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1
Rajaguru, Mudiyanselage Thilanki Maneesha Dahigamuwa. « Enhancement of Rainfall-Triggered Shallow Landslide Hazard Assessment at Regional and Site Scales Using Remote Sensing and Slope Stability Analysis Coupled with Infiltration Modeling ». Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7562.
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Landslides cause significant damage to property and human lives throughout the world. Rainfall is the most common triggering factor for the occurrence of landslides. This dissertation presents two novel methodologies for assessment of rainfall-triggered shallow landslide hazard. The first method focuses on using remotely sensed soil moisture and soil surface properties in developing a framework for real-time regional scale landslide hazard assessment while the second method is a deterministic approach to landslide hazard assessment of the specific sites identified during first assessment. In the latter approach, landslide inducing transient seepage in soil during rainfall and its effect on slope stability are modeled using numerical analysis.
Traditionally, the prediction of rainfall-triggered landslides has been performed using pre-determined rainfall intensity-duration thresholds. However, it is the infiltration of rainwater into soil slopes which leads to an increase of porewater pressure and destruction of matric suction that causes a reduction in soil shear strength and slope instability. Hence, soil moisture, pore pressure and infiltration properties of soil must be direct inputs to reliable landslide hazard assessment methods. In-situ measurement of pore pressure for real-time landslide hazard assessment is an expensive endeavor and thus, the use of more practical remote sensing of soil moisture is constantly sought. In past studies, a statistical framework for regional scale landslide hazard assessment using remotely sensed soil moisture has not been developed. Thus, the first major objective of this study is to develop a framework for using downscaled remotely sensed soil moisture available on a daily basis to monitor locations that are highly susceptible to rainfall-
triggered shallow landslides, using a well-structured assessment procedure. Downscaled soil moisture, the relevant geotechnical properties of saturated hydraulic conductivity and soil type, and the conditioning factors of elevation, slope, and distance to roads are used to develop an improved logistic regression model to predict the soil slide hazard of soil slopes using data from two geographically different regions. A soil moisture downscaling model with a proven superior prediction accuracy than the downscaling models that have been used in previous landslide studies is employed in this study. Furthermore, this model provides satisfactory classification accuracy and performs better than the alternative water drainage-based indices that are conventionally used to quantify the effect that elevated soil moisture has upon the soil sliding. Furthermore, the downscaling of soil moisture content is shown to improve the prediction accuracy. Finally, a technique that can determine the threshold probability for identifying locations with a high soil slide hazard is proposed.
On the other hand, many deterministic methods based on analytical and numerical methodologies have been developed in the past to model the effects of infiltration and subsequent transient seepage during rainfall on the stability of natural and manmade slopes. However, the effects of continuous interplay between surface and subsurface water flows on slope stability is seldom considered in the above-mentioned numerical and analytical models. Furthermore, the existing seepage models are based on the Richards equation, which is derived using Darcy’s law, under a pseudo-steady state assumption. Thus, the inertial components of flow have not been incorporated typically in modeling the flow of water through the subsurface. Hence, the second objective of this study is to develop a numerical model which has the capability to model surface, subsurface and infiltration water flows based on a unified approach, employing fundamental fluid dynamics, to assess slope stability during rainfall-induced transient seepage conditions. The developed model is based on the Navier-Stokes equations, which possess the capability to model surface, subsurface and infiltration water flows in a unified manner. The extended Mohr-Coulomb criterion is used in evaluating the shear strength reduction due to infiltration. Finally, the effect of soil hydraulic conductivity on slope stability is examined. The interplay between surface and subsurface water flows is observed to have a significant impact on slope stability, especially at low hydraulic conductivity values. The developed numerical model facilitates site-specific calibration with respect to saturated hydraulic conductivity, remotely sensed soil moisture content and rainfall intensity to predict landslide inducing subsurface pore pressure variations in real time.
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RAIMONDI, LUCA. « Valutazione e mitigazione dei rischi geo-idrologici derivanti da eventi catastrofici nell'area del Parco Nazionale delle Cinque Terre ». Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1007965.
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This research is included in the field of studies for the evaluation and mitigation of geo-hydrological risks deriving from catastrophic rainfall events conducted in the Cinque Terre National Park area (Liguria) by the Department of Earth Sciences of the Environment and Life of University of Genoa (Italy). This activity made it possible to create and test a mathematical simulation model, in a physically based GIS environment, capable of carrying out 3D slope stability analysis (extended to a spatial domain) according to the pluviometric conditions assumed in the calculations.
The experimentation first highlighted the limits of application of the "infinte slope" limit equilibrium method (LEM) used for the spatially 3D slope stability analysis in a GIS computerized geographical environment, also indicating improvement solutions for a more correct use. The input parameters of the soils (geotechnical, hydrogeological and geometric) entering the above mathematical expression were then examined. Their spatial distribution and their relationship with the local geo-morphometric-environmental control factors, on a basin and regional scale, were assessed, as well as their influence on the results was tested by comparing them with real phenomena and geomorphological processes observed in the chosen pilot area (i.e. Vernazza catchment affected on 25/10/2011 by a catastrophic rainfall event). All this experimentation led to the formulation of innovative calculation procedures and methods which were then coded in the Python programming language and developed in the open source QGIS application system in the form of executable "scripts".
The predictive ability of the new model was tested in the aforementioned basin, comparing the spatial output data derived from the mathematical simulation with the real distribution of the surface landslides obtained from the analysis of aerial photos and site surveys. In summary, the system showed excellent potential for the preventive localization of soil mobilization phenomena on the slopes of a territorial domain where, in a neighborhood of 25 m away from the focal landslide areas, it was able to identify the 84% of the phenomena that actually occurred with a probability of 93% of the total of the aforementioned areas (with only 7% of false alarms).
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Peterson, Jennifer Lynn. « Probability analysis of slope stability ». Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1070.
Texte intégralRésumé :
Thesis (Ph. D.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains viii, 91 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 63-64).
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Wanstreet, Pinar. « Finite element analysis of slope stability ». Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5480.
Texte intégralRésumé :
Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains xii, 86 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 80-82).
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Bakhtiari, Siamak. « Stochastic finite element slope stability analysis ». Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/stochastic-finite-element-slope-stability-analysis(c1b451d9-8bf6-43ff-9c10-7b5209fb45c1).html.
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In this thesis, the failures that occurred during the construction of the Jamuna Bridge Abutment in Bangladesh have been investigated. In particular, the influence of heterogeneity on slope stability has been studied using statistical methods, random field theory and the finite element method. The research is divided into three main parts: the statistical characterization of the Jamuna River Sand, based on an extensive in-situ and laboratory database available for the site; calibration of the laboratory data against a double-hardening elastoplastic soil model; and stochastic finite element slope stability analyses, using a Monte Carlo simulation, to analyse the slope failures accounting for heterogeneity. The sand state has been characterised in terms of state parameter, a meaningful quantity which can fully represent the mechanical behaviour of the soil. It was found that the site consists of predominantly loose to mildly dilative material and is very variable. Also, a Normal distribution was found to best represent the state parameter and a Lognormal distribution was found to best represent the tip resistance.The calibration of the constitutive model parameters was found to be challenging, as alternative approaches had to be adopted due to lack of appropriate test results available for the site. Single-variate random fields of state parameter were then linked to the constitutive model parameters based on the relationships found between them, and a parametric study of the abutment was then carried out by linking finite elements and random field theory within a Monte Carlo framework.It was found that, as the degree of anisotropy of the heterogeneity increases, the range of structural responses increases as well. For the isotropic cases, the range of responses was relatively smaller and tended to result in more localised failures. For the anisotropic cases, it was found that there are two different types of deformation mechanism. It was also found that, as the vertical scale of fluctuation becomes bigger, the range of possible structural responses increases and failure is more likely. Finally, it was found that the failed zones observed during the excavation of the West Guide Bund of the Jamuna Bridge Abutment could be closely predicted if heterogeneity was considered in the finite element analyses. In particular, it was found that, for such a natural deposit, a large degree of anisotropy (in the range of 20) could account for the deformation mechanisms observed on site.
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Liu, Ying, et 劉影. « Limit equilibrium methods for slope stability analysis ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B42576684.
