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Modelling multi-directional behaviour of piles using energy principlesLevy, Nina Hannah January 2007 (has links)
The loads applied to pile foundations installed offshore vary greatly from those encountered onshore, with more substantial lateral and torsional loads. For combined axial and lateral loading the current design practice involves applying an axial load to a deep foundation and assessing the pile behaviour and then considering a lateral load separately. For the problem of an altering directions of lateral loads (e.g. due to changes in the wind directions acting on offshore wind turbines) a clear design procedure is not available. There is thus a need for a clearly established methodology to effectively introduce the interaction between the four different loading directions (two lateral, one axial and one torsional). In this thesis, a model is presented that introduces a series of Winkler elasto-plastic elements coupled between the different directions via local interaction yield surfaces along the pile. The energy based method that is used allows the soil-pile system to be defined explicitly using two equations: the energy potential and the dissipation potential. One of the most interesting applications of this model is to piles subjected to a change in lateral loading direction, where the loading history can significantly influence the pile behaviour. This effect was verified by a series of experimental tests, undertaken using the Geotechnical Centrifuge at UWA. The same theory was then applied to cyclic loading in two dimensions, leading to some very useful conclusions regarding shakedown behaviour. A theoretically based relationship was applied to the local yielding behaviour for a pile subjected to a combination of lateral and axial loading, allowing predictions to be made of the influence of load inclination on the pile behaviour. The ability of this model to represent interaction between four degrees of freedom allows a more realistic approach to be taken to this problem than that considered in current design practice.
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Uppföljning av absoluta tjälrörelser : En fallstudie av väg E10 i KirunaElmehög, Hampus January 2019 (has links)
Detta examensarbete har haft som mål att undersöka tjällyftningen hos en väg i en fältstudie och utvärdera reliabiliteten hos två olika modeller för skattning av tjällyftning. Modellerna som har studerats är Trafikverkets nuvarande, vilken är implementerad i deras vägdimensioneringsverktyg PMS Objekt, samt segregation potential theory. Den studerade vägsträckan är belägen i Kiruna. I vägen har borrkärneprover tagits och vägens obundna lager, inklusive terassmaterial, har blivit analyserade i laboratorium. Dessa tester inkluderar både geoteknisk klassificering och endimensionella frysförsök på terassmaterialet. Materialets tjälfarlighet har klassificerats enligt både Trafikverkets eget och det amerikanska USACEs system. Alla prover, inklusive terrassmaterialet, består huvudsakligen av grus och sand. Enligt båda de använda klassificeringssystemen bedöms alla prover som icke tjälfarliga. Nivåmätningar utförda på vägen visar dock att tjällyftning ändå förekommer i vägen. Denna tjällyftning har inte kunnat modelleras framgångsrikt i PMS Objekt, där ingen tjällyftning alls fås trots att en dimensionerande vinter tillämpas i analysen. Däremot har en god överensstämmelse mellan bakåträknad och empiriskt beräknad tjälfarlighetsklassificering med SP0-värde enligt segregation potential theory kunnat ses. Även när detta beräknas utifrån utförda frysförsök fås en relativt god överensstämmelse. Studiens främsta fynd är att den visar på att även material som bedöms som ej tjällyftande enligt de två systemen för tjälfarlighetsklassificering faktiskt orsakar tjällyftning och att detta omfattar både terrass- och överbyggnadsmaterial. Studien visar att detta tjällyft främst beror på primärt lyft, varför klassificeringarna stämmer ganska väl om endast det sekundära lyftet avses. Studien har även visat på att Trafikverkets nuvarande modell är otillräcklig när det kommer till att modellera tjällyftning för grovkorniga jordar. Slutligen har studien även visat på möjligheten att bedöma jords tjälfarlighet med hjälp av segregation potential theory, även om också denna metod endast kan användas för att modellera sekundärt lyft. / The aim of the master thesis has been to examine the frost heaving of a road in a field study and to evaluate the reliability of two different models for estimation of frost heaving. The studied models are the current one of the Swedish Transport Administration, which is implemented in their road design tool PMS Objekt, and the segregation potential theory. The studied road section is located in