neogenních pánvích při jihozápadním okraji karpatské předhlubně na Moravě / Landslides in shallow Neogene basins along the southwestern margin of the Carpathian Foredeep in Moravia

Brdečková, Helena January 2019 (has links)
The Carpathian foredeep is a lengthwise depressed area in the Carpathian foreland. In Moravia, it is mainly filled with Neogene soils. The thesis focuses on the South Moravian landslides which occurred in shallow relicts of Neogene deposits along a foredeep margin which lie on the rocks of the Bohemian Massif. Landslide activity within these shallow basins is a result of a number of factors. In the theoretical part, important general features of landslide areas, their geological conditions and hydrogeological regime are investigated. Next, available data on the geomechanical behaviour of soils, often connected with these landslides, are summarized and evaluated. The case studies deal with the landslide localities Budkovice-Svízla, Brno-Bystrc and Znojmo. The case study of Budkovice-Svízla is based on an extensive engineering geological survey of the locality and the measurement of groundwater levels in the years 1988 – 2017. In the thesis, the hydrogeological regime of the area is analysed and a reconstruction of the ground surface before slope movement is carried out. The probable trigger mechanisms, the development of sliding and the efficiency of the executed remedies of the landslide are evaluated by numerical studies. In conclusion, general recommendations for an engineering-geological survey and building activities in the area of interest are formulated.
187

Reliability – based analysis of embankment dams

Liu, Xiaochen January 2019 (has links)
Embankment dams are widely used as water-retaining structures through the world. Two principal structural failure modes of embankment dams are internal erosion and slope instability. The objective of this thesis is to investigate the feasibility of applying probabilistic methods in embankment dam assessment. Compared to deterministic methods, probabilistic methods considers the variability in material properties and the results are more assessable. Meanwhile, the derived sensitivity factors of the variables can be used to find the most influential one.Through a literature review, it is found that the difficulties in defining a limit state function for the full process of internal erosion for embankment dams hold back the application of reliability-based methods. However, reliability-based methods have been recognized as suitable for slope stability assessment.In this thesis, both deterministic and probabilistic calculations have been performed for a homogenous embankment dam. The deterministic calculation is carried out in Slope/W to first find out the most critical slip surface. The failure probability of this slip surface is estimated by both Monte Carlo simulations in Slope/W and FORM analysis in Comrel. Then, the 34 most critical slip surfaces from Slope/W are chosen to calculate the system reliability with simple bounds and applied integration. The results from the deterministic and probabilistic calculations showed that the studied dam has a higher risk of failure than allowed. In the system reliability calculation, simple bounds gives a wide range, especially the upper bounds. It was found that classification of different slip surfaces into different groups with respect to geometry and material was useful to simplify the calculations. Not much improvement in accuracy of the system probability of failure is found when increasing the numbers (from 1 to 5) of the most critical slip surfaces from each group. Even the combination of 1 slip surface from each group only gives an error of 6.5%. Categorizing slip surfaces before performing a system reliability analysis is a good way for simplification of the calculations. Due to this, the criteria used for categorization of the slip surfaces are of interest. In this work, it was found that the slip geometry in combination with the materials included in the slip surface constitute a possible way forward to do this. / Fyllningsdammar används ofta som dämmande konstruktioner runt om i världen. Två potentiella brottmoder för fyllningsdammar är inre erosion och släntinstabilitet.Syftet med detta examensarbete är att undersöka möjligheten att tillämpa probabilistiska metoder vid utvärdering av fyllningsdammars säkerhet för dessa brottmoder. Jämfört med deterministiska metoder betraktar probabilistiska metoder även variationen i materialegenskaper. Erhållna känslighetsfaktorer för ingående variabler kan även användas för att hitta de som har störst inverkan på det studerade problemet.I litteraturstudien framkom att det är svårt att definiera en gränsfunktion som beskriver inre erosion för fyllnadsdammar, vilket begränsar dess användbarhet med probabilistiska metoder. För analys av släntstabilitet är dock probabilistiska metoder användbara. Både deterministiska och probabilistiska beräkningar av släntstabiliteten för en fyllnadsdamm har genomförts inom ramen för detta arbete. De deterministiska beräkningarna har utförts med programmet Slope/W, där den mest kritiska glidytan först har analyserats. Brottsannolikheten för dammen har beräknats med både Monte Carlo-simulering i Slope/W och FORM-analys i Comrel. En begränsning med att enbart beräkna brottsannolikheten för den mest kritiska glidytan är att brottsannolikheten kan underskattas då inverkan från andra potentiella glidytor inte beaktas. De potentiella glidytorna kan betraktas som ett seriesystem, där glidytorna är delvis korrelerade med varandra. För att studera denna fråga valdes de 34 mest kritiska glidytorna från Slope/W ut för att beräkna systemets tillförlitlighet. Resultaten från de deterministiska och probabilistiska beräkningarna visade att den studerade dammen hade en oacceptabel brottsannolikhet. I beräkningarna av gränserna för systemets brottsannolikhet visade resultaten att brottsannolikheten kan variera stort beroende på korrelationen mellan glidytorna. Genom att klassificera glidytorna i olika grupper med hänsyn till geometri och ingående material kan beräkningarna för systemets brottsannolikhet förenklas. Resultaten visade att noggrannheten i beräkningarna för brottsannolikheten av systemet inte förbättrades i någon större utsträckning när antalet valda glidytor (från 1 till 5) från varje grupp av likartade glidytor inkluderades i beräkningen. Kombinationen av 1 glidyta från varje grupp gav endast ett fel på 6,5% jämfört med om alla 34 glidytorna inkluderades. Kategorisering av glidytor av samma karaktär i olika grupper rekommenderas därför att genomföras innan systemets tillförlitlighet analyseras. I detta arbete framkom att glidytan geometri i kombination med ingående material i glidytan utgör ett lämpligt kriterium för att göra denna indelning.
188

