Les différents projets présentés dans cette thèse contribuent à la compréhension de plusieurs aspects clés de la circulation océanique. Le premier aspect que nous étudions porte sur les processus physiques à l'origine du mélange lié à la marée; deux processus ont été mis en évidence. Depuis la latitude critique vers l'équateur, la marée interne transfert son énergie à des ondes plus petite échelle via des instabilités triadiques résonnantes impliquant les ondes proche inertielles. Depuis la latitude critique vers le pôle, les ondes de marée interne continuent de transférer leur énergie à des ondes plus petite échelle, mais étonnamment ce transfert se fait entre la marée interne et des ondes évanescentes.Dans la deuxième étude, nous étudions l'effet d'un courant moyen sur la propagation et la dissipation des ondes de marée interne, générées à la topographie dans des simulations haute résolution. Dans ce cas, la dépendance en latitude de la dissipation de la marée interne est plus lisse et plus proche d'une constante. Ce changement de la dépendance en latitude peut être lié au décalage des fréquences des ondes de marée interne par effet Doppler, ce qui induit la génération d'ondes secondaires plus petite échelle.Dans la troisième étude, nous étudions l'effet d'une perturbation générée en amont sur la circulation dans le bassin amont dû à l'interaction entre la perturbation et un seuil hydrauliquement contrôlé. Les ondes de Kelvin et topographiques de Rossby, générées par une variation de l'afflux d'eau dans le bassin amont, perturbent l'écoulement au dessus du seuil et ainsi l'export d'eau. Cette perturbation est due à la réfraction des ondes sur le seuil à chaque passage, une fois qu'elles ont fait le tour du bassin amont. / The various projects presented in this thesis contribute to our understanding of various key aspects of the oceanic circulation. The first aspect that we investigate is the physical processes responsible for this tidal mixing, and we identify two processes. Equatorward of the critical latitude, internal tides transfer their energy to smaller-scale waves via triadic resonant instabilities involving near-inertial waves. Poleward of the critical latitude, internal tides still transfer energy to smaller-scale waves, but surprisingly this transfer takes place between the internal tide and evanescent waves.In the second study, we investigate the effect of a mean current on the propagation and the dissipation of internal tides generated at the topography in high-resolution simulations. In that case, the latitudinal dependence of the tidal energy dissipation is found to be smoother and closer to a constant. This change in the latitudinal dependence can be linked to the Doppler shift of the frequency of the internal tides, which impacts the generation of smaller-scale secondary waves.In the third study, we study the effect of an upstream disturbance on the upstream circulation by interaction with a hydraulically controlled sill. The Kelvin and topographic Rossby waves, generated by a change in the upstream inflow, perturb the flow through the channel and hence the water export. This perturbation is due to the refraction of the waves at the sill at each passage, once they go around the upstream basin.

The Deep Mixing Method (DMM) is a widely used, in-situ ground improvement technique that modifies and improves the engineering properties of soil by blending the soil with a cementitious binder. Laboratory specimens were prepared to represent soil improved by the wet method of deep mixing, in which the binder is delivered in the form of a cement-water slurry. To study the influence of curing temperature on the strength of the treated soil, specimens were cured in temperature-controlled water baths for the desired curing time. After curing, unconfined compressive strength (UCS) tests were conducted on the specimens. To investigate the optimum mix design for the wet method of deep mixing, UCS tests were performed to measure the strength of cured specimens, and laboratory miniature vane shear tests were conducted on uncured specimens to measure the undrained shear strength (su), which is used to represent the consistency of the mixture right after mixing. The consistency is important for field mixing because a softer mixture is easier to mix thoroughly. Based on the UCS test results, an equation that can provide a good fit to the strength data of the cured binder-treated soil is proposed. When the curing temperature was changed during curing, the UCS of the specimen cured at a low temperature and then cured at a high temperature was greater than the UCS of the specimen cured at a high temperature first. This seems to be due to different effects of elevated curing temperatures at early and late curing times on the cement reaction rates, such that elevating the curing temperature later produces a more constant reaction rate, which contributes to the reaction efficiency. An optimum mix design that minimizes the amount of binder while satisfying both a target strength of the cured mixture and a target consistency of the uncured mixture can be established by using the fitted equations for UCS and su. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases. / Master of Science / The Deep Mixing Method (DMM) is a ground improvement technique widely used to improve the strength and stiffness of loose sands, soft clays, and organic soils. The DMM is useful for both inland and coastal construction. There are two types of deep mixing. The dry method of deep mixing involves adding the binder in the form of dry powder, and the wet method of deep mixing involves mixing binder-water slurry with the soil. The strength of the cured mixture is significantly influenced by the amount of added cement and water, the curing time, and the curing temperature. This research evaluates the influence of curing temperature on the strength of cured cement-treated soil mixture. Mixture proportions and curing conditions also influence the consistency of the mixture right after mixing, which is important because it affects the amount of mixing energy necessary to thoroughly mix the binder slurry with the soil. This research developed and evaluated fitting equations that correlate the cured mixture strength and the uncured mixture consistency with mixture proportions and curing conditions. These fitting equations can then be used to select an economical and practical mix design method that minimizes the amount of binder needed to achieve both the desired cured strength and uncured consistency. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases.

