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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Putting the pieces together : A literature review on fire-cracked stone embankments and burnt mounds in Sweden / Många skärvor små : En litteraturstudie om skärvstensvallar och skärvstenshögar i Sverige

Lindgren, Ola January 2019 (has links)
In this thesis, an attempt is made to summarize the previous archeological research associated with two feature types in Sweden made from fire-cracked stones: the fire-cracked stone embankment and the burnt mound. The ?lim is to study how trends in interpretation and focus have developed. Furthermore, a compilation of ten excavation reports of burnt mounds between 2002 and 2013 is presented with the aim of determining their purpose, their usage of methods in general and petrography. The result of the summary confirms that there are discernable trends present and the result from the compilation of reports show that the larger scope is prioritized and that there are a number of commonly used methods, but that petrography is not among them.
62

Geomechanical testing of non-hardening grout : for determination of flowability and strength properties

Barrdahl, Axel January 2022 (has links)
Due to an increasing amount of aging tendencies in Swedish embankment dams, failures such as internal erosion has become a more common problem. Internal erosion is a phenomenon where certain soil material within the embankment dam is removed, often over a longer period of time. It is most common to occur at the inner core of the dam, and if it is allowed to continue for a longer time period the consequences can be disastrous. During the internal erosion, the inner material is washed out, creating larger voids and lowering the geotechnical stability of the dam. When larger voids start to appear, the seepage will increase allowing more material to be washed out and accelerating the process.  In order to repair an embankment dam, exposed to inner erosion, it requires both the location of the faults as well as a suitable method of repairing. A method to repair internal erosion is by using grout and injecting it into the location of the fault. The knowledge regarding what type of grout and how it should be treated is today lacking.  There are reasons to believe that a hardening mixture within an embankment dam using a till core will not cooperate well. For that reason, a grout with non-hardening properties is of interest. this thesis focuses on the Geomechanical strength parameters of two similar experimental non-hardening grouts. One with maximum grain size of 2 mm referred as grout 0/2, and one with maximum grain size of 4 mm, referred to as grout 0/4. The grouts consist of natural aggregates, calcium carbonate, water, bentonite, superplasticizer and defoamer.   The grouts are evaluated by its undrained shear strength, water content, bulk- and dry density using fall cone tests and uniaxial compressive strength tests. To evaluate the grouts angle of friction and angle of dilatancy together with young’s modulus, consolidated, drained triaxial tests were performed. Three tests with different consolidation pressures (50, 150 and 300 kPa) were performed for each grout. Since the grout will gain strength with time, the tests have been performed after certain number of days in order to see the development of the grouts. The laboratories stretch from 0 to 112 days since the time of mixing the grout, and was performed at Luleå University of technology.  Fall cone tests showed that the grout should most likely be mixed on site and left unstirred. Continuously stirring the grout quickly removed the grouts flowability which is why longer transportation should be avoided. At the same time, the accuracy of the grouts mixing is very demanding which needs to be taken into consideration.  Triaxial tests showed that the grout 0/2 had dilatant behavior for 50 and 150 kPa consolidation pressure while 300 kPa showed contractive behavior. The grout 0/4 had dilatant behavior for 50 kPa consolidation pressure while 150 and 300 kPa showed contractive behavior. A theory to explain this behavior was constructed where the bentonite is believed to be behind it. Bentonite slurries behave as a Bingham fluid, where it requires a certain amount of shear stress for the fluid to start to flow. With the same reasoning, the low consolidation pressures do not exceed that threshold, resulting in dilatant behavior. But once that threshold is surpassed the grout starts to contract. In addition, flow curve tests were performed for additives, superplasticizer and defoamer. Both these substances showed Newtonian behavior which leaves Bentonite to be the only additive with Binghamian behavior. / På grund av en ökad mängd med föråldrandetendenser hos svenska jordfyllningsdammar har brott så som inre erosion blivit ett alltmer vanligt problem. Inre erosion är ett fenomen där en viss jord inom jordfyllningsdammen är avlägsnad, generellt över en längre tidsperiod. Oftast inträffar detta vid den inre damkärnan och om erosionen är tillåten att fortskrida sig över en längre period kan konsekvenserna bli förödande. Inre erosion fungerar så att jordmaterial tvättas ut vilket skapar hålutrymmen och minskar den geotekniska hållfastheten för dammen. När större hålutrymmen bildats ökar läckaget som i sin tur tillåter mer material att bli urtvättat och processen blir accelererad. För att kunna reparera en jordfyllningsdam, utsatt för inre erosion, krävs både att platsen för brottet och metoden för att reparera är kända. En metod för att reparera inre erosion är genom att använda injektering och injektera hålutrymmet. Dock är kunskapen gällande vad för typ av injektering och hur den ska hanteras icke existerande i dagsläget. Det finns anledning att tro att ett härdande bruk inom en jordfyllningsdam, med en moränkärna, inte kommer samarbeta särskilt bra. På grund av det har ett bruk med icke-härdande egenskaper undersökt. Den här uppsatsen fokuserar på de geotekniska hållfasthetsegenskaperna för två liknande experimentella icke-härdande bruk. Ett med maximal kornstorlek på 2 mm benämnd som bruk 0/2 och ett med maximal kornstorlek på 4 mm, benämnd som bruk 0/4. Bruket består av natursand, kalciumkarbonat, vatten, bentonit, mjukgöringsmedel och skumdämpare. Bruken är utvärderade genom deras odränerade skjuvhållfasthet, vattenkvot, skrym- och torrdensiteten som har tagits fram från fallkorns-test och enaxiella trycktest (UCS).  För att utvärdera brukens friktionsvinkel och dilationsvinkel tillsammans med styvheten (initiella och 50 %) har konsoliderat, dränerat triaxiala tests utförts. Tre test med varierande konsolideringstryck (50, 150 och 300 kPa) har utförts för båda bruken. I och med att brukens hållfasthet kommer att öka med tiden, har testerna utförts efter ett visst antal dagar, för att se hur utvecklingen ser ut. Laborationerna har sträckt sig från 0 till 112 dagar sedan det att bruken har blandats, och utfördes vid Luleå Tekniska Universitet. Fallkornstesten visade att bruken bör med största sannolikhet blandas på arbetsplatsen och därefter förbli orörda. Kontinuerlig omrörning visade sig frånta brukens flytförmåga, vilket också är anledning till varför längre transporter bör undvikas. Samtidigt så är noggrannheten vid brukens blandning krävande vilket bör tas i beaktning. De triaxiala tester visade att bruk 0/2 visade ett dilatant beteende för både 50 och 150 kPa konsolideringstryck medan 300 kPa hade ett kontrakterande beteende. Bruket 0/4 hade dilatant beteende för 50 kPa konsolideringstryck medan 150 och 300 kPa visade kontrakterande beteende. En teori för att förklara detta beteende togs fram där bentoniten är den troliga orsaken. Bentonitblandningar (bentonite slurry) beter sig som en Bingham-vätska, där det krävs en viss mängd skjuvspänning för att få vätskan att börja flyta. Med samma resonemang applicerade på bruken innebar det att de låga konsolideringstrycken inte översteg tröskelvärdet, vilket resulterade i ett dilatant beteende. Däremot, när tröskelvärdet väl är överstiget börjar bruket att kontraktera istället. Det gjordes även flödestester på tillsatsmedlen, mjukgöringsmedel och skumdämpare. Testerna visade att båda medel betedde sig Newtoniskt, vilket lämnar bentoniten som det enda tillsatsmedlet med Bingham-beteende.
63

