O projeto estrutural de túneis envolve o conhecimento da variável convergência (fechamento radial) para definição da pressão atuante sobre o revestimento e do nível de descompressão do solo circundante (maciço). A adoção de modelos contínuos em elementos finitos consegue discretizar de forma mais adequada o modelo mecânico estrutural considerando a interação com o solo. Dessa forma, esta dissertação recai sobre a variação da razão de cobertura (profundidade) de um túnel, a fim de determinar a profundidade limite que o modelo numérico segue o padrão de tensões geostáticas crescentes com a profundidade versus um padrão geostático uniforme profundo. A validação do modelo numérico ocorre junto a soluções analíticas desenvolvidas por Park (2004) e Kirsch (1898) para túneis em maciços elásticos superficiais e profundos respectivamente. Nos exemplos analisados, quando a profundidade do eixo do túnel é dez vezes maior que seu diâmetro as convergências se aproximam daquelas dadas pelo GEOMEC 91 (Bernaud, 1991) e o túnel pode ser considerado profundo. A curva de assentamentos (recalques) foi considerada consequência importante a ser notada em túneis superficiais que mostraram um recalque máximo até duas vezes maior quando se reduz a profundidade Para esse estudo foram desenvolvidos scripts com profundidade variável adicionando a superfície de plasticidade de Drucker-Prager (utilizada em solos friccionais). O modelo numérico desenvolvido para túneis superficiais é validado junto a túneis reais instrumentados que tenham sido avaliados a partir de algum outro modelo contínuo, são eles: Heathrow Express, Green Park, Metrôs de Barcelona, Brasília e São Paulo com resultados variando entre 1,20% e 6,78%. Eventualmente, uma breve análise do desenvolvimento de tensões no revestimento para túneis circulares, elípticos e ferradura é realizada a fim de encontrar zonas de tração. Enquanto túneis em seção ferradura desenvolveram tração para qualquer profundidade devido ao formato retilíneo, túneis circulares precisaram se encontrar com baixa profundidade a fim de desenvolver zonas descomprimidas decorrentes da ovalização de túneis rasos. / The structural design of tunnels involves the knowledge of the variable convergence (radial closure) for the definition of the acting pressure upon the lining and for the decompression level of the involving soil (rockmass). The adoption of continuous models using finite element analysis (FEA) is able to assess the structural mechanical model accurately, concerning the soil interaction. This way, this work studies the covering ratio (depth) of tunnels, in a way to determine the threshold point which divides the geostatic growing stresses versus the deep uniform stresses pattern. The validation of the numerical model under an elastic rockmass is done by comparison with analytical solutions developed by Park (2004) and Kirsch (1898) for shallow and deep tunnels respectively. Regarding the analyzed examples, when the depth of the tunnel axis is ten times greater than its diameter; the convergences approach to the ones given by GEOMEC 91 (Bernaud, 1991) and the tunnel may be considered deep. The settlement through (ground movement) is considered an important consequence to be noticed upon shallow tunnels; these tunnels have led to a maximum settlement twice deeper when the covering ratio is shallow (H/D = 1). For this study, several scripts have been developed concerning the variable depth and adding the Drucker-Prager plasticity criterion for frictional soils. The numerical model developed for shallow tunnels is validated with other continuous models relied on real instrumentation of subway network tunnels, such as: Heathrow Express, Green Park, Barcelona, Brasília and São Paulo with the solutions ranging between 1,20% and 6,78%. Eventually, a brief analysis of the stress development in the lining for circular, ellipsoid and horseshoe tunnels is done in search of tension zones. In one hand, horseshoe tunnels develop tension for any depth due to its straight walls; in the other hand, circular tunnels need to have a small covering ratio in order to develop decompression zones caused by the shallow tunnels ovalization.

