The Finite Element and Boundary Element Methods are both well established numerical techniques for analysing a wide range of engineering problems. In the present thesis these numerical techniques are used for obtaining a more realistic picture of various characteristics of concrete gravity dams. The present work addresses the behaviour of gravity dams under static loading, and the developed analysis procedure/computer package can cater for a wide range of dam characteristics including: the three-dimensional behaviour of a gravity dam-foundation-abutments system; the non-linear behaviour of a dam and foundation materials; the sequential construction of a dam and impounding of the reservoir loading on the structure; the effect on stresses of interfaces and joints existing between a dam and its foundation, and in the body of a dam itself; the action of pore water pressure within the foundation, at the dam-foundation interface, and in the body of a gravity dam; etc. Using the purpose written computer package which can cater (in an efficient and accurate way) for the influence of all such factors, mathematical programming methods are, then, used to produce a powerful tool for the shape optimisation of gravity dams leading to safe, functional and economical solutions to the problem. In the course of developing the computer program, much care has been exercised as regards the appropriate selection of the finite element types, mesh configurations and mesh densities, in order to reflect (in an efficient fashion) the variation of stress gradients in the body of a gravity dam. In order to reduce high costs associated with a full three-dimensional analysis, a rather efficient method is developed which enables one to carry out equivalent twodimensional computer runs which will effectively simulate the actual three-dimensional behaviour of gravity dams in, for example, narrow valleys. The proposed approach reduces the dimensionality of an actual problem by one, thus, eliminating the main disadvantage of the finite element method in terms of high solution costs for threedimensional problems. As a result, the proposed method makes the solution procedure highly cost effective. By coupling the finite element-boundary element (FEBE) techniques, which can cater for the material non-linearities in the appropriate regions of the foundation, an attempt is made to by-pass the individual disadvantages of both these numerical techniques. It has, then, been possible to exploit the advantages of reducing the dimensionality of the foundation region by one using the boundary element technique, and, hence, come up with significant savings in terms of computer running times. Anisotropic tangent constitutive models for plain concrete under a general state of biaxial static monotonic loading for, both, plane-stress and plane-strain states of stresses are proposed which are simple in nature, and use data readily available from uniaxial tests. These models have been implemented into the computer program which is, then, used to investigate the influence of the step-by-step construction of the dam and the sequential impoundment of the reservoir loading on the state of stresses. The non-linear program is also used to analyse various characteristics of Bratsk concrete gravity darn (in Russia). The correlations between the numerical results and extensive field measurements on this darn, have been found to be encouraging. Isoparametric quadratic interface finite elements for analysing the darnfoundation interaction problem have also been developed. These elements have zero thickness and are based on an extension of the linear interface elements reported by others. The numerical problems of ill-conditioning (usually associated with zero thickness elements) are critically investigated using test examples, and have been found to be due to inadequate finite element mesh design. Non-linear elastic tangent constitutive models for simulating the shear stress-relative displacement behaviour of interfaces have also been developed, and are used to analyse the effects of including interface elements at the dam-foundation region of contact. It is shown that the inclusion of interface elements in the numerical analyses of the dam-foundation system leads to rather significant changes in the magnitudes of the critical tensile stresses acting at the heel of the dam, which have previously been evaluated (by others) using a rigid dam-foundation interconnection scheme. Effects of pore water pressure, acting as a body force throughout the foundation, the dam-foundation interface and the body of a gravity dam, are also critically studied, with the pore pressure values predicted by seepage analysis. Using an extensive set of numerical studies, a number of previously unresolved issues as regards the influence of pore pressures on the state of stresses are clarified. The effect of drainage on the state of stresses within the body of a dam is investigated, and an insight is also given into the effect of the uplift acting at the lift lines between successive layers of Roller Compacted Concrete (ReC) dams. A shape optimisation procedure for gravity dams based on the penalty function method and a sequential unconstrained minimisation technique is also developed. A number of shape optimisations of idealised gravity dams are carried out in order to compare the numerical results with previously available analytical solutions. The present work also caters for the effects of foundation elasticity and uplift on the optimal shape of a gravity dam. A numerical example is provided covering the shape optimisation of a hollow gravity dam. Finally, the shape optimisation of an actual dam (i.e. Tvishi gravity dam in Georgia) using the presently proposed procedures is carried out with the fmal results compared with those available from the project design team. Wherever possible. numerical outputs have been checked against available small or full scale test data or previously reported closed form solutions. Throughout this thesis very encouraging correlations between the present predictions and such experimental and theoretical data have been obtained.

