Dam Deformation Analysis Research Articles

Innovative Approach to Dam Deformation Analysis: Integration of VMD, Fractal Theory, and WOA-DELM

This paper introduces a novel and comprehensive model for the analysis of dam deformation trends, integrating the variational mode decomposition (VMD) method, fractal theory, and the whale optimization algorithm (WOA) to refine the deep extreme learning machine (DELM) model. This integration allows for a meticulous denoising process through VMD, effectively isolating pertinent signal characteristics from noise and measurement interference. Following this, fractal theory is utilized to conduct an in-depth qualitative analysis of the denoised data, capturing intricate patterns within the deformation trends. The model further evolves with the application of WOA to optimize the DELM model, thereby facilitating an integrated approach that merges qualitative insights with quantitative analysis. The efficacy of this advanced model is demonstrated through a case study, highlighting its capability to deliver accurate and reliable predictions that are in harmony with practical engineering scenarios. This research not only offers a robust framework for analyzing dam deformation trends but also sets a new standard in the field, providing a new solution for assessing structural integrity in hydrological engineering.

Multi-source monitoring data filtering assisted deformation analysis model updating of ultra-high rockfill dam

The deformation monitoring of ultra-high rockfill dams is now characterized by the applications of various monitoring instruments and the comparably dense measurement point deployment. The deformation analysis of rockfill dam can be greatly improved based on the multi-source monitoring data using the model updating technique. However, the model updating of rockfill dam faces challenges such as imbalanced spatial distribution of data, uneven data quality, and information redundancy, which leads to low performance and limits its application. Thus, this study proposes an innovative scheme for deformation analysis model updating, involving multi-source monitoring data filtering and model parameter identification. This scheme reduces the information redundancy, and ensures the finite element analysis (FEA) model of rockfill dam better reflects the actual deformation. The application in the 295 m Lianghekou rockfill dam demonstrates its notably enhancement of FEA accuracy, further improving the safety assessment.

Structural stability analysis of proposed Budhi Gandaki dam and optimization

High-rise arch dams are frequently employed in the construction of large storage-type hydropower projects due to their cost-effectiveness. This study presents the comparison in stress and deformation behavior of concrete dam and concrete face rock-fill dam under worst combination of loads. For illustrative purpose, the proposed double curvature arch dam of Budhigandaki Hydroelectric Project is chosen with some modifications. This study proposed the 3-D finite element method (FEM) for stress and deformation analysis of dam considering material non-linearity between concrete and rock-fill material following Drucker-Prager yield criteria. The proposed methodology is implemented through ANSYS 2021. The hydrodynamic pressure of reservoir water is modeled as added mass using Westergaard approach. The compressive and tensile stress developed in both types of dams are investigated and analyzed for different load combinations. The force acting at base of dam and deformation at crest level is also investigated. The results for both types of dam are found to be comparable which suggests that the wasteful volume of concrete can be replaced by consolidated soil (rock-fill) to decrease the overall construction cost of project.

Study on Influence of Numerical Simulation Accuracy on High Core Wall Rockfill Dam Deformation and Crack Analysis

With the increasing height of rockfill dams, detailed and effective numerical simulation for the dam design and construction has become increasingly important. This paper develops a detailed and effective finite element simulation program for the construction and impoundment process of high large-scale earth rockfill dams and studies the influence of numerical simulation accuracy on dam deformation and crack analysis. By establishing the subdivision mode of conventional elements, the mesh generation of detailed finite element simulation is realized. Using the row compression storage method and the MPI parallel method, the calculation program of the total stiffness matrix is developed on the Linux operating system. On the basis of the detailed simulation program above, the filling and impoundment process of Pubugou high core wall rockfill dam is simulated, and it is found that the influence of simulation accuracy on the core wall zone is greater than that on the rockfill zone. Compared with the dam construction process, the detailed simulation of the impoundment process is more necessary. When simulating the impoundment process, there is a significant effect of simulation accuracy on the simulation result of the upstream side of the core wall and the upstream filtration zone. So, it is necessary to simulate the impoundment process of the earth rockfill dam in detail. Moreover, using the detailed method to simulate the impoundment process of earth rockfill dams can more accurately predict dam cracks.