Climate changes alter species composition in both aquatic and terrestrial ecosystems. For establishment of species in a fish community, dispersal barriers, habitat structure and interactions between species act as a filter. The aim of this study was to examine changes in the fish community in Lake Tåkern, Sweden, by repeating a test-fishing in a lake 40 years after a previous test-fishing. Special interest was directed towards the possible establishment of bream (Abramis brama) and (Cyprinus carpio) which recently had been found in the lake. In addition, a decline of the low oxygen tolerant species crucian carp (Carassius carassius) and tench (Tinca tinca) was expected. Test-fishing was performed in June and August 2019 and combined with analyses of Environmental-DNA from samples in September 2019. A comparison with the average catch of 1978-1979 together showed that all cyprinid species had decreased in 2019. The hypoxic tolerant crucian carp decreased 16-fold in numbers, which was expected due to fewer events of cold winters and hypoxia. One bream was caught from the test-fishing and was also detected through eDNA-analysis. The ecological status of the fish community was classified as moderate but showed a high proportion of piscivore percids contra cyprinids, compared to six other shallow lakes in Sweden with similar characteristics. The high proportion of piscivore percids is probably contributing to the stability of the present clear-water state of the lake.

River confluences - locations where rivers join one another - are fundamental components of natural drainage networks. Differences in topography, geology, soils, land use, and human activities within watersheds upstream of confluences can produce differences in thermal or chemical properties of river flows and in the materials transported by these flows. Mixing is initiated along the mixing interface (MI) that develops between the two incoming streams with different properties. Therefore, the understanding of fluvial processes at confluences is important for determining river mixing both at and downstream of individual confluences and at the scale of drainage networks. The primary goal of this thesis is to describe the main mechanisms that control mixing and transport at river confluences and the role played by the complex flow structures in the flow and how they change with planform geometry and other flow and geometrical parameters. The study is carried out using Computational Fluid Dynamics modeling based on the state of the art Detached Eddy Simulation approach and High Performance Computing. By starting with a mixing layer between parallel streams with simple geometry, the model is validated based on laboratory experiment data. Moreover, some hypotheses regarding the growth of the mixing layer are amended with the extensive data provided by the model, which is a valuable supplement to the experiment. By performing a detailed parametric study in very long and wide domains for simplified cases one can focus on the spatial development of the MI and the large scale coherent structures forming within and in the vicinity of the MI without the complications of other factors. More specifically, the influence of velocity and density difference of the two streams, flow depth, inflow conditions and angles between the two streams on the spatial development of the MI is analyzed. The data resulting from these simulations conducted in simple geometries is a unique set of data which can be used to test and improve theoretical models used to predict global parameters describing flow and mixing at natural river confluences. In particular, this research uses for the first time well resolved Large Eddy Simulation based techniques to investigate how density differences between the incoming streams affect the spatial development of the mixing interface and mixing downstream of the confluence apex. In order to investigate flow dynamics, mixing processes and effects of temperature stratifications at natural river confluences with discordant bed, a series of simulations is performed for the confluence of the Ebro and Segre Rivers in Spain, which is one of the most studied confluences in Europe. With the detailed survey data of the confluence bed and flow conditions data provided, the goal is to understand the main mechanisms responsible for mixing at a confluence with a large bed discordance and how the velocity ratio between the two incoming streams affects mixing. Besides, more insights are provided that if temperature stratification effects affect significantly flow structure and mixing based on real conditions recorded at a natural confluence. The study provides a comprehensive set of flow data in the confluence including velocity, temperature distribution etc. It serves as important supplement to the field measurements, which are generally more difficult to obtain. It also allows estimating scale effects between field conditions and conditions at which laboratory experiments of confluence flow and mixing are conducted.

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 no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/82553 / TESIS