The first chapter investigates whether construction of the Bureau of Reclamation dams in the early twentieth century raise farm values and increase agricultural output? I construct a new county level panel data set from 1890 to 1920 with information on geography, climate, politics, agriculture, and major dams and then evaluate the effect of the Bureau of Reclamation dams on the value of farms and on crop productivity. Using fixed effect panel estimation, I find that new federal dam construction increased the average value of farm land by approximately 6.4 percent. When I apply an instrument to control for potential endogeneity, the effect of Bureau dams on the farm land value increases in size, although the estimate is no longer statistically significant. When examining the crop output, the only crop for which the dams had effects was alfalfa. In the second chapter I investigate the effect of the geographic, economic and political factors on dam construction at the beginning of the Bureau of Reclamation's operation in the American West. Applying county level data which has been linked from various data sources for the time period of 1900 to 1910, I show that the percentage of votes for Republicans in presidential elections has a significant and positive effect on major dam construction. The last chapter investigates the effect of climate change on US agriculture using county-level data from 1997 to 2007. Compared to previous contributions, we pay particular attention to the spatial heterogeneity across the climate zones and include the presence of extreme weather events. The lack of consideration for both effects may have led previous works to generate biased estimates and incorrect impact forecasts. While current approaches use projected climate variables derived from coarse resolution Global Climate Models (GCMs), we use data at a much finer resolution by relying on dynamically downscaled simulation data. Further, we pay particular attention to the spatial heterogeneity in the impact of climate among the climate zones. Chow-Wald tests indicate the presence of significant heterogeneity across zones in the effects of climate on land values.

Before 1978, Chinese dam policies were tallied with the political movement ¡§Big Leap¡¨, people all obeyed the order no matter they were under the situation of lacked of instruments. Sanmenxia can be a special sample. ZhouEnlai¡¦s chrisma made people did their best on dam projects. This could be said that dam construction policies were methods to show the authority of the leader and the state. And further, under the system of people¡¦s commune and SOEs, the state can totally control the society. After executing the opening reform policy in 1978, social organizations were in bud in China. Since 1994, environmental non-government organizations (ENGO) dramatically grew up and played an important role in anti-dam movements, in addition the international non-government organizations joined the movement, and then the two kinds of organizations became transnational advocacy networks. However, the transnational advocacy networks successfully stopped the projects of Nu River and Hutiaoxia. In this study, the documentary analysis is the key research methodology and the dam construction is the case to illustrate the purpose of constructing dam in China. Furthermore, this thesis would make a description of the reasons of anti-dam movements, the emergence of NGOs and ENGOs, and the cooperation with INGOs to confer the transforming State-Society relations in China.

