Abstract:Dam safety assessment is typically made by comparison between the outcome of some predictive model and measured monitoring data. This is done separately for each response variable, and the results are later interpreted before decision making. In this work, three approaches based on machine learning classifiers are evaluated for the joint analysis of a set of monitoring variables: multi-class, two-class and one-class classification. Support vector machines are applied to all prediction tasks, and random forest … Show more
“…Overall error analysis represented the cross-validation results of all measuring points in each measurement by calculating the mean absolute error (MAE). It analyzed the error sequence of each measurement as a whole, as seen in Equation (9). The lower the MAE, the higher the overall accuracy.…”
Section: Discussion On the Threshold Of Covariate Introductionmentioning
confidence: 99%
“…At present, the repair of safety monitoring data mainly starts from the dimension of time and mostly adopts linear regression analysis [6,7], principal component analysis [8], machine learning algorithm [9,10], and so on. Among them, Vazifehdan et al [11] proposed a method of combining a naive Bayesian network with tensor decomposition to repair missing data.…”
The safe operation of dams is related to the lifeline of the national economy, the safety of the people, and social stability, and dam safety monitoring plays an essential role in scientifically controlling the safety of dams. Since the effects of environmental variables were not considered in conventional monitoring data repairing methods (such as the single time series model and spatial interpolation model), a spatial model for repairing monitoring data combining the variable importance for projection (VIP) method and cokriging was put forward in this paper. In order to improve the accuracy of the model, the influence of different combinations of covariates on it was discussed, and the VIPj value greater than 0.8 was proposed as the threshold of covariates. The engineering verification shows that the VIP-cokriging spatial model had the advantages of high precision and strong applicability compared with the inverse distance weighting (IDW) model, the ordinary kriging model, and the universal kriging model, and the overall error can be reduced by more than 60%, which could better realize the expansion of the monitoring effect variable to the whole area of the dam space. The engineering application of the PBG dam showed that the model scientifically correlated the existing monitoring points with the spatial location of the dam, and reasonably repaired the measured values of the stopping and abnormal measured points, effectively ensuring that the spatial regular of the monitoring data could truly reflect the actual safety and operational status of the dam.
“…Overall error analysis represented the cross-validation results of all measuring points in each measurement by calculating the mean absolute error (MAE). It analyzed the error sequence of each measurement as a whole, as seen in Equation (9). The lower the MAE, the higher the overall accuracy.…”
Section: Discussion On the Threshold Of Covariate Introductionmentioning
confidence: 99%
“…At present, the repair of safety monitoring data mainly starts from the dimension of time and mostly adopts linear regression analysis [6,7], principal component analysis [8], machine learning algorithm [9,10], and so on. Among them, Vazifehdan et al [11] proposed a method of combining a naive Bayesian network with tensor decomposition to repair missing data.…”
The safe operation of dams is related to the lifeline of the national economy, the safety of the people, and social stability, and dam safety monitoring plays an essential role in scientifically controlling the safety of dams. Since the effects of environmental variables were not considered in conventional monitoring data repairing methods (such as the single time series model and spatial interpolation model), a spatial model for repairing monitoring data combining the variable importance for projection (VIP) method and cokriging was put forward in this paper. In order to improve the accuracy of the model, the influence of different combinations of covariates on it was discussed, and the VIPj value greater than 0.8 was proposed as the threshold of covariates. The engineering verification shows that the VIP-cokriging spatial model had the advantages of high precision and strong applicability compared with the inverse distance weighting (IDW) model, the ordinary kriging model, and the universal kriging model, and the overall error can be reduced by more than 60%, which could better realize the expansion of the monitoring effect variable to the whole area of the dam space. The engineering application of the PBG dam showed that the model scientifically correlated the existing monitoring points with the spatial location of the dam, and reasonably repaired the measured values of the stopping and abnormal measured points, effectively ensuring that the spatial regular of the monitoring data could truly reflect the actual safety and operational status of the dam.
“…On the other hand, some scholars have studied the anomaly identification of uplift pressure during the operation period of concrete dams, and the applicability of various anomaly identification methods is compared [19]. The membership cloud method was proposed for identifying abnormal data by Zhu et al [20], and the uplift pressure monitoring data of the Gongzui gravity dam is identified.…”
As an essential load of the concrete dam, the abnormal change of uplift pressure directly threatens the safety and stability of the concrete dam. Therefore, it is of great significance to accurately and efficiently excavate the hidden information of the uplift pressure monitoring data to clarify the safety state of the concrete dam. Therefore, in this paper, density-based spatial clustering of applications with noise (DBSCAN) method is used to intelligently identify the abnormal occurrence point and abnormal stable stage in the monitoring data. Then, an application method of measured uplift pressure is put forward to accurately reflect the spatial distribution and abnormal position of uplift pressure in the dam foundation. It is easy to calculate and connect with the finite element method through self-written software. Finally, the measured uplift pressure is applied to the finite element model of the concrete dam. By comparing the structural behavior of the concrete dam under the design and measured uplift pressure, the influence of abnormal uplift pressure on the safety state of the concrete dam is clarified, which can guide the project operation. Taking a 98.5 m concrete arch dam in western China as an example, the above analysis ideas and calculation methods have been verified. The abnormal identification method and uplift pressure applying method can provide ideas and tools for the structural diagnosis of a concrete dam.
“…Мониторинг нагрузок на конструкцию и ее реакцию на них может помочь в определении ненормального поведения этой конструкции. В целом мониторинг состоит как из измерений, так и из визуальных осмотров [2]. Для облегчения наблюдения за гидротехническими сооружениями они должны быть постоянно оборудованы соответствующими контрольноизмерительными приборами и/или пунктами наблюдения в соответствии с целями наблюдения, типом и размером сооружения, а также условиями площадки.…”
Structures with a large mass (dams) are exposed to internal and external natural and man-made factors that negatively affect both structural elements and the entire infrastructure facility. The impact leads to the instability of the geometric parameters of the building object and the relative displacements of its parts. Monitoring and measuring the parameters of this movement over certain periods of time gives specialists a clear idea of the nature of the changes. The above study allowed the development of technical recommendations for conducting accurate studies of the structural deformation of dams and hydraulic flood protection systems. Standards for accuracy, procedures and quality control have been defined for monitoring movements in hydraulic structures.
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