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22264号 / 理博第4578号 / 新制||理||1657(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 松四 雄騎, 教授 千木良 雅弘, 教授 岩田 知孝 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22756号 / 工博第4755号 / 新制||工||1744(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 細田 尚, 教授 戸田 圭一, 准教授 音田 慎一郎 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Liquid wastes discharged from industrial outfalls have been researched for many years in the past. Majority of past studies, initiated in 1960s, were experimental studies mainly focused on basics of discharges such as key geometrical properties. Eventually, more robust experimental studies were performed to measure the mixing properties of effluent discharges with various jet configurations and ambient water conditions. Discharges could be as a means of submerged diffusers or surface channels and receiving water could vary from a homogenous calm ambient to a very complex stratified turbulent cross flow ambient. Depending on the bathymetric and economic situation around an outfall project, submerged discharges are preferred designs for most of ocean outfalls. It is the reason that majority of past studies have evaluated the mixing characteristics of submerged jets. Since early 1990s, the numerical modelling has emerged to support complex fluid mechanic problems. Later in 1990s and early in 2000s, the use of computational fluid dynamic (CFD) tools emerged in predicting the jet properties for the effluent discharges. Since then different numerical models have been developed for different applications. Similar to experimental studies, most of numerical studies have been focused on the submerged dense jet discharges. The current study intends to stay focused on the numerical modelling of such jets too; however, to cover the gaps in the literature. To achieve this, a thorough literature review was performed on the past CFD studies of over past 20 years to better understand what was done and what the gaps are. The results of this thorough review revealed that although there has been a great progress in the CFD studies in the field of effluent discharges, there are some applications that have not been investigated before, yet. It was found that there are some discharge inclinations that were not studied numerically before. Four discharge angles of 60°,75°, 80° and 85° were selected in this study, as previous studies mostly focused on 30° and 45°. The higher inclinations are more suitable for deep water outfalls where terminal rise height of the jet does not attach to the ambient water surface. The numerical model OpenFOAM was used in this study which is based on the Finite Volume Method (FVM) applying LRR turbulence model closure. LRR turbulence models was proved to be a capable choice for effluent discharge modelling. The second gap identified in the comprehensive literature review completed was the submerged dense effluent discharge into shallow water with surface attachment (for both inclined and vertical discharges). There was no previous numerical study of such jets identified. Three different regimes were identified: full submergence, plume contact and centerline impingement regimes (i.e. FSR, PCR and CIR). Key geometrical and dilution properties of these jets at surface contact (Xs, Ss) and return point (Xr, Sr) were extracted numerically and compared to those available from experiments. Two discharge angles (30° and 45°) were investigated based on the available experimental data. Five Reynolds-averaged Navier-Stokes (RANS) turbulence models were examined in this study: realizable k-ε and k-ω SST models (known as two-equation turbulence models), v2f (four equations to model anisotropic behavior) and LRR and SSG turbulence models (known as Reynolds stress models - six equations to model anisotropic behavior). Vertical dense effluent discharges are popular in the design of outfall systems. Vertical jets provide the opportunity to be efficient for a range of ambient currents, where the jet will be pushed away not to fall on itself. This research work investigates worst case scenario in terms of mixing and dilution of such jets: vertical dense effluent discharges with no ambient current and in shallow water where jet impacts the surface. This scenario provides a conservative design criteria for such outfall systems. The numerical modelling of such jets has not been studied before and this research work provides novel, though preliminary, insights in simulations of vertical dense effluent discharges in shallow waters. Turbulent vertical discharges with Froude numbers ranging from 9 to 24 were simulated using a Reynolds stress model (RSM), based on the results from inclined dense discharges to characterize the geometrical (i.e., maximum discharge rise Zm and lateral spread Rsp) and dilution μmin properties of such jets. Three flow regimes were reproduced numerically, based on the experimental data: deep, intermediate and impinging flow regimes.

Topic of this master`s thesis is founding of the hightway bridge, which is located between Lipník and Bělotín. Thesis is aimed for creating shallow foundation and foundation on piles and choosing which option is better. All evaluations have been made without specialized software and than compared with GEO5 results. Better solution will be completed with procedure for construction and drawing documentation.

Tato diplomová práce se zabývá matematickým modelováním vodních vln v blízkosti pobřeží pomocí parciálních diferenciálních rovnic. Cílem této práce je formulace pohybových rovnic a jejich následné numerické řešení s grafickou interpretací dosažených výsledků.

This research involves shake table testing of 1g scale models that mimic the coupled seismic response of a structure on a shallow mat foundation and foundation soil (known as soil-foundation-structural-interaction or SFSI). In previous research, SFSI effects have been quantified through analytical models, numerical analyses, and limited field data. This research works towards increasing the amount of empirical data through scale model shake table testing. A suite of earthquake time histories is considered in evaluating a nominal 10th scale soil-structure model using a flexible wall barrel on a 1-D shake table. San Francisco Young Bay Mud (YBM) is used as the prototype soil and long period narrow building as the prototype structure. Foundation embedment depth, fundamental mode of the structure, and seismic loading function are varied to generate a large database of SFSI results under controlled conditions. The foundation level response is compared to free-field responses to determine the magnitude of the SFSI. The results confirm the effects of foundation embedment on the peak ground motion and the spectral acceleration at the predominant period of the structure. The foundation level accelerations are deamplified compared to free-field results. Results also confirm the legitimacy of the testing platform and program by comparing the data to previous experimental study.