Dispersive soils are prevalent in many areas of South Africa and the presence of these soils has not only posed a problem in earth dam construction but has led to problems with a number of road projects. The use of dispersive soils in roadway embankments and structures can lead to serious engineering problems if the soils are not accurately identified before use and appropriate mitigation measures taken. Although the causes and consequences of soil dispersion are well understood, the consistent and positive identification of dispersive soils still remains a problem. Many identification methods have been proposed but none has been completely successful. The current tests used for identification include the pinhole, double hydrometer, crumb and chemical tests, which are generally used in combination to obtain the most reliable outcome. These laboratory tests, however, have not always been entirely consistent, either when used in combination or individually, and it is possible that the reason lies in the actual testing procedures. Recent investigations have shown that in many cases the identification and classification problems appear to be related to inconsistencies in the test methods and testing protocols. This has been highlighted recently at various conferences and presentations in South Africa, with a recommendation that the problem be investigated fully. The main objective of this project was thus to carry out a detailed investigation into the current methods used for the testing and identification of dispersive soils. The test methods were thoroughly analysed and shortcomings identified. The differences in results and interpretation resulting from different test techniques are examined and solutions to overcome the problems proposed. A further objective of this study is the assessment of the interpretation of results obtained from dispersive soil chemical analysis. A pilot study was first carried out, which recognized deficiencies in the identification process resulting from problems with the test methods. The pilot study allowed for the identification of these shortcomings in the test methods and their modification. The modified methods were used in the full study to obtain more consistent and reliable results. The study found the pinhole test as well as the Gerber and Harmse (1987) ESP versus CEC chart to be highly unreliable. The double hydrometer and crumb tests are good indicators of dispersivity if carried out accurately and repeatably using a standard test method. The chemical analysis of the soils should be carried out using the standard methods employed by the Soil Science Society of South Africa. Final rating systems were also found to be unreliable since they put a great deal of weight on the poorly reproducible pinhole test. Emphasis is thus put on the test methods being as simple and unambiguous as possible to promote repeatability and reproducibility of the results. Recommendations are finally made proposing a suite of tests as well as a decision process which should be followed when faced with a potentially dispersive soil. This investigation was aimed solely at the evaluation of test protocols and not the suitability or specification of limits for any rating systems. This should now be assessed using the standard test methods proposed in this thesis. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Geology / unrestricted

The purpose of this rapport/paper is to summarize and compare three different reparation methods, which can be used in repairing damaged concrete dams, which are one of the most important parts of electricity production in Sweden. Most of big dams in Sweden built between1900- 1960 are in a great need of restoration. Time, harsh winter conditions and constant presence of water have caused great damages to these dams. There are numerous restoration methods, which can be used in dam reconstruction.  However, choosing the right method plays a crucial role in terms of economy and quality for the power plant companies. Due to negatively impacting global warming, carbon dioxide emissions can also be another concern for power plant companies when selecting a reparation method. Sometimes determining and choosing the “right” method is rather difficult when facing different reparation methods.  When deciding which method to choose, comparisons are made in terms of economy, quality, and carbon dioxide emissions causing global warming. The methods compared in this rapport are applying waterjet mechanical chiseling, and Chesterton filler.  Accordingly, some boundaries are set and some, but not all, factors are taken into account.  For example, winter expenses and transportation are not included in this rapport. The method which has been used in this study is both qualitative and quantitative. In the qualitative method, interviews, literature studies and experience of experts are gathered and used. The quantitative method used for calculation of costs and CO2 (e) emissions to the air. The study shows that in a minor spalled concrete damage, the waterjet method and Chesterton filler are appropriate with regards to quality.  