Modal Analysis And Research On Aqueduct

China’s South-to-North water diversion project is a matter of significant social and economic development projects. As a major water diversion project structure, aqueduct plays a vital role in the South-to-North water diversion project. Because of the large water in the aqueduct, the mass of the water and the aqueduct itself is very big. Besides, aqueduct goes through seismic areas, so it is very important to understand the dynamic characteristics of the aqueduct to aqueduct’s design.Modal testing and analysis are common means to obtain vibration characteristics. Natural frequencies, dumplings and modal shapes can be obtained through structure modal testing and analysis. These parameters are very important for understanding the dynamic characteristics, as well as seismic and other important aspects.Aqueduct has similar structure with the bridge. It also adopts Pile foundation. The problems of pile-soil interaction are often encountered when we design pile foundation. At present, pile-soil interaction on the structure should be further studied. To fully understand dynamic properties of the pile when consider pile-soil interaction, it is important to make a modal testing to identify the modal parameters, so we can have a better understanding of pile-soil interaction and its impact on the superstructure. In addition, it can also provide theoretical guidance for aqueduct structural design.In this paper, uTekL Dynamic Analysis System of WuHan uTekL Analysis Electronic Technology., Co Ltd was used to modal testing, and the experiment used a new device to put the acceleration sensor inside the steel pipe pile for the modal testing, which carried out in the soil bin of Structure Laboratory of Hunan University. Because of the specificity of the test object and the needs in analysis, a modal synthesis method was derived from two-part system, and successfully applied in modal synthesis in this paper. The results show that the method is effective and feasible under the premise of the two-part system.Simulation (finite element method) is another way to get the dynamic characteristics of a structure. In this paper, the pile-soil-pier model and the rigid foundation model was established by a finite element analysis software ABAQUS, which is very good at structural system analysis. Compared the results of calculation with the test and the pile-soil-pier foundation model with the rigid model; it shows that the results are consistent with the test results, and the maximum difference is less than 12.28%. Natural frequency of Pile-soil-pier model is much smaller than the natural frequency of rigid foundation model. In conclusion, when taking the pile-soil interaction into account, it has a greater impact on dynamic characteristics of a structure.