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1
Xu, Yao. "Analysis of dam failures and diagnosis of distresses for dam rehabilitation /." View abstract or full-text, 2010. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202010%20XU.
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Ari, Onur. "A Study On Dam Instrumentation Retrofitting: Gokcekaya Dam." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610283/index.pdf.
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Multi-purpose project requirements lead to construction of large dams. In order to maintain the desired safety level of such dams, comprehensive inspections based on use of a number of precise instruments are needed. The ideal dam instrumentation system should provide time-dependent information about critical parameters so that possible future behavior of the structure can be predicted. New dams are normally equipped with adequate instrumentation systems. Most of the existing dams, however, do not have adequate instruments or current instrumentation systems may not be in good condition. By implementing the modern equipment to existing dams, the uncertainty associated with the impacts of aging or unexpected severe external events will be reduced and possible remedial measures can be taken accordingly. This study summarizes the major causes of dam failures and introduces the instruments to be used to monitor the key parameters of a dam. The concept of the instrument retrofitting to an unmonitored dam is highlighted through a case study. A sample system is proposed for Gö<br>kç<br>ekaya Dam, with reference to an investigation of the current condition of the structure. The deficiencies observed during a site visit are listed and the corresponding rehabilitative repair measures are suggested. Finally, different alternatives of a new instrumentation system are introduced and compared in terms of technical and economical aspects.
3
Sezgin, Ozgun Ilke. "An Evaluation Study On Instrumentation System Of Cindere Dam." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609812/index.pdf.
Full textAbstract:
In this study, the first hardfill dam in Turkey, Cindere Dam, is evaluated
regarding current and alternative measurement systems in detail. Cindere
Dam is a notable project, especially with its height as an example of hardfill
dam, not only in Turkey but also in the world. First, the current
instrumentation system of Cindere Dam is evaluated as a whole with
reference to the parameters measured, instruments and data acquisition
system. Second, an alternative instrumentation system is developed by
using additional parameter and instruments to the current instrumentation
system. Furthermore, each instrumentation system equipped with manual
and automatic data acquisition systems is considered. The comparison
between the current and the alternative instrumentation systems are also
carried out in terms of technical and economical feasibility aspects.
Although, the current instrumentation system is found to be satisfactory, it
is observed that the alternative system promotes the current system in
various aspects without increasing the cost significantly.
4
Al, Maqbali Nasser. "Risk assessment of dams." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09ENS/09ensa316.pdf.
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Bibliography: leaves 101-104. Explores risk assessment of dams, a fundamental approach for dam safety measurement, providing a base on which all safety assessment and any appropriate regulation should be developed. Includes an overview of the relevant literature; an example of the application of this method by the South Australia Water Corporation; and it is also applied to the Wadi Al Jizzi Recharge Dam in the Sultanate of Oman. Conclusions and recommendations are presented on the applicability of risk assessment of dams method in the Sultanate of Oman.
5
Imbrogno, David F. "Analysis of Dam Failures and Development of a Dam Safety Evaluation Program." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406168902.
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Lismanis, Brandon. "Numerical Modelling of Dam Breaching." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24004.
Full textAbstract:
Until recently, research has been scarce in the field of physical modelling of dam breaching. Over the past few years, teams from the University of Ottawa, Canada, Delft University of Technology, Netherlands, and HR Wallingford, United Kingdom have worked on several physical models to help determine how various dam breaching characteristics vary due to changes in dam geometry and geotechnical properties. The purpose of this project is to use these new experimental data sets to compare and validate the applicability range of two existing pieces of software, MIKE11-DB and BREACH developed by the Danish Hydraulic Institute and National Weather Service, respectively. Several breaching characteristics such as the outflow hydrograph, peak flow, lag time, breaching time, breach width, and water level are considered in the present study. A sensitivity analysis is also performed on the model’s main input parameters and their sensitivity and performance is ranked accordingly.
7
Wishart, Jeremy Scott. "Overtopping Breaching of Rock-Avalanche Dams." Thesis, University of Canterbury. Civil Engineering, 2007. http://hdl.handle.net/10092/1193.
Full textAbstract:
River blockages formed by rock avalanches appear to pose a higher hazard potential than other landslide dams, given the extreme run-out distances and volumes of rock avalanche deposits. Recent research has identified rock avalanche deposits to have internal sedimentology consisting of a coarse surficial material (carapace) and a finer fragmented interior (body) potentially of critical importance to rock-avalanche dam stability. Physical scale modelling of overtopping failure and breach development in rock avalanche dams was used to quantify the influence of this sedimentology on critical breach parameters, and their prediction using existing embankment dam breach technologies. Results from this study indicate that the time to failure for rock avalanche dams is approximately twice that observed for homogeneous dams due to the armouring properties of the carapace; and that peak discharge is not significantly affected by sedimentology. While application of empirical, parametric, dimensional and physically based models indicated that uncertainty associated with predicted dam break discharges could range from ±19% to ±107%, no modelling technique was able to simulate the armouring phenomenon adequately. Comparison of actual and simulated breach evolution shows linear assumptions of breach depth and width development (as observed in homogeneous dams) to be incorrect. In the context of hazard management, the results suggest that empirical regression relationships should be used for rapid assessment of potential dam break flood magnitude.
8
Baron, Stefany A. "Cost Trends and Estimates for Dam Rehabilitation in the Commonwealth of Virginia." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98786.
Full textAbstract:
In recent years, the United States has seen a high demand for dam rehabilitation projects as most dam infrastructure has started to reach or exceed the expected life span of 50-70 years. Rehabilitation projects can be very expensive, however, and the funding options for dam owners are limited. To raise awareness, organizations such as ASDSO and the Virginia DCR release cost estimates every few years to encourage more investment in dam infrastructure. Unfortunately, many cost estimates have been made with limited data and outdated methodologies. This research collects a new sample of cost data for Virginia dam rehabilitation projects and uses it to assess key factors for cost estimating. Factors such as height, drainage area, hazard classification, and ownership type were used to make regression models that predict the cost of addressing Virginia's non-compliant dams. This study estimates that approximately $300 million is needed to address Virginia's 98 deficient high hazard, local government owned dams and that $122 million of that estimate is need for SWCD dams alone.<br>Master of Science<br>Dam rehabilitation refers to the repair, removal, or upgrade of an existing dam structure. Rehabilitation projects are done when dams start to exceed their intended life span (approximately 50-60 years) or when policy makers change the required safety standards. The demand for dam rehabilitation has been increasing for the past several years as more and more dams are being identified as unsafe, but the available funding for rehabilitation projects is limited and competitive to obtain for dam owners. To raise awareness, dam safety agencies release cost estimates every few years to encourage government leaders and the general public to take action. However, these estimates need to be taken with caution as they are often made with limited data availability and outdated methodologies. This research collects a new sample of cost data for Virginia dam rehabilitation projects that have occurred in the last 15 years. Dam characteristics such as height, watershed size, downstream risk potential, and ownership type were used to form equations that predict the cost of addressing Virginia's non-compliant dams. This study estimates that approximately $300 million is needed to address Virginia's 98 deficient high hazard, local government owned dams and that $122 million of that estimate is need for Virginia's Soil and Water Conservation District dams alone.
9
Boughoufalah, Mohamed. "Earthquake input mechanisms for dam-foundation interaction." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63932.
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Skempas, Marinos. "Dam abutment stability with particular reference to the Thisavros Dam." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339745.
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Udamulla, K. M. Lakshika Ayomi. "Engineering assessment of the safety of existing dams." Thesis, Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18565323.
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Yalcin, Emrah. "Ilisu Dam And Hepp, Investigation Of Alternative Solutions." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612366/index.pdf.
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This study is an assessment of a hydraulic solution not only rescues Hasankeyf with countless ancient monuments from inundation but also supplies the foreseen energy production of the Ilisu Dam and HEPP Project. An alternative composed of five dams on the Tigris River and its branches was developed as a result of the conducted hydro-meteorological, water potential, flood analysis and optimization studies considering the topographical and geological characteristics of the proposed dam locations. While there is a 27 percent decrease in the overall reservoir area compared to the existing project, 4426.1 hm3 of water can be stored in these dams with a fill volume of 14.8 hm3. Over this storage, determined according to the maximum water levels designated by considering the upstream schemes developed by General Directorate of State Hydraulic Works (DSI), General Directorate of Electrical Power Resources Survey and Development Administration (EIE) and incorporated companies according to Law No.4628, a volume of 3634.4 hm3 can be used as active storage. In the fully developed upstream stage, according to the conducted consecutive operation studies, while the existing project has an energy production capacity of 3094.3 GWh/year, the proposed project is capable of providing 3139.1 GWh/year with a smaller installed power although there is a slight decrease in the produced firm energy.
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Kitapcigil, Sulen Nur. "A Study On The Reliability-based Safety Analysis Of Hardfill Dams." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612802/index.pdf.
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Dams are important large structures providing vital benefits to human life. These
strategic structures are necessary in order to supply water and energy and to control
floods. Moreover, dams have important roles in regional development and national
economy. Thus, the design of dams deserves rigorous studies. Deterministic
approach may be acceptable for design of dams and may satisfy safety requirements
if large safety factors are used. However, such an approach will not be cost-effective
in economic terms. High safety factors utilized in deterministic approaches
necessitates large dimensions. One remedy for this overestimation is integrating
statistical information and techniques, such as Monte-Carlo simulations into the
analysis and design of dams. Probabilistic approaches may result in more
economical and reasonable designs. CADAM is a software program which allows
the user to analyze dams using Monte-Carlo simulation technique. Uncertainties
associated with tensile strength, peak cohesion, peak friction coefficient, normal
upstream reservoir elevation, drain efficiency and horizontal peak ground
acceleration are incorporated into stability and stress analysis using Monte-Carlo
simulations. In this thesis, utilization of CADAM software is demonstrated on a case
study. Cindere dam is evaluated in terms of structural safety
14
Vos, Adele. "Unsteady flow conditions at dam bottom outlet works due to air entrainment during gate closure : Berg River dam model." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71850.
