Study On Monitoring Method Of Deformation Characteristic For Concrete Gravity Dam Based On Optimized Screening Of Panel Data

Concrete gravity dam is one of the main dam types in river network,and its safety is related to people’s life and property safety and social stability.With the increase of service life and the approaching of design reference period,some concrete gravity dams have entered the aging period of advanced age.Due to the complex internal and external environmental impact,the overall performance degradation and dam material aging of some dam systems have occurred.How to reasonably perceive and control the service performance of dam systems has become a scientific problem of dam engineering.In this paper,the existing monitoring data analysis,effectiveness prediction and parameter identification are insufficient.Based on the dynamic panel monitoring data of concrete gravity dam,mathematical statistics,finite element simulation and signal processing are used to study the deformation monitoring method of concrete gravity dam,so as to realize the accurate prediction and early warning of dam deformation effect,in order to provide theoretical basis and decision support for the long-term safe operation of concrete gravity dam in service.The main research contents are as follows:(1)In view of the abnormal mutation phenomenon in the prototype observation sequence of the dam,based on the combination of the empirical wavelet transform theory and the local outlier factor identification mechanism,a diagnosis and treatment system for abnormal points is constructed to objectively restore the characteristics of monitoring information.In addition,in order to solve the problem of missing data panel,a multiple interpolation scheme based on Markov chain Monte Carlo theory is proposed.(2)In order to reasonably interpret the complex mapping relationship between the independent variable of environmental load and the dependent variable of structural effect,and weaken the mixed frequency signal interference caused by multi-source driving,the monitoring models of deformation signs of concrete gravity dams are established from three different theoretical levels.The inherent information laws of the prototype monitoring data are excavated,and the feedback is applied to the fitting prediction of dam structural displacement effect.(3)In order to further extrapolate the time-varying evolution law of dam structure performance and to overcome the limitations of traditional inversion methods for mechanical parameters of concrete gravity dams,such as inefficient solution and insufficient identification accuracy,an inversion method for equivalent mechanical parameters of concrete gravity dams based on artificial fish swarm algorithm optimization strategy is proposed on the basis of constructing its equivalent multiparameter back-analysis function.(4)Based on the calculation feedback of dam parameter identification and effectiveness monitoring digital model,the safety monitoring indexes of horizontal displacement of in-service concrete gravity dam are determined by confidence interval estimation method,small probability method of typical monitoring effect quantity and structural analysis method respectively,which provides management basis for operation and maintenance safety of dam structure.