The design of rubble mound breakwaters usually focuses on the main armor layer. A review of the existing literature reveals that different equations are used to design rock armors in non-breaking wave conditions. However, most rubble mound breakwaters are constructed in the depth-induced breaking zone where they are attacked by waves breaking in the foreshore; in these conditions, existing design equations are not valid. Therefore, in this PhD thesis, the hydraulic stability of double-layer rock armors is analyzed through a series of small-scale tests conducted with a bottom slope m=1/50. Based on test results, a new potential relationship is given to design rock armors in depth-limited breaking wave conditions with armor slope cot¿=1.5, stability numbers within the range 0.98¿Hm0/(¿Dn50)¿2.5, and relative water depth at the toe 3.75¿hs/(¿Dn50)¿7.50. When concrete units are used for the armor layer, mound breakwaters are usually protected by a toe berm. This toe berm is placed on the seafloor or underlayer, providing support for the concrete armor units which are placed later on the structure slope. Toe berm design is commonly related to the armor design; in non-breaking wave conditions, the mass of toe berm rocks is one order of magnitude lower than the units of the layer. In breaking wave conditions, however, the highest waves start breaking on the bottom and impact directly on the toe berm. This is the common case of rocky sea bottoms with m=1/10 or higher slopes and thus, a correct design of the toe berm is crucial to guarantee the armor stability. The present PhD thesis examines the hydraulic stability of rock toe berms placed on a m=1/10 bottom slope and in very shallow waters (0.5<hs/Dn50<5.01). Small-scale tests were conducted with double-layer cube armored breakwaters and rock toe berms with different widths (Bt) and thicknesses (tt). Firstly, a new equation is proposed to design emerged and submerged standard rock toe berms (Bt=3Dn50 and tt=2 Dn50) using three parameters: (1) deep water wave height, Hs0, (2) deep water wave length, L0p, and (3) water depth at the toe, hs. Secondly, the influence of toe berm width (Bt) on toe berm stability is analyzed introducing two new concepts to characterize wide toe berms (Bt>3Dn50): (1) the nominal toe berm or the most shoreward toe berm area which effectively supports the armor layer, and (2) the sacrificial toe berm or the most seaward toe berm area which serves to protect the nominal toe berm. Considering the nominal toe berm damage, a new method is developed to reduce the rock toe berm size (Dn50) by increasing the toe berm width (Bt) if the required rock size is not available at the quarries. Finally, cube armor damage is examined, and the influence of the placement technique on armor stability is also characterized from physical tests conducted with cubes randomly- and uniformly- placed on the armor in two layers. / El manto principal de los diques en talud suele estar formado por escollera natural o elementos prefabricados de hormigón; su función es resistir la acción del oleaje. Una revisión del estado del arte pone de manifiesto que son numerosas las fórmulas existentes para el diseño de mantos derivadas de ensayos físicos a escala reducida con oleaje sin rotura por fondo. Sin embargo, la mayoría de diques en talud se construyen en la zona de rompientes con oleaje limitado por fondo, donde las ecuaciones de diseño habituales no son del todo válidas. En esta tesis doctoral se analiza la estabilidad hidráulica de mantos bicapa de escollera, a partir de ensayos a escala reducida con pendiente de fondo m=1/50. En base a los resultados obtenidos de los ensayos físicos, se propone una nueva relación potencial para el diseño de mantos de escollera en condiciones de oleaje limitado por fondo, válida para taludes con cot¿=1.5, números de estabilidad 0.98¿Hm0/(¿Dn50)¿2.5, y profundidades relativas a pie de dique de 3.75¿hs/(¿Dn50)¿7.50. Cuando el manto principal está formado por elementos de hormigón, es habitual construir una berma de pie que proporciona apoyo a los elementos del manto y, en su caso, colabora en la protección de la zona inferior del dique contra la socavación. Dicha berma suele construirse con escollera natural y su peso está condicionado al de los elementos del manto en el caso de no haber rotura por fondo. El peso de los elementos de la berma de pie suele ser un orden de magnitud inferior al peso de las unidades del manto; sin embargo, si la pendiente de fondo es fuerte (p.e. m=1/10) y las aguas someras esta regla no se cumple ya que algunas olas rompen sobre el fondo impactando directamente sobre la berma de pie. En estos casos, el peso de la escollera de la berma puede sobrepasar el de las unidades del manto y su correcto diseño es crucial para garantizar la estabilidad del