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GUEDES, MARIA CECILIA SAFADY. « DISCUSSION ON PROBABILISTIC ANALYSIS OF SLOPE STABILITY ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1924@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORSão abordados alguns aspectos relativos à execução de análises probabilísticas em projetos de geotecnia. Apresenta-se um resumo dos conceitos de probabilidade e estatística, utilizados ao longo do trabalho. Descreve-se uma metodologia para a obtenção dos dados necessários à análise probabilística, incluindo a quantidade e a localização de amostras, o cálculo das médias e variâncias dos parâmetros do solo e a quantificação das incertezas relativas a estes valores. Apresenta-se o procedimento de execução dos três métodos probabilísticos mais utilizados em geotecnia com ênfase especial para o Método do Segundo Momento de Primeira Ordem. São executadas análises probabilísticas considerando, separadamente, variações de altura e inclinação de um talude de mineração sob condições drenadas. Avalia-se também a aplicação da metodologia de análise probabilística em situações não-drenadas, através da análise da estabilidade de um quebra-mar sobre argila mole.
Some aspects about probabilistic analysis of stability in geotechnical engineering are studied in this thesis. A summary about basic concepts of probability and statistics used along this work is presented. The methodology for obtaining the data needed for probabilistic analysis is described, including quantity and localization of samples, computation of mean and variance of soil properties and determination of uncertainties about these values. The procedures of three probabilistic methods which are useful in geotechnics are presented, with special emphasis on the first order second moment method (FOSM). Probabilistic analysis are made considering independent changes of height and inclination of a mine slope under drained conditions. The application of probabilistic analysis of a breakwater above a soft clay deposit under undrained conditions is also presented.
Se abordan algunos aspectos relativos a la ejecución de análisis probabilístico en proyectos de geotecnia. Se presenta un resumen de los conceptos de probabilidades y estadísticas, utilizados a lo largo del trabajo. Se describe una metodología para la obtención de los datos necesarios para el análisis probabilístico, incluyendo la cantidad y la localización de las muestras, el cálculo de las medias y variancias de los parámetros del suelo y la cuantificación de los errores relativos a estos valores. Se presenta el procedimientode ejecución de los tres métodos probabilísticos más utilizados en geotecnia con énfasis especial para el Método del Segundo Momento de Primer Orden. Se realizan análisis probabilísticos considerando, separadamente, variaciones de altura e inclinación de un talud de mineración en condiciones drenadas. También se evalúa la aplicación de la metodología de análisis probabilística en situaciones no-drenadas, a través de el análisis de la estabilidad de un quebra olas sobre arcilla blanda.
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SANDOVAL, MARTIN ALEXANDER PURIZAGA. « DETERMINISTIC AND PROBABILISTIC ANALYSIS OF SLOPE STABILITY ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=21816@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Na abordagem determinística compara-se o método do equilíbrio limite com o método dos elementos finitos na análise 2D da estabilidade de taludes em solo, determinando-se o valor do fator de segurança para vários exemplos de aplicação. No método dos elementos finitos quantifica-se a região da potencial superfície de ruptura que se comporta sob extensão, analisando-se a ocorrência de anisotropia de resistência ao longo da potencial superfície de deslizamento para situações envolvendo diferentes tipos de solo, ângulos de inclinação do talude e sequências de escavação. Conclui-se que o efeito da anisotropia é pouco significativo quando o ângulo de atrito do solo exceder a 10 graus. Por outro lado, devido à crescente aplicação da abordagem probabilística na prática da engenharia geotécnica, foram realizadas análises de confiabilidade de taludes empregando os métodos de Monte Carlo, do hipercubo latino e o método das estimativas pontuais alternativas, comparando-se os diferentes resultados obtidos e discutindo as principais vantagens da aplicação destes métodos.
In the deterministic approach the limit equilibrium method and the finite element method are compared for 2D analysis of soil slope stability, calculating the value of the safety factor in several numerical examples. In the finite element method the region of soil under strain extension is determined and the occurrence of strength anisotropy is investigated along the potential sliding surface for situations involving different types of soil, angles of slope inclination and excavation sequences. It is concluded that the effect of the anisotropy is negligible when the angle of friction is higher than 10 degress. Moreover, due to the increasing application of the probabilistic approach in the practice of geotechnical engineering, some reliability analyses were carried out using the Monte Carlo method, the Latin hypercube method and the method of alternative point estimates, comparing their different outputs and discussing the main advantages of their application in the analysis of soil slope stability problems.
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VECCI, ANDREA NASCIMENTO. « PROBABILISTIC ANALYSIS OF A MINE SLOPE STABILITY ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35100@1.
Texte intégralRésumé :
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
PROGRAMA DE EXCELENCIA ACADEMICA
BOLSA NOTA 10
Na prática geotécnica, a estabilidade de taludes é atualmente estudada apenas com análises determinísticas, obtendo-se o valor do Fator de Segurança (FS) da estrutura geotécnica. Estas análises são simplificadas, pois fornecem valores de FS sem considerar a variabilidade intrínseca dos solos e rochas. Desprezar as incertezas dos parâmetros geotécnicos pode levar a resultados pouco confiáveis sobre a segurança de taludes. Análises fundamentadas em conceitos estatísticos, chamadas probabilísticas, passam ser mais frequentes na geotecnia por permitirem considerar efeitos da variabilidade inerente aos materiais. Estas análises incorporam elementos estatísticos que possibilitam tratar FS como uma função e estudar suas propriedades. Como resultados finais, os métodos probabilísticos fornecem o índice de confiabilidade (beta) e a probabilidade de ruptura (Pr) da estrutura averiguada. Este trabalho aplica análises determinísticas e probabilísticas de um talude de 200m de altura da Mina do Cauê, Itabira, MG. A estabilidade do talude foi analisada por cinco métodos determinísticos usuais e três probabilísticos (FOSM, EP e MC). Os resultados indicam que a fixação da superfície crítica de ruptura fornece, em geral, valores de beta e Pr semelhantes aos obtidos quando a superfície pode variar livremente. Com a superfície crítica fixa observou-se, também, que os resultados de beta e Pr do talude variam significativamente com o método de equilíbrio limite adotado. Após comparação dos resultados, pode-se recomendar o uso de análises probabilísticas FOSM com base no método de Morgenstern-Price em análises semelhantes ao caso estudado.
In current geotechnical practice, slope stability assessments are usually carried out only based on deterministic methods, obtaining a value of Safety Factor (FS). These analyses are simplified because the FS values do not consider the natural variability of soils and rocks. Disregarding the uncertainties inherent to geotechnical parameters may lead to unreliable results of slope safety. Probabilistic analyses, based on statistical concepts, have become more frequent in geotechnical practice, as they allow incorporating the materials intrinsic variability. These analyses are based on statistical elements that allow treating the FS as a function and studying its properties. The probabilistic methods indicate the reliability index (beta) and the probability of failure (Pr) of the verified geotechnical structure. This work presents deterministic and probabilistic analyses of a 200m high slope at the Cauê Mine, located in Itabira, Minas Gerais, Brazil, with basis on five usual deterministic methods and three probabilistic techniques (FOSM, Point Estimates and Monte Carlo). The results indicate that fixing the critical deterministic surface generally gives values of beta and Pr similar to those achieved when the surface is free to vary. It was also concluded that, with a fixed critical surface, beta and Pr results change significantly, when different Limit Equilibrium methods are adopted. It is recommended to use probabilistic FOSM analysis with Morgenstern and Price stability method in analyses similar to the one presented herein.
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Howdyshell, James Robert. « Strain Compatibility Analysis in Slope Stability Modeling ». The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269113810.
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Liu, Ying. « Limit equilibrium methods for slope stability analysis ». Click to view the E-thesis via HKUTO, 2002. http://sunzi.lib.hku.hk/hkuto/record/B42576684.
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Azimi, Seyed Reza. « Soil Slope Stability Techniques : A Comprehensive Analysis ». Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/53048.
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The slope failure is a dangerous phenomenon for natural or man-made slopes. Such failures can be assess by different numerical or limit state methods. However, other new techniques can be utilized to simulate the slope failures in more effective ways in order to save the construction costs. In this research, a model based on particle image velocimetry is developed to analyze the behavior of slope stability. This method provide real time safety factors and instantaneous velocities of slope movement which are applicable for shallow slope failure studies.
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Sainak, Ala Naeem. « Three dimensional finite element analysis of slope stability ». Thesis, Oxford Brookes University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320546.