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Thesis (MSc)--Stellenbosch University, 2012.<br>ENGLISH ABSTRACT: A trial closure of the emergency gate of the Berg River Dam was undertaken by the Trans-
Caledon Tunnel Authority (TCTA) on 12 June 2008. The air vent downstream of the emergency
gate was designed to introduce air to mitigate the negative pressures that were expected in the
conduit during emergency gate operations. The emergency gate has to close when the radial
gate at the downstream end of the outlet conduit fails. Contrary to the theoretical design, the
measured air vent velocities in the field indicated that, while the emergency gate was closing,
very large volumes of air were apparently continuously being released from the air vent,
commencing when the gate was about 30% closed (i.e. 70% open). This is in contrast to what
the design intended, namely that air should have been drawn into the vent.
This thesis is concerned with the testing of a 1:14.066 physical model representing the outlet
works and air vent of the Berg River Dam as a means to determine the reasons for the release
of large volumes of air from the air vent during the trial closure in 2008. It also seeks solutions to
mitigate the excessive airflow from the air vent. It was concluded that the air velocity in the air
vent was independent of the rate of closure of the emergency gate, but to increase with
increasing water head. The problem at the Berg River Dam was determined to be one of air
blowback. Modifications were made to the configuration of the model in order to determine whether the
configuration of the outlet works caused air to be released from the air vent. It was determined
that the downward sloping roof at the outlet of the conduit, used to accommodate the radial gate
chamber, was the cause of the air blowback phenomenon. An additional air vent was fitted
directly onto the conduit at the constriction was found to be ineffective in reducing the air
blowback. It was concluded that there are no rational structural change that can prevent or
inhibit a recurrence of the blowback phenomenon in the Berg River Dam outlet conduit.
The recommendation follows that the outlet conduit should not be constricted by any structural
or mechanism further downstream in the conduit.<br>AFRIKAANSE OPSOMMING: ʼn Toetssluiting van die noodsluis van die Bergrivierdam is op 12 Junie 2008 deur die TCTA
(Trans-Caledon Tunnel Authority) uitgevoer. Die lugskag stroomaf van die noodsluis is ontwerp
om lug in te voer om die verwagte negatiewe drukke tydens die noodsluissluiting te beperk. Die
noodsluis moet sluit indien die radiaalsluis aan die einde van die uitlaatpyp sou faal. In
teenstelling met die teoretiese ontwerp, het die gemete lugsnelhede in die lugskag in die veld
aangedui dat groot volumes lug voortdurend uit die lugskag vrygelaat word wanneer die
noodsluis ongeveer 30% toe is (dit wil sê 70% oop). Dit is in teenstelling met die ontwerp, want
die lugskag is ontwerp vir die insuig van lug.
Hierdie tesis het ten doel om die redes vir die vrylating van groot volumes lug uit die lugskag vas
te stel met behulp van ʼn 1:14.066 fisiese skaalmodel van die uitlaatwerke en lugskag van die
Bergrivierdam soos getoets tydens die inwydingstoetssluiting in 2008. Die toetse op die model
het getoon dat die lugsnelheid in die lugskag onafhankik van die sluistoemaak tyd is, maar
verhoog met die toename in die watervlak. Die Bergrivier dam probleem was bepaal as die van
lug terugslag.
Die model is gewysig ten einde te bepaal of die spesifieke samestelling van die uitlaatwerke die
oorsaak van die vrystelling van lug uit die lugskag is. Die analises en verandering aan die uitleg
toon aan dat die skuins afwaartse dak van die uitlaattonnel om die radiaalsluiskamer te huisves
die rede was vir die vrylating van die lug uit die lugskag. ‘n Addisionele lugskag was gebou in
die dak van die uitlaattonnel reg bo die sametrekking, maar was oneffektief om die terug vloei
van lug te verminder. Die gevolgtrekking is dat daar geen rasionele strukturele verandering
aangebring kan word aan die Bergrivier dam om die vrystelling van lug uit die lugskag te
verhoed of te verminder nie. ’n Aanbeveling vir toekomstige ontwerpe is dus dat die uitlaattonnel nie beperkend by die uitlaatend
moet wees nie.
15
Reynolds, Sonel. "Evaluating the decision criteria for the prioritisation of South African dams for rehabilitation in terms of risk to human lives." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80288.
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Thesis (MScEng)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: In South Africa a large number of dams owned by the Department of Water Affairs (DWA) need to
be rehabilitated. This study investigated the decision process involved in the prioritisation of dams
for rehabilitation. DWA developed a risk analysis methodology for defining the risks associated with
dam safety, expressed as the combination of the probability and consequences of dam failure. These
risks are evaluated usingmultiple acceptability criteria to assess risk to human life and the economic,
social, socio-economic and environmental impacts of dam failure. In this study, the criteria used in
the decision process to evaluate the acceptability of life safety risks were evaluated by comparing
to international best practice methods, where the acceptability of risk to human life is commonly
assessed as the expected number of fatalities against life safety criteria presented as FN-criteria on
an FN-diagram.
Damrehabilitation should reduce the probability of dam failure, thereby reducing the risk to society
in terms of the expected lives lost. However, the rehabilitation works come at a cost and the level
of these investments are usually large. In addition, the rehabilitation of South African government
owned dams are financed by society and these financial resources are limited. Thus investments into
dam rehabilitation works should be worthwhile for society. Society’s Willingness to Pay (SWTP) for
safety was applied to South African dam safety to determine the acceptable level of expenditure into
life safety that is required by society.
Investments into improved safety levels are not always dictated by society, but could also be
driven by the decision maker or owner requiring an economically optimal solution for the rehabilitation.
Economic optimisation accounts for considerations additional to life safety, including economic
motivations, damage costs of dam failure as well as compensation costs for lives lost. Often
economic optimisation would govern the decision problem. Also, the DWA current evaluation does not take the cost of rehabilitation into account in any way. Thus, FN-criteria that primarily evaluates
life safety, but also incorporates a measure of economic efficiency, were suggested in this study.<br>AFRIKAANSE OPSOMMING: In Suid-Afrika moet ’n groot aantal dammewat deur dieDepartement vanWaterwese (DWA) besit
word gerehabiliteer word. Hierdie studie het die besluitnemingsproses ondersoekwat toegepasword
om damme te prioritiseer vir rehabilitasiewerke. DWA het ’n bestaande metodologie wat gebaseer is
op risiko-analise. Die risikos wat verband hou met damveiligheid word deur die metode bepaal en
word uitgedruk as die kombinasie van waarskynlikheid en die beraamde gevolge van damfaling.
Hierdie risikosword geëvalueer teenoor verskeie kriteriawat die aanvaarbaarheid van risikos teenoor
menselewens en die ekonomiese, sosiale, sosio-ekonomiese en omgewingsimpakte van damfalings
assesseer. In hierdie studie word die kriteria wat gebruik word in die besluitnemingsproses om die
aanvaarbaarheid van risikos teenoor menselewens te bepaal geëvalueer deur die kriteria te vergelyk
met metodes wat internasionaal as beste praktyk beskou word. Internasionaal word die aanvaarbaarheid
van risikos teenoor menselewens oor die algemeen as die verwagte aantal sterftes teenoor
lewensveiligheidskriteria FN-kriteria op ’n FN-diagram geassesseer.
Dam rehabilitasiewerke behoort die waarskynlikheid van damfaling te verminder, sodoende verminder
die risiko teenoor die samelewing in terme van verwagte sterftes. Die rehabilitasiewerke
vereis finansiële beleggings, en hierdie beleggings is gewoonlik groot. Verder word die rehabilitasie
van Suid-Afrikaanse damme wat deur DWA besit word deur samelewing gefinansier en hierdie finasiële
hulpbronne is beperk. Dus moet hierdie beleggings die moeite werd wees vir die samelewing.
Die samelewing se bereidwilligheidomte betaal ("SWTP") vir veiligheid word toegepas in Suid-
Afrikaanse damveiligheidomdie aanvaarbare vlak van beleggings vir ’n verbeterde veiligheid teenoor
menselewens wat deur die samelewing vereis word te bepaal.
Beleggings in verbeterde damveiligheidsvlakke word egter nie altyd bepaal deur die samelewing
nie,maar kan ook gedryf word deur die besluitnemer of eienaar wat ’n ekonomies optimale oplossing
vir die rehabilitatiesewerke vereis. Ekonomiese optimering neem oorwegings addisioneel tot lewensveiligheid in ag, insluitend ekonomiese motiverings, skade kostes as die dam faal, sowel as
vergoedingskostes vir die verwagte sterftes. Ekonomiese optimering beheer dikwels die besluitnemingsprobleem.
Verder neem die huidige DWA besluitnemingssproses in geen manier die kostes
van rehabilitasie in ag nie. Dus word FN-kriteria wat hoofsaaklik veiligheid teenoor menselewens
evalueer,maar wat ook ’n mate van ekonomiese doeltreffendheid insluit, voorgestel in hierdie studie.
16
Knutsson, Roger. "Tailings Dam Performance : Modeling and Safety Analysis of a Tailings dam." Licentiate thesis, Luleå tekniska universitet, Geoteknologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18084.
