The Analysis Of Aqueduct Imposed Multi-point Seismic Waves By Considering The Large Sloshing Of Water

This thesis discusses the large-amplitude sloshing water of the large-scale flume that is under strong earthquake and fluid-solid dynamic coupling effect which caused by interaction of flume's sloshing water and sidewall. This paper also studies the travelling wave effect under different situation such as long-span flume's supporting points standing on different types of ground and multi-support point excitation. At the end, it comes with some meaningful conclusions that providing a reference for the study of aseismatic design of large-scale flume.First of all, it takes the Trifunac method of Frequency Integral for O-axis modification about time-history curves of earthquake's acceleration, which avoids baseline drifting caused by accumulated integration error when calculating time-hisory of speed and displacement. It makes preparation for taking time-history analysis of flume.After that, it takes analysis of dynamic characteristics of flume, which contains some essential parameters of natural frequency and mode of vibration. Natural frequency is not only the index of structural dynamic properties but also the basis of judging whether the structure would be in resonance. It assesses the rationality of flume's structural model through analyzing the characteristics of natural frequency.It takes Lagrange-Euler method to describe the water in the flume that is under fluid-solid dynamic coupling as nonlinearity. Then, considers supporting and non-supporting points for consideration respectively and creates flume model of uniform and multiple-support excitation. It analyses the large-amplitude sloshing water in the aqueduct and multi-support excitation's time difference effect on flume.It shows that:First, the interaction of structure and fluids could make the structure produce an effect that is similar to TLD. As a result, the water in the flume could afford more damping force and improve the efficiency of energy dissipation. So compared with empty flume model, it can reduce maximum displacement obviously. Secondly, Multi-support input with different speed waves has obvious effect on long-span flume's dynamic response, and different inputs reduce the sloshing amplitude but increase the stress distribution on the structure. The mainly reason about relative displacements'change of cross-section's both ends of the bottom is that interval of multi-input is changed. The stress change that caused by earthquake increases along with the decreases of the earthquake wave speed. Flume is a crucial conveyance structure, the rubber waterproofing strap of two flumes' cross section will be torn up when relative displacement is too large. And this will cause severely leaking that would endanger the safety of flume. Consequently, this factor should be taken full account of in designing.Investigations of different water depth through single-support earthquake input models and multi-support earthquake models have been conducted in this research, the result has shown that firstly, as the water body increases in the flume, the maximum displacement of mid-span section in the plume declined first then increased subsequently, and the displacement of mid-span section of the plume reaches its maximum value when there is no water body in the flume. This is mainly because the interaction effect of fluid and solid was taken into consideration in the simulating model, which the excitation intervals received between two ends of the structure became longer as the decrease of the input earthquake wave speed, that the interaction between system and the fluid induced a damping effect to the system, thereafter the water body in the flume provided more damping onto the system, ameliorating the energy dissipation of the whole system, which significantly reduced the maximum displacement of the system. Secondly, as the water body increases in the flume, the maximum displacement of mid-span section in the plume declined first then increased subsequently also caused by the reason that as the water level increases, the weight of the upper part of the flume raises, that enhanced the earthquake effect on the functional flume. The displacement value of mid-span section of the flume drop to its minimum value when there is no water in the flume, that is because the flume and its slot buttress are connected using the method of hinge joint, which diminish the dynamic response of the plume by the co-action effect of the system and the fluid. From all discussed above, a conclusion can be obtained that when analyzing the anti-seismic issue for high-span system like flumes, the influence on such system during earthquake under different water depth should be taken into consideration.