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LOPEZ, CARLOS NACIANCENO MEZA. « PROBABILISTIC METHODS APPLIED TO SOIL SLOPE STABILITY ANALYSIS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33136@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Comumente as análises de estabilidade de taludes são realizadas mediante métodos determinísticos, os quais visam o cálculo de um fator de segurança único assumindo os valores dos parâmetros de resistência como representativos e fixos. Estes métodos não conseguem avaliar as incertezas existentes nas propriedades do solo e tampouco indicam a proporção de influência que tem cada parâmetro de resistência no valor do fator de segurança. Os métodos probabilísticos, com base nas teorias de probabilidade, confiabilidade e estatística, permitem estimar a influência dessas incertezas nos cálculos determinísticos, com a possibilidade de prever mais amplamente o risco de insucesso associado a um projeto geotécnico de estabilidade de taludes. O presente trabalho estuda a aplicação de três métodos probabilísticos (Monte Carlo, Hipercubo Latino e Estimativas Pontuais Alternativas) na avaliação de estabilidade de taludes, com auxílio de métodos de equilíbrio limite no cálculo do fator de segurança. Com objetivo de inferir o impacto das variáveis aleatórias nas estimativas de probabilidade e confiabilidade, bem como da importância de uma quantificação adequada dos valores de desvio padrão, são realizadas comparações dos resultados obtidos com métodos probabilísticos e determinísticos (método das fatias, método dos elementos finitos) discutindo as principais vantagens, dificuldades e limitações nas aplicações dos mesmos em problemas de estabilidade de taludes de solo.
Slope stability analyses are usually carried out using deterministic methods, which aim the calculation of a single safety factor assuming the values of the shear strength parameters as representative and fixed. These methods fail to assess the uncertainties in soil properties and do not indicate the proportion of influence that each resistance parameter has on the final value of the safety factor. The probabilistic methods, based on probability, reliability and statistical theories, allow the estimation of the influence of these uncertainties on the deterministic calculations, with the possibility to broadly predict the risk of failure associated with a geotechnical slope stability project. This dissertation studies the application of three probabilistic methods (Monte Carlo, Latin Hypercube, and Alternative Point Estimates) in the evaluation of slope stability, with aid of limit equilibrium methods for the calculation of safety factors. In order to infer the impact of random variables on the estimates of probability and reliability, as well as the importance of an adequate quantification of the standard deviation values, comparisons are made among the results obtained with probabilistic and deterministic methods (limit equilibrium method, finite element method), discussing the main advantages, difficulties and limitations in their application to soil slope stability problems.
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DAVILA, ANGEL MAURICIO JAIME. « NUMERICAL ANALYSIS OF BAMBOO PILES FOR SLOPE STABILITY ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35682@1.
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O crescimento populacional descontrolado e o desenvolvimento urbano desordenado têm testemunhado danos severos em assentamentos humanos no mundo. Fenômenos naturais extremos, como consequência de uma mudança climática abrupta, como o intenso aumento do índice pluviométrico, provocaram incidentes de deslizamentos de taludes que dificilmente seriam ignorados desde as últimas décadas. Pilhas feitas de materiais convencionais como a madeira, aço e concreto têm sido tradicionalmente utilizados para a estabilização de taludes, com a finalidade de evitar incidentes de desabamentos de aterros. O presente trabalho estuda o uso de um material não convencional, o bambu da espécie Dendrocalamus Giganteus (DG) para estabilidade de taludes, como uma alternativa de material para pilha mais amigável ao ambiente graças a sua disponibilidade geográfica e capacidade de absorção de gases de efeito estufa. Suas dimensões e mais importantes suas propriedades mecânicas, são totalmente compatíveis com as de um elemento de estaca estabilizadora de taludes. Uma análise do Método dos Elementos Finitos (FEM) foi desenvolvida no software PLAXIS para testes em 2 e 3 dimensões. Usando um modelo de encosta instável reforçada com estacas de bambu para observar a interação do solo-estaca e avaliar o fator de segurança
(FS). Os resultados mostraram que as capacidades das pilhas de bambu são uma alternativa promissora para a estabilidade de taludes.Uncontrolled population growth and disorderly urban development had witnessed severe human settlement damages worldwide. Extreme natural phenomena consequence of abrupt climate change such as intense rainfall index increment had provoked landslides incidents hardly to ignore since last decades. Piles made of conventional materials such as timber, steel and concrete have traditionally been used for slope stabilization in order to prevent landslides incidents. The present paper studies the use of a non conventional material, the bamboo of the Dendrocalamus Giganteus (DG) species as bamboo-pile for slope stability, to become a more environmental friendly pile material alternative. Its dimensions and more important its mechanical properties, besides its geographical availability and greenhouse gases absorbing capabilities totally matches for an ecologic slope stabilizing pile element. Finite Element Method (FEM) analysis of bamboo-pile was developed on PLAXIS software for 2 and 3 dimensional tests. An unstable slope model condition was reinforced with bamboo-piles to observe the soil-pile interaction and evaluate the safety factor (SF). The results showed that the capabilities of the bamboo-piles are a promising alternative for slope stability.
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Albataineh, Nermeen. « SLOPE STABILITY ANALYSIS USING 2D AND 3D METHODS ». University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1153719372.
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Rashed, Azadeh <1983>. « A New Prediction Model for Slope Stability Analysis ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6628/1/Doctoral_Thesis-_A_New_Prediction_Model_for_Slope_Stability_Analysis.pdf.
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The instability of river bank can result in considerable human and land losses. The Po river is the most important in Italy, characterized by main banks of significant and constantly increasing height. This study presents multilayer perceptron of artificial neural network (ANN) to construct prediction models for the stability analysis of river banks along the Po River, under various river and groundwater boundary conditions. For this aim, a number of networks of threshold logic unit are tested using different combinations of the input parameters. Factor of safety (FS), as an index of slope stability, is formulated in terms of several influencing geometrical and geotechnical parameters. In order to obtain a comprehensive geotechnical database, several cone penetration tests from the study site have been interpreted. The proposed models are developed upon stability analyses using finite element code over different representative sections of river embankments. For the validity verification, the ANN models are employed to predict the FS values of a part of the database beyond the calibration data domain. The results indicate that the proposed ANN models are effective tools for evaluating the slope stability. The ANN models notably outperform the derived multiple linear regression models.
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Rashed, Azadeh <1983>. « A New Prediction Model for Slope Stability Analysis ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6628/.
Texte intégralRésumé :
The instability of river bank can result in considerable human and land losses. The Po river is the most important in Italy, characterized by main banks of significant and constantly increasing height. This study presents multilayer perceptron of artificial neural network (ANN) to construct prediction models for the stability analysis of river banks along the Po River, under various river and groundwater boundary conditions. For this aim, a number of networks of threshold logic unit are tested using different combinations of the input parameters. Factor of safety (FS), as an index of slope stability, is formulated in terms of several influencing geometrical and geotechnical parameters. In order to obtain a comprehensive geotechnical database, several cone penetration tests from the study site have been interpreted. The proposed models are developed upon stability analyses using finite element code over different representative sections of river embankments. For the validity verification, the ANN models are employed to predict the FS values of a part of the database beyond the calibration data domain. The results indicate that the proposed ANN models are effective tools for evaluating the slope stability. The ANN models notably outperform the derived multiple linear regression models.
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Wei, Yukun. « Slope stability assessment through field monitoring ». Thesis, KTH, Jord- och bergmekanik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-239955.
Texte intégralRésumé :
Deterministic methods have been used in geotechnical engineering for a long period, such as slope stability calculations. However, only applying deterministic methods is subjective and imperfect. There is a demand to develop a systematic methodology to link the assessed slope stability and field measurement data, which is also known as inverse analysis and forward calculation. Based on the Nya Slussen project, this thesis includes the development of a methodology, deterministic calculation for 4 cross sections using finite element program Plaxis 2D and probabilistic calculation for one section. Deterministic analyses showed satisfying results for all the studied cross sections since their factors of safety exceeded the minimum requirement. In probabilistic design, three parameters were found to have the most uncertainties through sensitivity analysis (undrained shear strength of clay, Young’s modulus of clay and friction angle of fill). Inverse analysis was done by testing different values of them in Plaxis and to try to match the displacement components provided by field measurement. After finding the best optimization for all the parameters, forward calculation gave a final factor of safety. It is suggested that both of the methods should be utilized together for better assessment.
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Awad, Barre Mohamed 1955. « APPLICATION OF THE SIMPLEX METHOD TO SLOPE STABILITY ANALYSIS ». Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276340.