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Storage and management of mine waste are both needed in the mining industry. After mineral extraction of the ore, there are generally leftovers with insufficient economical value that need to be taken care of. The finest grained fractions are referred to as tailings. Since every mine site and every tailings impoundment is unique, there is unfortunately not an universal answer to proper management that can be applied everywhere. Even though local guidelines and regulations can be considered to give a best practice in terms of design, there is correspondingly a need for dam safety stewardship on an operational level. Without such stewardship, not even the best designed dams or facilities would be fully controlled in terms of safety. Conversely, even badly designed dams can be operated in safe manners with good stewardship and surveillance programs. The coupling between design and stewardship is therefore important in order to reach proper tailingsmanagement.In the design of tailings dams, a certain value of the factor of safety for slopes of the dams is normally striven for to secure stability. The value is generally based on national regulations and/or guidelines. In Sweden the factor of safety should not be lower than 1.5 under normal conditions. In the guidelines, recommendations are often given on dam surveillance and field measurements of e.g. pore water pressure, deformations and seepage. Field measurements are taken, but are generally assessed in terms of trends (change with time) and not by comparison to anticipated performance.In this study, numerical modeling has been used for stability analyses and dam performance, as predictions of deformations and pore water pressure levels. An upstream tailings dam located in northern Sweden has been used as a case. The granular materials being part of the model based were described based upon geotechnical investigations (field and lab). The tailings material was modeled, on a constitutive level, by the Hardening Soil model. Good agreement betweensimulated behavior and laboratory tests was achieved. Other dam materials were simulated by the Mohr-Coulomb model.The model was built as a staged construction model where historical events between 1992 and 2013 were simulated. The historical events included dam raises, increased beach elevations, remedial works etc. The simulations of historical events were used for facilitating comparison with field measurements. By means of inclinometer data, horizontal deformations were measured and evaluated for a period of six years. These deformations were accurately simulated, which was considered to verify the numerical model. By this verification, the model is considered accurate enough to be used for simulating future events. Both stability and corresponding dam performance were computed, by simulating a period of 10 years. The stability analyses were used for the set-up of rockfill support plans, i.e. where and when remedial works are needed in order to maintain a certain safety level. The corresponding values in deformations and pore water pressures were used for the set-up of alert levels for each measuring unit. These alert levels will help the engineer in field with data interpretation, where the simulated values are compared with field measurements taken. The proposed methodology is recommended for tailings dams in general, which reduces the gap between design and stewardship. Hence, one step closer to proper tailings management is taken.<br>Godkänd; 2015; 20151026 (rogknu); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Roger Knutsson Ämne: Geoteknik/Soil Mechanics Uppsats: Tailings Dam Performance Modeling and Safety Analysis of a Tailings Dam Examinator: Professor Sven Knutsson Institutionen för samhällsbyggnad och naturresurser Avdelning Geoteknologi Luleå tekniska universitet Diskutant: Technical Director Annika Bjelkevik Tailings Consultant Scandinavia AB Stockholm Tid: Fredag 27 november 2015 kl 13.00 Plats: F1031, Luleå tekniska universitet
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Yilmazturk, Sema Melek. "Three Dimensional Dynamic Response Of A Concrete Gravity Dam." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615455/index.pdf.
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Hydroelectric power is a commonly used alternative source of energy in developing countries. In this regard, concrete gravity dams are the most preferred dam type especially with the developments in the engineering industry. Roller compacted concrete became more popular in dam construction due to its advantages of speed and economy. Several methods are used for the design of concrete gravity dams by analyzing the dam response under static and dynamic loads. This study provides three dimensional linear dynamic analysis of roller compacted concrete gravity dam with a complete dam-foundation-water interaction by using EACD-3D-08 program. Foundation flexibility was included with damping and mass using boundary elements. Three dimensional solid elements were used for the idealization of the dam and water with using finite element methods. Compressibility of water with reservoir absorption was studied. In the light of USACE, performance criteria of linear analyses were assessed. Parametric study was conducted to determine the most influential parameters on the dam response. The importance and necessity of three dimensional analyses were investigated by comparing with linear two dimensional analyses. Linear analyses were then compared with three dimensional nonlinear analyses. In conclusion, the realistic dam seismic response can only be obtained by using three dimensional linear analyses with full interaction of dam-foundation-water.
18
Ramoejane, Mpho. "The genetic integrity of Labeo capensis and L. umbratus (Cyprinidae) in South Africa in relation to inter-basin water transfer schemes." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1013049.
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The Orange-Fish and Cookhouse tunnels that are part of a major inter-basin water transfer scheme (IBT) act as a pathway for several fish species from the Orange River system to enter the Great Fish and Sundays River systems in South Africa. These include Labeo capensis and L. umbratus. Labeo capensis was restricted to the Orange River system before the inter-basin water transfer scheme. Labeo umbratus occurred naturally in the Orange River and in southern flowing river systems. Previous studies showed that the two species hybridise in Hardap Dam, located in a tributary of the Orange River system in Namibia. There are also unconfirmed reports of hybrids from Darlington Dam on the Sundays River system. The aim of the thesis was to confirm hybridisation in Hardap Dam, assess whether hybridisation between L. capensis and L. umbratus has occurred in Darlington Dam and to gain a better understanding of the diversity of these two species. Morphology (morphometrics and meristics), a nuclear S7 intron and the mitochondrial cytochrome ♭ gene were used to assess for hybridisation. A total of 275 specimens were analysed from across the geographical range of the two species. The two species could be distinguished using morphometrics (dorsal fin base, interorbital width and operculum to eye distance) and meristics (lateral line, origin of the dorsal fin to lateral line, origin of the pelvic fin to lateral line and caudal peduncle scale counts) characters. Hybrids from Hardap and Darlington dams were placed between the two species clusters. Labeo umbratus from the Orange River and southern flowing rivers formed a single cluster. The two species could also be distinguished from each other with six nuclear DNA mutations and hybrids were heterozygous at such sites in both dams. Labeo umbratus populations from the Orange River and southern flowing rivers (Gouritz, Gamtoos, Sundays, Bushmans, Great Fish and Nahoon) formed a single lineage. Analysis of mitochondrial DNA, however, revealed that L. umbratus populations from the Orange River and southern flowing rivers were two lineages that differ from each other by 5 mutations. Labeo capensis could be differentiated from both these lineages. Being maternally inherited, mitochondrial DNA did not reveal hybridisation, but ten specimens with L. capensis haplotypes were found in the Darlington Dam. In Hardap Dam, however, it appears that only L. capensis mitochondrial DNA haplotypes persist, despite morphological and nuclear DNA analysis suggesting that both morphs and hybrids of the two species occur. The genetic integrity of these Labeo species has therefore been compromised in at least Hardap and Darlington dams. The Great Fish and Sundays populations are considered to be under threat of complete introgression. The Kat River and Slagboom Dam populations that were isolated before the IBTs have to remain isolated to protect the genetic integrity of the southern lineage of L. umbratus in these two systems.
19
Karakaya, Koray. "Numerical Simulation Of The Kirazlikopru Dam Failure On The Gokirmak River." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606039/index.pdf.
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Numerical dam break analyses of Kirazlikö<br>prü<br>Dam are performed under
various hydraulic scenarios. Kirazlikö<br>prü<br>Dam is located on the Gö<br>kirmak
River near the city of Bartin. The objective of these analyses is to investigate
adverse effects of such dam break failure on the regions downstream of the
dam. The numerical model used in the simulations is FLDWAV, which is
developed by the National Weather Service (NWS) in the United States. It
appears that most adversely effected regions are those that are closest to the
dam location. The results of these simulations can be used sufficiently to
prepare emergency action plans in case of possible failures.
20
Durieux, Johan Hendrik. "Development of a practical methodology for the analysis of gravity dams using the non-linear finite element method." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-06232009-152815/.
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Bliss, Michael A. "Procedures to Perform Dam Rehabilitation Analysis in Aging Dams." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33157.
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There are hundreds of existing dams within the State of Virginia, and even thousands more specifically within the United States. A large portion of these dams do not meet the current safety standard of passing the Probable Maximum Flood. Likewise, many of the dams have reached or surpassed the original design lives, and are in need of rehabilitation. A standard protocol will assist dam owners in completing a dam rehabilitation analysis. The protocol provides the methods to complete the hydrologic, hydraulic, and economic analysis. Additionally, alternative augmentation techniques are discussed including the integration of GIS applications and linear programming optimization techniques. The standard protocol and alternative techniques are applied to a case study. The case study includes a set of flood control dams located in the headwaters of the South River watershed in Augusta County, VA. The downstream impacts of the flood control dams on the city of Waynesboro are demonstrated through the hydrologic and hydraulic analysis.<br>Master of Science
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Chung, Kin-wah, and 鍾健華. "Plover cove dam building." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31981999.
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Chung, Kin-wah. "Plover cove dam building." Hong Kong : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?
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Whitten, Jordan. "The Boone Dam Project." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3585.
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The photographer discusses his work in “The Boone Dam Project”, a Masters of Fine Art exhibit held at the Tipton Gallery, Johnson City, Tennessee from March 18 through March 29, 2019. The exhibition consists of a collection of 14 large color archival inkjet prints from a large body of work that surveys a lakeside community’s landscape and residents affected by lowered lake levels during a dam repair. A catalog of the exhibit is included at the end of this thesis.
Whitten examines formal and conceptual influences through historical and contemporary photographers. Images included are works made by Robert Adams, Stephen Shore, Alec Soth, Susan Lipper. Influences outside of photography are discussed through literary works of Flannery O’Connor and Raymond Carver. Critical influence regarding landscape and human interactions is presented in regards to essays by J.B. Jackson.
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Pearson, Adam Jeffrey. "River response to dam removal: the Souhegan River and the Merrimack Village Dam, Merrimack, New Hampshire." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1333.
