Research On Seismic Response Of Double-body Aqueduct Structure Considering Water Mass

In China, the total water resource is rich, but the average amount of per captia is notenough. Meanwhile, the distribution of water resource is extremely uneven in time and space,which leads to the serious lack of water in some parts of our country. In order to solve thecurrent situation of water resource uneven distribution, our country has bulit a series oftrans-regional, trans-basin and long-distance water diversion projects. In these large-scalewater diversion projects, aqueduct is widely used as a kind of cross-linked hydraulicstructures. With the increasing of water delivery flow, the traditional single-body aqueductcan’t meet the requirement of practical engineering. As a new type of aqueduct structure,multi-body aqueduct has been widely applied in the South to North Water Diversion Project.The Shuangji River aqueduct and Ming River aqueduct are double-body aqueduct, the CaoRiver aqueduct is three-body aqueduct. Because of the large aqueduct body and huge watermass on the piers, these aqueducts are typical " heavy top and light bottom" structures. Underthe earthquake action, the structures have no enough seismic resistance.The aqueduct will occur violent vibration under the earthquake action, the water body intank shell will have some accordingly shaking. The more intense shaking role of water bodyis, the stronger the coupled effect of the water body and structure is, which is a complexinteraction problem of fluid and structure. However, the current specifications of hydraulicearthquake-resistance haven’t mention the design methods and principles of the aqueductfluid-structure coupling, so it is necessary to study the dynamic response of aqueduct structureunder seismic action with combining the fluid-structure coupling theory and aqueduct.In this thesis, taking the Shuangji River double-body aqueduct of the South to NorthWater Diversion Project as example，the three-dimension dynamic model considering watermass influence is established by the finite element software ANSYS. Then the naturalvibration characteristics considering water mass are abtained. It is shown that the naturalvibration frequency of the aqueduct is decreased with the increasing of water mass in theaqueduct.The more the water increases, the more the frequency decreases. The aqueductnatural vibration period is extended due to the exsistence water in the aqueduct; water inaqueduct has little effect on the main vibration mode for Shuangji River aqueduct.With time history anslysis methd, the seismic responses including two aspects ofdynamic displacement and dynamic stress under the action of different earthquake waveswere analyzed.The calculation results show that under different seismic wave action,transverse displacement and stress of aqueduct structure are increased with the increasing ofwater level, this is due to the water body makes the weight of the upper structure increase,which makes the forces acting on the structure increase; In the dynamic analysis of large-scale aqueduct,we should consider the influence of water mass and establish reasonble dynamicmodel.