Reliability – based analysis of embankment dams

Liu, Xiaochen January 2019 (has links)
Embankment dams are widely used as water-retaining structures through the world. Two principal structural failure modes of embankment dams are internal erosion and slope instability. The objective of this thesis is to investigate the feasibility of applying probabilistic methods in embankment dam assessment. Compared to deterministic methods, probabilistic methods considers the variability in material properties and the results are more assessable. Meanwhile, the derived sensitivity factors of the variables can be used to find the most influential one.Through a literature review, it is found that the difficulties in defining a limit state function for the full process of internal erosion for embankment dams hold back the application of reliability-based methods. However, reliability-based methods have been recognized as suitable for slope stability assessment.In this thesis, both deterministic and probabilistic calculations have been performed for a homogenous embankment dam. The deterministic calculation is carried out in Slope/W to first find out the most critical slip surface. The failure probability of this slip surface is estimated by both Monte Carlo simulations in Slope/W and FORM analysis in Comrel. Then, the 34 most critical slip surfaces from Slope/W are chosen to calculate the system reliability with simple bounds and applied integration. The results from the deterministic and probabilistic calculations showed that the studied dam has a higher risk of failure than allowed. In the system reliability calculation, simple bounds gives a wide range, especially the upper bounds. It was found that classification of different slip surfaces into different groups with respect to geometry and material was useful to simplify the calculations. Not much improvement in accuracy of the system probability of failure is found when increasing the numbers (from 1 to 5) of the most critical slip surfaces from each group. Even the combination of 1 slip surface from each group only gives an error of 6.5%. Categorizing slip surfaces before performing a system reliability analysis is a good way for simplification of the calculations. Due to this, the criteria used for categorization of the slip surfaces are of interest. In this work, it was found that the slip geometry in combination with the materials included in the slip surface constitute a possible way forward to do this.
189

Evaluation of methods for rock mass characterization and design of rock slopes in crystalline rock / Utvärdering av metoder för karaktärisering av bergmassa och dimensionering av slänter i kristallint berg