Texte intégral
21
Musa, Zulkarnain 1964. « An accelerated conjugate direction procedure for slope stability analysis ». Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276912.
Texte intégralRésumé :
CSLIP2 (De Natale, 1987) is the only slope stability program that utilizes a "direction set" optimization routine in its search for the minimum safety factor. However, CSLIP2 which employs Powell's Conjugate Direction Method permits only the horizontal and vertical directions (x and y) to be used as the initial direction set. The efficiency of the existing search routine is improved by replacing the x-y coordinate directions with initial directions that are parallel to and perpendicular to the principal axis of the safety factor contours.
22
Shen, Hong. « Non-deterministic analysis of slope stability based on numerical simulation ». Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2012. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-96370.
Texte intégralRésumé :
In geotechnical engineering, the uncertainties such as the variability and uncertainty inherent in the geotechnical properties have caught more and more attentions from researchers and engineers. They have found that a single “Factor of Safety” calculated by traditional deterministic analyses methods can not represent the slope stability exactly. Recently in order to provide a more rational mathematical framework to incorporate different types of uncertainties in the slope stability estimation, reliability analyses and non-deterministic methods, which include probabilistic and non probabilistic (imprecise methods) methods, have been applied widely. In short, the slope non-deterministic analysis is to combine the probabilistic analysis or non probabilistic analysis with the deterministic slope stability analysis. It cannot be regarded as a completely new slope stability analysis method, but just an extension of the slope deterministic analysis. The slope failure probability calculated by slope non-deterministic analysis is a kind of complement of safety factor. Therefore, the accuracy of non deterministic analysis is not only depended on a suitable probabilistic or non probabilistic analysis method selected, but also on a more rigorous deterministic analysis method or geological model adopted.
In this thesis, reliability concepts have been reviewed first, and some typical non-deterministic methods, including Monte Carlo Simulation (MCS), First Order Reliability Method (FORM), Point Estimate Method (PEM) and Random Set Theory (RSM), have been described and successfully applied to the slope stability analysis based on a numerical simulation method-Strength Reduction Method (SRM). All of the processes have been performed in a commercial finite difference code FLAC and a distinct element code UDEC.
First of all, as the fundamental of slope reliability analysis, the deterministic numerical simulation method has been improved. This method has a higher accuracy than the conventional limit equilibrium methods, because of the reason that the constitutive relationship of soil is considered, and fewer assumptions on boundary conditions of slope model are necessary. However, the construction of slope numerical models, particularly for the large and complicated models has always been very difficult and it has become an obstacle for application of numerical simulation method. In this study, the excellent spatial analysis function of Geographic Information System (GIS) technique has been introduced to help numerical modeling of the slope. In the process of modeling, the topographic map of slope has been gridded using GIS software, and then the GIS data was transformed into FLAC smoothly through the program built-in language FISH. At last, the feasibility and high efficiency of this technique has been illustrated through a case study-Xuecheng slope, and both 2D and 3D models have been investigated.
Subsequently, three most widely used probabilistic analyses methods, Monte Carlo Simulation, First Order Reliability Method and Point Estimate Method applied with Strength Reduction Method have been studied. Monte Carlo Simulation which needs to repeat thousands of deterministic analysis is the most accurate probabilistic method. However it is too time consuming for practical applications, especially when it is combined with numerical simulation method. For reducing the computation effort, a simplified Monte Carlo Simulation-Strength Reduction Method (MCS-SRM) has been developed in this study. This method has estimated the probable failure of slope and calculated the mean value of safety factor by means of soil parameters first, and then calculated the variance of safety factor and reliability of slope according to the assumed probability density function of safety factor. Case studies have confirmed that this method can reduce about 4/5 of time compared with traditional MCS-SRM, and maintain almost the same accuracy.
First Order Reliability Method is an approximate method which is based on the Taylor\'s series expansion of performance function. The closed form solution of the partial derivatives of the performance function is necessary to calculate the mean and standard deviation of safety factor. However, there is no explicit performance function in numerical simulation method, so the derivative expressions have been replaced with equivalent difference quotients to solve the differential quotients approximately in this study. Point Estimate Method is also an approximate method involved even fewer calculations than FORM. In the present study, it has been integrated with Strength Reduction Method directly.
Another important observation referred to the correlation between the soil parameters cohesion and friction angle. Some authors have found a negative correlation between cohesion and friction angle of soil on the basis of experimental data. However, few slope probabilistic studies are found to consider this negative correlation between soil parameters in literatures. In this thesis, the influence of this correlation on slope probability of failure has been investigated based on numerical simulation method. It was found that a negative correlation considered in the cohesion and friction angle of soil can reduce the variability of safety factor and failure probability of slope, thus increasing the reliability of results.
Besides inter-correlation of soil parameters, these are always auto-correlated in space, which is described as spatial variability. For the reason that knowledge on this character is rather limited in literature, it is ignored in geotechnical engineering by most researchers and engineers. In this thesis, the random field method has been introduced in slope numerical simulation to simulate the spatial variability structure, and a numerical procedure for a probabilistic slope stability analysis based on Monte Carlo simulation was presented. The soil properties such as cohesion and friction angle were discretized to continuous random fields based on local averaging method. In the case study, both stationary and non-stationary random fields have been investigated, and the influence of spatial variability and averaging domain on the convergence of numerical simulation and probability of failure was studied.
In rock medium, the structure faces have very important influence on the slope stability, and the rock material can be modeled as the combination of rigid or deformable blocks with joints in distinct element method. Therefore, much more input parameters like strength of joints are required to input the rock slope model, which increase the uncertainty of the results of numerical model. Furthermore, because of the limitations of the current laboratory and in-site testes, there is always lack of exact values of geotechnical parameters from rock material, even the probability distribution of these variables. Most of time, engineers can only estimate the interval of these variables from the limit testes or the expertise’s experience. In this study, to assess the reliability of the rock slope, a Random Set Distinct Element Method (RS-DEM) has been developed through coupling of Random Set Theory and Distinct Element Method, and applied in a rock slope in Sichuan province China.
23
Mummery, Gavin Thomas. « Developing a high-resolution bioengineering model for slope stability analysis ». Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435426.
Texte intégral
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COSTA, SUZANA SANTOS. « SLOPE STABILITY ANALYSIS OF UNSATURATED ANISOTROPIC SOILS CONSIDERING PROGRESSIVE FAILURE ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2001. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2039@1.
Texte intégralRésumé :
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORNo presente trabalho realizou-se a implementação de um programa de análise de estabilidade de encostas incluindo aspectos não convencionais tais como ruptura progressiva, anisotropia de resistência e considerações de não saturação do solo. O método generalizado das cunhas de Sarma 79 foi utilizado para consideração destes aspectos, tomando-o como base para o desenvolvimento desta nova ferramenta analítica, aplicável ao estudo da estabilidade de encostas em solos residuais não saturados. A simulação dos efeitos da ruptura progressiva foi realizada a partir do trabalho desenvolvido por Huaman (1991), na Puc-Rio. O programa desenvolvido apresenta rotinas de geração automática da superfície de ruptura e do conjunto das inclinações críticas das interfaces das cunhas, além de diversas formas de consideração das poropressões, incluindo a possibilidade de ocorrência da sucção. Além do critério de ruptura de Mohr-Coulomb foi implementado um modelo anisotrópico de resistência que permite a representação de uma anisotropia que pode existir, mesmo em solos homogêneos, de acordo com a metodologia apresentada por Bicalho (1991). Os resultados obtidos através das rotinas implementadas foram comparados com os existentes na literatura, resultantes de análises realizadas por outros métodos de análise, comprovando desta forma, a eficiência do programa desenvolvido neste trabalho.
Here a computer software including non traditional issues as progressive failure, anisotropy and unsaturated soil for general slope stability analysis is implemented.The generalized method Sarma 79 was the base to consider these non-traditional issues on this new tool for the slope stability study of unsaturated residual soils.The progressive failure simulation effects were carried out following Huaman (1991) in his work at PUC-Rio, and aspects of anisotropy followed the work by Bicalho (1991). The computer program has subroutines that automatically construct the critical failure surfaces of any shape and the critical inclination of wedges set besides several ways of considering water pressures and suction ocurring. The strength anisotropy model allows to consider micro structural anisotropy within the context of the Mohr- Coulomb failure criterion. The results from the developed tool were compared with ones published on the current literature.