Kiruna, in the northern part of Sweden. The road has been cored and the unbound layers of it, including the subgrade, have been analyzed in laboratory. These analyses include both geotechnical characterization and one-dimensional frost heave tests of the subgrade material. The frost susceptibility of the collected material has been classified according to both the Swedish Transport Administrations system and the American USACE’s system. All samples, including the subgrade, consist mainly of gravel and sand. According to both the used classification systems all samples are classified as not frost susceptible. However, the elevation measurements of the road show that frost heaving occurs in it despite this. This heaving has not been possible to model successfully in the program PMS Objekt. In it the frost heave prediction yields no heave at all, despite applying a design winter (worst case) in the analysis. A good conformity has however been observed between back-calculated and empirically evaluated frost susceptibility using segregation potential theory. A quite good conformity has also been observed when the same thing is evaluated from the preformed freeze tests. The most important finding of the study is that even material that is categorized as non-frost susceptible according to the two studied systems actually does heave. This finding includes both subgrade aswell as the unbound material in the superstructure. It has been found that the total frost heave observed in this study originates mainly from primary heaving, meaning the studied systems are quite correct in their frost susceptibility classification if only secondary heaving is intended. The study has also shown that the current model applied in PMS Objekt is poor in predicting the amount of heaving in coarse subgrades. Finally, the study has also shown the possibility to evaluate a soils frost susceptibility using segregation potential theory, although this model aswell is only applicable to secondary heave
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ÅTERANVÄNDNING AV SCHAKTMASSOR / RECYCLING OF EXCAVATED SOILTengelin, Elin, Vetterlund-Handberg, Martina January 2018 (has links)
Syfte: Återanvändningen av schaktmassor inom anläggningsbranschen är i dagsläget begränsad. Bland annat på grund av otydliga regelverk samt låga kostnader och hög tillgänglighet av jungfruliga material. Trots att schaktmassor har en hög potential att återanvändas finns det andra alternativ för överskottsmassor som uppstår i ett projekt som är mer fördelaktiga för entreprenörer. Svårigheterna kring återanvändning av schaktmassor är det som skall undersökas och målet med rapporten är följaktligen att undersöka möjligheterna att främja återanvändning av schaktmassor inom anläggningsbranschen. Målet kommer att besvaras med hjälp av två frågeställningar: (1) Hur kan återanvändningen av schaktmassor främjas inom anläggningsbranschen? (2) Hur kan en återanvändningsterminal öka återanvändningen av schaktmassor? Metod: Metoderna som valts för att samla empiri till studien är litteraturstudie, dokumentanalys och intervjuer. Litteraturstudien och dokumentanalysen skapade en kunskapsuppbyggnad inom ämnet som bland annat låg till grund för utformningen av intervjuerna. Intervjuerna har genomförts tillsammans med tio respondenter från åtta olika företag inom anläggningsbranschen. Resultat: De regelverk och lagar som finns kring hanteringen av schaktmassor ses som det största hindret för återanvändningsmöjligheterna. Svårigheterna att få ekonomisk vinst i återanvändningsprocessen samt långa transporter är också bidragande orsaker. Även de geotekniska egenskaperna på schaktmassornas kan vara problematiskt, dels för att massorna skall klassificeras enligt sin byggbarhet samt att de skall vara jämförbara med jungfruligt material. Konsekvenser: Slutsatserna som dragits utifrån studien är att det krävs ett ökat samarbete inom branschen för att återanvändningen av schaktmassor skall främjas. Tydligare kommunikation behövs samt att planering kring masshanteringen bör ske i ett tidigare skeden i projekten. De regelverk och riktlinjer som finns idag behöver omarbetas för att bli tydligare och möjliggöra för ökad återanvändning. En återanvändningsterminal av storskalig verksamhet som placeras centralt skulle bidra till att återanvändningen av schaktmassor ökar vilket minskar miljöpåverkan och gynnar branschen. Begränsningar: Studien är begränsad och utförd inom Jönköpings län och intervjurespondenterna är valda utefter de verksamheter som verkar inom länet. Arbetets generaliserbarhet begränsar sig till Sverige eftersom att regelverk och tillvägagångssätt gällande hantering av schaktmassor ser olika ut i andra länder. Nyckelord: Utgrävd mark, återanvändning av schaktmassor, återanvändningsterminal, återanvändning av bergmaterial.