Deformation and Stability Analysis of a Core Rockfill Dam with Leakage

The No. 4 clay core rockfill dam of the Gongming Reservoir experienced leakages when the reservoir water level was low. To analyze the leakage causes, a series of seepage tests were conducted on the dam materials in this paper. And a three-dimensional finite element stress-seepage coupled calculation model of the dam was established to study the deformation and stresses of the dam under the condition of normal storage water level and the sharp drop in the storage level. The test results show that the permeability coefficient of the clay core material is close to that of the dam shell material, resulting in the leakage of the dam under the condition of the low-water level. The simulation results show that the dam deforms a little under the condition of normal storage water level and the sharp drop in the storage level, and the stress distribution under the condition of the sharp drop in the storage level is basically consistent with that under the condition of normal storage water level. The safety factors of the dam under the two conditions meet the requirements of the specification, but the margin of the safety factor is small.

Deformation analysis of Legemera earthen embankment dam under static condition

Deformation analysis of Legemera earthen embankment dam under static condition

As-Built Inventory and Deformation Analysis of a High Rockfill Dam under Construction with Terrestrial Laser Scanning.

The construction of large earth/rock fill dams, albeit its remarkable progress, still relies largely on past experiences. Therefore, a comprehensive yet dependable monitoring program is particularly beneficial for guiding the practice. However, conventional measurements can only produce limited discrete data. This paper exploits the potential of the terrestrial laser scanning (TLS) for an accurate inventory of as-built states of a concrete-faced rockfill dam under construction and for a full-field analysis of the 3D deformation pattern over its upstream face. For the former, a well-designed 3D geodetic system, with a particular consideration of the topography, promises a regulated acquisition of high-quality and blind-zone-free point cloud at field and also eases the cumbersome data registration process while maintaining its precision in house. For the latter, a problem-tailored processing pipeline is proposed for deformation extraction. Its core idea is to achieve a highly precise alignment of the point clouds with Iterative Closed Point algorithms from different epochs in datum areas that displays a featured, undeformed geometry at stable positions across epochs. Then, the alignment transformation matrix is applied to the point clouds of respective upstream face for each epoch, followed by pairwise comparisons of multiple adjusted point clouds for deformation evaluation. A processing pipeline is used to exploit the peal scene data redundancy of the GLQ dam acquired at six different epochs. Statistical analysis shows that satisfactory accuracy for deformation detection can be repeatably achieved, regardless of the scanner’s positioning uncertainties. The obtained 3D deformation patterns are characterised by three different zones: practically undeformed, outward and inward deformed zones. Their evolutions comply well with real construction stages and unique 3D valley topography. Abundant deformation results highlight the potential of TLS combined with the proposed data processing pipeline for cost-efficient monitoring of huge infrastructures compared to conventional labor-intense measurements.

Deformation Analysis of an Ultra-High Arch Dam under Different Water Level Conditions Based on Optimized Dynamic Panel Clustering

During the operation period, the deformation of an ultra-high arch dam is affected by the large fluctuation of the reservoir water level. Under the dual coupling of the ultra-high dam and the complex water level conditions, the traditional variational analysis method cannot be sufficiently applied to its deformation analysis. The deformation analysis of the ultra-high arch dam, however, is very important in order to judge the dam safety state. To analyze the deformation law of different parts of an ultra-high arch dam, the panel data clustering theory is used to construct a Spatio-temporal characteristic model of dam deformation. In order to solve the difficult problem of the fluctuating displacement of dam deformation with water level effect, three displacement component indexes (absolute quantity, growing, and fluctuation) are proposed to characterize dam deformation. To further optimize the panel clustering deformation model, the objective weight coefficient of clustering comprehensive distance is calculated based on the CRITIC (CRiteria Importance Through Inter-criteria Correlation) method. The zoning rules of the ultra-high arch dam are established by using the idea of the CSP (Constraint Satisfaction Problem) index, and the complex water level of the reservoir is simulated in the whole process. Finally, the dynamic cluster analysis of dam deformation is realized. Through a case study, three typical working conditions including the rapid rise and fall of water level and the normal operation are calculated, and the deformation laws of different deformation zones are analyzed. The results show that the model can reasonably describe the deformation law of an ultra-high arch dam under different water levels, conveniently and intuitively select representative measuring points and key monitoring parts, effectively reducing the analysis workload of lots of measuring points, and improve the reliability of arch dam deformation analysis.

