scholarly journals A Deformation Prediction Model of High Arch Dams in the Initial Operation Period Based on PSR-SVM-IGWO

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Mingjun Li ◽  
Jiangyang Pan ◽  
Yaolai Liu ◽  
Hao Liu ◽  
Junxing Wang ◽  
...  
Keyword(s):  
Time Series ◽  
Phase Space ◽  
Entropy Method ◽  
Arch Dam ◽  
Support Vector ◽  
Initial Operation ◽  
High Arch Dam ◽  
Deformation Prediction ◽  
Arch Dams ◽  
Operation Period

The deformation prediction of the dam in the initial stage of operation is very important for the safety of high dams. A hybrid model integrating chaos theory, support vector machine (SVM), and an improved Grey Wolf Optimization (IGWO) algorithm is developed for deformation prediction of dam in the initial operation period. Firstly, the chaotic characteristics of the dam deformation time series will be identified, mainly using the Lyapunov exponent method, the correlation dimension method, and the Kolmogorov entropy method. Secondly, the SVM-IGWO model based on phase space reconstruction (PSR) is established for deformation forecasting of the dam in the initial operation period. Taking SVM as the core, the deformation time series is reconstructed in phase space to determine the input variables of SVM and the GWO algorithm is improved to realize the optimization of SVM parameters. Finally, take the actual monitoring displacement of Xiluodu super-high arch dam as an example. The engineering application example shows that, compared with the existing models, the prediction accuracy of the PSR-SVM-IGWO model established in this paper is improved.

scholarly journals Zoning Elastic Modulus Inversion for High Arch Dams Based on the PSOGSA-SVM Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Bo Chen ◽  
Xiao Fu ◽  
Xuyuan Guo ◽  
Chongshi Gu ◽  
Chenfei Shao ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Search Algorithm ◽  
Arch Dam ◽  
Support Vector ◽  
Inversion Method ◽  
Training Set ◽  
High Arch Dam ◽  
Arch Dams ◽  
Inversion Model ◽  
High Arch Dams

Real-time monitoring of the actual elastic modulus is essential and necessary to ensure the safe operation of arch dams. The zoning elastic modulus of a high arch dam is inversed by using deformation safety monitoring data in the operation period, based on the particle swarm optimization with gravitation search algorithm for support vector machine (PSOGSA-SVM) method. Firstly, the measured data of multipoints with a pendulum are separated to construct the initial sample training set; then, an optimal inversion model is established to reflect the complex nonlinear relationship between the mechanical parameters of the high arch dam and the deformation of measured points; finally, the PSOGSA-SVM method is used to train and dynamically update the training set so as to realize the optimization solution of the inversion model. The proposed inversion method is successfully applied to a high arch dam in China to verify its feasibility and validity. The results show that the actual elastic modulus of the dam body is much larger than the initial elastic modulus, which is beneficial to structural stability.

Weight Analysis on Influencing Factors of Reservoir Basin Deformation

2013 ◽  
Vol 405-408 ◽  
pp. 617-620
Author(s):  
Er Feng Zhao ◽  
Li Bing Zhang
Keyword(s):  
Simulation Model ◽  
Influence Factor ◽  
Element Model ◽  
Entropy Method ◽  
Deformation Monitoring ◽  
Water Levels ◽  
Arch Dam ◽  
High Arch Dam ◽  
Arch Dams ◽  
Reservoir Basin

Reservoir basin deformation monitoring data of some high arch dams has shown that the upstream of the dam subsided while the downstream warped upward slightly. Therefore, combining reservoir basin with high arch dam and foundation, the widespread finite element model is built and the reservoir basin deformation and its influence factor weight are determined through the simulation of the bedrock depth, the extending length of the upstream and downstream and different water levels based on an improved entropy method. The engineering simulation model has proved the reservoir basin deformation mechanism. Moreover, the reservoir basin deformation will tend to converge when the simulation model expands to certain extent. The research can provide suggestions for deformation doubts occurring during the high arch dam operation.

scholarly journals Seismic Assessment of Arch Dams Using Fragility Curves

2015 ◽  
Vol 1 (2) ◽  
pp. 14-20 ◽  
Author(s):  
Vandad Kadkhodayan ◽  
S. Meisam Aghajanzadeh ◽  
Hasan Mirzabozorg
Keyword(s):  
Fragility Curves ◽  
Routine Data ◽  
Seismic Assessment ◽  
Arch Dam ◽  
The Other ◽  
Intensity Measure ◽  
Limit States ◽  
High Arch Dam ◽  
Arch Dams ◽  
Engineering Demand Parameter

