Articles de revues sur le sujet « ARCH GRAVITY DAMS »
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1
Li, Zhong, Yan Peng Zhu et Xiao Ri Song. « Simplified Design Method of Debris Arch Detention Dams Structure and Its Application in Highway ». Advanced Materials Research 446-449 (janvier 2012) : 186–90. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.186.
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As a debris detention structure, small arch dams have some characteristics of small size, big storage capacity, and economic compared with gravity dams In this paper, according to the work environment and force behaviors of debris detention structure, adopting Trial-load Method, and only considering the conditions of radial deformation compatibility at arch crown, a simplified method is derived, which is suitable for the calculation of small-scale debris arch dams. Examined by calculating an example, this method is simplified, and convenient to programmed, and easy to be mastered by engineering and technical personnel for debris detention structure design and calculation, and calculation accuracy can meet the project requirements.
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Lin, Gao, et Zhiqiang Hu. « Earthquake safety assessment of concrete arch and gravity dams ». Earthquake Engineering and Engineering Vibration 4, no 2 (décembre 2005) : 251–64. http://dx.doi.org/10.1007/s11803-005-0008-9.
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Chen, Pei Pei, et Guo Xin Zhang. « Study on the Prevention Measures and Causes of Cracks in Arch Crests of Galleries in High Concrete Dams ». Advanced Materials Research 919-921 (avril 2014) : 813–19. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.813.
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More and more high dams with huge reservoirs have been built in China in recent years. A lot of research work on the causes of cracking in galleries of low concrete dams has been carried out at present, while studies on that of high concrete dams are less with the lack of systematic cognition. Based on that, the research on high concrete dams is conducted in this paper, using the method of finite element simulation. It is proven that self-weight action has more influence on the stress of arch crests of galleries existing in high concrete dams, especially the galleries whose overlying concrete height is relatively high. And surface cracks tend to appear in arch crests of these galleries under gravity. In the end, measures for improvement of the stress of arch crest are put forward, of which the effect of enlarging reinforcement is relatively obvious.
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Li, Bo, Li Li Liu, Da Zhi Li et Jun Liang. « Chang Law Analysis of the Horizontal Displacement of the Arch Crest Dam Section of the Geheyan Concrete Gravity Arch Dam ». Applied Mechanics and Materials 170-173 (mai 2012) : 2013–16. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2013.
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Monitoring data of the arch crown dam section of the Geheyan concrete gravity arch dam were qualitatively and quantitatively analyzed. The analysis results show that the measured data and year changes of the dam horizontal displacement are small, the influence of the water level and temperature on the arch crown dam section is normal, the influence of the aging on the dam horizontal displacement is little, and the aging component has become stable. Therefore, it can be shown that the arch crown dam section of the Geheyan concrete gravity dam is in elastic state, and the horizontal displacement is accord with general deformation law of concrete arch dams.
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Vicente, D. J., J. San Mauro, F. Salazar et C. M. Baena. « An Interactive Tool for Automatic Predimensioning and Numerical Modeling of Arch Dams ». Mathematical Problems in Engineering 2017 (2017) : 1–12. http://dx.doi.org/10.1155/2017/9856938.
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The construction of double-curvature arch dams is an attractive solution from an economic viewpoint due to the reduced volume of concrete necessary for their construction as compared to conventional gravity dams. Due to their complex geometry, many criteria have arisen for their design. However, the most widespread methods are based on recommendations of traditional technical documents without taking into account the possibilities of computer-aided design. In this paper, an innovative software tool to design FEM models of double-curvature arch dams is presented. Several capabilities are allowed: simplified geometry creation (interesting for academic purposes), preliminary geometrical design, high-detailed model construction, and stochastic calculation performance (introducing uncertainty associated with material properties and other parameters). This paper specially focuses on geometrical issues describing the functionalities of the tool and the fundamentals of the design procedure with regard to the following aspects: topography, reference cylinder, excavation depth, crown cantilever thickness and curvature, horizontal arch curvature, excavation and concrete mass volume, and additional elements such as joints or spillways. Examples of application on two Spanish dams are presented and the results obtained analyzed.
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Darbre, Georges R. « Instrumentation de barrages par accélérographes ». Canadian Journal of Civil Engineering 22, no 1 (1 février 1995) : 150–63. http://dx.doi.org/10.1139/l95-014.
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A better understanding of the dynamic behaviour of dams requires strong-motion instrumentations. In particular, it is necessary to observe the free-field motions at the dam sites and the effective motions along the abutments, and to determine the dynamic properties of dams and their response to severe earthquakes. Instrumentation schemes are developed for arch dams, gravity dams and embankment dams, considering specific observational needs and objectives. The technical specifications to be satisfied by the accelerographs and the arrays are developed. Four arrays, which have been installed in Swiss dams ranging in height from 120 to 285 m, for a total of 29 triaxial accelerographs, are also presented. Key words: earthquakes, strong motions, instrumentation, accelerographs, dams.