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Thesis advisor: Noah P. Snyder<br>The Souhegan River is a tributary of the Merrimack River that drains a 443 km2 watershed in southern New Hampshire. The lowermost barrier on the Souhegan River, the Merrimack Village Dam (MVD), was demolished and removed in August and September 2008. The modern MVD impoundment contained at least 62,000 m3 of sediment, mostly sand. Analysis of topographic and historical maps, and photographs suggests that approximately twice the area of what is now the modern impoundment has been affected by over 200 years of damming at the site. I use repeat surveys of cross sections and the river longitudinal profile, and sediment samples, to document the response of the Souhegan River to the MVD removal. A base level drop of 3.9 m caused immediate incision of the sand-sized sediment and channel widening. The impoundment later segmented into a non-alluvial, bedrock and boulder controlled reach; and a quasi-alluvial sand and gravel reach with erosion and deposition modulated by the presence of vegetation on the channel banks. One year after the removal, the Souhegan River has excavated 38,100 m3 (65%) of the sediment in the modern impoundment. The response of the Souhegan River was rapid and the channel and floodplain continue to evolve toward a quasi-equilibrium configuration. Continued response will be substantially influenced by the establishment of vegetation within the former impoundment and the magnitude and frequency of high discharge events<br>Thesis (MS) — Boston College, 2010<br>Submitted to: Boston College. Graduate School of Arts and Sciences<br>Discipline: Geology and Geophysics
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Ozbek, Selim Emre. "Numerical Modeling of Seepage in Koyunbaba Dam." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1512481079405287.
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Conlon, Maricate. "A Hindcast Comparing the Response of the Souhegan River to Dam Removal with the Simulations of the Dam Removal Express Assessment Model-1." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3318.
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Thesis advisor: Noah P. Snyder<br>Dam removal is a widely used river restoration technique. Historically, dams produced hydropower, controlled flooding, and provided water storage, but currently many dams in the United States, specifically low head dams in New England, are obsolete. This study aims to assess the ability of a simple morphodynamic sediment transport model, Dam Removal Express Assessment Model (DREAM-1), developed by Cui et al. (2006a). I compare simulations to a dam removal monitoring project that quantified the physical response of the Souhegan River to the removal of the Merrimack Village Dam (MVD), Merrimack, NH. Pearson et al. (2011) reported results of field monitoring from August 2007-May 2010 and found that the Souhegan River responded to dam removal in two phases: initial rapid incision of impoundment sediment induced by immediate base level drop of 3.9 m (~50% of impounded sediment eroded in ~2 months), followed by an event-driven phase in which impoundment sediment eroded primarily during floods. The reach downstream of the dam showed a similar two-phase response, with rapid deposition in the first three weeks after dam removal followed by bed degradation to the pre-removal elevation profile within a year. I have continued the field methods of Pearson et al. (2011) for the past two survey periods, June 2011 and July 2012. Using five years of comprehensive field data, I conduct a hindcast to compare the sediment erosion and deposition patterns predicted by DREAM-1 to the observed downstream response of the Souhegan River. I model the changes in bed elevation for the downstream and upstream channel reaches at intervals that correspond with the dates of four longitudinal profile surveys and seven annual cross-section surveys. Results of the hindcast show that DREAM-1 predicts channel elevation accurately within one meter and with average discrepancy of ±0.35 m when compared to average channel bed elevations of each cross-section. DREAM-1 successfully simulates two phases of upstream channel response, rapid impoundment erosion followed by a longer period of gradual sedimentation change. However, DREAM-1 erodes to base elevation within 11 weeks after dam removal (erosion of the 88% impoundment sand), leaving little sand for transport during the later survey periods. This overestimation of impoundment erosion is likely the product of limitations of the model, specifically the simplification of channel cross-sections with constant width throughout the simulation. The model assumes uniform lateral sediment transport in the impoundment and does not capture the variation in width due to incision and channel widening. This hinders the ability of the model to simulate some details of the sediment budget developed by Pearson et al. (2011) and extended with recent surveys<br>Thesis (MS) — Boston College, 2013<br>Submitted to: Boston College. Graduate School of Arts and Sciences<br>Discipline: Earth and Environmental Sciences
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Bledsoe, Lee Anne. "An Investigation of Groundwater Flow in the Vicinity of Patoka Dam, Indiana." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1539.
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Several dams throughout the United States have been built on karst terrains, where soluble limestone bedrock has been dissolved to form features such as caves, sinkholes, and underground rivers. In such karst regions, subsurface hydrology can play an integral role in the condition, operation, and safety of dams and should be considered during risk assessment. Patoka Dam, near Jasper, Indiana, is situated on a well-developed karst landscape/aquifer system, faces significant potential challenges, and recently underwent risk assessment. A groundwater flow investigation using multiple fluorescent tracer tests, analysis of water-table elevations, isopach mapping of the Glen Dean Limestone, and spring hydrograph analysis was performed to better understand local groundwater hydrology in the vicinity of the existing water-control structures. Dye-tracing results identified the local flow direction as south to north and the mean dye travel time from injection locations to Robert Hall Cave Spring (RHCS) as 8- 11 feet per hour. These results also indicate that groundwater is bypassing the control structures in the vicinity of the cut-off wall, but the geometry of these flow paths is not clear. The recharge area for RHCS, a significant groundwater discharge point downstream from Patoka Dam, was delineated and the existence of a groundwater divide in the area of the dike was confirmed. The location of this groundwater-basin boundary follows an estimation of where the Glen Dean Limestone outcrops along the perimeter of the dissected ridge that lies between Patoka Lake and RHCS. Spring hydrograph analysis shows that spring discharge is primarily influenced by local precipitation events. However, precipitation events can result in increased pool elevation making the relationship between spring discharge and pool elevation unclear within the data set. This groundwater investigation has provided a clearer characterization of the hydrogeology within the vicinity of Patoka Dam. In combining the various hydrogeologic results, some insight into the function and geometry of the local karst network that could potentially affect the integrity of the dam and/or dike structures has been provided.
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Ulgen, Deniz. "Dynamic Response And Permanent Displacement Analysis Of Akkopru Dam." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/1260461/index.pdf.
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In this study, dynamic response of Akkö<br>prü<br>Dam under earthquake motions is analyzed and the permanent displacements are evaluated. Initially, the critical slip surface of the dam and the corresponding yield acceleration are determined by using the computer program SLOPE. Then, by employing the finite element program SAP2000, static analyses are performed to obtain the mean effective stresses which are used in the determination of dynamic material properties of the dam. Four different scenario earthquakes having a magnitude of 7 are used in the dynamic analyses. Two of those scenarios are taken from European Strong Motion Database and the others are generated by XS artificial earthquake generation program prepared by Erdik (1992). Dynamic analyses of the dam are carried out by the finite element program TELDYN. Permanent displacements of the critical slip surface are calculated by utilizing the Newmark method. Consequently, for an earthquake having a magnitude of M=7 and a peak ground acceleration of 0.20g, the maximum permanent displacement of the dam is found to be 15.90 cm. Furthermore, the permanent displacements of the dam are calculated under base motions having different peak ground acceleration values and it is observed that the rate of increase in the amount of permanent displacements is greater than the increase in the amount of peak ground accelerations.
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Winker, Henning. "Post-impoundment population dynamics of non-native common carp Cyprinus Carpio in relation to two large native cyprinids in Lake Gariep, South Africa." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1005156.
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To contribute to the understanding of the invasion biology of common carp Cyprinus carpio in southern Africa, this thesis investigated the life history, relative abundance, long-term population demographics and trophic niche utilisations of non-native common carp C. carpio in relation to two endemic cyprinids, Orange River mudfish Labeo capensis and smallmouth yellowfish Labeobarbus aeneus in South Africa‟s largest impoundment, Lake Gariep. The growth zone deposition rates in astericus otoliths of the three species were validated as biannual for C. carpio and as annual for L. capensis and L. aeneus, which allowed for reliable estimation of lengths-at-age upon which growth, age-at-maturity and mortality rates could be estimated. Cyprinus carpio exhibited fast growth, matured relatively early at two years of age and attained a maximum age of seven years. Labeo capensis grew significantly slower, but attained older ages of up to 12 years. Females showed notably delayed maturation at approximately six years of age. The life history parameter estimates for L. aeneus were similar to those of L. capensis. These species-specific life history characteristics contributed to a substantially higher population growth potential of C. carpio compared to L. capensis and L. aeneus. Delta-lognormal and delta-gamma Generalized Linear Models (GLMs) were used to analyse patterns of relative abundance of L. capensis, L. aeneus and C. carpio. The application of these GLMs was necessary to account for large proportions of zeros and strong skewness in the catch-per-unit-effort (CPUE) from experimental gillnet and fisheries-dependent angler surveys. Confidence intervals around predicted abundance indices were obtained through the development of a generalised parametric bootstrap procedure. The resulting standardised abundance indices were coupled with results from analysis of stable isotope ratios of fish tissues and potential food resources and revealed that C. carpio was mainly confined to soft-bottom habitats, where it predominantly foraged on benthic invertebrates. Labeo capensis was abundant in a wide range of benthic habitats and was consumed basal food resources such as detritus. Labeobarbus aeneus was found to feed mostly on pelagic zooplankton. There were no significant interspecific differences in trophic niche space, suggesting limited resource competition among the three species. Standardised historical and contemporary gillnet CPUE data indicated slow population growth rates of L. capensis and L. aeneus during the first ten years postimpoundment, but showed high biomass levels some four decades after impoundment. These results could be corroborated by stochastic age-structured production model (ASPM) simulations. In contrast to the two endemic species, the gillnet CPUE of C. carpio showed a clear „boom and bust‟ pattern, which, based on ASPM simulations, could be best explained by increased food availability during the first five years postimpoundment, followed by suboptimal conditions thereafter. Together, these results provided evidence that the establishment of the C. carpio population did not prevent the slow but successful long-term establishment of the two large endemic cyprinids. Both endemic fishes revealed specialised feeding within the impoundment.
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Svensen, Daniel. "Numerical analyses of concrete buttress dams to design dam monitoring." Thesis, KTH, Betongbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189250.