dique. Además de estudiar la estabilidad del manto principal de diques de escollera, la presente tesis doctoral analiza también la estabilidad hidráulica de bermas de pie de escollera ubicadas en fondos con pendiente m=1/10 y aguas someras (0.5<hs/Dn50<5.01), en base a ensayos físicos a escala reducida realizados con mantos bicapa de cubos y bermas de escollera con diferentes dimensiones. En primer lugar, se propone una nueva ecuación para el diseño de bermas escollera estándar (Bt=3Dn50 y tt=2 Dn50), tanto emergidas como sumergidas, a partir de tres parámetros: (1) altura de ola en aguas profundas, Hs0, (2) longitud de onda en aguas profundas, L0p, (3) profundidad a pie de dique, hs. Posteriormente, se analiza la influencia del ancho de la berma (Bt) en su estabilidad hidráulica, introduciendo dos nuevos conceptos para caracterizar bermas de pie anchas (Bt>3Dn50): (1) berma nominal o zona de la berma de pie sobre la que realmente apoya el manto principal, y (2) berma de sacrificio o zona de la berma de pie que protege a la berma nominal. A partir del daño de la berma de pie nominal, se propone un nuevo método para reducir el tamaño de piedra (Dn50) incrementando el ancho de la berma (Bt) cuando no se disponga del tamaño requerido en cantera. Finalmente, se examina el daño del manto de cubos y se analiza la influencia del método de colocación sobre el mismo, a partir de ensayos realizados con mantos bicapa de cubos con colocación aleatoria y uniforme. / El mantell principal dels dics en talús sol estar format per roca o elements prefabricats de formigó, la seva funció és resistir l'acció de l'onatge. Una revisió de l'estat de l'art manifesta que són nombroses les equacions de disseny existents per a condicions d'onatge no trencat. No obstant això, la majoria de dics en talús es construeixen a la zona de rompents amb onatge limitat per fons, on les equacions de disseny existents no són del tot vàlides. En aquesta tesi doctoral s'analitza l'estabilitat hidràulica de mantells bicapa de roca, a partir d'assajos a escala reduïda realitzats amb pendent de fons m = 1/50. En base als resultats obtinguts dels assajos, es proposa una relació potencial per al disseny de mantells de roca en condicions d'onatge limitat per fons vàlida per a talussos amb cot¿ = 1.5, nombres d'estabilitat 0.98¿Hm0/(¿Dn50) ¿2.5, i profunditats relatives a peu de dic de 3.75¿hs/(¿Dn50)¿7.50. Quan mantell principal està format per elements de formigó , és habitual construir una berma de peu que proporciona suport als elements del mantell i, si escau, col¿labora en la protecció de la zona inferior del dic contra la soscavació. Aquesta berma sol construir amb roca i el seu pes està condicionat al dels elements del mantell en el cas de no haver trencament per fons. El pes dels elements de la berma de peu sol ser un ordre de magnitud inferior al pes de les unitats del mantell; però, si el pendent de fons és fort ( p.e. m = 1 /10) i les aigües someres aquesta regla no es compleix ja que algunes onades trenquen sobre el fons impactant directament sobre la berma de peu. En aquests casos, el pes de la roca de la berma pot sobrepassar el de les unitats del mantell, i el seu correcte disseny és crucial per garantir l'estabilitat del dic. A més d'estudiar l'estabilitat del mantell principal de dics de roca, la present tesi doctoral analitza també l'estabilitat hidràulica de bermes de roca ubicades en fons amb pendents m = 1/10 i aigües someres (0.5<hs/Dn50<5.01), utilitzant assajos a escala reduïda realitzats amb mantells de doble capa de cubs i bermes de roca amb diferents dimensions. En primer lloc, es proposa una nova equació per al disseny de bermes de roca estàndard (Bt = 3 Dn50 i tt = 2 Dn50), tant emergides com submergides, a partir de tres paràmetres: (1) alçada d'ona significant en aigües profundes, Hs0, (2) longitud d'ona en aigües profundes, L0p, i (3) profunditat a peu de dic, hs. Posteriorment, s'analitza la influència de l'amplada de la berma (Bt) en la seua estabilitat hidràulica, introduint dos nous conceptes per caracteritzar bermes de peu amples (Bt > 3 Dn50): (1) berma nominal o zona de la berma de peu sobre la qual recolza el mantell principal, i (2) berma de sacrifici o zona de la berma de peu que protegeix la berma nominal. A partir del dany de la berma de peu nominal, es proposa un nou mètode per reduir el tamany de roca (Dn50) incrementant l'amplada de la berma (Bt) quan no es disposi de la mida requerit en pedrera. Finalment, s'examina el dany del mantell de cubs i s'analitza la influència del mètode de col¿locació sobre el mateix , a partir d'assajos realitzats amb mantells bicapa de cubs amb col¿locació aleatòria i uniforme. / Herrera Gamboa, MP. (2017). Mound Breakwater Design in Depth-Limited Breaking Wave Conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/82553