Stress and Deformation Analysis of High Concrete Face Rockfill Dam Based on COMSOL Multiphysics

In order to study the stress and deformation characteristics of the high concrete face rockfill dam over 100 meters, in this paper, Duncan-Zhang E-B nonlinear elastic hyperbolic model is adopted, the finite element software COMSOL Multiphysics is used to establish the model and the MATLAB function is used for secondary development to analyze the stress and deformation of the concrete face rockfill dam of the Panshitou reservoir. The stress and deformation characteristics of the concrete face rockfill dam at the completion period, normal water storage condition, designed flood level condition and checked flood level condition are obtained through analysis, which provide theoretical guidance for the construction and operation of the high concrete face rockfill dam of more than 100 meters.

Improving Dam Deformation Analysis Using Least-Squares Variance Component Estimation and Tikhonov Regularization

AbstractSeveral least-squares adjustment techniques were tested for dam deformation analysis. Deformation monitoring had only been studied horizontally. Simulated observations were first performed ...

Long-term deformation analysis of Shuibuya concrete face rockfill dam based on response surface method and improved genetic algorithm

Due to the size effects of rockfill materials, the settlement difference between numerical simulation and in situ monitoring of rockfill dams is a topic of general concern. The constitutive model parameters obtained from laboratory triaxial tests often underestimate the deformation of high rockfill dams. Therefore, constitutive model parameters obtained by back analysis were used to calculate and predict the long-term deformation of rockfill dams. Instead of using artificial neural networks (ANNs), the response surface method (RSM) was employed to replace the finite element simulation used in the optimization iteration. Only 27 training samples were required for RSM, improving computational efficiency compared with ANN, which required 300 training samples. RSM can be used to describe the relationship between the constitutive model parameters and dam settlements. The inversion results of the Shuibuya concrete face rockfill dam (CFRD) show that the calculated settlements agree with the measured data, indicating the accuracy and efficiency of RSM.

A new distributed time series evolution prediction model for dam deformation based on constituent elements

The construction of a mathematical model to predict dam deformation can provide an important basis for judging its operating condition. Due to several time-varying factors, such as water level, temperature and aging, the dam prototype monitoring data series shows non-linear and non-stationary features, which increase the difficulty of dam deformation prediction and analysis. For this reason, a novel distributed deformation prediction model (DDPM), which combines transformation ideology with structured methodology, is proposed to improve the reliability of deformation prediction. DDPM starts by considering three constituent elements of dam deformation series using time series decomposition, and a multi-model fusion strategy is adopted. The trend, periodic and remainder components are separately predicted through constructing the optimal fitting, weight window and remainder generation sub-models. The three predicted components are aggregated as the final predicted output based on an underlying data model. The accuracy and validity of DDPM are verified and evaluated by taking a concrete dam in China as an example and comparing prediction performance with well-established models. The simulation results indicate that DDPM can not only extract more potential data features to obtain good deformation prediction effect, it can also reduce the complexity of mathematical modeling. Furthermore, two other functions of DDPM, including missing value handling and anomaly detection, are also discussed, which ultimately realize the integrated configuration of deformation prediction and data cleaning. The new model provides an alternative method for prediction and analysis of dam deformation and other structural behavior.