The dry deep mixing method is widely used to improve a soft clay soil to increase the shear strength as well as to reduce the time for consolidation. It is a mechanical mixing process that makes parts of the soil stiffer than its original strength. It is mainly applicable to soft clay or peat soil.   In this master thesis, the objective was set to perform a comparative analysis on the prediction of the settlements of a clay soil improved by lime/cement columns (LCC). The theoretical settlement predictions were made using two analytical and numerical modeling. A case study was carried out on a part of Stockholm bypass project where LCC was applied to improve soft clay for a foundation of a concrete trough. Field measurements of the vertical deformation of the improved soil were performed using settlement plates to compare the analytical and numerical results. The first analytical method was performed based on the recommendation of TK Geo 13 (2013) while the second method was performed based on the concept of a composite ground. In the case of the numerical method, FEA was performed using 2D plane strain model in Plaxis simulation. The performance of the geometry and combined matching models were investigated to convert the axisymmetric to plane strain model. The variation in stiffness of the columns were taken into consideration by applying two stiffness values 30 and 33 MPa for the upper and lower half of the column respectively. A preload of 58 kPa was applied on the improved clay soil to simulate the time-dependent consolidation settlement due to the stress addition. A comparison was carried out between the results obtained from the analysis and a field measurement. The two analytical methods produced a better agreement with the field measurement regarding long-term consolidation settlement and a reasonable agreement concerning the rate of consolidation. The numerical analysis showed a good agreement with the benchmark concerning both the long-term consolidation settlement as well as the rate of consolidation. The geometry matching model gave a reasonable result regarding correctness of the result compared with the combined matching. Based on the results obtained in this study, the numerical methods had a better agreement with the measurements. / Jordförstärkning med kalkcementpelare är en vanlig metod för förstärkning av lösa jordar genom ökning av den blandade jordens hållfasthet samt minskning av konsolideringstiden. Metoden är en mekanisk process som ökar jordens styvhet och är främst tillämpbar i lös leror men även organiska jordar.   Detta examensarbete har syftat till att jämföra sättningsberäkningar i lera som är förstärk med KC-pelare. De teoretiska beräkningarna har utförts genom två analytiska modeller samt numerisk modellering. En fallstudie har utförts på del av Förbifart Stockholm där jordförstärkning av lös lera med KC-pelare har använts inför grundläggning av ett betongtråg. Resultat från fältmätningar av installerade markpeglar har jämförts med resultat från de teoretiska sättningsberäkningarna.   Den första beräkningsmetoden utfördes i enlighet med rekommendationer från TK Geo 13 (2013) och den andra metoden är baserad på principer för kompositjordar. Den numeriska beräkningen har utgjorts av FEM-modellering i 2D i programmet Plaxis. För att anpassa en plan-töjningsmodell till en axialsymmetrisk modell har inverkan av geometrin samt kombinerad anpassning av modell studerats. Hänsyn har tagits till KC-pelarnas styvhet genom att använda två olika värden (30 resp. 33 MPa) för KC-pelarnas övre respektive undre del. En överlast om 58 kPa applicerades på KC-pelarförstärkt området för att påskynda den tidsberoende konsolideringssättningarnas förlopp som orsakas av överlastens tillskottspänningar.   Baserat på resultat från uppmätta sättningar jämfört med beräkningar, har följande slutsatser dragits. Jämförelser mellan resultaten har visat på en rimlig överrensstämmelse mellan de två analytiska metoderna och utförda fältmätningar avseende långtids konsolideringssättningar. Den numeriska beräkningen har visat en god överensstämmelse med fältmätningar med hänsyn till både konsolideringssättningar och konsolideringsgraden. Den geometriskt anpassade modellen visade ett rimligare resultat i förhållande till den kombinerade anpassade modellen. Sammanfattningsvis bedöms det att den numeriska modelleringen stämmer bättre överens med resultaten från uppmätta sättningar i förhållande till analytiska beräkningar.