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Contribuições ao uso de novas tecnologias da informação e comunicação no ensino de engenhariaFerreira Filho, Raymundo Carlos Machado January 2005 (has links)
Neste trabalho, descreve-se o processo de produção de tecnologias educacionais e de Tecnologias da Informação e Comunicação (TICs), relacionando-as ao uso do ensino em Engenharia Geotécnica. Desenvolveu-se um sistema de informação baseado num modelo que integra recursos educacionais produzidos em diferentes formatos eletrônicos e um software baseado na Web para gestão destes recursos e das informações da disciplina Fundações. O software, denominado ENGEO, auxilia a estruturação do conhecimento envolvido no domínio de aplicação, fornecendo ao professor, ou equipe de gestão, ferramentas remotas de administração dos conteúdos e dos recursos educacionais. Aos alunos, a aplicação ENGEO fornece disponibilidade de informações e de conteúdo em um ambiente flexível. Este aplicativo foi desenvolvido para o curso de Engenharia Geotécnica, particularizado para Engenharia de Fundações, com o objetivo de introduzir e incentivar a utilização de sistemas baseados na Web para compartilhamento de conteúdo das disciplinas, implementar Tecnologias de Informação e Comunicação em aplicações para fins educacionais e fomentar discussões a respeito da identidade e perfil do Engenheiro e o papel da TICs no processo de formação do profissional de Engenharia. / This research describes and analyzes the production of an educational applicative based on Communication and Information Technologies (ICTs) developed for the field of Geotechnical Engineering. An information system based on a model that integrates produced educational sources in different digital formats and a Web software developed for management of these sources is described. The software, denominated as ENGEO, contains information related to the subject of Foundation Engineering. It assists structuring the knowledge in the domain of application, organizing in the Web various medias related to the subject, enabling remote administration by the lecturer or management team from tools implemented using Information and Communication Technologies (ICTs). Attempts are made to produce free and flexible assess to students of the contents of course. The experience was designed to stimulate a debate on the needs and identity of engineers and to put into perspective the role of ICTs in producing such identity.