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Old concrete buttress dams are sensitive to cracking if exposed to large temperature variations. The cracks can make dams sensitive to failure, depending on the size and location of the cracks. These problems can be overcome by lowering the temperature variations and stabilizing the dams. Insulation walls can be built to lower the temperature variations, and the area inside the insulation wall can be climate controlled to ensure a constant temperature. Stabilizing measures could be installing tendons, anchoring monoliths to the foundation or to keep parts of the monolith together. However, the best way to make sure the dam is functioning as expected is to monitor the behavior of the dam through different sensors. The sensors should be connected to some kind of dam monitoring software, which can indicate whether the dam is going to fail in a near future. For this to work, some kind of alert and alarm values has to be determined. The main purpose for this project is to develop a finite element model that could be used to simulate the real behavior of a concrete buttress dam and predict the future behavior of the dam. This makes it possible to determine alert and alarm values for monitoring equipment installed on the dam. Some steps are necessary to be able to create a finite element model representing the real behavior and to predict the future behavior of a dam. A first step is calibration of the model against real measurements, and during the calibration process it is important to evaluate the predictions made. A second step is to determine the normal variation in the behavior of the dam. A last step is to define suitable alert and alarm values, where the alert values are based on the normal variation of the dam and the alarm values are based on failure analyses. The results show that it is possible to calibrate a finite element model with sufficient accuracy in order for it to be used for predictions of the dams behavior. The results show two failure modes of the concrete buttress dam which deviate from previous research, where post-tensioned tendons were not included. From the results, information is given about where to place sensors to be able to capture a failure, how well the finite element model is calibrated, and what the alarm values should be. Furthermore, the results show that the evaluation of predictions made in the calibration process is of utmost importance to achieve a model representing the real behavior.<br>Gamla betonglamelldammar är känsliga för sprickbildning om de utsätts för stora temperaturvariationer. Sprickor kan göra dammarna känsliga för brott, beroende på storlek och placering av sprickorna. Dessa problem kan övervinnas genom att sänka temperaturvariationerna och stabilisera dammarna. Isoleringsväggar kan byggas för att sänka temperaturvariationerna, och området innanför isoleringsväggen kan klimatkontrolleras för att säkerställa en konstant temperatur. Stabiliserande åtgärder skulle kunna vara att installera spännkablar, förankring av monoliten till berggrunden eller att hålla ihop delar av monoliten. Emellertid är det bästa sättet att se till dammen fungerar som förväntat för att övervaka beteendet hos dammen genom olika sensorer. Givarna borde anslutas till någon form av programvara för dammövervakning, som kan indikera om dammen kommer att gå till brott inom en snar framtid. För att detta ska fungera måste någon form av mjuka och hårda larmvärden bestämmas. Huvudsyftet för detta projekt är att skapa en finit elementmodell som kan användas för att simulera det verkliga beteendet hos en betonglamelldamm och förutsäga framtida beteende av dammen för att kunna bestämma mjuka och hårda larmvärden för vald övervakningutrustning på dammen. Några steg är nödvändiga för att kunna skapa en finit elementmodell som representerar det verkliga beteendet och göra det möjligt att förutsäga det framtida beteendet av en damm. Ett första steg är kalibrering av modellen mot riktiga mätningar och under kalibreringsprocessen är det viktigt att utvärdera predikterade värden. Ett andra steg är att bestämma den normala variationen av dammens beteende. Ett sista steg är att definiera lämpliga värden för mjuka och hårda larmvärden, där de mjuka värdena baseras på dammens normala variation och de hårda larmvärdena på brottsanalyser. Resultaten visar att det är möjligt att kalibrera en finit elementmodell med tillräckligt god noggrannhet att den kan användas för prediktering av dammens beteende. Resultaten visar två brottmoder av betonglamelldammen som skiljer sig från tidigare studier där spännkablar inte hade inkluderats. Från resultaten ges information om var sensorer ska placeras för att kunna fånga ett brott, hur väl finita elementmodellen kalibrerats, och vilka de mjuka och hårda larmvärdena bör vara. Dessutom visar resultaten att utvärderingen av predikteringar som gjorts i kalibreringsprocessen är av yttersta vikt för att uppnå en modell som representerar det verkliga beteendet.
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Kanupreiya. "Analysis of gravity dam-foundation system for jointed rock foundations without and with shear seams." Thesis, IIT Delhi, 2019. http://eprint.iitd.ac.in:80//handle/2074/8055.
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Lejon, Anna G. C. "Ecosystem response to dam removal." Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-55586.
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This thesis aims to improve our understanding of how riverine ecosystems respond to dam removal. Riverine and particularly riparian ecosystems are among the most variable and important features of all landscapes. They connect landscape elements both longitudinally and laterally, and are governed by processes such as flooding, erosion and deposition that create dynamic, diverse and heterogeneous habitats. In fact, riparian zones are among the world’s most species-rich habitats. Worldwide there are millions of dams that fragment stream and river systems, regulate flows and degrade ecosystems. Dams impact freshwater, marine and terrestrial ecosystems and threaten biodiversity by disrupting organism movements and energy flows in the landscape. An important upstream effect of dams is inundation of habitats and development of new shorelines around impounded areas. Effects downstream of dams are mainly caused by changed hydrological regimes and retention of organic and inorganic materials in reservoirs, leading to reduced transport and dispersal of for example seeds to reaches downstream. The removal of dams create expectations that biota will eventually recover. We have studied a number of dam removal projects in Sweden. Our experimental results showed that following dam removal, newly exposed soils in former impoundments were rapidly colonized by pre-removal species. Their species richness increased slightly with time and their species composition indicated a slow change towards that in the reference site. In addition, the vegetation in formerly impounded areas showed a direction of change from lentic riparian plants (high proportion of aquatics) towards lotic ones, consisting of native perennials typical of free-flowing streams. We also found that the apprehensions that former impoundments would turn into pools of mud did not come true; in fact, a process towards more pristine channel morphology was observed. After removal there was erosion and downstream transport of sediment. We found only minor effects on macroinvertebrate communities. For example, a few species decreased over the years, suggesting that dam removal in itself might cause a temporary disturbance. This highlights the importance of long-term studies after dam removal, and also the importance of comparisons with pre-removal conditions and stretches unaffected by dams. Thorough documentation of executed dam removal projects and distribution of the results and experiences are tremendously important in the planning process of future decommissioning projects. Also, our experiences have taught us that in order to attain a successful dam removal it is important to involve stakeholders such as non-governmental organizations and local inhabitants in the process.
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Carlberg, Sofia, and Frida Andersson. "Skador inom dam- och herrishockeyn." Thesis, Karlstads universitet, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-33307.
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Baker, Raymond. "Concrete blocks for dam spillways." Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334011.
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Wu, Juliana S. B. Massachusetts Institute of Technology. "Characterizing the dam break release." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92213.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (page 41).<br>The failure of a dam can cause disastrous consequences, thus understanding the nature of a dam break is of utmost importance. A model of a dam break was built and used to profile the resulting wave. The gate release was characterized to check for consistency, maximum velocity, and it's profile. Matlab code was created to analyze both the gate speed and the wave velocity. The maximum velocity was 1503.2 cm/s and there a 30% deviation at most.The wave velocity was found to increase as the water reservoir height was increased. An equation was derived that had a 0.96 correlation coefficient thus proving that the relationship between velocity and reservoir height was accurate. Further research can be done using a cantilevered plate downstream of the dam break to analyze the forces generated.<br>by Juliana Wu.<br>S.B.
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Levin, Wendy. "Meeting at The Tellico Dam." Digital Commons at Loyola Marymount University and Loyola Law School, 1992. https://digitalcommons.lmu.edu/etd/644.
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Sawadogo, Ousmane. "Scour of unlined dam spillways." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5331.
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Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010.<br>ENGLISH ABSTRACT: The scour process of unlined spillways is an important research topic of value in engineering practice.
In South Africa numerous unlined spillway dams have experienced severe erosion. This led, in some
cases, to the costly concrete lining of spillways for erosion protection. On the other hand, the erosion
of unlined spillways can lead to damage to, and even failure of dams and consequently can affect public
safety, properties, infrastructure and the environment. In this regard, methods to predict erosion of
unlined spillways are therefore needed as tools in the risk management and design of existing unlined
spillways as well as future spillway structures.
The prediction of the rock scouring process is challenging and empirical formulas have been established
to predict incipient conditions for scour. These empirical methods however do not predict the rate of
scour or the ultimate equilibrium rock scour.
The key objective in this study was to investigate the applicability of a non-cohesive two-dimensional
(2D) sediment transport hydrodynamic mathematical model to simulate unlined spillway scour. A
physical model flume test was set up to simulate rock scour represented by uniformly sized polyethylene
cubes. The flume slope and discharge were varied in the different test scenarios. The 2D mathematical
model correctly predicted the extent and location of scour as observed in the laboratory tests. Temporal
changes in the scour formation were also predicted with reliability. This was achieved by only calibrating
the hydraulic roughness of the 2D model, and by specifying the ”rock ” particle settling velocity and
material density. The simulation results were satisfactory, providing an accurate and detailed erosion
prediction. From this, the mathematical modelling was validated by using a field case study.
The results obtained with the mathematical model were promising for non-cohesive cases and could be
applied to field prototype cases if the rock joint structure is known. This would typically apply in fault
zones, where the joints would give an idea of the rock size to be used in the mathematical model. In
general, where jointed rock is more massive and acts ”cohesive ”, rock parameters describing critical
scour conditions for the rock in terms of stream power are required to be built into the mathematical
models.<br>AFRIKAANSE OPSOMMING: Die uitskuringsproses van onbelynde oorlope is ’n belangrike navorsingsonderwerp in die ingenieurspraktyk.
In Suid-Afrika word ernstige erosie in baie onbelynde oorlope van damme ondervind. In sommige
gevalle het dit gelei tot die duur belyning van oorlope met beton, om die oorlope te beskerm. Aan die
anderkant kan die erosie van onbelynde oorlope lei tot groot skade en selfs tot die faling van ’n dam. Dit
kan weer lei tot skade aan eiendom, infrastruktuur en die omgewing, en die publiek in die gevaar stel.