25
FLORES, EMERSON ALEX FIGUEROA. « PROBABILISTIC ANALYSIS OF SLOPE STABILITY CONSIDERING SPATIAL VARIABILITY OF SOIL ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12093@1.
Texte intégralRésumé :
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORFreqüentemente as análises de estabilidade de taludes são feitas por métodos determinísticos, nos quais é obtido um Fator de Segurança (FS). Estes métodos não quantificam as incertezas existentes nas variáveis de entrada (parâmetros de resistência) na análise. Tampouco mostram detalhes sobre qual variável afeta mais o resultado. Os métodos probabilísticos permitem superar estes problemas. A presente pesquisa tem como objetivo comparar dois métodos probabilísticos geralmente utilizados (Estimativas Pontuais e Segundo Momento). Três projetos utilizados comumente na geotecnia são analisados: barragem de rejeitos, talude de solo e aterro sobre argila mole.Um aspecto importante na análise probabilística é a quantificação adequada do desvio padrão. É sabido que as propriedades dos solos mostram uma correlação no espaço, pelo que o desvio padrão calculado por métodos clássicos da estatística é superestimado em comparação ao valor real no campo. El-Ramly (2001) desenvolveu uma metodologia para o cálculo da probabilidade de ruptura considerando a correlação espacial das propriedades do solo. Esta metodologia é de difícil aplicação prática. Serão, portanto, avaliadas na presente pesquisa as técnicas geralmente usadas de probabilidade e estabilidade de taludes, juntamente com um fator de correção proposto por Vanmarcke (1977a). Estas técnicas de probabilidade de estabilidade de taludes são factíveis de serem utilizadas junto com este fator de correção. Verificou-se que o Método de Segundo Momento é de mais fácil utilização, e portanto adequado para emprego em projetos geotécnicos.
The analysis of slope stability is often determined by deterministic methods, in which a Factor of Security (FS) is obtained. These methods do not quantify the uncertainty in the input variables (strength parameters). Neither these methods show details which variable affects mostly the outcome results. The probabilistic methods allow overcoming these restrictions. This study aims at comparing two probabilistic methods of general use (Point Estimates and First Order Second Moment). Three projects commonly used in geotechnical engineering are analyzed: tailings dam, slope soil and embankment on soft clay. An important aspect of the probabilistic analysis is the proper quantification of the standard deviation. It is known that the soil properties show a correlation in space, so the standard deviation, calculated by traditional methods of statistics, is overestimated when compared to the real field value. El-Ramly (2001) developed a methodology for calculating the probability of failure considering the spatial correlation of the soil properties. This methodology is difficult to apply in practice. The present study will therefore evaluate the techniques generally used in probability of failure of slopes. These probability techniques applied to slope stability can be used together with a correction factor proposed by Vanmarcke (1977b). The Second Moment Method was found to be easier to use, and therefore more suitable for geotechnical projects.
26
Abifadel, Nassim Riyad 1964. « Application of Powell's conjugate direction method to slope stability analysis ». Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276652.
Texte intégralRésumé :
Slope stability problems often arise in construction engineering projects. They are major problems in dams construction and mines excavation. For the purpose of improving the efficiency of slope stability analysis, the optimization method suggested by Powell (1964) is used to locate the critical failure surface. The reader should bear in mind the possibility of applying optimization to a wide variety of different civil engineering problems.
27
Oge, Ibrahim Ferid. « Slope Stability Analysis And Design In Elbistan-collolar Open Cast Mine ». Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609939/index.pdf.
Texte intégralRésumé :
Slope stability is an important aspect of geotechnical engineering. Input
parameters for the analysis are the governing factors and they must be determined
accurately and precisely. Field investigations, laboratory testing and back analyses
are vital instruments for the input parameters.
This study presents the results of slope stability analysis for the soil slopes at
Elbistan-Çö
llolar lignite mine. After executing the drilling programme, samples taken from the drilling work, delivered to soil mechanics laboratory for testing. The basic input parameters, namely cohesion and friction angle determined at soil mechanics laboratory were compared to the parameters obtained from back analysis of a large scale slope failure. Input parameters for the analysis are determined by this way. After determining the input parameters, slope stability analyses were carried out both for the permanent and temporary slopes in AfSin-Elbistan lignite basin, Ç
ö
llolar sector. The effect of ground water on the stability of slopes was investigated in detail and maximum safe slope angles were determined for different water levels. For limit equilibrium analysis, Rocscience SLIDE software, for finite difference analysis in 3-D, Itasca FLAC3D was used. In the limit equilibrium analyses both circular and composite failures were considered. Shear strength reduction method is used for the finite difference method. The results between limit equilibrium and 3-D finite difference methods were compared. When the failure surfaces obtained from the finite difference analyses were imposed to limit equilibrium analysis, computations are resulted in lower factor of safety values for limit equilibrium analysis.
28
Henderson, Susan Jane. « Analysis of the long-term slope stability of waste-rock dumps / ». Title page, table of contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phh4972.pdf.
Texte intégral
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Davies, Owen. « Numerical analysis of the effects of climate change on slope stability ». Thesis, University of Newcastle upon Tyne, 2011. http://hdl.handle.net/10443/1211.
Texte intégralRésumé :
Embankments and cuttings form an integral part of the infrastructure of the UK. These earthwork structures are susceptible to a number of external influences which can ultimately affect their stability. Climate is one of these influences. There have been many observational correlations drawn between climate and slope deformation and eventual failure. A change in climate is therefore likely to impact on slope stability. It is widely agreed within the scientific community that the climate is changing. Future climates are likely to consist of higher average temperatures, wetter winters and drier summers. It is therefore important that we assess the impacts of future climate on slope stability in order to maintain vital infrastructure. This thesis describes the development of a novel numerical modelling procedure which allows the assessment of the effects of climate on slope deformation and rate of failure. The procedure employs the use of established hydrological and geotechnical numerical models to firstly calculate the pore pressure response to climate and secondly calculate the mechanical response to pore pressure. The hourly climate data required by the modelling procedure can be obtained from MET office weather stations for back analysis simulations or can be generated for present and future climates using a weather generator. The numerical modelling procedure has been used with present and future climatic data to assess the impacts of climate change on a diagnostic embankment and a cutting in the Newbury area. The procedure has also been used with historical weather data to back analyse an instrumented natural slope in Belfast, in order to determine the failure mechanism. The development and implementation of the modelling procedure lead to the following key findings. Firstly, laboratory and field permeability measurement techniques are wholly inadequate in measuring macroscopic permeability characteristics of clay slopes. Secondly, slope deformation magnitude is closely linked to annual maximum pore pressures. Wet years and increased wet year frequency will therefore considerably increase deformation and failure rate. Thirdly, the permeability of a slope will determine whether it will be more or less susceptible to increased failure rates when subjected to a future climate scenario. The strength of the study presented here is the amalgamation of the three separate disciplines of climatology, hydrology and geotechnical engineering in order to quantify the significance of each on the stability of slopes.
30
Al-Karni, Awad 1962. « Application of the BFGS quasi-Newton method to slope stability analysis ». Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276994.
Texte intégralRésumé :
Mana computer programs have been developed for solving slope stability problems. Since slope stability problems can be characterized as optimization problems, many optimization techniques can be used for searching for the lowest safety factor for a given problem and the corresponding critical slip surface. Most of the slope stability programs use the direct search method which requires only the function value (i.e., safety factor value). In this thesis, a new optimization technique, the Broyden (1970), Fletcher (1970), Goldfarb (1970), and Shanno (1970) (BFGS) quasi-Newton optimization method, is used in conjunction with the STABR program of Lefebvre (1971) to solve slope stability problems. This method of optimization requires the function value and the first derivative value, which can be found by the finite difference method. A new program CSLIP3, incorporating the BFGS technique, is used to solve a variety of realistic slope stability problems. It is determined that CSLIP3 is reliable and efficient.
31
Sanders, Jonathon D. « Developing a GIS Tool for Infinite Slope Stability Analysis (GIS-TISSA) ». Thesis, Michigan Technological University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10617403.