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Sättningar i torvmaterialet : En fallstudie om användning av förstärkningsmetoden "förbelastning i form av överlast" på jordmaterial av torv / Settlement in peat material : -A case study regarding the usage of insurance methods “preloading in the form of overloads” on soil material of peatAli, Rebaz, Alshami, Ahmed January 2018 (has links)
Purpose: The aim of this degree project is to control the set-up for a longer period by means of the workplace at the use of the total station for then comparing calculated outcomes with real outcomes. Method: A combination of both quantitative and qualitative studies have been used in this degree project, consisting of literature studies and a case study including interviews, document analyzes, site visits and measurements. The case study is based on an ongoing project in the municipality of Nassjo, where a skate park is constructed and whose soil consists of peat. Preload in the form of overload has been applied. Findings: The result indicates the occurrence of a difference between calculated outcome and actual outcome regarding set rate and time course when using preload in the form of overload. The deviation is about 20 cm. Preload in the form of overload is a good method for peat land, but it is unlikely to be remarkably improved by vertical drainage. Implications: In view of the measurements produced by the authors, this shows that the method of loading in the form of overload on peat field works, however, gives the calculation model which has been used to be uncertain. The result described in more detail regarding vertical drainage on peat fields will not accelerate the process because the peat is already well drained. This means that it will cost extra without benefiting from the method. Limitations: The work has limited to two reinforcement methods on peat fields. A case study has been limited to only one area. There was preload in the form of overload, whose soil material consists of peat. Keywords: Peat, Permeability, Preloading in the form of overload, settlements, total station, vertical drainage, water quota. / Syfte: Syftet med detta examensarbete är att kontrollera sättningen under en längre period genom mätningar som skett på arbetsplatsen vid användning av totalstation för sedan kunna jämföra beräknat utfall med verkligt utfall. Metod: En kombination av både kvantitativa och kvalitativa studier har använts i detta examensarbete, bestående av litteraturstudier och en fallstudie inbegripande intervjuer, dokumentanalyser samt platsbesök och mätningar. Fallstudien grundar sig i ett pågående projekt i Nässjö kommun där det byggs en skatepark vars jordmaterial består av torv och där förbelastning i form av överlast har tillämpats. Resultat: Resultatet indikerar på förekomsten av en skillnad mellan beräknat utfall och verkligt utfall gällande sättningshastighet och tidsförlopp vid användning av förbelastning i form av överlast. Avvikelsen ligger på ungefär 20 cm. Förbelastning i form av överlast är en bra metod för torvmark men att det sannolikt inte anmärkningsvärt går att förbättra genom vertikaldränering. Konsekvenser: Med hänsyn till de mätresultat som rapportförfattarna har bringat fram visar detta att metoden förbelastning i form av överlast på torvmark fungerar, dock ger beräkningsmodellen som har använts osäkra resultat. Resultatet som beskrivs mer detaljerat gällande vertikaldränering på torvmark kommer inte påskynda processen eftersom torven redan är väl dränerad d.v.s. porerna är genomträngliga och vattnet kan lätt rinna ut vid användning av förbelastning i form av överlast. Detta innebär att det kommer medföra extra kostnader utan att få nytta av metoden. Begränsningar: Arbetet har begränsats till två förstärkningsmetoder på torvmark. En fallstudie har begränsats till endast ett område, där förbelastning i form av överlast utförs på jordmaterial som består av torv. Nyckelord: Förbelastning i form av överlast, permeabilitet, sättningar, Torv, totalstation, vertikaldränering, vattenkvot.
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Contribuições ao uso de novas tecnologias da informação e comunicação no ensino de engenhariaFerreira Filho, Raymundo Carlos Machado January 2005 (has links)
Neste trabalho, descreve-se o processo de produção de tecnologias educacionais e de Tecnologias da Informação e Comunicação (TICs), relacionando-as ao uso do ensino em Engenharia Geotécnica. Desenvolveu-se um sistema de informação baseado num modelo que integra recursos educacionais produzidos em diferentes formatos eletrônicos e um software baseado na Web para gestão destes recursos e das informações da disciplina Fundações. O software, denominado ENGEO, auxilia a estruturação do conhecimento envolvido no domínio de aplicação, fornecendo ao professor, ou equipe de gestão, ferramentas remotas de administração dos conteúdos e dos recursos educacionais. Aos alunos, a aplicação ENGEO fornece disponibilidade de informações e de conteúdo em um ambiente flexível. Este aplicativo foi desenvolvido para o curso de Engenharia Geotécnica, particularizado para Engenharia de Fundações, com o objetivo de introduzir e incentivar a utilização de sistemas baseados na Web para compartilhamento de conteúdo das disciplinas, implementar Tecnologias de Informação e Comunicação em aplicações para fins educacionais e fomentar discussões a respeito da identidade e perfil do Engenheiro e o papel da TICs no processo de formação do profissional de Engenharia. / This research describes and analyzes the production of an educational applicative based on Communication and Information Technologies (ICTs) developed for the field of Geotechnical Engineering. An information system based on a model that integrates produced educational sources in different digital formats and a Web software developed for management of these sources is described. The software, denominated as ENGEO, contains information related to the subject of Foundation Engineering. It assists structuring the knowledge in the domain of application, organizing in the Web various medias related to the subject, enabling remote administration by the lecturer or management team from tools implemented using Information and Communication Technologies (ICTs). Attempts are made to produce free and flexible assess to students of the contents of course. The experience was designed to stimulate a debate on the needs and identity of engineers and to put into perspective the role of ICTs in producing such identity.
