| The Central Yunnan Water Diversion Project is a landmark project among the 172 major water conservancy projects identified by the State Council.It is a strategic foundation to fundamentally solve the problem of water shortage in central Yunnan,effectively improve the water environment of central Yunnan,and ensure sustainable development in Yunnan engineering.The aqueduct(bridge through the water)is an important water conveyance structure for crossing rivers and rivers in valleys in the water diversion project in central Yunnan.It is a typical "top-heavy" structure.At present,the seismic design of an aqueduct can only refer to relevant seismic design codes in highway or railway bridges,and such codes do not involve design methods and related principles of fluid-structure coupling.Therefore,the aqueduct’s static and dynamic response considering fluid-structure coupling studies is Important.This article takes the Luzhi River arch aqueduct in the central Yunnan water diversion project as an example,and mainly does the following research and analysis:(1)Study the influence of the flow velocity on the aqueduct structure under normal flow conditions.The calculation results show that the current design flow velocity of 1.0m / s-2.5m / s in the tank has a limited influence on the horizontal and vertical fluid-structure coupling response of the aqueduct,and it can be ignored for structural analysis of.(2)Calculation results based on fluid domain,a large-scale finite element software is used to establish a static analysis model that considers unidirectional fluidstructure coupling.There is no water in the aqueduct,half of the water is in the aqueduct,and there are three working conditions for the designed water level in the aqueduct.By comparing the vertical deflection and stress results of the main part of the aqueduct under different working conditions,it evaluates the safety performance of the structure on the one hand,and provides certain calculations for the new and reinforced design of the aqueduct on the other.(3)Study the characteristics and laws of the natural vibration characteristics of arched aqueducts.Based on the static model analysis,the displacement-pressure format finite element method in a fluid-structure interaction(FSI)system is used to simulate the effect of the water body on the aqueduct wall.The water body is simulated using a three-dimensional acoustic unit(Fluid 30).The modal calculation is performed under different working conditions.The calculation results show that the existence of water in the trough reduces the natural frequency of the aqueduct,and has little effect on the main mode shape;the transverse aqueduct of the aqueduct has low rigidity in the transverse direction,which requires attention during design.(4)The software is used to establish the finite element dynamic model of the aqueduct.There are two working conditions: no water in the aqueduct and water in the aqueduct.First,the modal calculation of the aqueduct is performed,and the calculation results are compared with the ANSYS modal calculation results.Then,the response spectrum calculation of the aqueduct is performed to study the relationship between the internal force and displacement response of the main aqueduct of the aqueduct and the direction of seismic input.Time history analysis method,the seismic response calculation of the aqueduct under the input of different seismic waves.The calculation results show that the vertical earthquake action has a great influence on the axial force of the arch foot;the maximum value of the internal force response of the arch foot occurs at the arch foot position,which should be the focus of seismic design;the lateral stiffness of the arch ring is weak and the lateral displacement is obvious.For the calculation of the seismic response of arched aqueducts,the effects of vertical earthquakes and the presence of water bodies cannot be ignored.The results of the two calculation methods are comprehensively compared to ensure the comprehensiveness and accuracy of the results. |
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