Gottlander, Johanna Unknown Date (has links)
Construction of rock slopes is needed in many civil work projects. It is for example very common in road and railway cuts, but other applications include excavation for tunneling or building foundations, where perhaps sensitive constructions are present in the immediate vicinity. In Sweden the majority of the rock is hard crystalline bedrock of relatively good quality, and the fracture orientation have a large effect of the stability of the rock slope.If the geology is not properly considered for when the design of the slope is carried out, it can result in slope failure, with severe consequences. This applies especially if the rock slope is high, but unwanted effects like increased excavation and construction costs, could occur also in smaller slopes if the risks are not identified and managed. However, it is difficult to standardize design of rock slopes in fractured hard crystalline rock because of the uncertainties and variations in the geological conditions during the design phase.Rock mass characterization systems like Rock mass rating, RMR (Bieniawski 1989) and the Qsystem (Barton, Lien och Lunde 1974) are commonly used to describe the general rock mass quality. Whilst a good rock mass quality is generally easier to construct in, stability problems do occur due to structural geology in rock slopes even in good rock mass quality. The application of these systems in rock slopes can be problematic as they do not describe the geometry of the slope and how the fractures daylight in the slope face. Instead, stereonets can be used to visualize this, but fracture parameters of large importance for stability (persistence, roughness and alteration) are traditionally not presented in a stereonet analysis. Additionally, these parameters and the structural geological conditions can be difficult to predict and can vary significantly over short distances, why it can be difficult to forecast and predict failure in the design face.Slope instability due to large sliding and wedge failures have been observed in a large number of slopes in crystalline rock, and a standard method for design of rock slopes is lacking. This has given rise to the research question of how best to describe rock mass conditions, how to design slopes in crystalline rock and how to manage these risks during construction.To investigate this, three rock slopes where large failure had occurred were selected for the case study and were mapped, characterized and analyzed. The results from the case study showed that all rock slopes investigated had in common that failure had occurred along fractures of large persistence. This highlights the importance of evaluating the geology in the correct scale and suggest that lineament studies and other elevation based interpretation are perhaps more useful than previously thought. It also came to light that the planning and design process is inflexible which in many cases lead to large risks being overlooked or left unnoticed.A flow chart for risk classification was produced and suggested for aid in decision making aiming at simplifying project management of rock slopes, as well as aiding in visualization of the risk that rock slopes can be associated to.
190

An Enhanced Data Model and Tools for Analysis and Visualization of Levee Simulations

Griffiths, Thomas Richard 15 March 2010 (has links) (PDF)
The devastating levee failures associated with hurricanes Katrina and Rita, and the more recent Midwest flooding, placed a spotlight on the importance of levees and our dependence on them to protect life and property. In response to levee failures associated with the hurricanes, Congress passed the Water Resources Development Act of 2007 which established a National Committee on Levee Safety. The committee was charged with developing recommendations for a National Levee Safety Program. The Secretary of the Army was charged with the establishment and maintenance of a National Levee Database. The National Levee Database is a critical tool in assessing and improving the safety of the nation's levees. However, the NLD data model, established in 2007, lacked a structure to store seepage and slope stability analyses – vital information for assessing the safety of a levee. In response, the Levee Analyst was developed in 2008 by Dr. Norm Jones and Jeffrey Handy. The Levee Analysis Data Model was designed to provide a central location, compatible with the National Levee Database, for storing large amounts of levee seepage and slope stability analytical data. The original Levee Analyst geoprocessing tools were created to assist users in populating, managing, and analyzing Levee Analyst geodatabase data. In an effort to enhance the Levee Analyst and provide greater accessibility to levee data, this research expanded the Levee Analyst to include modifications to the data model and additional geoprocessing tools that archive GeoStudio SEEP/W and SLOPE/W simulations as well as export the entire Levee Analyst database to Google Earth. Case studies were performed to demonstrate the new geoprocessing tools' capabilities and the compatibility between the National Levee Database and the Levee Analyst database. A number of levee breaches were simulated to prototype the enhancement of the Levee Analyst to include additional feature classes, tables, and geoprocessing tools. This enhancement would allow Levee Analyst to manage, edit, and export two-dimensional levee breach scenarios.

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