Daarom is dit nodig dat daar besin word oor metodes om erosie in onbelynde oorlope te voorspel, sodat
die risiko bestuur kan word en om te sorg vir die beter ontwerp van onbelynde oorlope in die toekoms.
Dit is moeilik om die uitskuringsproses te voorspel, maar empiriese formules is bestaan om die aanvang
van uitskuring te voorspel. Hierdie empiriese metodes voorspel egter nie die snelheid waarteen die
uitskuring sal plaasvind of die uiteindelike mate waartoe dit sal gebeur nie.
Die hoofdoelwit van hierdie studie was om die toepasbaarheid van ’n nie- kohesie, twee-dimensionele
(2D) hidrodinamiese wiskundige model te ondersoek, om sodoende die uitskuring van onbelynde oorlope
te simuleer. ’n Fisiese model om die uitskuring van rots te simuleer is ook gebou. Die rots is deur polietileen
blokkies van dieselfde grootte gemodelleer. Verskillende kanaalhellings en deurstromings is in
verskillende toetse gebruik. Die 2D wiskundige model het volgens die waarnemings in laboratorium
toetse, die mate en ligging van die uitskuring korrek voorspel. Veranderinge wat met verloop van tyd in
die uitskuring formasie plaasgevind het, is ook betroubaar voorspel. Dit is gedoen deur die hidrouliese
ruheid van die 2D model te kalibreer en deur te spesifiseer hoe vinnig die ”rots ” deeljies afsak en wat die
digtheid van die materiaal is. Die uitslag van die simulasie was bevredigend en het die erosie akkuraat
en in detail voorspel. Die wiskundige modellering is gevalideer deur middel van ’n gevallestudie.
Die uitslae wat met die wiskundige model verkry is, is belowend, en geld vir nie-kohesie gevalle. Dit kan
op prototipe gevalle in die veld toegepas word as die rots se naatstruktuur bekend is. Dit kan toegepas
word in foutsones waar die nate ’n aanduiding sal gee van die grootte van ”rotse ” wat in die wiskundige
model gebruik moet word. Maar as die rots baie groot is en die kohesie goed is, is dit nodig om meer
parameters betreffende uitskuringstoestande gekoppel aan stroomdrywing, in die wiskundige model te
gebruik.
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Fontana, Ilaria. "Interface problems for dam modeling." Thesis, Université de Montpellier (2022-….), 2022. http://www.theses.fr/2022UMONS020.
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Les équipes d’ingénierie ont souvent recours aux simulations numériques par éléments finis pour étudier et analyser le comportement des ouvrages hydrauliques de grande dimension. Pour les ouvrages en béton, les modèles doivent être en mesure de prendre en compte le comportement non-linéaire des discontinuités aux diverses zones d’interfaces localisées en fondation, dans le corps du barrage ou à l’interface entre la structure et la fondation. Il faut non seulement être capable de représenter le comportement mécanique non-linéaire de ces interfaces (rupture, glissement, contact), mais également de prendre en compte l’écoulement hydraulique à travers ces ouvertures.Dans le cadre de cette thèse, nous nous focalisons d’abord sur la question du comportement des interfaces, que nous abordons à travers le modèle des zones cohésives (CZM). Ce dernier, introduit dans divers codes de calcul par éléments finis (avec éléments finis de joint), est une approche pertinente pour décrire la physique des problèmes de fissuration et de frottement au niveau de discontinuités géométriques. Bien que le CZM a été initialement introduit pour prendre en compte que le phénomène de rupture, nous montrons dans cette thèse que son utilisation peut être étendue aux problèmes de glissement en s'appuyant sur le formalisme élasto-plastique éventuellement couplé à l'endommagement. En outre, des lois de comportement hydromécaniques non-linéaires peuvent être introduites pour modéliser la notion d’ouverture de fissure et le couplage avec les lois d’écoulement fluide. Au niveau mécanique, nous travaillons dans le cadre des matériaux standard généralisés (SGM), qui fournit une classe de modèles qui satisfont d’une manière automatique des principes de la thermodynamique tout en possédant des bonnes propriétés mathématiques utiles pour la modélisation numérique robuste. Nous adaptons le formalisme SGM volumique à la description des zones d'interface. Dans cette première partie de la thèse, nous présentons nos développements faites dans l'hypothèse de SGM adaptée aux CZM, capable de reproduire les phénomènes physiques observés expérimentalement : rupture, frottement, adhésion.En pratique, les non-linéarités du comportement des zones d’interface sont dominées par la présence de contact, ce qui engendre des difficultés numériques importantes pour la convergence des calculs par élément fini. Le développement de méthodes numériques efficaces pour le problème de contact est donc une étape clé pour atteindre l’objectif de simulateurs numériques industriels robustes. Récemment, l’utilisation de techniques d’imposition faible des conditions de contact à la Nitsche a été proposée comme moyen pour réduire la complexité numérique. Cette technique présente plusieurs avantages, dont les plus importants pour nos travaux sont: 1) possibilité de gérer une vaste gamme de conditions (glissement avec ou sans frottement, non interpénétration, etc); 2) la technique se prête à une analyse d'erreur a posteriori rigoureuse. Ce schéma basé sur les conditions d’interface faibles représente le point de départ pour l’estimation d’erreur a posteriori par reconstruction équilibrée de la contrainte. Cette analyse est utilisée pour estimer les différentes composantes d’erreur (p.e., spatiale, non-linéaire), et pour mettre en place un algorithme de résolution adaptatif, ainsi que des critères d’arrêt pour les solveurs itératifs et le réglage automatique d’éventuels paramètres numériques.L'objectif principal de la thèse est donc de rendre robuste la simulation numérique par éléments finis des ouvrages présentant des discontinuités géométriques. On aborde cette question sous angle double : d’un côté on revisite les méthodes existantes de représentation de fissuration en travaillant sur la loi de comportement mécanique pour les joints ; de l’autre on introduit une nouvelle méthode a posteriori pour traiter le problème de contact et propose son adaptation pour les modèles d’interfaces génériques<br>Engineering teams often use finite element numerical simulations for the design, study and analysis of the behavior of large hydraulic structures. For concrete structures, models of increasing complexity must be able to take into account the nonlinear behavior of discontinuities at the various interfaces located in the foundation, in the body of the dam or at the interface between structure and foundation. Besides representing the nonlinear mechanical behavior of these interfaces (rupture, sliding, contact), one should also be able to take into account the hydraulic flow through these openings.In this thesis, we first focus on the topic of interface behavior modeling, which we address through the Cohesive Zone Model (CZM). This model was introduced in various finite element codes (with the joint elements), and it is a relevant approach to describe the physics of cracking and friction problems at the geometrical discontinuities level. Although initially the CZM was introduced to take into account the phenomenon of rupture, we show in this thesis that it can be extended to sliding problems by possibly relying on the elasto-plastic formalism coupled to the damage. In addition, nonlinear hydro-mechanical constitutive relations can be introduced to model the notion of crack opening and the coupling with the laws of fluid flow. At the mechanical level, we work in the Standard Generalized Materials (SGM) framework, which provides a class of models automatically satisfying some thermodynamical principles, while having good mathematical and numerical properties that are useful for robust numerical modeling. We adapt the formalism of volumetric SGM to the interface zones description. In this first part of the thesis, we present our developpements under the hypothesis of SGM adapted to CZM, capable of reproducing the physical phenomena observed experimentally: rupture, friction, adhesion.In practice, nonlinearities of behavior of interface zones are dominated by the presence of contact, which generates significant numerical difficulties for the convergence of finite element computations. The development of efficient numerical methods for the contact problem is thus a key stage for achieving the goal of robust industrial numerical simulators. Recently, the weak enforcement of contact conditions à la Nitsche has been proposed as a mean to reduce numerical complexity. This technique displays several advantages, among which the most important for our work are: 1) it can handle a wide range of conditions (slip with or without friction, no interpenetration, etc.); 2) it lends itself for a rigorous a posteriori error analysis. This scheme based on the weak contact conditions represents in this work the starting point for the a posteriori error estimation via equilibrated stress reconstruction. This analysis is then used to estimate the different error components (e.g., spatial, nonlinear), and to develop an adaptive resolution algorithm, as well as stopping criteria for iterative solvers and the automatic tuning of possible numerical parameters.The main goal of this thesis is thus to make the finite element numerical simulation of structures with geometrical discontinuities robust. We address this question from two angles: on one side, we revisit the existing methods for the crack representation working on the mechanical constitutive relation for joints; on the other, we introduce a new a posteriori method for the contact problem and we propose its adaptation for the generic interface models
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Nilsson, Isak, and Leonard Sandström. "Behavior prediction of concrete dams." Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289385.
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As many dams were built around 1950, the expected life span of these dams are about tobe reached. With this, the need for monitoring and increased understanding of the damsstructural integrity increases. In order to prevent failures, two warning signals are defined;alert and alarm. The main difference being that the first indicates an unexpected changein behavior that needs to be addressed and evaluated in the near future, while the otherrequires that immediate action must be taken to ensure the safety of the dam.This report aims to evaluate the applicability of different models for designing alert values.In order to achieve this goal, two case studies have been performed. The first being onSchlegeis, an arch dam in Austria, and the second Storfinnforsen, a concrete buttress damin Sweden. The methods used are finite element modelling as well as data-based models.Data-based models work on the presumption that the dam behaviour is governed by variationsin environmental conditions such as temperature and water level. The report hasevaluated two commonly used data-based models, hydrostatic thermal time (HTT) and hydrostaticseasonal time (HST), as well as two machine learning based models artificial neuralnetworks (ANN) and boosted regression trees (BRT).The programs used in this report are BRIGADE plus for finite element method and MATLABfor the multi-linear regression analyses HTT and HST, as well as boosted regressiontrees. The neural networks were constructed in Python using TensorFlow and Keras API.The result from the case studies is that the commonly used data-based models HST andHTT perform well enough for creating predictions and alert levels when given a sufficientamount of historical data, approximately 3-5 years. Machine learning such as artificial neuralnetworks while comparable in prediction quality does not further increase the understandingof the dam behaviour and can due to the complexity of designing an appropriate networkstructure be less suited for this type of analysis. Finite element models can also capturethe behavior of the dam rather well. It is however not as accurate as data-based modelswhen sufficient data is available. An FE-model should be used for definition of alert valueswhen insufficient data exists after the dam conditions have been significantly altered, orwhen newly constructed. The main advantage that machine learning provides is that theyperform better for non-linear behavior than multi-linear regression.