Texte intégralRésumé :
The Probabilistic Infinite Slope Analysis model (PISA-m) is a widely used computer program that uses infinite slope equations to calculate the spatially varying Factor of Safety of slopes. ESRI’s ArcGIS software and accompanying geoprocessing tools have become a mainstay in spatial data processing, and received full support for Python with the release of version 10. With many of the geoprocessing tools now available as a Python function, the software can be used for physics-based spatial landslide hazard analysis. A model that mimics PISA-m and its processing of normally distributed soil properties was created using the Python utility as a tool for ArcGIS. The newly created ArcGIS tool is referred as the GIS Tool for Infinite Slope Stability Analysis (GIS-TISSA). The tool was tested using the example data from PISA-m and case-study data from the district of Kannur, Kerala, India. The results from both areas highlight how different slope calculations can affect the overall calculation of the Factor of Safety, as well as the new model’s ability to accurately predict Factor of Safety of slopes in an area.
32
XIONG, Jun. « Study on Simulation methods of Groundwater Behavior for Slope Stability Analysis ». 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/97968.
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33
Logan, Kenneth Scott. « Analysis of Wireless Tiltmeters for Ground Stability Monitoring ». Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32009.
Texte intégralRésumé :
Tiltmeters can be used in the mining environment to monitor slope stability by making use of gravitational force to measure angles of inclination relative to horizontal. Tiltmeters typically use accelerometers, which output a voltage measurement that can be related to angle of tilt. Though wireless tiltmeters already exist today, they lack certain ruggedness and sensitivity preventing use in mines. The purpose of this project was to investigate the feasibility of using already existing wireless tiltmeters in the mining setting. Additionally, a new wireless tiltmeter was designed which could be specially tailored for the needs of monitoring hazardous rock bodies in both surface and underground mines. By recording angles of any slope, either in a surface mine or underground, over extended periods of time, changes in readings can infer instabilities in the rock mass underlying the slope being measured. By placing many tiltmeters in a mesh on a surface slope or underground roof, rib, or other face, the entire surface can be monitored. Compared to the measurements of a single point using one instrument, a dense network can be extremely useful in detecting rock movement.
Many monitoring techniques are in use already in mines. Traditional methods of monitoring, though undeniably useful, are often time consuming. By utilizing wireless devices that transmit data back to a single location, data acquisition and analysis time can be minimized, saving the mine employee hours as well as down time. As surface mines continue to deepen, and underground mines continue to progress further from the surface, the extent of necessary monitoring continues to increase: this widening range will require greater time for proper monitoring, unless an automated system is implemented. With proper wireless equipment, real time monitoring of an entire mine is possible.Master of Science
34
Vega-Cortes, Liselle. « Evaluation of Analysis Methods used for the Assessment of I-walls Stability ». Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31047.
Texte intégralRésumé :
On Monday, 29 August 2005, Hurricane Katrina struck the U.S. gulf coast. The storm caused damage to 169 miles of the 284 miles that compose the Hurricane Protection System (HPS) of the area. The system suffered 46 breaches due to water levels overtopping and another four caused by instability due to soil foundation failure. The Interagency Performance Evaluation Task Force (IPET) conducted a study to analyze what happened on the I-wall breach of the various New Orleans flood control structures and looked for solutions to improve the design of these floodwalls.
The purpose of the investigation, describe in this document, is to evaluate different methods to improve the analysis model created by IPET, select the best possible analysis techniques, and apply them to a current cross-section that did not fail during Hurrican Katrina. The use of Finite Element (FE) analysis to obtain the vertical total stress distribution in the vicinity of the I-wall and to calculate pore pressures proved to be an effective enhancement. The influence of overconsolidation on the shear strength distribution of the foundation soils was examined as well.Master of Science
35
Styles, Thomas Daniel. « Numerical modelling and analysis of slope stability within fracture dominated rock masses ». Thesis, University of Exeter, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496103.
Texte intégralRésumé :
Numerical modelling of rock slopes can involve a number and variety of techniques, the selection and requirement of which depends on the factors deemed to control the potential for Instability. This thesis presents a number of case studies involving slopes in fractured rock, encompassing a range of scales. The case study slopes have provided a means to question the way in which particular slope instabilities should be analysed. Currently there are few methods available for analysing the complex behaviour within slopes of fractured rock. A review of available techniques is given within this thesis, with the use of limit equilibrium, finite element and hybrid methods, to highlight their specific advantages and limitations for the chosen case study slopes. By modelling slope Instability within fractured rock, the understanding of both discrete and mass behaviour increases considerably. Numerical modelling can therefore be used as a tool to help improve both the safety and efficiency of open pit mining and the management of natural rock slopes.
36
Vajirkar, Mrutyunjay. « SLOPE STABILITY ANALYSIS OF CLASS I LANDFILLS WITH CO DISPOSAL OF BIOS ». Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3491.
Texte intégralRésumé :
Land filling provides a major, safe, and economical disposal route for biosolids and sludges. With an expanding world, the demand for larger and higher capacity landfills is rapidly increasing. Proper analysis and design on such fills have pushed the boundaries of geotechnical engineering practice, in terms of proper identification and assessment of strength and deformation characteristics of waste materials. The engineering properties of Municipal Solid Waste (MSW) with co-disposal of biosolids and sludges with regards to moisture characteristics and geotechnical stability are of utmost importance. Significant changes in the composition and characteristics of landfill may take place with the addition of sludges and biosolids. In particular, the stability of waste slopes needs to be investigated, which involves the evaluation of the strength properties of the mixture of the waste and biosolids. This thesis deals with impact of the addition of biosolids on the geotechnical properties of class I landfill as determined from field investigations. The geotechnical properties are evaluated using an in-situ deep exploration test, called the Cone Penetration Test (CPT). CPT provides a continuous log of subsurface material properties using two measuring mechanisms, namely, tip resistance and side friction. The areas receiving biosolids are compared with areas without, to evaluate the effect of landfilling of biosolids. The required geotechnical shear strength parameters (angle of internal friction and cohesion) of MSW and biosolids mixture are determined by correlation with CPT results similar to the procedure followed in evaluating soil properties. The shear strength parameters obtained from the CPT data are then used to study the stability of different slope configurations of the landfill. The slope stability analysis is conducted on the various landfill models using the computer software SLOPE/W. This software was designed for soils but was found to be suitable for modeling landfills, as the waste is assumed to act similar to a cohesionless soil. Based on the field investigations, the angle of internal friction was found to be about 29° and the determination of any cohesion was not possible. It was concluded that the most suitable practical solution to adding biosolids into the landfill was in the form of trenches. From the slope stability study, it was found that the factor of safety reduces significantly with the introduction of biosolids due to a reduction in shear strength and increase in the overall moisture content. From a parametric study, the stability of a 1:2 side slope with an angle of friction lower than about 20° was found to be less than the safe limit of 1.5. In addition, the factors of safety for landfills with trenches extending close to the edges of the slopes were also found to be unsafe and this situation needs to be avoided in practice.M.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
37
Pilgrim, Nicholas Kumoi. « Observation and analysis of slope stability with seepage in centrifuge model earthquakes ». Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321493.
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Arnold, Patrick. « Probabilistic modelling of unsaturated slope stability accounting for heterogeneity ». Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/probabilistic-modelling-of-unsaturated-slope-stability-accounting-for-heterogeneity(fb3d214c-8a42-4a2c-81c2-bda45e9ae7af).html.
Texte intégralRésumé :
The performance and safety assessment of geo-structures is strongly affected by uncertainty; that is, both due a subjective lack of knowledge as well as objectively present and irreducible unknowns. Due to uncertainty in the non-linear variation of the matric suction induced effective stress as a function of the transient soil-atmosphere boundary conditions, the unsaturated state of the subsoil is generally not accounted for in a deterministic slope stability assessment. Probability theory, accounting for uncertainties quantitatively rather than using "cautious estimates" on loads and resistances, may aid to partly bridge the gap between unsaturated soil mechanics and engineering practice. This research investigates the effect of uncertainty in soil property values on the stability of unsaturated soil slopes. Two 2D Finite Element (FE) programs have been developed and implemented into a parallelised Reliability-Based Design (RBD) framework, which allows for the assessment of the failure probability, failure consequence and parameter sensitivity, rather than a deterministic factor of safety. Utilising the Random Finite Element Method (RFEM), within a Monte Carlo framework, multivariate cross-correlated random property fields have been mapped onto the FE mesh to assess the effect of isotropic and anisotropic moderate heterogeneity on the transient slope response, and thus performance. The framework has been applied to a generic slope subjected to different rainfall scenarios. The performance was found to be sensitive to the uncertainty in the effective shear strength parameters, as well as the parameters governing the unsaturated soil behaviour. The failure probability was found to increase most during prolonged rainfall events with a low precipitation rate. Nevertheless, accounting for the unsaturated state resulted in a higher slope reliability than when not considering suction effects. In a heterogeneous deposit failure is attracted to local zones of low shear strength, which, for an unsaturated soil, are a function of both the spatial variability of soil property values, as well as of the soil-water dynamics, leading to a significant increase in the failure probability near the end of the main rainfall event.