In the present paper, the IDA approach is applied to analyzing a thin high arch dam. The parameters of Sa, PGA and PGV are used as intensity measure (IM) and the overstressed area (OSA) is utilized as engineering demand parameter (EDP) and then, three limit states are assigned to the considered structure using the IDA curves. Subsequently, fragility curves are calculated and it is showed that the PGA is a better parameter to be taken as IM. In addition, it is found that the utilizing the proposed methodology, quantifying the qualitative limit states is probable. At last, having the fragility curves and considering their slope in addition to the other routine data which can be extracted from these curves, one may be able to conclude that in what performance level the considered dam body seems to be weak and needs retrofitting works.

scholarly journals The Effect of Shear Sliding of Vertical Contraction Joints on Seismic Response of High Arch Dams with Fine Finite Element Model

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Shengshan Guo ◽  
Jianxin Liao ◽  
Hailong Huang ◽  
Hui Liang ◽  
Deyu Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Response ◽  
Element Model ◽  
Arch Dam ◽  
Slip Condition ◽  
Dead Load ◽  
High Arch Dam ◽  
Arch Dams ◽  
Contraction Joints

The contraction joints of arch dams with and without shear keys are simplified to be with no-slip condition and with relative sliding condition, respectively. Based on the Lagrange multiplier method, a contact model considering the manner of independent cantilever dead load type with no-slip condition and relative sliding condition is proposed to model the nonlinearities of vertical contraction joins, which is special to the nonlinear analysis of arch dams considering the manner of dead load type. Different from the conventional Gauss iterative method, the strategy of the alternating iterative solution of normal force and tangential force is employed. The parallelization based on overlapping domain decomposition method (ODDM) and explicit message passing using distributed memory parallel computers is employed to improve the computational efficiency. An existing high arch dam with fine finite element model is analyzed to investigate the effect of shear sliding of vertical joints on seismic response of the arch dam. The result shows that the values of maximum principal tensile stress under relative sliding condition are significantly greater than those under no-slip condition.

Arch Dam Deformation Prediction Model Based on PSO-SVM

2013 ◽  
Vol 351-352 ◽  
pp. 1306-1311 ◽  
Author(s):  
Jing Yang Liu ◽  
He Zhi Liu
Keyword(s):  
Prediction Model ◽  
Large Scale ◽  
Small Sample ◽  
Arch Dam ◽  
Support Vector ◽  
Model Parameters ◽  
Deformation Prediction ◽  
Dam Foundation ◽  
Model Based ◽  
Dam Deformation

Arch dam has gradually evolved as one of dam type as main large-scale hydraulic project, dam deformation prediction is an important part of dam safety monitoring, and it is difficult to forecast because of the complicated nonlinear characteristics of the monitoring data. Support Vector Machine (SVM) could solve the small sample, nonlinear high dimension problem due to the excellent generalization ability, and hence it has been widely used in the forecast of arch dam deformation. However, the forecast results considerably depend on the choice of SVM model parameters. In this paper, Particle Swarm Optimization (PSO), which has the characteristic of fast global optimization, was applied to optimize the parameters in SVM, and then the dam deformation prediction model based on PSO-SVM could be established. The model is applied to a certain arch dam foundation prediction. The accuracy of this employed approach was examined by comparing it with multiple regression method. In a word, the experimental results indicate that the proposed method based on PSO-SVM can be used in arch dam deformation prediction.

scholarly journals Nonlinear Response of High Arch Dams to Nonuniform Seismic Excitation Considering Joint Effects

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Masoomeh Akbari ◽  
Mohammad Amin Hariri-Ardebili ◽  
Hasan Mirzabozorg
Keyword(s):  
Structural Response ◽  
Incompressible Material ◽  
Arch Dam ◽  
High Arch Dam ◽  
Arch Dams ◽  
Base Level ◽  
Nonlinear Responses ◽  
Wave Passage ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying

Nonuniform excitation due to spatially varying ground motions on nonlinear responses of concrete arch dams is investigated. A high arch dam was selected as numerical example, reservoir was modelled as incompressible material, foundation was assumed as mass-less medium, and all contraction and peripheral joints were modelled considering the ability of opening/closing. This study used Monte-Carlo simulation approach for generating spatially nonuniform ground motion. In this approach, random seismic characteristics due to incoherence and wave passage effects were investigated and finally their effects on structural response were compared with uniform excitation at design base level earthquake. Based on the results, nonuniform input leads to some differences than uniform input. Moreover using nonuniform excitation increase, stresses on dam body.