京都大学 / 新制・課程博士 / 博士(工学) / 甲第25262号 / 工博第5221号 / 新制||工||1996(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 岸田 潔, 教授 安原 英明, 准教授 橋本 涼太 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

[pt] A alteração de rochas e juntas provoca modificações em suas propriedades, levando à redução da resistência do maciço rochoso e, consequentemente, à redução da segurança das obras de engenharia. O processo de alteração modifica o material e altera seu comportamento geomecânico. Esta pesquisa apresenta os estudos realizados para avaliação do comportamento mecânico das juntas rochosas dos maciços de gnaisse que compõem o circuito hidráulico do Aproveitamento Hidrelétrico Simplício, em função de sua alteração. Foram realizadas compilação e análise de dados obtidos em pesquisas anteriores, para parametrização das juntas em diferentes níveis de alteração. As análises de estabilidade determinísticas mostraram que o processo de alteração das juntas de gnaisse pode reduzir significativamente o fator de segurança do talude, em até metade de seu valor inicial. Além disso, as análises probabilísticas mostraram um aumento da probabilidade de ruptura de aproximadamente 10 por cento entre as classes de alteração estudadas. Os resultados mostram a importância da avaliação do nível de alteração das juntas nos projetos de engenharia. / [en] Rock and joint alteration leads to modifications in their properties, resulting in a reduction of rock mass strength and consequently a decrease in the safety of engineering structures. The alteration process changes the material and alters its geomechanical behavior. This research presents the studies conducted to evaluate the mechanical behavior of rock joints in the gneiss massifs that make up the hydraulic circuit of the Simplicio Hydroelectric Plant due to their alteration. Compilation and analysis of data from previous research were carried out to parameterize the joints at different levels of alteration. Deterministic stability analyses showed that the alteration process of gneiss joints can significantly reduce the slope safety factor by up to half of its initial value. Furthermore, probabilistic analyses revealed an increase in failure probability of approximately 10 percent among the studied alteration classes. The results underscore the importance of assessing the level of joint alteration in engineering projects.

Landslides are one of the most widespread, yet difficult to predict, geohazards in the world. Theyrepresent a major threat to society, which is why it is so important to understand and study them.Landslide detection is one of the approaches that help scientists to gain a better knowledge of landslides,how they form and the characteristics they hold. In this work, a new landslide detection technique istested in the Klarälven Region, Sweden. The method involves using multi-temporal DEMs generatedfrom LiDAR point clouds from 2010 and 2020. Once two respective DEMs are generated from theoriginal point cloud data sets, a DEM of Difference (DoD) is obtained by subtracting the 2010 DEMfrom the 2020 DEM. The DoD highlights areas of vertical change over the ten-year period. In order todetect potential landslides, a Level of detection (LoD) threshold is applied, as well as a second upperthreshold filtering out elevation difference resulting from anthropogenic activities. Lastly, a spatialthreshold is applied to eliminate any remaining potential errors clusters that are too small to belandslides. Once this stage is completed, the study area is surveyed, focusing on certain areacharacterised by particular slope angles and soil types most likely to exhibit mass movement. Thishelped in the analysis and interpretation of the data. In order to discuss the results as fully as possible,four types of region were studied in more detail using four representative examples. Since a few doubtfulcases were found, potential sources of error are also being explored. Despite minor inaccuracies, themethod appears to be a relevant technique for detecting differences in altitude, even if it also considersunnatural mass movements.