39
Masi, Elena Benedetta. « The root reinforcement in a distributed slope stability model : effects on regional-scale simulations ». Doctoral thesis, 2020. http://hdl.handle.net/2158/1192258.
Texte intégralRésumé :
The shallow landslides are hazardous mass movements commonly triggered by intense rainfall. The hazardousness of these events is mainly due to their common evolution in rapid mass movements as debris avalanches and flows and to the frequently occurring in the form of clusters of events. Because of their characteristics, the forecasting is a particularly valuable tool to protect people and infrastructures from this kind of landslide events.
The presence of vegetation on hillslopes significantly reduces the slopes susceptibility to the shallow landslides, and the stabilising action is mainly due to the reinforcement of the soil by the roots. The spatial variation of the root reinforcement should be therefore considered in distributed slope stability analyses. However, the natural variability of the parameter makes it challenging to insert the root reinforcement into the models.
Many approaches to the problem were tested, but nowadays there are still lacking a distributed slope stability model capable of very quick processing in which the root reinforcement is considered and an approach to estimate the root cohesion at the regional scale that it has been tested in very wide areas and for long period-simulations.
In this study, we present the effect of the root cohesion on slope stability simulations at the regional scale obtained using a physically-based distributed slope stability model, the HIRESSS (HIgh REsolution Slope Stability Simulator). The HIRESSS model was selected for the purposes, being capable of rapid processing even in wide areas thanks to the parallel structure of its code. The simulator was modified to insert the root reinforcement among the geotechnical parameters considered to computing the factor of safety in probabilistic terms, and for this purpose a commonly adopted model for the root cohesion was chosen.
To build a map of the root cohesion for the study areas, the distribution of plant species in the area was obtained from vegetation distribution map and in situ surveys, then a value of root cohesion and a range of variation was defined for each plant species based on the most recent literature in this field, finally, to reproduce the natural variability, the root reinforcement was treated as variable in Monte Carlo simulations, as well as the other geotechnical parameters.
The results of the simulations for the study areas were processed and analysed in order to evaluate the effect of the root cohesion on the failure probabilities and the adopted approach to estimate the root cohesion at the regional scale. The comparative analyses carried out on the results of the simulations performed inserting or not the root reinforcement brought out little differences between the two from the point of view the failure probabilities, particularly when the saturated conditions of the soil are reached.
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Based on the findings of this research, it is considered that a root cohesion model different to the one adopted is preferable in the context of the shallow landslides, in applications in which working with failure probabilities (instead of factor of safety values) is desirable, and in areas similar to the ones of the study.
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Liu, Kuan-Lin, et 劉冠麟. « Slope stability analysis under extreme rainfall in slate slope ». Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7e8yj9.
Texte intégralRésumé :
碩士國立高雄第一科技大學
營建工程系碩士班
106
With global warming and climate change issues, extreme rainfall events in the future may become the normal, causing severe disaster events will be more frequent. During the rainy season such as typhoon and heavy rain, severe rainfall often induces more serious slope disasters. Analysis of the devastating heavy rainfall in Taiwan in the past two decades, the occurrence of slope disasters is mostly caused by "excessive continuous rainfall" or "short-duration rainfall". For mild metamorphic slate, its erosion resistance is higher than that of mud or shale. However, the slate is easily split along its cleavage direction and turned into a finely- cut sheet. When subjected to long-term gravity and weathering, the material of shale will gradually become weaken and turn into creep. That is, during the deformation process of slate slope, joint fissures will gradually grow out. When the rainfall infiltration leads to groundwater level rise, the possibility of rock debris collapse will increase. In this study, high- risk areas with deep collapse were selected for analysis, taking Songmao Landslide area in Lishan District and Sinsing Landslide area in Jinfeng Township, Taitung County as examples. To simulate groundwater level rise caused by rainfall, this study conducted SEEP/W module of GeoStudio numerical software. The groundwater level monitoring data will be used for verification. Then, the SLOPE/W module of GeoStudio numerical software is used for slope stability analysis. Exploring the relationship between groundwater level rise and safety factor of slope is one of the main task in this study. The uncertainty of rainfall caused by extreme weather is researched herein. In this study, the design of rainfall patterns such as advanced, intermediated, delayed and uniform rainfalls models were simulated. This study tried to establish a deep- seated landslide disaster warning system. After simulation analysis and verification, the relationship between rainfall duration and accumulated rainfall and the relationship between the maximum groundwater level cumulative rainfall and water level elevation were proposed as the evaluation criteria. The relevant research results are as follows: (1) Relationship between rainfall duration (X) and cumulative rainfall (Y): When FS=1.05 of Songmao Landslide area, the upper bound is Y=-7.221*X+1844.052, and the lower bound Y=-7.221 *X+1630. The FS=1.0 of Sinsing Landslide area, Y=0.35*X+371.98; when FS=1.05, Y=0.021*X+143.56. (2) Relationship between cumulative rainfall at the highest groundwater level (X) and rise of groundwater level (Y): In Songmao Landslide area, the relationship of cumulative rainfall at the highest groundwater level and rise of groundwater level is Y=0.00387*X; and when Y=3m, FS=1.05; Y=6m, FS=1.0. In Sinsing Landslide area, the relationship is Y=0.00789*X; and when Y=1.0m, FS=1.05; Y=3.87m, FS=1.0.
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Bijoy, A. C. « Comparative Studies On Slope Stability Analysis ». Thesis, 1999. http://etd.iisc.ernet.in/handle/2005/1603.
Texte intégral
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郭 et 郭易方. « Uncertainty of slope stability analysis methods ». Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ez33q5.
Texte intégralRésumé :
碩士國立中央大學
土木工程學系
105
The norms related to slope stability in Taiwan are generally based on the overall factor of safety, but the analysis process for safety factor is not required in detail. Whenever a disaster coming, it is easy to be controversial. Conventional limit equilibrium method for analysis can quickly get a potential surface and factor of safety. It’s still trusted by the engineering community. Engineers need to rely on their experience, because these methods of slices have different assumptions. In this paper, a series analysis for 43 cases by limit equilibrium method. Different commercial program, search method and method of slices are used to analyze simple slopes, natural slopes, and embankment dam. Points out the emphasis of the analysis process, and discusses the three factors that cause the uncertainty. The results show that the commercial program has the most significant effect on the analysis of the circular sliding surface, and search method is second. The influence of the slicing method is the most regular and predictable. When analyzing the non-circular surface, applicability of search methods and method of slices for the case needs to be considered.
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Wang, Jun-Min, et 王竣民. « Rainfall Induced Unsaturated Slope Stability Analysis ». Thesis, 2019. http://ndltd.ncl.edu.tw/handle/nyt4hy.
Texte intégralRésumé :
碩士國立臺灣大學
土木工程學研究所
107
Taiwan is a rainy country in the world. There is abundant rainfall all year. Rainfall is one of the main causes of mountain slope disasters. In recent years, the behavior of unsaturated soil has been incorporated into the slope stability analysis. The matric suction is present in the unsaturated soil, and it provides force to resist the sliding force. After consider matric suction, the factor of safety will be higher than that without considering the matric suction. In this study, PLAXIS 2D was used for slope stability analysis to investigate the influence of slope, fitting parameters of vG model, permeability coefficient and rainfall events on unsaturated slopes. Using the relationship between of the matric suction, factor of safety and failure surface to judge the difference of each soil parameters. According to the results, the wetting band is an important factor, it makes the matric suction of surface soil decrease rapidly, and the shear strength of soil is also decreases, which easily causes the slope to failure. At the rainfall event 3, if the permeability coefficient is large, the rainwater will flow to deeper soil and raise the groundwater level, and the saturation of the wetting band will be low relatively.
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Chang, Shih-Hao, et 張世豪. « Numeric Analysis of Slope Stability at an Open Cut Slope ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/uwetzr.