Morphological filters in floodplain for DEM-extracted data – using Minimum Bounding Circle & Youden Index

Jin, Peng 06 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Floods are one of the worst disasters in the United States. Each year, the government allocates a tremendous amount of manpower and money on flood prevention initiatives. As the first defense line, levees provide protection from temporary flooding (Makhdoom, 2013). These embankments are broadly classified according to the areas they protect, which could either be urban or agricultural levees within floodplains. In the U.S., most of the levees are handled by government agencies such as the U.S. Army Corps of Engineers and the Federal Emergency Management Services. On the other hand, non-levee embankments created by individual farmers (Olson & Morton, 2013) or naturally formed levee-like structures may not be in the government database. The initial purpose of this research was to assist Polis center on the “Mapping of Non-Levee Embankments in the Indiana” project. The non-levee embankments are not certified or engineered levee-like structures. They, therefore, impose lateral constraints on flood flows, reducing the floodplain storage capacity and increasing the flood velocity. These non-levee embankments can cause stream erosion and downstream flooding. Therefore, it is important to know the locations of these features. The first part of the proposed method adapted the Empirical Bayesian theorem and the low pass filter techniques to extract elevated linear features from LiDAR elevation data – Digital Elevation Model (DEM). The second part of the proposed methods combined the Minimum Bounding Circle (MBC) method and the Youden Index to locate the optimal threshold value that can be used to determine whether the extracted features are levee-like structures. The focus of this study is not only limited to artificial levee-like structures, but also takes the natural levees, or any potential levee-like structures into account because this study assumes all embankments play important roles during flood events.
64

Dynamic Analysis of River Embankments during Earthquakes based on Finite Deformation Theory Considering Liquefaction / 液状化を考慮した有限変形理論に基づく地震時の河川堤防の動的解析