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Rahman, Alaa Jabbar, Ali Majdi et Wissam Khlaf Obied. « Evaluation of safety in arch dam using post analysis including inertia force and temperature variations of water ». Technium : Romanian Journal of Applied Sciences and Technology 2, no 1 (7 janvier 2020) : 56–65. http://dx.doi.org/10.47577/technium.v2i1.42.
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Dams considered as one if very important infrastructure, they are lifeline structures and have a vital role our economics and social life. A concrete gravity dam is one of wide used dam worldwide, it constructed from reinforced concrete and his typical cross section is triangular, the other type is arch section. A gravity dam can be combined with an arch dam into an arch-gravity dam for areas with massive amounts of water flow but less material available for a purely gravity dam. The inward compression of the dam by the water reduces the lateral (horizontal) force acting on the dam. Thus, the gravitation force required by the dam is lessened, i.e. the dam does not need to be so massive. The aim of this paper is to obtain a preliminary post analysis for an arch gravity dam by considering of typical applied loads that effects on it. In order to check and verify the dam and ensure the assumptions used during this process, the dam is analysed in different type of major effects such as own weight, water pressure, temperature and static load intertie generated from seismic load. These loads are presented in this paper in different cases, totally five cases combined between all these factors as explain in details in the section of methodology.To achieve the target of this study, modelling of an arch dam, reservoir and foundation provided by finite element using software ANSYS. An arch dam with height of 41.5 m is studied in this paper to simulate the reality of the future dam that will be erected as accurate as possible. The response of the dams is represented by the maximum displacement of it and also the stresses in each case. The results of all analysis were compared in the five cases mentioned above to determine the impact of each case as well as the worst case affecting the safety of the dam.
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Xu, Qiang, Jian Yun Chen et Jing Li. « Study on System Reliability of Gravity Dam ». Applied Mechanics and Materials 351-352 (août 2013) : 1677–82. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.1677.
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Reliability analysis is an emerging field of structural engineering which is very significant in structures of great importance like arch dams, large concrete dams etc. The research objective is to design and construct a new method for the analysis of the system reliability of dam. The failure paths are searched out after failure mode and composite performance functions are set. Bayes formula and Cauchy-Schwarz Inequality are adopted to deduce the upper limit of failure probabilities in some failure modes that can obtain the failure probability of system of dam. A test example is given to verify this method. Compared with other conventional algorithm, this method has the strong points: more failure paths are considered and more safety methods are used to estimate the system reliability of dam.
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Nitta, Yasushi, et Takashi Yoshida. « Field Verification and Evaluation of Technology Towards Introduction of Underwater Inspection Vehicle ». Journal of Disaster Research 13, no 4 (1 août 2018) : 624–36. http://dx.doi.org/10.20965/jdr.2018.p0624.
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The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) aims to perform underwater inspection of dams using vehicles instead of divers, to address the deterioration of infrastructures, considering the shortage of engineers and technicians in the near future, in order to improve inspection safety. To this end, the technology for underwater inspection vehicles was publicly invited to conduct the verification of the technology at the concrete gravity dams and concrete arch dams, managed by MLIT. This paper reports the contents of the field verification, evaluation of the technology, and the results of the trial introduction, assuming practical operation.
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Wang, Huai Liang, et Yu Qing Ren. « Mechanical Properties of Roller Compacted Concrete under Triaxial Stress State ». Applied Mechanics and Materials 351-352 (août 2013) : 497–500. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.497.
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Considering the true mechanical states of roller compacted gravity and arch dams, the strength experiments of the roller compacted concrete (RCC) specimens with two graded-aggregates made from a high arch dam are carried out. These specimens are of three kinds: body specimens, layer-treated specimens and layer-untreated specimens and the tests include direct shear and triaxial compressive-compressive-shear, tensile-compressive-shear tests. The shear strength of three kinds of specimens under different stress states is analyzed systematically. By regression of the tests results, respective failure criterions for RCC under different combined loads are proposed.
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Lin, Gao, Jianguo Du et Zhiqiang Hu. « Earthquake analysis of arch and gravity dams including the effects of foundation inhomogeneity ». Frontiers of Architecture and Civil Engineering in China 1, no 1 (février 2007) : 41–50. http://dx.doi.org/10.1007/s11709-007-0004-4.
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Chen, Hou-Qun, De-Yu Li et Sheng-Shan Guo. « Damage–Rupture Process of Concrete Dams Under Strong Earthquakes ». International Journal of Structural Stability and Dynamics 14, no 07 (24 juillet 2014) : 1450021. http://dx.doi.org/10.1142/s0219455414500217.
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A new concept for establishing the damage model for high concrete dams under earthquakes based on damage mechanics is presented in this paper. Unlike the conventional approach of considering the residual deformation by means of plastic-damage coupling, the proposed approach relates the degraded apparent elastic moduli of loading and unloading directly to the material experimental data. As such, the nonlinear analysis of the seismic response of dam-foundation systems is simplified and more reasonable, with no recourse to plastic-damage coupling. To verify the proposed approach of damage–rupture process for high concrete dams, the seismic behaviors of the Koyna gravity dam in India and the Shapai RCC arch dam in China both subjected to strong earthquakes were examined. It is demonstrated that the proposed approach can be reliably used to study the damage–rupture behavior of concrete dams under strong earthquakes.
