scholarly journals Unit Root Analysis Method of Actual Crack Behavior of the Concrete Dam Based on Residuals of the Monitoring Model

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Bo Xu ◽  
Zhanchao Li ◽  
Jinlei Zhao
Keyword(s):  
Unit Root ◽  
Monitoring Data ◽  
Estimation Methods ◽  
Analysis Method ◽  
Concrete Dam ◽  
Monitoring Model ◽  
Crack Behavior ◽  
Autoregression Model ◽  
Root Analysis ◽  
Behavior Based

Analysis on the actual crack behavior is of important significance to evaluate safety of the concrete dam. In this paper, mainly based on the research status on cracks of the concrete dam, the unit root analysis method of actual crack behavior of concrete dam is proposed based on the monitoring data and autoregression model, aiming to enrich the analysis methods of crack behavior of concrete dam and deepen the understanding of crack behavior of concrete dam. Firstly, the feasibility of analyzing actual crack behavior based on residual sequence of the crack opening displacement monitoring model is discussed. Next, the basic principle of the unit root analysis method of crack behavior is elaborated and the unit root analysis method of actual crack behavior is established by studying prior conditions of the autoregression model and parameter estimation methods of the autoregression model, as well as determination criteria of the model order. Finally, the proposed unit root analysis method of actual crack behavior is applied to analyze monitoring data of a concrete gravity-arch dam. The result shows that the unit root analysis method of actual crack behavior is relatively simple and convenient in practical application, which is an available method to evaluate crack behavior based on data in dam health monitoring.

scholarly journals Amplitude domain analysis of strong range and Doppler spread radar echos

2008 ◽  
Vol 26 (8) ◽  
pp. 2419-2426 ◽  
Author(s):  
J. Vierinen ◽  
M. S. Lehtinen ◽  
I. I. Virtanen
Keyword(s):  
Domain Analysis ◽  
Doppler Spread ◽  
Estimation Methods ◽  
Radar Target ◽  
Analysis Method ◽  
Novel Method ◽  
Head Echo

Abstract. We present a novel method for analyzing range and Doppler spread targets in the amplitude domain using linear statistical inversion. The result of the analysis is an estimate of the range dependent amplitude behaviour of the target backscatter during the time that the transmission passes the target. A meteor head echo and strong backscatter from artificially heated regions of the ionosphere are used to demonstrate this novel analysis method. Plans to apply amplitude-domain radar target estimation methods to more complicated noisy underdetermined targets are also briefly discussed.

scholarly journals Crack-Considered Elastic Net Monitoring Model of Concrete Dam Displacement

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiingmei Zhang ◽  
Chongshi Gu
Keyword(s):  
Water Pressure ◽  
Elastic Net ◽  
Arch Dam ◽  
Time Dependent ◽  
Concrete Dams ◽  
Displacement Monitoring ◽  
Concrete Dam ◽  
Monitoring Model ◽  
Proposed Model ◽  
Dependent Component

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.

Unit root analysis

2020 ◽  
Author(s):  
Steve Cook
Keyword(s):  
Unit Root ◽  
Root Analysis

scholarly journals Nonparametric Change Point Diagnosis Method of Concrete Dam Crack Behavior Abnormality

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Zhanchao Li ◽  
Chongshi Gu ◽  
Zhongru Wu
Keyword(s):  
Statistical Model ◽  
Change Point ◽  
Hot Spot ◽  
Test Method ◽  
Point Problem ◽  
Concrete Dam ◽  
Change Point Problem ◽  
Crack Behavior ◽  
Diagnosis Method ◽  
Nonparametric Statistical

The study on diagnosis method of concrete crack behavior abnormality has always been a hot spot and difficulty in the safety monitoring field of hydraulic structure. Based on the performance of concrete dam crack behavior abnormality in parametric statistical model and nonparametric statistical model, the internal relation between concrete dam crack behavior abnormality and statistical change point theory is deeply analyzed from the model structure instability of parametric statistical model and change of sequence distribution law of nonparametric statistical model. On this basis, through the reduction of change point problem, the establishment of basic nonparametric change point model, and asymptotic analysis on test method of basic change point problem, the nonparametric change point diagnosis method of concrete dam crack behavior abnormality is created in consideration of the situation that in practice concrete dam crack behavior may have more abnormality points. And the nonparametric change point diagnosis method of concrete dam crack behavior abnormality is used in the actual project, demonstrating the effectiveness and scientific reasonableness of the method established. Meanwhile, the nonparametric change point diagnosis method of concrete dam crack behavior abnormality has a complete theoretical basis and strong practicality with a broad application prospect in actual project.

Study on Determining Safety-Monitoring Index for Concrete Dam Based on Cloud Model

2012 ◽  
Vol 226-228 ◽  
pp. 1106-1110 ◽  
Author(s):  
Dong Qin ◽  
Xue Qin Zheng ◽  
Song Lin Wang
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Cloud Model ◽  
Safety Monitoring ◽  
Monitoring Data ◽  
Concrete Dam ◽  
Deterministic Function ◽  
Monitoring Index

The paper, based on analyzing original monitoring data, employs forward and backward cloud algorithm in studying determining safety-monitoring index for concrete dam ,which integrates randomness and fuzziness into of qualitative concept of digital features. By means of above monitoring data, its digital characteristics can be easily transformed to the “quantitative-qualitative- quantitative” change. The final generated quantitative value constitutes the cloud diagram where each droplet demonstrates the characterization of raw monitoring data. At the same time, it also shows the randomness and fuzziness of monitored value. we can study out the safety monitoring indexes according to different remarkable levels by using the probability density function and deterministic function which completed by cloud algorithm. In the end, it is obtained with practice that this method is more suitable and reliability.

Application of Improved BP Neural Network Model in Uplift Pressure Monitoring

2011 ◽  
Vol 304 ◽  
pp. 24-30
Author(s):  
Yi Tao Mei ◽  
Dong Jian Zheng ◽  
Lei Xu
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Measured Data ◽  
Pressure Monitoring ◽  
Concrete Dam ◽  
Slow Convergence ◽  
Uplift Pressure ◽  
Monitoring Model ◽  
Actual Application ◽  
Bp Neural Network Model

The network structure, initial weights and initial thresholds were optimized to solve some problems, such as over-fitting and slow convergence rate in standard BP Neural Network. Combining the base seepage character of concrete dam, a uplift pressure monitoring model is established in this paper with measured data of a actual concrete dam . The advantage of the presented model is tested and validated by actual examples. It has positive significance in the actual application.

Sign in / Sign up

Export Citation Format

Share Document