Sadeghi, Hamidreza 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18241号 / 工博第3833号 / 新制||工||1587(附属図書館) / 31099 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 木村 亮, 教授 三村 衛, 准教授 木元 小百合 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
65

Study on River Dyke Breach Characteristics by Overtopping Flow / 越流による河川堤防の決壊特性に関する研究

Bhattarai, Pawan Kumar 24 September 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19282号 / 工博第4079号 / 新制||工||1629(附属図書館) / 32284 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 藤田 正治, 准教授 川池 健司 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
66

Evaluation of long-term performance of sodium silicate grouted in embankment dams

Fu, Jenny January 2019 (has links)
Embankment dams is the most common type of dams in operation inSweden today. Due to the nature of embankment dams, seepage throughthem will always occur. If the seepage velocity exceeds a critical velocity,internal erosion is initiated, which could lead to damage in form of pipingand sinkholes. To treat this problem, remedial grouting has beenperformed involving a combination of conventional grouts, i.e. cement andcement-bentonite as well as sodium silicate, which is a chemical grout thatalso known as water glass. Regarding the sodium silicate grout, there isconcern about the long-term permanence.The aim of this thesis has been to study the potential performance ofsodium silicate grouted in embankment dams. The first part of this thesisis a literature review of the general behavior of sodium silicate as a grout,its degradation processes and the factors that could induce degradation.The second part suggests monitoring methods to control and evaluate theperformance of the treated dam and the grout if degradation has occurred.Findings from literature generally indicates a high risk of instability andlow permanence of sodium silicate when grouted in an embankment dam.This type of grout will undergo degradation mainly in two forms: syneresisinduced shrinkage and leaching due to grout erosion or dissolution. As thedegradation has developed, an increase in permeability of the repaireddam core is a potential consequence.How the potential degradation of sodium silicate will affect the treateddams is suggested to be observed by monitoring the permeability of thegrouted core. Applicable monitoring methods for this purpose aremeasurements of pore pressure and temperature using piezometers. Thesecond direct method of monitoring a changed dam behavior is suggestedto be leakage analysis, in order to detect potentially increased leakagebecause of the grout degradation. An indirect way to investigate the damperformance is suggested to be monitoring of the grout state. Measurementof ion concentration of sodium and silicon respectively in leakage waterusing selective-ion electrodes will reveal any increase in ion concentrationdue to the potential grout dissolution or leaching.
67

Škola, základ života - Soubor školských staveb v Ostravě na Černé louce / School, the Foundation of Life – a Complex of Educational Buildings in Ostrava, Cerna louka

Vančurová, Jitka January 2014 (has links)
The goal of my project is to find how the contemporary school should look like.
68

Svratecké nábřeží v Brně - architektonicko urbanistická studie / Svratka Embankment in Brno - Architectural and Urban study

Hynková, Tereza January 2014 (has links)
Diploma thesis deals with embankment of the river Svratka in Brno. The project follows two previous semesters when I elaborated the analysis of embankment and also designed small interventions. The project tries to support the activities along the river to attract people to visit its embankment. One of the designed interventions is the "Sculpture Park" - nature gallery of sculptures. The thesis also deals with the design of objects which are dedicated to housing for the elderly. This housing is supplemented by public facilities which serve both accommodated people and people nearby.
69

Redevelopment of Skeppsbron quay in Stockholm, Sweden

Starostina, Alexandra January 2017 (has links)
No description available.
70

Experimental analysis of unreinforced and reinforced piled embankment subjected to cyclic loads

Aqoub, Khaled M. A. January 2018 (has links)
Reinforced piled embankment technique is becoming increasingly utilised for the construction over soft grounds. Most of the studies focused on studying the behaviour of piled embankments that are loaded with static surcharge load. However, less attention has been given to the behaviour of piled embankments under cyclic loading conditions. In this study, an experimental programme has been undertaken to improve our understanding for the behaviour of unreinforced and reinforced shallow piled embankments subject to cyclic loadings that are applied over a specific area of the embankment. The results showed that arching of the soil was adversely affected during the initial stages of cyclic loading regardless of the embankment height. However, regain of strength and recovery of the arching effect was observable during further stages of cyclic loadings. Inclusion of reinforcement layers was found to enhance the performance of load transfer mechanisms. The surface settlement increased with raising the embankment height and reduced with increasing the number of reinforcement layers. Two preliminary experimental studies have been carried out in order to be able to understand and design the main experiment. The results showed that with increasing number of reinforcement layers, enormous cycles of loading could be applied without experiencing excessive deformation or loss of bearing resistance. Furthermore, it was observed that alternating the direction of movement significantly affected the formation of arching during the initial cycles irrespective of the embankment height. / Higher Education Institute of the Libyan Government

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