Texte intégralRésumé :
碩士國立臺北科技大學
土木與防災研究所
99
The staggering price of a property in urban Taipei results in high efficiency of land use and extreme density of buildings. In light of the proximity of the foundations of most buildings to other buildings or underground utility and considering the soft and weak clay underlying the geologic formation of Taipei Basin, diaphragm wall is the preferred construction method for deep excavations, as to prevent inclining of or damage to neighboring structures due to soil decompression, excessive lateral displacement or ground settlement. Open cut slope is rarely seen as the foundation excavation method of choice in Taipei Basin. An open cut slope excavation at a site located in the Keelung River K1 zone north of Keelung River and south of Tatun volcano group was studied. PLAXIS, a 2D finite element analysis program, was combined with jobsite observation data for comparison and verification. With the comparison result mentioned above, the effects of changes in the depth of bedrock at the studied jobsite to the failure surface of the excavation were investigated. The predominant control factors were explored to find out the influence of these factors to the soil slide through the simulation of PLAXIS with the penetration depth of soldier piles, groundwater table and the location of strutting as the variables.
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Tseng, Hui-Ti, et 曾惠蒂. « Slope stability analysis using the deformation analysis method ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/39502935238320756201.
Texte intégralRésumé :
碩士國立成功大學
資源工程學系碩博士班
93
Because of its inferior geological conditions and environmental factors, geological hazards like landslides are of great concern in Taiwan. The stability of soil slopes which mainly involves factor of safety is analyzed by the limit equilibrium method (LEM) and the deformation analysis method. The objective of this thesis is to investigate the stability of soil slope problem by using a numerical analysis procedure combining with the deformation analysis method, in which the stress-strain character of soil mass can be considered. The focus of this thesis is on the stability of soil slopes, in terms of factor of safety (FS) and failure surface location. Determination of the FS in numerical analysis method is mainly based on the concept of reduction in shear strength, and the corresponding failure surface is fairly found from the shear strain rate contour. It should be noticed that the critical slip surface is not an unique line. A narrow yielding zone was developed when the slope started to fail and any slip surface passing through the yield zone could be the failure surface. The main advantage of the proposed method for slope stability analysis over the traditional limit equilibrium method is that no assumption needs to be made in advance about the slice side forces, the location or shape of the slip surface. The factor of safety obtained by the proposed procedure is in a good agreement with that determined by the Bishop’s and Janbu’s methods. However, the proposed procedure can provide the designers a more solidly based concept in slope stability analysis.
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Chen, Kuo-Nan, et 陳國男. « Slope Stability Analysis and Slope Protection Method Using the Neural Network ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/61692091943673676003.
Texte intégralRésumé :
碩士國立成功大學
資源工程學系碩博士班
93
This paper presents a procedure of the slope stability analysis and slope protection method for soft rocks by using the back propagation neural network. The relationship between parameters of slope and slope stability analysis is often vague and less understood. Under these circumstances, back propagation neural network formalisms have an advantage in being able to learn and generalize from examples without knowledge of rules. The back propagation neural network is currently the most widely used algorithm for connectionist learning. This proposed method was used to predict the slope stability analysis and slope protection method for soft rocks of the No. 10 National Highway in southern Taiwan. In this paper, the slope stability analysis network architecture consists of seven neurons in the input layer, one hidden layers with fifteen neurons and five output neurons and the Sum Squared Relative Error (SSRE) reduced to 33.33% . The slope protection method network architecture consists of seven neurons in the input layer, one hidden layers with twelve neurons and five output neurons and the Sum Squared Relative Error (SSRE) reduced to 16.67% . The results show that the developed neural network model demonstrated a promising result and predicted the desired goal fairly successfully.
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Hung-ChingYang et 楊宏慶. « Influence of Rainfall Intensity and Slope Characteristics on Slope Stability Analysis ». Thesis, 2012. http://ndltd.ncl.edu.tw/handle/30236453887959959231.
Texte intégralRésumé :
碩士國立成功大學
資源工程學系碩博士班
100
The rainfall is the most important factor in slope stability, and the rainfall infiltration is affected by the behavior of soil in the unsaturated zone. The unsaturated state is very common in nature, but the analysis of unsaturated zone is very difficult, therefore, we use the Slope/w and Seep/w modules in the Geo-Studio program to simulate slope stability and rainfall infiltration. In this study, we change rainfall intensity and slope condition to get the relationship between factor of safety and time, and discuss the influence of rainfall intensity and slope characteristics on slope stability. In the study, we discuss the different nature of slope, such as slope material, slope angle, slope height, the groundwater table deep and rainfall patterns. Results indicated that the slope becomes more danger when the slope angle, slope height and rainfall intensity increase, and the hydraulic conductivity of the material determines the impact of the rainfall on slope stability. It has less influence than the rainfall intensity on slope stability when we change the depth of groundwater table depth. In the part of rainfall patterns, the results show that it has great connection between slope stability and occurrence of peak rainfall intensity. In this study, we also discuss the slope failure at the Shanher Stream and the Xiao Lin village, and analysis the slope failure time which are induced by the rainfall. In the case of Xiao Lin village, the simulation result of failure time has an error of one hour, and the result of Shanher Stream is quite consistent with the actual failure time.
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St, George J. D. (John D. ). « Probabilistic methods applied to slope stability analysis ». 1991. http://hdl.handle.net/2292/2242.
Texte intégralRésumé :
In slope stability analysis, as with other areas of geotechnical engineering, there is a high degree of uncertainty associated with design parameters. Engineers rely heavily on historical information and present performance to establish criteria. The observational approach which is essentially taking a Bayesian stance is advocated in most projects. The purpose of this study was to develop a method which will augment current design practice for mine slope stability, with the use of strength parameters derived from the back analysis of failures. A computerised database system for the storage of slope instability cases was developed using a commercial package. This enabled consistent and complete records of failures to be stored and recalled for analysis. To utilize these back analysis results in a probabilistic framework, a Bayesian approach was formulated to calculate the probability distribution of c-φ. Two separate likelihood functions were derived from the observations of slope failures in similar materials for 1) The functional relationship between the c-φ parameters required to meet critical equilibrium conditions. 2) The average normal and shear stress conditions on the failure surface. Uniform prior distributions were used to assess the likelihood function. Strength properties from tests and other sources were collated into informative priors and the corresponding posterior distributions defined. Both likelihood functions produced results in agreement with reported test results. A probabilistic model based on the first-order second moment approach was developed to cope with circular and non-circular slope stability analyses. The spatial variability of the random variables was incorporated into this model and by considering the contributions of the end resistance a quasi 3-D probability of failure was derived. All the case studies were analysed using this model with the posterior strength parameters. It was found that the spatial variability only had a major effect when the range of influence of the variability was small compared to the size of the slope. Both watertable and model error had much greater effect on the variance. The 3-D aspects of failure were investigated and a lateral release factor was introduced to assess the importance of the end resistance on the failure probability. A predictive analysis was presented to demonstrate the use of these methods in slope design. End resistance was shown to have most impact on 3-D probability of failure.
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« Discussion on probabilistic analysis of slope stability ». Tese, MAXWELL, 1997. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=1924:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.
Texte intégral
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Wang, Sung-Chu, et 王崧竹. « Slope stability analysis under seismic force using programmable stability number ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/63295465516063727771.
Texte intégralRésumé :
碩士義守大學
土木與生態工程學系碩士班
99
Taiwan belongs to the Asian earthquake-prone areas, and due to natural disasters in recent years like the earthquake in Yunnan, China and Japan’s 311 earthquake, etc. Taiwan, however, is also in this seismic belt. Additionally Taiwan is mountainous area with many slopes, therefore the slope safety factor in design is a major concern and very important. This study is based on the Taylor’s method in 1973, in which the stability number was related with the slope angle, and designed to analyze the safety factor of a simple homogeneous soil slope with the application of seismic forces (but without consideration of ground water, anchor forces etc.), and a computer program based on this study is developed. With this program, it will help to reduce the estimating error, and the need to repeated attempt and therefore very time-saving. With the use of STABL6 in the studies of slope stability analysis, sorting out the relationship between the stability numbers and slope angle with different friction angles Phi ranging from 10° ~ 25°. This program can be quickly simulated to get the factor of safety with different seismic forces. Without the requirement of the use of a large number of calculation and iterations, as long as the input of slope angle Beta, height H, the soil unit weight Gamma, soil friction angle Phi, soil cohesion C and seismic forces are given, one can take advantage of this program to quickly get the the safety factor of the slope.