Research Progress of Protected Plunge Pool of High Arch Dam

2014 ◽  
Vol 919-921 ◽  
pp. 1244-1247 ◽  
Author(s):  
Ying Kui Wang ◽  
Ren Qiang Liao
Keyword(s):  
Energy Dissipation ◽  
Southwest China ◽  
Arch Dam ◽  
Research Progress ◽  
Project Design ◽  
High Arch Dam ◽  
Arch Dams ◽  
Plunge Pool ◽  
Large Investment ◽  
High Arch Dams

The security researches of energy dissipation were always the focus in the High arch dams. Statistically, the trajectory type energy dissipation is the most widely used in the built high arch dams, and the protected plunge poor were always set downstream the dam body. However, the widely used protected plunge poor need large investment with the disadvantage of complicated operation and maintenance. Along with the construction of concrete high arch dam in the Southwest China, the “Reventment-Protected and Non-Bottom-Protected Plunge Pool” has been studied and proposed, which has the advantage of more simplified project design and more economy investment.

scholarly journals Chaotic Vibration Prediction of a Free-Floating Flexible Redundant Space Manipulator

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Congqing Wang ◽  
Linfeng Wu
Keyword(s):  
Time Series ◽  
Phase Space ◽  
Prediction Model ◽  
Dynamic Model ◽  
Chaotic Time Series ◽  
Joint Torque ◽  
Support Vector ◽  
Space Manipulator ◽  
Chaotic Vibration ◽  
Vibration Prediction

The dynamic model of a planar free-floating flexible redundant space manipulator with three joints is derived by the assumed modes method, Lagrange principle, and momentum conservation. According to minimal joint torque’s optimization (MJTO), the state equations of the dynamic model for the free-floating redundant space manipulator are described. The PD control using the tracking position error and velocity error in the manipulator is introduced. Then, the chaotic dynamic behavior of the manipulator is analyzed by chaotic numerical methods, in which time series, phase plane portrait, Poincaré map, and Lyapunov exponents are used to analyze the chaotic behavior of the manipulator. Under certain conditions for the joint torque optimization and initial values, chaotic vibration motion of the space manipulator can be observed. The chaotic time series prediction scheme for the space manipulator is presented based on the theory of phase space reconstruction under Takens’ embedding theorem. The trajectories of phase space can be reconstructed in embedding space, which are equivalent to the original space manipulator in dynamics. The one-step prediction model for the chaotic time series and the chaotic vibration was established by using support vector regression (SVR) prediction model with RBF kernel function. It has been proved that the SVR prediction model has a good performance of prediction. The experimental results show the effectiveness of the presented method.

The Research on the Relation between Flexibility Coefficient and Buckling Stability of High Arch Dam

2012 ◽  
Vol 594-597 ◽  
pp. 1932-1935
Author(s):  
Hui Li ◽  
Zheng Zhong Wang ◽  
Xuan She
Keyword(s):  
Differential Method ◽  
Arch Dam ◽  
Present Condition ◽  
High Arch Dam ◽  
North West ◽  
Arch Dams ◽  
South West ◽  
Buckling Stability ◽  
Flexibility Coefficient ◽  
High Arch Dams

As a result of many high arch dams that are building and would be built in the south-west and north-west of China, arch dam is a kind of compressed thin buckle, not only effect by tension, but also by deformation. Thinner dam body with usage of increased levels of concrete and optimum designing, the local regions of high arch dams approach thin shell structure，which will lead to the structural buckling. Base on the above present condition, this paper would establish a series of generalized high and thin arch dam models whose height are 240m, and make theoretical analysis based on one of the crown- cantilever method- differential method for them, which attempts to provide a new method for the" critical flexibility coefficient ". At last, this paper would provide the relation between coefficient and buckling stability of high arch dam

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