Stress and deformation analysis of double curvature arc dams using finite element method (FEM): A case of budhi gandaki hydropower project

High rise arc dams are widely used in the development of storage type hydropower project because of the economic advantage. Among different phases considered during the lifetime of dam, control of dam’s safety and performance becomes more concerned during the lifetime. This paper proposed the 3 – D finite element method (FEM) for stress and deformation analysis of double curvature arc dam considering the non – linearity of foundation rock following the Hoek – Brown Criterion. The proposed methodology is implemented through MATLAB scripting language and studied the double curvature arc dam proposed for Budhi Gandaki hydropower project. The stress developed in the foundation rock, compressive and tensile stress acting on the dam are investigated and analysed for the reservoir level variation. Deformation at the top of the dam and in the foundation rock is also investigated. In addition to that, stress and deformation variation in the foundation rock is analysed for various rock properties.

Deformation analysis of high CFRD considering the scaling effects

In this paper, a predictive method accounting for the scaling effects of rockfill materials in the numerical deformation analysis of rockfill dams is developed. It aims to take into consideration the differences of engineering properties of rockfill materials between in situ and laboratory conditions in the deformation analysis. The developed method is based on the modification of model parameters used in the chosen material model, which is, in this study, an elasto-plastic model with double yield surfaces, i.e., the modified Hardening Soil model. Datasets of experimental tests are collected from previous studies, and a new dataset of the Nam Ngum 2 dam project for investigating the scaling effects of rockfill materials, including particle size, particle gradation and density, is obtained. To quantitatively consider the influence of particle gradation, the coarse-to-fine content (C/F) concept is proposed in this study. The simple relations between the model parameters and particle size, C/F and density are formulated, which enable us to predict the mechanical properties of prototype materials from laboratory tests. Subsequently, a 3D finite element analysis of the Nam Ngum 2 concrete face slab rockfill dam at the end of the construction stage is carried out using two sets of model parameters (1) based on the laboratory tests and (2) in accordance with the proposed method. Comparisons of the computed results with dam monitoring data indicate that the proposed method can provide a simple but effective framework to take account of the scaling effect in dam deformation analysis.

Dam deformation analysis based on BPNN merging models

Hydropower has made a significant contribution to the economic development of Vietnam, thus it is important to monitor the safety of hydropower dams for the good of the country and the people. In this paper, dam horizontal displacement is analyzed and then forecasted using three methods: the multi-regression model, the seasonal integrated auto-regressive moving average (SARIMA) model and the back-propagation neural network (BPNN) merging models. The monitoring data of the Hoa Binh Dam in Vietnam, including horizontal displacement, time, reservoir water level, and air temperature, are used for the experiments. The results indicate that all of these three methods can approximately describe the trend of dam deformation despite their different forecast accuracies. Hence, their short-term forecasts can provide valuable references for the dam safety.

A novel model of dam displacement based on panel data

Deformation monitoring is the main program in the area of dam safety. Because statistical model is simple and intuitive, it is widely used in dam safety monitoring. However, in dam's displacement statistic model, there is a high degree of linear relationship between influence factors. Due to the influence of multicollinearity, models calculated with traditional methods are not accurate and stable. Besides, because of dam integrity, each part of dam is interrelated and interactive. Currently, single point or multipoints displacement monitoring models cannot accurately reflect the actual dam running state. In this paper, the theory of panel data is introduced to dam deformation analysis. Panel data contain time series data and cross section data, which is able to solve serious multicollinearity problem of traditional regression method. Moreover, all measuring points are classified into several groups according to their similar deformation law. Based on the random-coefficient model of panel data, potential relationship between different measuring points is built. Take 1 hydropower station, for example, to examine that random-coefficient model is able to improve the modeling situation that estimators are not significant and simultaneously provide a stable model, which explores a new approach for the research of dam displacement monitoring.