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Jablonski, A. M., et J. L. Humar. « Three-dimensional boundary element reservoir model for seismic analysis of arch and gravity dams ». Earthquake Engineering & ; Structural Dynamics 19, no 3 (1990) : 359–76. http://dx.doi.org/10.1002/eqe.4290190306.
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Zhou, Qiu Jing, Peng Gao, Zhao Guang Gong et Hai Feng Li. « Working Performance of Anti-Arch Segments on the Left Bank Slope of Xiangjiaba Gravity Dam ». Applied Mechanics and Materials 580-583 (juillet 2014) : 2063–70. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.2063.
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The working performance of gravity dam with an anti-arch shape differs from that of conventional gravity dams. To understand the working performance of anti-arch segments on the bank slope of Xiangjiaba dam, linear and non-linear finite element methods were used to analyze the deformation, stress as well as the state of transverse joint and cracks during the operation period. The coefficient of anti-sliding stability of each dam segment and the safety degree of dam body were also calculated. The results show that under the conditions of non-grouting of transverse joints and well grouting of cracks, the deformation rules are consistent for all segments investigated and accord well with that of the conventional gravity dam. Both the dam heel and dam toe are subjected to compressive stress. In the cold seasons, there is a tensile stress region on the top of the dam body, where the tensile stress is smaller than the tensile strength. The transverse joints are opened, while the cracks are generally closed under compression and stable on the whole. The anti-sliding stability coefficient and the safety degree of each dam segment are above 3.0, which satisfies the design code.
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Furgani, L., M. A. Hariri-Ardebili, M. Meghella et S. M. Seyed-Kolbadi. « On the Dynamic Capacity of Concrete Dams ». Infrastructures 4, no 3 (31 août 2019) : 57. http://dx.doi.org/10.3390/infrastructures4030057.
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The purpose of this joint contribution is to study the maximum dynamic load concrete dams can withstand. The so-called “dynamic capacity functions” for these infrastructures seems now technically and commercially feasible thanks to the modern finite element techniques, hardware capabilities, and positive experiences collected so far. The key topics faced during the dynamic assessment of dams are also discussed using different point of view and examples, which include: the selection of dynamic parameters, the progressive level of detail for the numerical simulations, the implementation of nonlinear behaviors, and the concept of the service and collapse limit states. The approaches adopted by local institutions and engineers on the subject of dam capacity functions are discussed using the authors’ experiences, and an overview of time and resources is outlined to help decision makers. Three different concrete dam types (i.e., gravity, buttress, and arch) are used as case studies with different complexities. Finally, the paper is wrapped up with a list of suggestions for analysts, the procedure limitations, and future research needs.
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Hu, Jiang, et Suhua Wu. « Statistical modeling for deformation analysis of concrete arch dams with influential horizontal cracks ». Structural Health Monitoring 18, no 2 (10 mars 2018) : 546–62. http://dx.doi.org/10.1177/1475921718760309.
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Several concrete dams all over the world exhibit severe cracks. It is very important to investigate the influence of cracks on the long-term behavior of dam structures to ensure safe operation. The interpretation of measured dam displacements is usually based on statistical hydrostatic-seasonal-time and hydrostatic-thermal-time models. The main purpose of this article is to present a statistical hydrostatic-thermal-crack-time model to interpret displacements of concrete arch dams with influential horizontal cracks. The hydrostatic-thermal-crack-time model is applied to analyze the Chencun dam, an arch–gravity dam with a large-scale horizontal crack on the downstream face. The crack stretches horizontally across most of the dam blocks. Its crack mouth opening displacement had been continually increasing even after reinforcement treatment, accompanied by abnormal deformation characteristics of the arch–cantilever system. A three-dimensional finite element model, containing the pre-existing crack using special gap elements, is built to reproduce the structural response, assess the contribution of the crack on the registered movements, and obtain the relationship between the crack mouth opening displacement and the dam crest displacement. Based on this, the hydrostatic-thermal-CMOD-time model considering crack mouth opening displacement is developed. Compared with the traditional models, the hydrostatic-thermal-crack-time model is expected to provide a better fit accuracy. The results also show that the crack and the corresponding reinforcement measure have a significant effect on the deformation behavior of the dam. This can provide some useful indications for concrete structures with similar problems.
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Dou, Siqi, Junjie Li et Fei Kang. « Parameter identification of concrete dams using swarm intelligence algorithm ». Engineering Computations 34, no 7 (2 octobre 2017) : 2358–78. http://dx.doi.org/10.1108/ec-03-2017-0110.