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Kungsängslerans krypsättning : Analys av dess storleksordning och krypparametrar samt förslag på lämplig beräkningsmetod / Creep of Kungsängen clay : Analysis of its order of magnitude and creep parameters, and proposition of appropriate calculation methodNylander, Maria January 2018 (has links)
Kungsängen är ett centralt beläget område i Uppsala. Området har stora mäktigheter av lera som når drygt 100 meters djup på sina håll. För att bygga på denna typ av jord måste långtidssättningar såsom konsolidering och krypning tas i beaktning. Att fastställa och beräkna krypningens storlek är dock svårt på grund av att det är en matematiskt komplicerad process. Det råder även oenigheter gällande när krypning inträder under sättningsförloppet samt gällande lämplig beräkningsmetod. För att erhålla en djupare förståelse för Kungsängslerans krypning samt för att finna en lämplig beräkningsmetod togs detta arbete fram i samarbete med Bjerking. Höjdavvägningar från dubbar och fixpunkter belägna i Kungsängen sammanställdes och resultaten visade att byggnader i Kungsängen som byggdes för 80–170 år sedan utsätts för krypning än idag. Medelvärdet av den relativa krypsättningen erhölls till 0,134 promille av lermäktigheten per år för dubbavvägningarna respektive 0,067 för fixpunktsavvägningarna. Ytterligare påvisade resultaten att både tid och lermäktighet var två drivande faktorer bakom Kungsängslerans krypning. Den europeiska standarden Eurokod 7 undersöktes för att finna förslag på beräkningsmetoder för krypning. Standarden hade dock inga konkreta förslag utan hänvisade till allmänt erkända metoder. Av denna anledning undersöktes tidsmotståndsteorin samt Chalmersmodellen med kryp. Tidsmotståndsteorin beräknade både realistiska och överskattade krypsättningar beroende på typ av lera. Vissa lerprover antydde att laster under cirka 45 kPa gav en försumbar krypning med andra lerprover indikerade annorlunda. Tidsmotståndsteorin har dock potential att vara en lämplig metod för beräkning av Kungsängslerans krypsättning. Chalmersmodellen med kryp tillämpades för att modellera ödometerförsök och resultaten visade att modellen generellt överskattade den totala deformationen och underskattade kryphastigheten. För att kunna förkasta eller verifiera modellen som lämplig vid beräkning av krypsättningar för Kungsängslera bör dock utförligare studier genomföras. / Kungsängen, a central area in Uppsala of Sweden, has a considerable depth of clay which stretches down to 100 m at some sites. In order to build at this type of soil one has to take long-term settlements into consideration, such as consolidation and creep. However, methods for calculating the latter aren’t straight forward since the mathematics behind the process is complicated. The starting time of creep is still unsettled and this is also the case regarding calculation methods. In order to enhance the understanding of creep of Kungsängen clay this study was developed in collaboration with Bjerking AB. Altimetry data from studs and fixed points from Kungsängen was compiled and the results showed that buildings in Kungsängen are experiencing creep even though some of them were built 80–170 years ago. The mean value of relative creep was found to be 0,134 per mille/year for the stud data and 0,067 per mille/year for fixed points. Another finding was that time and depth of clay were two factors behind the creep of Kungsängen clay. Another aim of the study was to investigate creep calculations methods in Eurocode 7. However, it was found that no method was proposed in the standard and therefore some other methods such as the time resistant theory and the Chalmer’s model with creep were investigated. It was found that the time resistant theory predicted creep realistically but with an overestimation in some cases, depending on the type of clay. Some clay specimen gave a negligible creep for loads under 45 kPa and other specimen indicated otherwise. All in all, this suggests that the time resistant theory might be an appropriate creep calculation method for the clay of Kungsängen. The Chalmer’s model with creep overestimated the total deformation but underestimated the creep when modelling odometer loads. Even so, the study of the model was not detailed enough in order to reject it or not. Therefore, a more detailed study of the model should be considered.