Mechanical chiseling is the cheapest method, and the Chesterton filler method releases the least amount of carbon dioxide to the air of all methods. Hopefully, the comparison in this rapport can aid those who want to choose a reparation method based on the criterias for the outcome/method. / Dammkonstruktioner är en av de viktigaste delarna av elproduktionen i Sverige. De flesta av de stora betongdammarna i Sverige som är byggda mellan 1900 och 1960 är i behov av reparation. Åldern, svåra vinterförhållanden och ständig närvaron av vatten påverkar dammarna negativt och orsakar skador i betongen. Det finns gott om olika reparationsmetoder som kan användas vid dammreparationer. Att välja rätt metod vid reparationer kan spela en avgörande roll när det gäller ekonomi och kvalitet för kraftverksbolagen. Då de olika metoderna resulterar i olika mycket koldioxidutsläpp till luften och därmed effekt på den globala uppvärmningen är just koldioxidutsläppen en annan faktor som kan beaktas av elbolagen när de vill välja en reparationsmetod. Valet av reparationsmetod är inte lätt. Ofta går det att välja mellan flera olika metoder. Syftet med denna rapport att upprätta sammanfattningar för tre olika reparationsmetoder vid reparation av betongdammar, samt en jämförelse mellan dessa metoder. Jämförelser har gjorts i förhållande till ekonomi, kvalitet och koldioxidutsläpp till luften. De reparationsmetoder som har jämförts i denna rapport är vattenbilning, mekanisk bilning och Chesterton spackel. För att möjliggöra jämförelsen i denna studie har några avgränsningar gjorts i för de faktorer som jämförts, bland annat har vinterkostnader och transporter inte inkluderats i jämförelsen.   Metoden i denna uppsats bygger på kvalitativ och kvantitativ studie. Den kvalitativa studien består av litteraturstudier och intervjuer genom samtal och email, och den kvantitativa studien består av beräkningar för kostnader och CO2 (e)-utsläpp med hjälp av grundvärden och faktorer för 1 m² betongyta. Studien visar att vid en enkel frostskada så är vattenbilningsmetoden och Chestertonspackel lämpligast med avseende på kvalitet. Mekanisk bilning är billigast och Chestertonspackel släpper ut minst koldioxid till luften. Förhoppningsvis kan jämförelsen i denna rapport hjälpa de som vill välja reperationsmetod baserat på önskade kriterier för slutresultatet. / <p>2017-06-27</p>

Για την κάλυψη των αναγκών της ύδρευσης στην Αθήνα, έγιναν μελέτες με σκοπό την ενίσχυση του υδατικού δυναμικού του ταμιευτήρα Μόρνου. Η ενίσχυση του ταμιευτήρα περιελάμβανε την κατασκευή του φράγματος στον ποταμό Ευήνο, περιοχής Αγ. Δημητρίου καθώς και της ενωτικής σήραγγας. Η σήραγγα αυτή θα μετέφερε νερό από τον ταμιευτήρα του Ευήνου στον ταμιευτήρα του φράγματος του Μόρνου. Για την διεξαγωγή της κατασκευής του έργου χρειάστηκαν αρκετές γεωλογικές και τεχνικογεωλογικές μελέτες. Αυτές είχαν ως σκοπό την προτροπή από τυχόν αστοχίες. Οι μελέτες αυτές περιείχαν εργασίες υπαίθρου αλλά και εργαστηριακές δοκιμές. Στο πρώτο μέρος της εργασίας αρχικά τοποθετείται γεωγραφικά το φράγμα. Ακολουθεί μια ανάλυση των τμημάτων και των συνοδών έργων του φράγματος καθώς και για τις κατολισθήσεις που προέκυψαν κατά την κατασκευή του. Επίσης παρουσιάζονται η λιθολογία, η τεκτονική, η υδρογεωλογία της περιοχής της θέσης κατασκευής αλλά και οι συνέπειες που θα μπορούσαν να προκληθούν από την κατασκευή του φράγματος. Στο δεύτερο μέρος αυτής της εργασίας αναλύονται κάποιες από τις εργαστηριακές και επιτόπου δοκιμές, που πραγματοποιήθηκαν στο στάδιο προμελέτης του έργου. Οι επιτόπου περιλαμβάνουν τη διάνοιξη των γεωτρήσεων και την τοποθέτηση πιεζομέτρων. Οι εργαστηριακές ασχολούνται με τα δείγματα από τις γεωτρήσεις, προσδιορίζοντας κάποια από τα χαρακτηριστικά τους όπως τα φυσικά και τις παραμέτρους αντοχής τους καθώς και την ορυκτολογία τους. Στη συνέχεια, ακολουθεί ανάλυση των αποτελεσμάτων που προέκυψαν και η καταγραφή τους σε διαγράμματα. Στο τέλος, παρουσιάζονται τα συμπεράσματα και το παράρτημα με τους χάρτες από την περιοχή μελέτης. / Extended research took place in order to cover the waterwork needs of Athens and reinforce water dynamic of Mornos reservoir. This reservoir reinforcement include the construct of dam in Evinos river and the integrative tunnel. The tunnel will transfer water from Evinos to Mornos reservoir. For the building of this dam there was need of many geological and geotechnical studies. These studies prevent the dam’s failure. The following studies contain both field tests and controlled laboratory tests. The first part of this study explains the geographical position of the dam (A. Dimitrios area). The rest of the study focuses on parts review, recommendable works and occurring landslides during its construction. Lithology, tectonics and hydrogeology on the building area is also included along with the consequences of the dam construction on the area. The second part analyzes the laboratory and field work tests. The above tests took place at the preliminary design stage of the dam. The filled work tests include the boring of test drillings and the placement of piezometers. The main pursuit of the lab studies is to determine some of the rock characteristics like general physic properties, mechanical strength and mineralogy. The results of the lab studies were used for the formation of specific diagrams. The end of this study summarizes the conclusions of the tests and includes an appendix of the maps of this area.