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Purpose Parameter identification is an important issue in structural health monitoring and damage identification for concrete dams. The purpose of this paper is to introduce a novel adaptive fireworks algorithm (AFWA) into inverse analysis of parameter identification. Design/methodology/approach Swarm intelligence algorithms and finite element analysis are integrated to identify parameters of hydraulic structures. Three swarm intelligence algorithms: AFWA, standard particle swarm optimization (SPSO) and artificial bee colony algorithm (ABC) are adopted to make a comparative study. These algorithms are introduced briefly and then tested by four standard benchmark functions. Inverse analysis methods based on AFWA, SPSO and ABC are adopted to identify Young’s modulus of a concrete gravity dam and a concrete arch dam. Findings Numerical results show that swarm intelligence algorithms are powerful tools for parameter identification of concrete structures. The proposed AFWA-based inverse analysis algorithm for concrete dams is promising in terms of accuracy and efficiency. Originality/value Fireworks algorithm is applied for inverse analysis of hydraulic structures for the first time, and the problem of parameter selection in AFWA is studied.
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Buffi, Giulia, Piergiorgio Manciola, Laura De Lorenzis, Nicola Cavalagli, Fabrizio Comodini, Andrea Gambi, Vittorio Gusella, Marco Mezzi, Wolfgang Niemeier et Claudio Tamagnini. « Calibration of finite element models of concrete arch-gravity dams using dynamical measures : the case of Ridracoli ». Procedia Engineering 199 (2017) : 110–15. http://dx.doi.org/10.1016/j.proeng.2017.09.169.
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Zhang, Jingmei, et Chongshi Gu. « Crack-Considered Elastic Net Monitoring Model of Concrete Dam Displacement ». Mathematical Problems in Engineering 2021 (11 novembre 2021) : 1–15. http://dx.doi.org/10.1155/2021/6950538.
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Displacement monitoring data modeling is important for evaluating the performance and health conditions of concrete dams. Conventional displacement monitoring models of concrete dams decompose the total displacement into the water pressure component, temperature component, and time-dependent component. And the crack-induced displacement is generally incorporated into the time-dependent component, thus weakening the interpretability of the model. In the practical engineering modeling, some significant explaining variables are selected while the others are eliminated by applying commonly used regression methods which occasionally show instability. This paper proposes a crack-considered elastic net monitoring model of concrete dam displacement to improve the interpretability and stability. In this model, the mathematical expression of the crack-induced displacement component is derived through the analysis of large surface crack’s effect on the concrete dam displacement to improve the interpretability of the model. Moreover, the elastic net method with better stability is used to solve the crack-considered displacement monitoring model. Sequentially, the proposed model is applied to analyze the radial displacement of a gravity arch dam. The results demonstrate that the proposed model contributes to more reasonable explaining variables’ selection and better coefficients’ estimation and also indicate better interpretability and higher predictive precision.
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Zhao, Er Feng, Yu Feng Jiang et Yan Ling Gu. « High Arch Dam Reservoir Basin Deformation & ; Effect on Dam Operating Status ». Applied Mechanics and Materials 670-671 (octobre 2014) : 651–54. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.651.
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With the development of 300m super-high dams are built in the southwest of China, reservoir water gravity will make the settlement of the reservoir basin, which will make dam tilt upstream. In the paper, reservoir settlement will be studied in-depth on the basis of monitoring data analysis and numerical simulation comprehensively. First, reservoir basin will be sinking with the rising of the upstream water gradually according to level monitoring data. Second, those affect factors of FEM calculation have been explored comparatively, such as displacement modes, element geometry and boundary conditions. Third, reservoir, dam and foundation are integrated into a whole to establish a wide spread finite element model. At last, reservoir deformation and its influence factors are determined through the simulation of the bedrock depth, the extending length of the upstream and downstream and different water levels. Those methods have been applied into an engineering project and analysis results show that the settlement of the reservoir will make high arch dam tilt upstream, the higher of the water level, the larger of the horizontal displacement. Accordingly, reservoir deformation should be considered deeply on the appraisement of super-high arch dam operating status in future.
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Cheng, Xiang, Qingquan Li, Wei Zhou et Zhiwei Zhou. « External Deformation Monitoring and Improved Partial Least Squares Data Analysis Methods of High Core Rock-Fill Dam (HCRFD) ». Sensors 20, no 2 (13 janvier 2020) : 444. http://dx.doi.org/10.3390/s20020444.
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External deformation monitoring of high core rock-fill dams (HCRFDs) is an important and difficult part of safety monitoring. The traditional method of external deformation monitoring and data analysis for HCRFDs is to use a total station for small angle observations and establish a regression model to analyze the results. However, the small angle method has low accuracy and a low automation degree, and there is multicollinearity between the independent variables, which affects the parameter estimation and leads to the failure of model establishment. The angle forward intersection method is adopted in this paper for observation, and an improved partial least squares method (IPLS) is proposed to eliminate the multicollinearity of the independent variables. Compared to the traditional method, the improved observation method exhibits high accuracy and a high automation degree. The new data analysis method can not only eliminate multicollinearity but also improve the interpretation ability of the model. The data from the initial stage of water storage shows that the displacement increases with the increase in the upstream water level and time, and the speed of water storage is proportional to the displacement. The water level and time are the main influencing factors. This conclusion provides a theoretical basis for reservoir management departments to control water levels and gate opening and closing. The method in this paper can be applied to arch dams, gravity dams, and other types of waterpower engineering systems.
