Simulation Of Far Field Energy Dissipation For High Intake Tower Bedrock In Meizoseismal Area

Intake tower is set in the L-shaped foundation. Intake tower is the first building of water intake and discharge, which can act as flood, sediment discharge building, can also be used for water supply, irrigation and water power generation building. The design quality of intake tower is not only relation to its own functions, but also the entire hydropower station operation.Compared with dam maintain stable by gravity alone, intake tower maintain stable by gravity and tower back rock support.As long as the stress of base surface within the rock allowable stress, the intake tower overall instability will not occur. Therefore, the most concerned about intake tower is the seismic performance.Intake tower seismic performance is to research the structure-foundation dynamic interaction. In this dissertation, artificial boundaries, especially viscous boundary and visco-elastic artificial boundary are used to analysis the intake tower and foundation interaction. In addition to general structure-foundation dynamic interaction, intake tower seismic performance should consider the impact of tower back rock. Traditional seismic analysis majority use fixed boundary model and not consider the mass of foundation, which introduces nonexistent reflection seismic wave. In order to eliminate impact of fixed boundary and consider seismic performance of intake tower, this series of studies carried out. The major contents in this dissertation are as follows:(1) Some structure-foundation dynamic interaction methods were systematically summarized. Based on artificial boundary theory and its implementation process, analyze viscous artificial boundary and visco-elastic artificial boundary. At the same time, Lysmer, Deeks, Liao Zhenpeng, Liu Jingbo and Du Xiuli artificial boundaries is reviewed.(2) Introduction dynamic analysis finite element method of solid medium, liquid medium and liquid-solid two-phase saturated medium and dynamic analysis methods of intake tower. Comparing the difference between fixed boundary and visco-elastic artificial boundary with liquid-solid two-phase saturated medium example.(3) For the real simulation of structure-foundation dynamic interaction, seismic wave data is processing and implements seismic wave data input of viscous and visco-elastic artificial boundary.(4) By the redevelopment of ABAQUS finite element software, write UVE.for (User subroutine to define viscous elements) and UVEE.for (User subroutine to define visco-elastic elements) program for implement viscous and visco-elastic artificial boundary. And combination it with implicit finite element method applied to dynamic analysis of intake tower.(5) As the intake tower is set in the L-shaped foundation, it is necessary to analyze the impact on intake tower of different wave input direction. By derivation P wave and SV wave oblique wave incidence formula, using examples show its correctness and analyze the impact on intake tower of different wave input direction.(6) Analyze the impact of backfilling height of intake towers rock. Elasto-plastic damage model is used to simulate cracking and the stress re-distribution under the action of the earthquake.(7) Trash rack framework and tower body are the main structures of intake tower, trash rack is flexible system compared with the tower body. Under strong earthquake, the interaction of flexible framework and rigid tower body can not be ignored, thus the longitudinal stays which connect trash rock framework and tower body are the most vulnerable parts. Optimization the longitudinal stays with cover plates can effectively reduce the stress concentration and coordinate the stiffness differences of entire structural system. Optimization measure is very favorable to the seismic design of intake tower.All approaches show that viscous artificial boundary and visco-elastic artificial boundary can be achieved by the redevelopment of ABAQUS, and example results show that the artificial boundary results are more accurate and reasonable than the fixed boundary. Meanwhile, the backfilling height of intake tower rock and input direction of seismic wave significantly affect stress and deformation of intake tower. Elasto-plastic damage model is more realistic simulation stress distribution of intake tower; the results are significant to efficient selection of the appropriate shape and set up the evaluation criteria of structural safety.