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Contribuições ao uso de novas tecnologias da informação e comunicação no ensino de engenhariaFerreira Filho, Raymundo Carlos Machado January 2005 (has links)
Neste trabalho, descreve-se o processo de produção de tecnologias educacionais e de Tecnologias da Informação e Comunicação (TICs), relacionando-as ao uso do ensino em Engenharia Geotécnica. Desenvolveu-se um sistema de informação baseado num modelo que integra recursos educacionais produzidos em diferentes formatos eletrônicos e um software baseado na Web para gestão destes recursos e das informações da disciplina Fundações. O software, denominado ENGEO, auxilia a estruturação do conhecimento envolvido no domínio de aplicação, fornecendo ao professor, ou equipe de gestão, ferramentas remotas de administração dos conteúdos e dos recursos educacionais. Aos alunos, a aplicação ENGEO fornece disponibilidade de informações e de conteúdo em um ambiente flexível. Este aplicativo foi desenvolvido para o curso de Engenharia Geotécnica, particularizado para Engenharia de Fundações, com o objetivo de introduzir e incentivar a utilização de sistemas baseados na Web para compartilhamento de conteúdo das disciplinas, implementar Tecnologias de Informação e Comunicação em aplicações para fins educacionais e fomentar discussões a respeito da identidade e perfil do Engenheiro e o papel da TICs no processo de formação do profissional de Engenharia. / This research describes and analyzes the production of an educational applicative based on Communication and Information Technologies (ICTs) developed for the field of Geotechnical Engineering. An information system based on a model that integrates produced educational sources in different digital formats and a Web software developed for management of these sources is described. The software, denominated as ENGEO, contains information related to the subject of Foundation Engineering. It assists structuring the knowledge in the domain of application, organizing in the Web various medias related to the subject, enabling remote administration by the lecturer or management team from tools implemented using Information and Communication Technologies (ICTs). Attempts are made to produce free and flexible assess to students of the contents of course. The experience was designed to stimulate a debate on the needs and identity of engineers and to put into perspective the role of ICTs in producing such identity.
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Strain Accumulation Due to Cyclic LoadingsMohamad, Mamdouh January 2018 (has links)
The formation of plastic strains in non-cohesive soils due to large number of loading cycles is a phenomenon of great importance in geotechnical and civil engineering. It constitutes a considerable cause for failures and deformations in various types of engineering applications including pavements. Strain accumulation due to cyclic loading has been studied for years through different models. This thesis reviews various models and focuses on the Bochum model through which, the most contributing soil and traffic parameters on permanent strains formation in pavement subgrades can be figured out. This represents the base for studying the serviceability of increasing the gross weights of vehicles that affect the behavior and size of cyclic loading. This was discussed through investigating the efficacy of increasing the number of vehicle axles and through increasing the vehicle gross weight while keeping the number of axles to check their impacts at the levels of strain formation in soil and consequently on its deformation. The results showed a considerable difference in settlements after changing the axle configurations of vehicles through increasing its number of axles. The work is expected to open a new area of scientific research in pavement designs seeking for ideal configurations of vehicle axles and to provide an advanced approach for studying soil deformations due to higher cyclic loadings.