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Moran, Rafael, Miguel Ángel Toledo, Javier Peraita et Raffaella Pellegrino. « Energy Dissipation in Stilling Basins with Side Jets from Highly Convergent Chutes ». Water 13, no 10 (12 mai 2021) : 1343. http://dx.doi.org/10.3390/w13101343.
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Spillways with Highly Converging Chutes (HCCs) are a non-conventional alternative that can be applied to achieve a higher outflow capacity when the weir length exceeds the width of the valley at the toe of gravity or arch dams. This kind of spillway has been used in the past, but no general studies have yet been published. This article summarizes experimental research work aiming to increase the knowledge of the effect of some design parameters of HCCs on the energy dissipation in the stilling basin at the toe of the dam. As a comparison reference, we use the Type I stilling basins, widely known by the technical dam engineering community. The obtained results show that spillways with HCCs are a promising alternative to traditional designs, combining the ability to increase the weir length with a high capacity to dissipate energy through the impingement effect of the frontal and the side jets inside the stilling basin.
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Chen, Yijun, Chongshi Gu, Bangbin Wu, Chenfei Shao, Zhongru Wu et Bo Dai. « Inversion Modeling of Dam-Zoning Elasticity Modulus for Heightened Concrete Dam Using ICS-IPSO Algorithm ». Mathematical Problems in Engineering 2019 (9 avril 2019) : 1–13. http://dx.doi.org/10.1155/2019/9328326.
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A new approach was developed for the inversion modeling of dam-zoning elasticity modulus for heightened concrete dam, with old and new concrete zones. The proposed inversion modeling procedure takes advantage of the improved cuckoo search (ICS) algorithm and improved particle swarm optimization (IPSO) algorithm to adjust the mechanical parameters, which are used as input. An objective function is constructed based on the horizontal displacement increment by using the finite element method (FEM) and statistical analysis of the prototype monitoring data. One ideal arch dam model and one actual heightened concrete dam were taken as examples. The proposed method was used to implement the optimal selection of the dam-zoning elasticity modulus. The inversion analysis results indicate that the mechanical parameters identification method for heightened concrete gravity dams proposed in this article is accurate and has a fast convergence rate. Consequently, it can be applied as a reliable model to identify the dam-zoning elasticity modulus in practical engineering applications.
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Farinha, Maria Luísa Braga, Nuno Monteiro Azevedo, Noemi Alejandra Schclar Leitão, João Rocha de Almeida et Sérgio Oliveira. « Sliding Stability Assessment of Concrete Dams Using a 3D Discontinuum Hydromechanical Model Following a Discrete Crack Approach ». Geotechnics 2, no 1 (26 janvier 2022) : 133–57. http://dx.doi.org/10.3390/geotechnics2010006.
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Evaluation of the sliding stability of concrete dams requires the use of numerical tools not only able to simulate the coupled hydromechanical behavior but also able to adequately represent the foundation discontinuities and the specific features of dam foundations. The formulation of a three-dimensional (3D) small displacement finite element model based on interface elements to simulate the discontinuities is presented. In this model, the hydraulic behavior is simulated assuming that the water flow occurs only along channels located at the edges of the triangular interface elements that simulate the discontinuities. The model is used to perform coupled hydromechanical analysis of a large arch-gravity dam and to assess safety against dam base sliding, assuming different constitutive models at the dam/foundation interface and two different approaches: (i) strength reduction method and (ii) amplification of the hydrostatic pressure, assuming an increase in the reservoir level. The present study shows that consistent results are obtained with the proposed numerical model and that stability analysis should preferably be carried out using the method of increasing the hydrostatic pressure and the corresponding uplift pressures, as this methodology leads to significantly lower safety factors.
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Chen, Bo, Zhongru Wu, Jiachen Liang et Yanhong Dou. « Time-Varying Identification Model for Crack Monitoring Data from Concrete Dams Based on Support Vector Regression and the Bayesian Framework ». Mathematical Problems in Engineering 2017 (2017) : 1–11. http://dx.doi.org/10.1155/2017/5450297.
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The modeling of cracks and identification of dam behavior changes are difficult issues in dam health monitoring research. In this paper, a time-varying identification model for crack monitoring data is built using support vector regression (SVR) and the Bayesian evidence framework (BEF). First, the SVR method is adopted for better modeling of the nonlinear relationship between the crack opening displacement (COD) and its influencing factors. Second, the BEF approach is applied to determine the optimal SVR modeling parameters, including the penalty coefficient, the loss coefficient, and the width coefficient of the radial kernel function, under the principle that the prediction errors between the monitored and the model forecasted values are as small as possible. Then, considering the predicted COD, the historical maximum COD, and the time-dependent component, forewarning criteria are proposed for identifying the time-varying behavior of cracks and the degree of abnormality of dam health. Finally, an example of modeling and forewarning analysis is presented using two monitoring subsequences from a real structural crack in the Chencun concrete arch-gravity dam. The findings indicate that the proposed time-varying model can provide predicted results that are more accurately nonlinearity fitted and is suitable for use in evaluating the behavior of cracks in dams.