Bygg- och anläggningssektorn är ansvarig för en betydande del av Sveriges totala koldioxidutsläpp och står inför stora utmaningar när den nu skall försöka minska dess klimatpåverkan. Bygg- och anläggningssektorn behöver under det kommande decenniet hitta lösningar och arbetssätt som halverar sektorns totala koldioxidutsläpp. Entreprenörer kommer att behöva hitta sätt att effektivt genomföra både befintliga lösningar och sådana som inte ännu inte finns tillgängliga. Det här examensarbetet har undersökt vilka nyckelfaktorer som finns för ett lyckat genomförande av nya lösningar med låg klimatpåverkan vid väg- och anläggningsprojekt. Som en fallstudie undersöktes implementeringen av Multicem vid två av Skanskas projekt. Multicem är ett klimatmässigt fördelaktigt alternativ till produkten kalkcement och används vid genomförande av inblandningspelare i jordförstärkningssyfte. Fallstudien tillsammans med litteratur och intervjuer bidrog till slutsatser om vad som måste till för att projekt skall kunna genomföra klimateffektiviseringsåtgärder. Det som har observerats är att projekts möjlighet att klimateffektivisera beror på projekt-, organisations- och sektorspecifika faktorer och tydligt försvåras av bygg- och anläggningssektorns projektstruktur. Studien visar att nyckelfaktorer på projektnivå är att lösningar introduceras tidigt, är ekonomiskt fördelaktiga och kan implementeras enkelt med hjälp av standardiserade arbetssätt. Dessutom måste tidigare erfarenheter spridas effektivt inom organisationen, så att erfarenheter från projekt blir tillgängliga för nya projekt. Organisatoriska nyckelfaktorer för lyckad klimateffektivisering är engagerad ledning på alla nivåer och samverkan mellan olika aktörer och olika projekt. Examensarbetet visar även att bygg- och anläggningssektorn är beroende av att ett övergripande arbete för klimateffektivisering sker inom sektorn. Entreprenörer är beroende av att grönt innovationsarbete pågår i hela leverantörskedjan för att möjliggöra nya fördelaktiga arbetssätt. Dessutom är Trafikverkets roll vid upphandlingsskeden och kravställning ytterst viktig eftersom myndigheten styr arbetet som entreprenörer och andra aktörer kan utföra. / The construction industry accounts for a major part of Sweden’s overall carbon dioxide emissions, and is because of that, today facing significant challenges in its aim to mitigate the industry’s total climate impact. During the coming decade, the Swedish infrastructure construction industry must find solutions that can mitigate its carbon dioxide emissions by 50 per cent. This means that contractors will have to find ways to efficiently implement both existing and innovative solutions. This master’s thesis has researched which key factors apply for successful implementation of green solutions at infrastructure development. As a case study, the implementation of the product Multicem at two of Skanska’s developments was researched. Multicem is a product that can be used in dry deep mixing in order to limit carbon emissions. The case study, together with literature and interviews, provided conclusions on which factors are relevant for successful implementation of solutions that result in less carbon dioxide emissions. The research shows that a project’s capacity to mitigate its emissions is decided by projectspecific, organisational and sectorial factors, and is limited by the construction industry’s project-based characteristics. The study shows that key aspects on a project-level are that the solutions ought to be introduced during an early phase, be economically beneficial and also be implemented easily through standardised working routines. Additionally, earlier experiences must be spread efficiently within the organization so that internal knowledge can be accessible for new developments. Organisational key factors for successful green innovation are: engaged managerial personnel and cooperation between different companies and developments. The results from this master’s thesis show that the construction industry is dependent on that climate change mitigation efforts are taken within the whole industry. In order to develop beneficial solutions and methods, contractors are reliant on that the entire supply chain work towards green innovation. Additionally, the Swedish Transport Administration’s role when designing contracts and legislation is of the outmost importance, since it as an authority regulates the work contractors and consultants perform.

Deep Mixing involves the introduction of cementitious or specially formulated solutions directly into the ground through the use of purpose built blending injection augers. The system is mainly designed to increase strength and reduce compressibility of treated soil. In the first stage of the research effective mixture ratios and mixture types of stabilizing agents were investigated for soft clays (CL form Eymir lake and kaolinite) by means of unconfined compression (UC) tests on stabilized soils. The unconfined compressive strength (UCS) values were obtained for 7,28,90 and 365 days of curing time. The ratio of elastic modulus at 50% failure load (E50) to (UCS) of the stabilizing agents were also investigated. In the second part of the research programme, deep mixed model columns with the three column materials and four different column spacings are formed within the large scale consolidation tanks, and the consolidation characteristics of deep mixed improved clay were investigated. Based on the results of large scale consolidation tests on deep mixed columnar improved soft clay, compressibility characteristics of improved soft clay were determined in relation to spacing of columns namely, effective replacement ratio and binder content. The cement content (also UCS) of the column material was found to be the most important parameter for the improvement effects of DMM applications. Validity of the relations for the estimation of bulk compression modulus of soilcrete were discussed. The use of constrained modulus of the soil and the column material were found to be effective in predicting the compression modulus of the soilcrete. Settlement reduction factor versus replacement ratio and cement content relations were determined which may be used for preliminary design works. The stresses on the soil and the columns were backcalculated from the settlement values. The stress ratios were obtained.