Application of the Periodic Average System Model in Dam Deformation Analysis

Dams are among the most important hydraulic engineering facilities used for water supply, flood control, and hydroelectric power. Monitoring of dams is crucial since deformation might have occurred. How to obtain the deformation information and then judge the safe conditions is the key and difficult problem in dam deformation monitoring field. This paper proposes the periodic average system model and creates the concept of “settlement activity” based on the dam deformation issue. Long-term deformation monitoring data is carried out in a pumped-storage power station, this model combined with settlement activity is used to make the single point deformation analysis, and then the whole settlement activity profile is drawn by clustering analysis. Considering the cumulative settlement value of every point, the dam deformation trend is analyzed in an intuitive effect way. The analysis mode of combined single point with multipoints is realized. The results show that the key deformation information of the dam can be easily grasped by the application of the periodic average system model combined with the distribution diagram of settlement activity. And, above all, the ideas of this research provide an effective method for dam deformation analysis.

A phase space reconstruction based single channel ICA algorithm and its application in dam deformation analysis

Separating noise, systematic errors and deformation components that are caused by different forces such as water pressure and temperature should be identified from dam deformation monitoring data to facilitate effective dam deformation analysis and consequently determine the potential dam structural damage. As source signals are assumed to be mutually independent, independent component analysis (ICA) can be used to separate the source signals from their mixtures. In addition to signal independence, another requirement of ICA theory is that the number of mixtures should not be less than that of source signals. Unfortunately, in most cases of dam deformation monitoring, only a single channel of observed displacement data is available for each monitoring point. Therefore, ICA with single channel data input (called single channel ICA) is necessary in the application of deformation analysis. In this paper, we apply a phase space reconstruction based single channel ICA (PSR-ICA) algorithm to de-noise deformation monitoring data and separate deformation components introduced by different forces from these de-noised data. A numerical simulation is conducted, and results indicate that PSR-ICA is an efficient tool not only for denoising data but also for separating deformation components caused by different forces. PSR-ICA is then further utilised to process the displacement monitoring data of Wuqiangxi Dam. Results indicate that the two extracted main displacement components are nearly consistent with the displacement components; temperature and water level are used as variables and are computed by using a regression model. Both numerical simulated and real life dams demonstrate that PSR-ICA is an effective tool for separating deformation components by different causative forces and is therefore beneficial to dam deformation analysis.

Landslide dam deformation analysis under aftershocks using large-scale shaking table tests measured by videogrammetric technique

The Ms 8.0 Wenchuan earthquake triggered at least 257 landslide dams. More than 849 aftershocks with magnitudes higher than Ms 4.0 occurred after the Wenchuan earthquake by 12 March, 2012 (Shen et al., 2013), which might largely influence the structure and soil properties of these dams. This paper aims to study the dynamic deformation of landslide dams under aftershocks through larger scale shaking table tests. Videogrammetric technique was applied to measure the dynamic deformation of the model dams. Two groups of shaking table tests were conducted with two types of landslide dam materials: one with quartz sands containing 10% kaolin (Dam I) and the other with only quartz sands (Dam II). The dam deformation and its influencing factors were analyzed with the results measured by videogrammetric technique. The deformations were generally higher on the surface of the dams, either on the crest or on the both upstream and downstream slopes. Higher peak ground acceleration (PGA) resulted in larger dam deformations due to higher seismic force. The deformations under the combination of X- and Z-directional shakings were larger than those under X-directional shaking for sufficient vibratory compaction. Water rising led to the increase of dam deformations because that the water seepage reduced the effective soil stress, especially reduced the matric suction. The settlements of the dam composed of more fine particles were larger than that composed of large particle size because that the soil pores in the former were filled more sufficiently with fine particles. The aftershocks may not directly trigger the failures of landslide dams, but accelerate the overtopping failures by lowering the dam crest with settlement and cracking.

Deformation Analysis of Dam with the Improved Wavelet Threshold

This paper introduces the traditional soft and hard threshold wavelet denoising and its improved algorithm,and denoise a dam’s deformation data with MATLAB programming. Compared with previous methods, the improved algorithm improves the de-noising effect quite a lot, the RMSE is obviously decreased while the signal-to-noise is obviously increased,the improved algorithm’s comprehensive precision is higher. Finally,we made a prediction for the results of improved threshold function wavelet de-noising with the use of Kalman filter model and got a good prediction effect,demonstrates that the improved method is an effective denoising method,and shows certain superiority through comparison.