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Jiao, Yantao, Liping Cheng, Ning Wang, Sizhe Wang et Luyao Ma. « Calculation and Analysis of Temperature Damage of Shimantan Concrete Gravity Dam Based on Macro–Meso Model ». Materials 15, no 20 (13 octobre 2022) : 7138. http://dx.doi.org/10.3390/ma15207138.
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Considering that ANSYS software will automatically quit or the computer will freeze when generating random aggregate models of concrete by using some existing methods that are based on the ANSYS parametric design language (APDL), a new method of random aggregate placement using the ESEL command in APDL and the rotation of the local coordinate system is proposed in this paper. According to this method, a multiscale macroscopic and mesoscopic finite element model of the No. 9 non-overflow dam section of Shimantan dam is constructed. In addition, considering that most of the damage models adopted by the existing mesoscale simulation of concrete damage and fracture cannot take into account the interaction between aggregates, interfacial transition zone (ITZ), and mortar, an improved anisotropic temperature damage model is proposed in this paper. The aggregate placement simulation results show that the method presented in this paper can quickly generate two-dimensional (2D) random concrete aggregates, and the generation of three-dimensional (3D) aggregates can also be completed in a very short time, which can greatly improve the aggregate generation efficiency. Moreover, the aggregate shape generated by this method is very close to the real concrete aggregate shape. The crack propagation simulation results show that the sudden rise and fall of temperature can cause damage in the mortar and ITZ of concrete inside the dam body, which is the main reason for the generation of macroscopic through-cracks in the No. 9 non-overflow dam section of Shimantan dam during the operation period. Finally, it can be learned from the results that the method presented in this paper is reasonable and feasible, and can be extended to the crack propagation simulation of some other concrete gravity and arch dams.
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Xiang, Xia, Jiankang Chen, Hui Wang, Liang Pei et Zhenyu Wu. « PS Selection Method for and Application to GB-SAR Monitoring of Dam Deformation ». Advances in Civil Engineering 2019 (7 décembre 2019) : 1–15. http://dx.doi.org/10.1155/2019/8320351.
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Ground-based synthetic aperture radar (GB-SAR) is a relatively new technique that can be used to monitor the deformation of large-volume targets, such as dams, slopes, and bridges. In this study, the permanent scatterer (PS) technique is used to address the issues encountered in the continuous monitoring of the external deformation of an arch-gravity dam in a hydraulic and hydropower engineering structure in Hubei, China; the technique includes large image data sizes, high accuracy requirements, a susceptibility of the monitoring data to atmospheric disturbances, complex phase unwrapping, and pronounced decoherence. Through an in-depth investigation of PS extraction methods, a combined PS selection (CPSS) method is proposed by fully taking advantage of the signal amplitude and phase information in the monitored scene. The principle and implementation of CPSS are primarily studied. In addition, preliminarily selected PS candidates are directly used to construct and update a triangular irregular network (TIN) to maintain the stability of the subsequent Delaunay TIN. To implement this method, a differential-phase standard-deviation threshold method is proposed to extract PSs that are highly spatially coherent and consistent. Finally, the proposed CPSS was applied to the safety monitoring of the dam. The monitoring results are compared with conventional inverted plumb line monitoring results, and the proposed CPSS is found to be effective and reliable.
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Albano, Raffaele, Leonardo Mancusi, Jan Adamowski, Andrea Cantisani et Aurelia Sole. « A GIS Tool for Mapping Dam-Break Flood Hazards in Italy ». ISPRS International Journal of Geo-Information 8, no 6 (29 mai 2019) : 250. http://dx.doi.org/10.3390/ijgi8060250.
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Mapping the delineation of areas that are flooded due to water control infrastructure failure is a critical issue. Practical difficulties often present challenges to the accurate and effective analysis of dam-break hazard areas. Such studies are expensive, lengthy, and require large volumes of incoming data and refined technical skills. The creation of cost-efficient geospatial tools provides rapid and inexpensive estimates of instantaneous dam-break (due to structural failure) flooded areas that complement, but do not replace, the results of hydrodynamic simulations. The current study implements a Geographic Information System (GIS) based method that can provide useful information regarding the delineation of dam-break flood-prone areas in both data-scarce environments and transboundary regions, in the absence of detailed studies. Moreover, the proposed tool enables, without advanced technical skills, the analysis of a wide number of case studies that support the prioritization of interventions, or, in emergency situations, the simulation of numerous initial hypotheses (e.g., the modification of initial water level/volume in the case of limited dam functionality), without incurring high computational time. The proposed model is based on the commonly available data for masonry dams, i.e., dam geometry (e.g., reservoir capacity, dam height, and crest length), and a Digital Elevation Model. The model allows for rapid and cost-effective dam-break hazard mapping by evaluating three components: (i) the dam-failure discharge hydrograph, (ii) the propagation of the flood, and (iii) the delineation of flood-prone areas. The tool exhibited high accuracy and reliability in the identification of hypothetical dam-break flood-prone areas when compared to the results of traditional hydrodynamic approaches, as applied to a dam in Basilicata (Southern Italy). In particular, the over- and under-estimation rates of the proposed tool, for the San Giuliano dam, Basilicata, were evaluated by comparing its outputs with flood inundation maps that were obtained by two traditional methods whil using a one-dimensional and a two-dimensional propagation model, resulting in a specificity value of roughly 90%. These results confirm that most parts of the flood map were correctly classified as flooded by the proposed GIS model. A sensitivity value of over 75% confirms that several zones were also correctly identified as non-flooded. Moreover, the overall effectiveness and reliability of the proposed model were evaluated, for the Gleno Dam (located in the Central Italian Alps), by comparing the results of literature studies concerning the application of monodimensional numerical models and the extent of the flooded area reconstructed by the available historical information, obtaining an accuracy of around 94%. Finally, the computational efficiency of the proposed tool was tested on a demonstrative application of 250 Italian arch and gravity dams. The results, when carried out using a PC, Pentium Intel Core i5 Processor CPU 3.2 GHz, 8 GB RAM, required about 73 min, showing the potential of such a tool applied to dam-break flood mapping for a large number of dams.