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Maturation of Clay Seals in Deep Bore Holes for Disposal of Radioactive waste : Theory and ExperimentsYang, Ting January 2017 (has links)
KBS-3 and very deep borehole (VDH) concepts are two major types of long-term geologicaldisposal methods for high-level radioactive waste (HLW) isolating from the biosphere. TheKBS-3V concept for isolating the HLW at the depth of 400-500 m, is the officially proposedoption in Sweden and has been the subject of considerable research in the past few decades,while the VDH concept was considered as an option in the 1950s but later became discouragedbecause of insufficient experience in drilling technology. The greatest merit of the VDHconcept is that the almost stagnant groundwater in the deep boreholes prevents the transport ofthe possible release of radionuclides into the rock or up to the ground level. Since variousdisadvantages of the KBS-3V concept were found in previous research, the superiority of VDHconcept attracted the researchers to continue studying it into the late 1980s.The geological repositories of both of KBS-3V and VDH types primarily consist of a naturalbarrier (host rock) and of an engineering barrier (also known as a buffer/backfill barrier).According to the principle of IAEA and national relative research organizations, thebuffer/backfill material should have low permeability and good expandability, as well assuitable physical and sealing properties.The thesis concerns the VDH concept and is focused on the construction and performance ofthose parts of the sealed repository that are not affected by high temperature or gamma radiation.In the lower part of a VDH repository, the clay packages containing HLW will be exposed tohigh temperature (100-150 ) in the borehole and to highly saline groundwater. In theinstallation phase of HLW, the groundwater will be pumped out and replaced by medium-softsmectite clay mud in which the HLW packages are installed vertically. During the hydrationand maturation of the clay components, the microstructural reorganization, water transport,migration of clay particles and redistribution of the density of the components take place. Thematuration determines the transient evolution of the clay seals and influences the rheologicaland soil mechanical behavior in the installation phase. The maturation of clay system alsodetermines their ultimate sealing potential of VDH repositories.This study presents the work carried out for investigating the maturation of the buffer-backfillclay in the HLW deep borehole. Initially in the study three types of clays, the Namontmorillonite,magnesium-rich and illite-smectite mixed layer clays, were examined for estimating their performance as the barrier candidate material. This is mainly presented in theliterature review. The experimental study was conducted on montmorillonite GMZ clays andI/S mixed-layer Holmehus clay. The expandability and permeability tests were carried out forinterpretation of the recorded swelling development and assessment of the effect of the salineconditions, with the goal of deriving a relationship between swelling pressure and hydraulicconductivity for different dry densities. The maturation tests of initially fully-saturatedHolmehus clay and partly saturated GMZ clay were performed. During the tests, the shearstrength mobilised by the relative movement of densified mud and migrated dense clay -contained in a perforated central tube - were determined. According to the results of shearstrength tests, the maximum operation time or the number of clay packages to be placed in asingle operation was evaluated, whilst the suitable saturation degree of the dense clay wasdiscussed as well.A model of the maturation of initially water-saturated clay seals based on Darcy’s law wasworked out and the evolution of the clay components in a lab-scale borehole using Holmehusclay were performed and compared with the experimental recordings. Good agreementsbetween the physical behaviors of the theoretical simulations and the measurements wasachieved by which the validity of the model was verified. Using the results, the hydration andsoil migration in the entire maturation process were presented in diagram. The model was alsoused for preliminary evaluation of the maturation products in real boreholes by assuming thesame Holmehus clay as used in the tests. Two constellation of borehole and dense clay withdifferent diameters, 80 cm borehole /60 cm clay and 80cm/50cm, were assumed. The resultsrespecting dry density and hydraulic conductivity of the ultimate maturation products, and thedegree of homogeneous of the buffer and backfill clay system in the assumed boreholes, arepresented and discussed. The options of different mineral types and initial physical propertiesof the candidate buffer clays provide a reference for engineering barrier design of HLW disposalin VDH.
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