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Cheng, Fang. "Sediment transport and channel adjustments associated with dam removal." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1110384150.
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Thesis (Ph. D.)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains xiv, 99 p.; also includes graphics. Includes bibliographical references (p. 91-94). Available online via OhioLINK's ETD Center.
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Bramsäter, Jenny. "Closure of Lilla Bredsjön Tailings Dam : an Evaluation of the Long-Term Dam Safety Measures." Thesis, KTH, Vattendragsteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210320.
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The mining industry contributes to enormous amounts of waste all over the world, which places high demands on tailings dams. In Sweden, there are strict regulations regarding the management and treatment of tailings dams, but some dams that were built before these regulations existed still pose a threat to the environment. Lilla Bredsjön in Dalarna, Sweden, is an example of an old tailings dam that has not been treated properly. Boliden, which is the owner of the dam, and the county board of Dalarna are currently in meetings regarding the responsibilities of old polluted sites in Garpenberg, where Lilla Bredsjön is included. This study aims to investigate possible remediation measures of the dams at Lilla Bredsjön in order to achieve long- term stability upon closure of the facility. Lilla Bredsjön is 350 000 m2 large and contains three impoundments; dam 1 to the east, dam 2 to the south and dam 3 to the north. Dam 1 is seven meters at its highest point whereas dam 2 and 3 both are three meters high. All of the dams are classified to a consequence level of 3, meaning that the consequences in case of a failure would be negligible. They are built using the centerline method with impermeable cores of moraine. The tailings are partly covered with sludge mixed with biomass ash, but no proper closure method have been implemented. A geotechnical investigation was conducted to obtain more information about the geometry, construction and foundation of each dam. It could be observed that dam 1 consisted of a moraine core and support fill, both constructed using the Christmas tree principle. Dam 2 consisted of a coarse and fine filter in the upstream part of the dam, whereas the rest of the dam consisted of a moraine core. Dam 3 consisted of tailings and a moraine core, and was like dam 1 also constructed using the Christmas tree principle. The downstream slopes of all dams are moreover very steep with slope angles of approximately 34o. Seepage and stability calculations were therefore performed in the software GeoStudio. In GeoStudio, two different analysis tools were used; SEEP/W to calculate seepage and SLOPE/W to calculate slope stability. Four hydraulic load cases were analyzed in the calculations: present conditions, flooded conditions, potential maximum seepage and present conditions with lower permeability of the tailings. The result shows that all of the dams are unstable in their present con- ditions, both with original and lower permeability of the tailings, as well as at flooded conditions. The required safety factor is however fulfilled at potential maximum seepage. The stability highly depends on the pore pressure inside the dams, which in turn depends on the choice of closure method. Based on the result from the stability calculations it can be concluded that if a dry cover is chosen as the closure method, it will probably be enough to reinforce the existing dams to achieve long-term stability. If, on the other hand, a raised groundwater level is chosen, more extensive solutions in terms of for example completely new impoundments directly downstream of the existing ones are most likely needed. Before a decision regarding the closure method is taken, it is hence very difficult to come to a conclusion regarding suitable remediation measures of the dams.<br>Gruvindustrin bidrar med enorma mängder avfall över hela världen, vilket ställer höga krav på gruvdammar. I Sverige finns det strikta förordningar gällande hanteringen och efterbehandlingen av gruvdammar, men en del dammar som byggdes innan dessa förordningar existerade utgör fortfarande ett hot mot miljön. Lilla Bredsjön i Dalarna är ett exempel på en gammal gruvdamm som inte blivit efterbehandlad tillräckligt. Boliden, som äger dammen, har möten med Länsstyelssen Dalarna angående ansvarsförhållanden gällande gamla förorenade områden i Garpenberg där även Lilla Bredsjön ingår. Denna studie syftar till att undersöka möjliga efterbehandlingsmetoder av dammarna vid Lilla Bredsjön för att uppnå långtidsstabilitet i samband med nedläggning av anläggningen. Lilla Bredsjön är 350 000 m2 stor och består av tre uppdämningar; damm 1 i öst, damm 2 i söder och damm 3 i norr. Damm 1 är sju meter som högst medan damm 2 och 3 båda är tre meter höga. Samtliga dammar är klassificerade till konsekvensklass 3, vilket betyder att konsekvenserna i händelse av ett dammbrott är försumbara. Dammarna är byggda med uppåtmetoden och har tätkärnor av morän. Magasinet är delvis täckt med slam utblandat med biobränsleaska, men ingen riktig efterbehandling har utförts. En geoteknisk undersökning genomfördes för att erhålla mer information om geometrin, konstruktionen och grundläggningen av varje damm. Det observerades att damm 1 består av en tätkärna av morän samt stödfyllning som båda konstruerades med julgransprincipen. Damm 2 består av ett grov- och finfilter i uppströmsdelen av dammen medan resten av dammen består av en tätkärna av morän. Damm 3 består av anrikningssand och en tätkärna av morän, och var liksom damm 1 konstruerad med julgransprincipen. Nedströmsslänterna på alla dammar är väldigt branta med en vinkel på ungefär 34o. Genomströmnings- och stabilitetsberäkningar genomfördes därför i programmet GeoStudio. I GeoStudio användes två olika verktyg; SEEP/W för att beräkna genomströmning och SLOPE/W för att beräkna släntstabilitet. Fyra olika hydrauliska belastningsfall analyserades i beräkningarna: normalfallet, överdämning, dimensionerat läckage och normalfallet med lägre permeabilitet på anrikningssanden. Resultatet visar på att samtliga dammar är instabila i deras nuvarande skick, beräknat på normalfallet med både ursprunglig och lägre permeabilitet på anrikningssanden, samt vid överdämning. Den erforderliga säkerhetsfaktorn är däremot uppfylld vid dimensionerat läckage. Stabiliteten är starkt beroende av portrycket inuti dammarna, vilket i sin tur är beroende av vilken efterbehandlingsmetod som väljs för magasinet. Baserat på resultatet från stabilitetsberäkningarna kan det konstateras att om torrtäckning väljs som efterbehandlingsmetod så räcker det förmodligen med att förstärka nuvarande dammar för att uppnå långtidsstabilitet. Om, å andra sidan, en förhöjd grundvattennivå väljs behövs med största sannolikhet en mer omfattande lösning, till exempel helt nya dammar direkt nedströms de nuvarande. Innan ett beslut gällande efterbehandlingsmetod av magasinet har tagits är det alltså väldigt svårt att dra en slutsats gällande den mest lämpliga efterbehandlingsmetoden av dammarna.
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McMullen, Thomas M. "The St. Francis Dam collapse and its impact on the construction of the Hoover Dam." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1672.
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Thesis (M.S.) -- University of Maryland, College Park, 2004.<br>Thesis research directed by: Dept. of Civil and Environmental Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Wästlund, Dag. "Progressive failure research on foundation surface of the Longtan gravity dam." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-161213.
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The most common failure of concrete gravity dams is sliding along the foundation surface. This thesis studies progressive failure of the Longtan dam on the upper Hongshuie river in china.Two methods are used in this thesis; the Safety Reserve Factor (SRF) method and the Overload method. The SRF-method is used as a tool to study sliding failure along the foundation weak layer of the Longtan dam. Strength reduction coefficients decrease the cohesion and friction angle values for the weak layer of the foundation. Simulations with reduced shear strength parameter values gives information about the development of the plastic zone. The ultimate bearing resistance and the failure path along the foundation are obtained. The safety reserve coefficient is established through the strength reduction coefficients, when the plastic zone of the foundation is totally coalescent. To analyse the development of the plastic zone along the dam foundation with the strength reserve method, the commercial finite element software MSC.Marc is used. The results of the Safety Reserve Factor method (SRF) show that the failure of the dam is highly related to the strength of the interface between the dam and rock foundation. The strength reserve factor is determined to 2.4. The Overload method gives a visual deformation shape of the dam structure and pressure load at the moment of failure.<br>Dammar har används i mer än 5000 år (Yang et al. 1999) och är fortfarande en viktig källa för energiutvinning. Det största antalet dammar finns i Kina och man tror att det finns över 80,000 dammar i landet (Shapiro 2001). En ökning av dammars kapacitet och antal sker, vilket resulterat i ett behov av bättre sätt för att utvärdera säkerhetsparametrar som betongkvalité, styvhet och homogenitet av bergmassa. Simuleringar av dammkonstruktioner kan ge värdefull information om dessa parametrar och kan därigenom bidra till att förbättra en damms stabilitet och sänka konstruktionskostnader. I det här examensarbetet utvärderas och modelleras Longtan dammen i övre Hongshui floden i Kina. Den vanligaste orsaken till haveri av betongdammar är glidning mellan betonglager och bergmassan. I den här rapporten simuleras ett svagare lager mellan betong och bergmassa och utvecklingen av kontaktbrottsvägen visualiseras och utvärderas med progressiva haveri metoden. Det svagare lagrets hållfasthetskoefficienter; friktionsvinkel och kohesion, reduceras för att analysera utbredningen av den plastiska zonen. Resultaten visar att en överskridning av draghållfastheten för betong börjar vid dammens häl och att kompressionsbristningsgränsen överskrids vid dammens tå när hållfasthetskoefficienterna reduceras. Säkerhetsreservskoefficienten för Longtan dammen erhålls då gränsytan mellan betong och berg är helt plastisk. För att analysera utbredningen av den plastiska zonen längs med dammfundamentet med progressiva haveri metoden används den kommersiella finita element mjukvaran MSC.Marc. Resultaten från säkerhetskoefficientfaktormetoden visar att ett haveri av gravitations dammar är i hög grad relaterad till hållfastheten mellan betongen och bergets gränsyta. Säkerhetskoefficientfaktorn bestäms till 2.4. För att bestämma Longtan dammens maximala vattenbelastningskapacitet används Överbelastningsmetoden. Det maximala vattentryck som Longtan dammen klarar av utan att haverera simuleras med hjälp av en vätska vars densitet ökas mellan modellkörningar. Dammens förskjutning når till sist en punkt där den ökar kraftigt och dammens mutationsdeformationstillstånd har uppnåtts. En visuell deformationsbeskrivning av dammen ges genom modellkörningar och överbelastningsfaktorn bestäms.