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Cortijo-García, Alexandro, María Amelia De-Miguel-Sin-Monge, Jesús Rodríguez-Gamero, Marcos García-Alberti et Antonio Alfonso Arcos-Álvarez. « Aplicación de BIM a la modelización de una presa arco = BIM Application to an Arch dam modeling ». Anales de Edificación 7, no 3 (31 décembre 2021) : 20–25. http://dx.doi.org/10.20868/ade.2021.4971.
Texte intégralRésumé :
Building Information Modelling (BIM) es una metodología de trabajo basada en la modelización 3D que ofrece a los profesionales involucrados en los proyectos la información y herramientas necesarias para planificar, diseñar, construir y gestionar edificios e infraestructuras. El objetivo principal de este proyecto es el empleo de la metodología BIM para llevar a cabo la modelización de una presa arco-gravedad, partiendo para ello de la superficie de la cuenca y la geometría de la presa en cuestión. Es importante destacar que, según la literatura científica consultada, se trata de una de las primeras experiencias BIM dedicadas a este ámbito de la ingeniería civil, las presas. Esto es todavía más relevante al haber tenido en cuenta su auscultación. En primer lugar, se procedió a modelizar el conjunto presa - terreno. Para ello, se comenzó llevando a cabo la excavación y cuantificación del volumen de tierras necesario para la cimentación de la presa mediante el software de Autodesk, Civil 3D. A continuación, se modeló en Revit la presa arco de considerables dimensiones. Tras representar cada uno de los bloques que conforman la presa, se definieron las galerías y el aliviadero, de labio fijo y perfil creager. Para la gestión de la presa, y de cara a la explotación, se distinguieron diferentes aparatos de auscultación. Mediante DYNAMO se parametrizaron dichos aparatos y se les asoció una serie de datos y resultados en una hoja de cálculo. De esta forma, se hace posible visualizar la evolución de las medidas tomadas a lo largo de su vida útil y en cada una de las horas fijadas, representando gráficamente los valores obtenidos. Finalmente se empleó la aplicación InfraWorks para poder integrar el terreno y la presa arco para la presentación de la solución final.AbstractBuilding Information Modelling (BIM) is a working methodology based on 3D modelling that provides professionals involved in projects with the information and tools necessary to plan, design, construct and manage buildings and infrastructures. The main objective of this project is the use of BIM methodology to carry out the modelling of an arch-gravity dam, starting from the surface of the basin and the geometry of the dam in question. It is important to highlight that, according to the scientific literature consulted, this is one of the first BIM experiences dedicated to this field of civil engineering, dams. This is even more relevant as its auscultation has been taken into account. First, the dam-terrain complex was modelled. To do this, we began by excavating and quantifying the volume of earth required for the dam foundations using Autodesk's Civil 3D software. Next, the arch dam of considerable dimensions was modelled in Revit. After representing each of the blocks that make up the dam, the galleries, and the spillway, with a fixed lip and creager profile, were defined. For the management of the dam, and with a view to its operation, different auscultation devices were distinguished. These devices were parameterised using DYNAMO and a series of data and results were associated with them in a spreadsheet. In this way, it is possible to visualise the evolution of the measurements taken throughout their useful life and at each of the set times, graphically representing the values obtained. Finally, the InfraWorks application was used to integrate the terrain and the arch dam for the presentation of the final solution.
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Bendjaballah, Soumaya, Redha Lakehal, Farid Aimer, Rabeh Bouharagua, Radouane Boukarroucha et Abdelmalek Brahami. « False aneurism of the aortic arch with bypass on the left lung. A case report ». Batna Journal of Medical Sciences (BJMS) 5, no 1 (25 décembre 2018) : 82–83. http://dx.doi.org/10.48087/bjmscr.2018.5119.