The development of an interactive computer model for managing geologic hazards databases is vital and long overdue. As highway rockslopes continue to age and become more unstable and earthen dams are subjected to ever increasing flood events, a more proactive management system is required in order to provide timely information to planners and emergency personnel on demand. In recent years, deaths have occurred associated with both highway rockslides and earthen dam failures in southwest Virginia. In February 1991, a rockfall event occurred on Route U.S. 11 in the City of Radford, VA, which resulted indirectly in a highway accident and fatality. The incident made all parties aware that rockfalls from aging highway roadcuts within the city limits pose some threat to the motoring public (Watts et al., 1996). Additionally, in June 1995, the Timberlake dam in Lynchburg, VA, failed due to flash flooding from intense summer storms. Two people died on highways downstream of the dam, even though emergency personnel were on the scene. The lack of organized critical information about the dam, its downstream flood inundation zone, and its emergency action plan contributed to the tragedy. The outcome of the ensuing litigation is pending. In the case of the City of Radford, a user-friendly interactive database containing structural stereonet analysis, digital images, hazardous slope conditions, and maintenance records would provide a proactive approach to rockslope maintenance by allowing the slopes to be ranked in terms of geologic and traffic conditions. Appropriate remediation measures can then be taken in the most cost-effective manner. In the case of the Timberlake dam failure, a database containing critical information about the dam, its upstream watershed characteristics, downstream flood inundation zones, and emergency action plan could have been accessed by state geologists and emergency dispatchers. Appropriate measures could have been taken to deal with the event as it was unfolding. / Master of Science

Yes / The existing analytical solutions of dam-break flow do not consider simultaneously the effects of wet downstream bottom and bed slope on the dam-break wave propagation. In this study, a new analytical solution for the shallow-water equations (SWE) is developed to remove this limitation to simulate the wave caused by an instantaneous dam-break. The approach adopts the method of characteristics and has been applied to simulate the dam-break flows with different downstream water depths and slopes. The analytical solutions have been compared with predictions by the lattice Boltzmann method and the agreement is good. Although the proposed analytical solution treats an idealized case, it is nonetheless suitable for assessing the robustness and accuracy of numerical models based on the SWE without the frictional slope. / The National Key Research and Development Program of China (Grant No: 2018YFC1505000), National Natural Science Foundation of China (Grant Nos: 51879179; 51579166) and Sichuan Science and Technology Program (No. 2019JDTD0007); Open Fund from the State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University (SKHL1809). .

Yes / The instability of soil slopes is directly related to both the shear parameters of the soil material and the groundwater, which usually causes some uncertainty. In this study, a novel method, the element failure probability method (EFP), is proposed to analyse the failure of soil slopes. Based on the upper bound theory, finite element discretization, and the stochastic programming theory, an upper bound stochastic programming model is established by simultaneously considering the randomness of shear parameters and groundwater level to analyse the reliability of slopes. The model is then solved by using the Monte-Carlo method based on the random shear parameters and groundwater levels. Finally, a formula is derived for the element failure probability (EFP) based on the safety factors and velocity fields of the upper bound method. The probability of a slope failure can be calculated by using the safety factor, and the distribution of failure regions in space can be determined by using the location information of the element. The proposed method is validated by using a classic example. This study has theoretical value for further research attempting to advance the application of plastic limit analysis to analyse slope reliability. / National Natural Science Foundation of China (grant no. 51564026), the Research Foundation of Kunming University of Science and Technology (grant no. KKSY201904006) and the Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province (grant no. ZJRM-2018-Z-02).

Yes / The bed slope and the tailwater depth are two important ones among the factors that affect the propagation of the dam-break flood and Favre waves. Most previous studies have only focused on the macroscopic characteristics of the dam-break flows or Favre waves under the condition of horizontal bed, rather than the internal movement characteristics in sloped channel. The present study applies two numerical models, namely, large eddy simulation (LES) and shallow water equations (SWEs) models embedded in the CFD software package FLOW-3D to analyze the internal movement characteristics of the dam-break flows and Favre waves, such as water level, the velocity distribution, the fluid particles acceleration and the bed shear stress, under the different bed slopes and water depth ratios. The results under the conditions considered in this study show that there is a flow state transition in the flow evolution for the steep bed slope even in water depth ratio α = 0.1 (α is the ratio of the tailwater depth to the reservoir water depth). The flow state transition shows that the wavefront changes from a breaking state to undular. Such flow transition is not observed for the horizontal slope and mild bed slope. The existence of the Favre waves leads to a significant increase of the vertical velocity and the vertical acceleration. In this situation, the SWEs model has poor prediction. Analysis reveals that the variation of the maximum bed shear stress is affected by both the bed slope and tailwater depth. Under the same bed slope (e.g., S0 = 0.02), the maximum bed shear stress position develops downstream of the dam when α = 0.1, while it develops towards the end of the reservoir when α = 0.7. For the same water depth ratio (e.g., α = 0.7), the maximum bed shear stress position always locates within the reservoir at S0 = 0.02, while it appears in the downstream of the dam for S0 = 0 and 0.003 after the flow evolves for a while. The comparison between the numerical simulation and experimental measurements shows that the LES model can predict the internal movement characteristics with satisfactory accuracy. This study improves the understanding of the effect of both the bed slope and the tailwater depth on the internal movement characteristics of the dam-break flows and Favre waves, which also provides a valuable reference for determining the flood embankment height and designing the channel bed anti-scouring facility. / National Natural Science Foundation of China (Grant No: 51879179, 52079081), the Open Fund from the State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University (SKHL1809) and the Sichuan Science and Technology Program (No. 2019JDTD0007)