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Andersson, Joel, and Ludvig Hagberg. "Stability Analysis of High Concrete Dams : Longtan Dam - a case study." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67719.
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Desmond, Marissa Grace. "Damn the city, dam the suburbs : redefining the single family home." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57510.
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Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>"February 2010." Cataloged from student submitted PDF version of thesis.<br>Includes bibliographical references (p. 158).<br>Today, we no longer realize public perception of home ownership in the United States is primarily shaped by government sponsored programs. In the 1940's, however, it was these programs that created a change in the options for where to buy homes. What was previously the country became a place to live. Starting with the upper classes of society, white Americans began leaving the city for the suburbs. Buying a home, or investing in a future home through the purchase of war bonds, was a patriotic duty. With money from the GI Bill, developments like Levittown made it easy for Americans to invest in this government "propaganda." Much like the "white flight" of the 1940's, numerous upper class families are relocating to now up and coming neighborhoods within the city; the direction is reversed, the effect is the same. If we take it as a given that this gentrification of the city is the first step in the "white flight" of today, we can hypothesize that the rest of suburbia is bound to follow. This thesis proposes that community based housing projects, located in the inner towns surrounding cities, be recast as a new alternative to the suburban detached single family home. In light of the 2008 housing crash, numerous Americans are no longer able to afford their homes in either the suburbs or the city. With rents in the cities so high, and bound to go higher with the current demand, a two-bedroom apartment may be all some families can afford. However, two bedrooms in city are not an acceptable alternative to today's equally unaffordable suburban detached reality. Through the government sponsored programs of today and a focus on community living, a new housing type can emerge to re-house those displaced by today's housing crisis.<br>by Marissa Grace Desmond.<br>M.Arch.
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Charatpangoon, Bhuddarak. "SEISMIC SAFETY EVALUATION OF EARTH DAM AND POSSIBLE REHABILITATION METHODS." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/192169.
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Ferrari, Carla Rolim. "Avaliação de efeitos ambientais de efluentes radioativos de mineração de urânio sobre as características físicas, químicas e diversidade da Comunidade Zooplanctônica na Unidade de Tratamento de Minérios, Represa das Antas e Represa Bortolan, Poços de Caldas (M.G)." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-24032011-160237/.
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A represa das Antas e represa Bortolan fazem parte da Sub-Bacia Hidrográfica do Ribeirão das Antas, sendo que a primeira sofre impacto de uma mineradora de urânio (UTM/INB), uma vez que recebe despejos de efluentes radioativos tratados procedentes de DAM, já a represa Bortolan recebe maior influência da malha urbana de Poços de Caldas. O objetivo do presente estudo foi analisar a diversidade da comunidade zooplanctônica, bem como realizar a caracterização física e química da UTM/INB e represas das Antas e Bortolan. Diferenças em relação às condições físicas, químicas e a comunidade foram verificadas entre os ambientes. Na UTM/INB as condições químicas da água apresentaram-se não favoráveis ao desenvolvimento do zooplâncton. A represa das Antas apresentou condições ambientais intermediárias entre a UTM/INB e represa Bortolan, devido provavelmente ao lançamento de efluentes em condições inadequadas pela UTM/INB. Na represa Bortolan as concentrações de nutrientes e clorofila a explicaram a maior densidade e, portanto, a maior diversidade das espécies zooplanctônicas.<br>The Antas and Bortolan Dams are part of the Ribeirão das Antas Hydrographical Sub-Basin, being that the Antas Dam suffers impact from a uranium mining (UTM/INB), once it receives discharges of treated radioactive effluents derived from DAM, while Bortolan Dam suffers greater influence from the urban area of Poços de Caldas. The objective of the current study was to analyze the zooplanktonic community\'s diversity, as well as to perform the physical and chemical characterizations of UTM/INB and Antas and Bortolan Dams. Differences related to the physical and chemical conditions and the community were verified among the environments. In UTM/INB, the water\'s chemical conditions were not favorable to zooplankton development. The Antas Dam presented intermediate environmental conditions between UTM/INB and Bortolan Dam, probably due to the release of effluents in inadequate conditions, done by UTM/INB. In Bortolan Dam, the concentrations of nutrients and chlorophyll a have justified the higher density and thus, the greater diversity of zooplanktonic species.
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Korkmaz, Seda. "Evaluation Of Concrete Face Rockfill Alternative For Dam Type Selection: A Case Study On Gokceler Dam." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610572/index.pdf.
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In this study a recent dam type, concrete face rockfill dam (CFRD), its design and behaviour is overviewed. The design features of Gö<br>kç<br>eler Dam are introduced as a case study. Selection of concrete face rockfill type for Gö<br>kç<br>eler Dam Project is discussed together with the other two alternatives, namely earth core rockfill (ECRD) and roller compacted concrete (RCC) dam. Gö<br>kç<br>eler Dam type selection as concrete face rockfill dam is also verified by an economic analysis conducted calculating internal rate of return for all alternative types. In cost analysis a currency independent defined unit cost (DUC) is specified to verify the time independent validity of the economic analysis.
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Pimentel, Torres Gaspar Ana Patricia. "Contribution to control uncertainties in numerical modelling of dam performances : an application to an RCC dam." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2014. http://www.theses.fr/2014ECAP0053/document.
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L’application des approches probabilistes pour tenir compte des incertitudes dans le domaine des barrages est un sujet en développement. Cependant, la plupart des études ont été réalisées sur l’évaluation de la sécurité des barrages pendant leur service. Ce travail de thèse vise à appliquer ce type d’approches et à faire une contribution à l’analyse de risque des barrages en béton compacté au rouleau (BCR) d`es sa construction, à l’aide d’une simulation numérique. Les travaux présentés dans ce manuscrit proposent l’application d’une méthodologie qui vise à quantifier la vulnérabilité vis-à-vis de l’apparition de la fissuration pendant la construction du barrage, ce qui peut affecter `a long-terme la perméabilité et par conséquent, compromettre son comportement structurel. Pour ce faire, l’accent est mis sur les incertitudes liées à quelques caractéristiques des matériaux (e.g., résistance, rapport eau-ciment, entre autres) et aux conditions environnementales pendant la phase de construction. Un modèle thermo-chemo-mécanique est utilisé pour décrire le comportement du BCR. En ce qui concerne le modèle probabiliste, deux aspects sont étudiés: i) comment les incertitudes liées aux variables d’entrée sont propagées dans le modèle, et ii) quelle est l’influence de leur dispersion par rapport à la dispersion totale de la sortie. Ce dernier est évalué par l’intermédiaire d’une analyse de sensibilité globale effectuée avec la méthode RBD-FAST. En outre, la variabilité spatiale des paramètres d’entrée est aussi prise en compte à travers des champs aléatoires bidimensionnels. Par ailleurs, un couplage entre des méthodes de fiabilité et la méthode d’éléments finis est effectué de façon à évaluer le potentiel de fissuration dans chaque couche de BCR lors de sa construction en utilisant un concept de densité de fissuration. Comme résultat important issu de ce travail de recherche, des courbes de probabilité pour la densité de fissuration sont obtenues au niveau de chaque couche en fonction de leur âge et des conditions aux limites, ce qui est considérée comme étant une contribution originale de cette thèse.La méthodologie proposée peut être utilisé pour aider à comprendre comment les incertitudes vont affecter le comportement du barrage pendant sa construction et servir d’appui dans le futur pour améliorer et soutenir la phase de conception du projet de barrage<br>The use of fully probabilistic approaches to account for uncertainties within dam engineering is a recently emerging field on which studies have been mostly done concerning the safety evaluation of dams under service. This thesis arises within this framework as a contribution on moving the process of risk analysis of dams beyond empirical knowledge, applying probabilistic tools on the numerical modelling of a roller compacted concrete (RCC) dam during its construction phase.The work developed here aims to propose a methodology so as to account for risks related to cracking during construction which may compromise the dam’s functional and structural behaviour.In order to do so, emphasis is given to uncertainties related to the material itself (i.e.strength, water-to-cement ratio, among others) as well as to ambient conditions during the construction phase of RCC dams. A thermo-chemo-mechanical model is used to describe theRCC behaviour. Concerning the probabilistic model, two aspects are studied : how the uncertainties related to the input variables are propagated through the model, and what is the influence of their dispersion on the dispersion of the output, assessed by performing a global sensitivity analysis by means of the RBD-FAST method. Also, spatial variability of some input parameters is accounted for through bi-dimensional random fields. Furthermore, a coupling between reliability methods and finite element methods is performed in order to evaluate the cracking potential of each casted RCC layer during construction by means of a cracking density concept. As an important outcome of this applied research,probability curves for cracking density within each casted layer as functions of both age and boundary conditions are predicted, which is believed to be an original contribution of this thesis. The proposed methodology may therefore be seen as a contribution to help engineers understand how uncertainties will affect the dam behaviour during construction and rely on it inthe future to improve and support the design phase of the dam project