Studies On The Fatigue Comulative Damage Analysis Of Concrete Gravity Dam Under The Static And Dynamic Characteristics

A multitude of hundreds of meters level concrete-gravity dams are being built or ready to be built in the southwest part of China,which is rich in water resources and always been a bad area for high intensity earthquakes,therefore,the research on seismic safety and seismic capability of dams are very important.In frequent earthquake area,fatigue damage of concrete will appears because of continuous earthquake influence,this is another reason leads to concrete-gravity dam destroyed failures.In this paper,taking an concrete-gravity dam as example, research on fatigue cumulative damage and static and dynamic characteristics of concrete-gravity dam were carried out.Firstly,static and dynamic force characteristics were studyed deeply through the three-dimensional finite element static and dynamic analysis method.The static force analysis of the gravity dam was reserched under the conditions of normal water level and construction period;modal analysis of this dam was also analyzed by subspace iteration method,its self-vibration characteristics were also gained.Dynamic calculations of the dam were conducted for different seismic intensity levels through mode decomposition response spectrum method and time-history method,distribution rules of stress and displacement in dam were analyzed contrastively. Seismic responses of dam in different seismic intensity levels were analyzed as well.According to concrete fatigue damage,damage quantity values under different strains was gained through using relation curves of relation between damage quantity and fatigue strain,the strain values of dams were gaind from static and dynamic analysis,then eveluating the fatigue condition of concrete and analyzing the destructive characteristic of dam from the strain values.On the hand,condition of damage under different intensities were analyzed,transformation law of damage was gained contrastively under the condition of intensity increase,the transformation law of damage under same intensty and different dynamic computation methods, the fatigue level of concrete would also be analyzed contrastively through the relation curves under different degrees of reliability.In the end, judging the destroy result through comparing through damage quantity and static and dynamic force calculation whether is consistent.The research work in this paper has combined practical engineering closely,based on strain from static and dynamic force analysis. The relation curves of concrete strain and damage quantity have been fittedjudging concrete fatigue properties from defining damage quantity, the fatigue evaluation has been made, I hope the research results will provide value of reference for the constructions of concrete-gravity dam.