Texte intégralRésumé :
Introduction : La localisation anévrysmale au niveau de la crosse aortique est exceptionnelle, plus rare que celle d’aorte ascendante. C’est une affection grave vu le risque de rupture imposant une chirurgie urgente. Le diagnostic repose sur l’angioscanner et l’angioIRM thoracique. Ce cas est pour nous l’occasion de faire rappeler la gravité de cette affection aussi bien pour les malades que pour les chirurgiens cardiaques. Méthodes : Nous rapportons l'observation d'un adulte âgé de 53 ans aux antécédents d’une chute du premier étage d’un bâtiment il y a deux ans, hospitalisé pour exploration d’une hémoptysie de moyenne abondance et la découverte à la radiographie pulmonaire d’une opacité du lobe supérieur du poumon gauche. Devant cette image suspecte, un angioscanner thoracique a été réalisé montrant le faux anévrysme de la crosse aortique. L’ECG était sans particularité. Le bilan biologique montrait une anémie. Le patient a été opéré sous circulation extracorporelle établie entre l’artère fémorale et la veine fémorale avec hypothermie profonde et arrêt circulatoire. L’exploration peropératoire montre un énorme faux anévrysme de la crosse aortique colmaté par le lobe supérieur du poumon gauche avec fistulisation du faux anévrysme dans ce dernier. L’intervention avait consisté après mise à plat du faux anévrisme en la réparation de la perte de substance aortique par un patch en dacron latéral sous arrêt circulatoire et aveuglement de la brèche pulmonaire. Résultats : Les suites postopératoires immédiates étaient défavorables avec décès du patient par choc cardiogénique réfractaire. Conclusion : Les progrès de l'imagerie font de l'angioTDM et l’angioIRM les examens de choix dans la détection des faux anévrismes de la crosse aortique. L'indication opératoire est formelle dans tous les cas de faux anévrismes de la crosse aortique car l'évolution spontanée est mortelle. En fait, le véritable traitement est la chirurgie ou l’endovasculaire.
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« Limiting state of rock foundation of gravity and arch dams ». International Journal of Rock Mechanics and Mining Sciences & ; Geomechanics Abstracts 29, no 2 (mars 1992) : A119. http://dx.doi.org/10.1016/0148-9062(92)92497-z.
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Rezaiee-Pajand, M., M. S. Kazemiyan et A. Aftabi Sani. « A Literature Review on Dynamic Analysis of Concrete Gravity and Arch Dams ». Archives of Computational Methods in Engineering, 2 mars 2021. http://dx.doi.org/10.1007/s11831-021-09564-z.
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Zoorabadi, M., et Trevor G. Carter. « Assessment of concrete–rock contact shear behaviour based on in situ shear tests ». Dams and Reservoirs, 3 février 2022, 1–10. http://dx.doi.org/10.1680/jdare.21.00006a.
Texte intégralRésumé :
Defining shear strengths of concrete–rock contacts is extremely important for designing concrete structures such as arch and gravity concrete dams that are constructed on rock. Assessment of 34 large-scale in situ direct shear tests conducted on concrete–rock contacts of various roughnesses is presented in this paper. Evaluation of the peak strength results at moderate-to-low stress ranges, indicates that a non-linear trend with maximum at moderate roughness (joint roughness coefficient, JRC = 11–12) can reasonably represent relationships between peak and apparent shear strengths, shear stiffness and shear displacement relationships with respect to JRC. Apparent residual strength parameters appear to show a more linear Mohr–Coulomb to slightly non-linear trend with JRC and applied normal stress.
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Andi, M., H. Dashti-Naserabadi et M. Beyklarian. « Investigating the nonlinear dynamic seismic response of double curvature arch dams under spatial and temporal excitation of heterogeneous ground motion ». Revista Internacional de Métodos Numéricos para Cálculos y Diseño en Ingeniería 37, no 3 (2021). http://dx.doi.org/10.23967/j.rimni.2021.12.004.
Texte intégralRésumé :
One of the factors affecting the dynamic state of the dams that may cause damages to the dam is the change under the spatial and temporal Excitation of the Heterogeneous ground Motion. Therefore, in different states the stress, strain, displacement and hydrostatic pressure indices are changed and led to serious damage to the dam. In this study, Karun 3 dam is investigated which is classified as one of the double curvature arch and gravity dams. For this purpose, using ABAQUS software, these indices have been investigated and controlled and the effectiveness of indices in this dam has been investigated in nonlinear dynamic seismic state. Northridge, Kobe, Bam, Hector, Chi-Chi and Manjil earthquakes are applied to the Karun 3 Dam. The results showed that due to the large amplitude and periodicity of the near-fault mappings, under the near-field earthquake, the deformation of the Karun 3 dam is greater than the far-field fault zone. As the height of the Karun 3 Dam rises, the effectiveness of far-field earthquakes declines and near-field earthquakes show more impact on the structure. In far-field earthquakes, stress changes due to earthquakes with maximum dynamic acceleration, the relative percentage of mises stress change is 15.5% and maximum dam crest change is 68.5 mm, and for near-field earthquakes is 25% and maximum dam crest change is 100 mm.