Regional landslide risk, as it is most commonly defined, is a product of the following: hazard, vulnerability and exposed population. The first objective of this research project is to estimate the regional landslide hazard level by calculating its probability of slope failure based on maximum slope angles, as estimated using data provided by digital elevation models (DEM). Furthermore, it addresses the impact of DEM resolution on perceived slope angles, using local averaging theory, by comparing the results predicted from DEM datasets of differing resolutions. Although the likelihood that a landslide will occur can be predicted with a hazard assessment model, the extent of the damage inflicted upon a region is a function of vulnerability. This introduces the second objective of this research project: vulnerability assessment. The third and final objective concerns the impact of urbanization and population growth on landslide risk levels.

A estabilidade de taludes naturais é um tema de grande interesse ao engenheiro geotécnico, face às significativas perdas econômicas, e até mesmo humanas, resultantes da ruptura de taludes. Estima-se que a deflagração de escorregamentos já provocou milhares de mortes, e dezenas de bilhões de dólares em prejuízos anuais em todo o mundo. Os fenômenos de instabilização de encostas são condicionados por muitos fatores, como o clima, a litologia e as estruturas das rochas, a morfologia, a ação antrópica e outros. A análise dos condicionantes geológicos e geotécnicos de escorregamentos proporciona a apreciação de cada um dos fatores envolvidos nos processos de instabilização de encostas, permitindo a obtenção de resultados de interesse, no que diz respeito ao modo de atuação destes fatores. O presente trabalho tem como objetivo a utilização da Lógica Nebulosa (Fuzzy) para criação de um Modelo que, de forma qualitativa, forneça uma previsão do risco de escorregamento de taludes em solos residuais. Para o cumprimento deste objetivo, foram estudados os fatores envolvidos nos processos de instabilização de encostas, e a forma como estes fatores se interrelacionam. Como experiência do especialista para a elaboração do modelo, foi analisado um extenso banco de dados de escorregamentos na cidade do Rio de Janeiro, disponibilizado pela Fundação Geo-Rio. Apresenta-se, neste trabalho, um caso histórico bem documentado para a validação do Modelo Fuzzy e análises paramétricas, realizadas com o objetivo verificar a coerência do modelo e a influência de cada um dos fatores adotados na previsão do risco de escorregamento. Dentre as principais conclusões, destaca-se a potencialidade da lógica nebulosa na previsão de risco de escorregamentos de taludes em solo residual, aparecendo como uma ferramenta capaz de auxiliar na detecção de áreas de risco. / The stability of slopes is a topic of great interest to the geotechnical engineer, given the significant economic losses, and even human, resulting from the slopes collapse. Its estimated that the landslides outbreak has already caused thousands of deaths and tens of billions of dollars in annual losses worldwide. The phenomena of instability of slopes are conditioned by many factors, such as climate, the lithology and structures of rock, the morphology, the anthropic and others. The analysis of geological and geotechnical conditions of landslides provides an appraisal of each of the factors involved in the processes of instability of slopes, allowing the achievement of results of interest with regard to the mode of action of factors. The current work aims at the use of Fuzzy Logic to create a model that, in qualitative form, provide an estimate of the risk of landslides on the slope of residual soil. To fulfill this objective, we studied the factors involved in the processes of instability of slopes, and how these factors are interrelated. As experience of the expert to the development of the model was examined an extensive database of landslides in Rio de Janeiro, provided by the Geo-Rio Foundation. It is presented in this work, one history case well documented for the validation of the Fuzzy Model and parametric analysis, conducted with the objective to verify the consistency of the model and influence of each of the factors used to predict the risk of landslides. Among the main findings includes the capability of Fuzzy Logic in predicting risk of landslides on the slope of residual soil, appearing as a tool capable of assisting in the detection of areas of risk.