Excavations in soft clays come with a number of specific challenges. The use of lime-cement columns in the passive zone of such works represents a promising solution to some of these problems, such as basal heave stability or excessive deformations. Nevertheless, lime-cement columns in the passive zone of excavations in soft clays are not yet widely used and studied. Knowledge about this improvement method is still limited, particularly when it comes to numerical modelling. They have mostly been studied numerically using simple geometries or constitutive models that do not allow to represent the key features of the material, that could influence the behaviour of the structure. Thus, there is a need for more investigations regarding precise modelling tools for this type of problems. In this study, an advanced constitutive model named the Concrete model was employed to capture the mechanical behaviour of the lime-cement improved soil material. A boundary value problem representing an excavation in soft clay supported by sheet pile walls and lime-cement columns was studied using a three dimensional finite element model that included the Concrete model for lime-cement column panels. The results show that the Concrete model is able to capture the behaviour of lime-cement improved clay very well. Key features such as strain hardening and strain softening are well represented. The results of the boundary value problem were compared to field measurements and it was showed that the Concrete model employed in a three dimensional finite element representation of the problem is able to give realistic results. / Schakter i lös lera medför ett antal specifika utmaningar. Användningen av kalk-cementpelare i den passiva zonen i sådana fallen är en lovande lösning på några av dessa problem, t.ex. jordhävning eller stora deformationer. Kalk-cement pelare i den passiva zonen av schakter i lös lera har dock ännu inte använts och studerats i någon större utsträckning i Sverige. Kunskapen om denna metod är fortfarande begränsad, särskilt när det gäller numerisk modellering. Denna förstärkningsmetod har studerats numeriskt med hjälp av enkla geometrier eller konstitutiva modeller som inte gör det möjligt att representera materialets viktigaste egenskaper som kan påverka konstruktionens beteende. Det finns därför ett behov av mer forskning för en precis modellering för denna typ av problem. I den här studien användes en avancerad konstitutiv modell (Concrete model) för att simulera det mekaniska beteendet hos det kalkcementstabiliserade jordmaterialet. Ett gränsvärdesproblem som representerar en schakt i lös lera som stöds av spontväggar och kalkcementpelare studerades med hjälp av en tredimensionell finita elementmodell. Resultaten visar att den advancerade konstitutiva modellen kan simulera beteendet hos kalkcementstabiliserad lera mycket väl. Viktiga egenskaper som t.ex. töjningshärdning och töjningsuppmjukning är väl representerade. Resultaten av gränsvärdesproblemet modellering jämfördes med fältmätningar och det visades att konstitutiva modellen som används kan ge realistiska resultat. / Les excavations dans les argiles molles présentent de nombreuses difficultés. L’utilisation de colonnes en chaux-ciment dans la zone passive de ces structures représente une solution prometteuse à certains de ces défis, tels que le soulèvement de la base ou les déformations excessives. Néanmoins, l’utilisation et l’étude des colonnes en chaux-ciment dans la zone passive des excavations dans les argiles molles ne sont pas généralisées et les connaissances à ce sujet sont encore limitées, notamment en ce qui concerne la modélisation numérique. La plupart des études numériques se basent sur des géométries simples ou des modèles constitutifs ne permettant pas de représenter certaines particularités du comportement du matériau, qui pourraient influencer le comportement de la structure. Il est donc nécessaire d’approfondir les recherches sur les outils de modélisation pour ce type de problème. Dans cette étude, un modèle constitutif avancé (Concrete model) a été utilisé pour reproduire le comportement mécanique de l’argile stabilisée à la chaux et au ciment. Un problème de valeurs aux limites représentant une excavation dans de l’argile molle soutenue par des murs de palplanches et des colonnes en chaux-ciment a été étudié à l’aide d’un modèle d’éléments finis tridimensionnel. Les résultats montrent que le modèle employé permet de reproduire le comportement de l’argile stabilisée à la chaux-ciment de manière très satisfaisante. Les particularités du comportement du matériau, telles que l’écrouissage et l’adoucissement, sont bien représentées. Les résultats du problème de valeurs aux limites ont été comparés aux mesures sur le terrain et il semble que ce modèle constitutif, employé dans une représentation tridimensionnelle par éléments finis du problème, soit capable de donner des résultats réalistes.