Centrifuge Modeling Of Seismic Stability Of Arch Dam-Abutment

Research on earthquake behavior of arch dams is one of the key issues in dam engineering. This thesis carried out a series of dynamic centrifuge modeling experiment, studying on the arch dam-abutment seismic stability, and the seismic failure of arch dams under dynamic loads. The research is carried out through model tests on the centrifuge shaking table for dynamic response of the dam model, and then compared with the distinct element method using 3DEC and the finite element analysis using ABAQUS for verification. The main contents are as follows:1. The similarity relationship of dynamic centrifuge test is derived out on the basis of similarity theory. Model is designed and made based on the similarity relationship. The material of the dam model is a mixture of barite and bentonite, which was most commonly used by the hydraulic laboratory for the modeling of arch dams. A series of material tests are carried out to find the appropriate ratio of combination, and then the dam model is made.2. A gap measure is designed and made to measure the displacement of the gap opening. The liner relationship between the opening of the gap and the voltage of the electric bridge is first derived out based on analysis, then several gap measures are processed and calibrated. It is found that the gap measure behaves well in dynamic test and gives reasonable results.3. The dynamic response of arch dam-abutment is obtained through dynamic centrifuge test. The impulse load and white-noise load is applied to acquire the frequency of the dam model, and harmonic load is applied to acquire the dynamic response of the model, including acceleration, strain and the opening of the discontinuity. Then the disciplines of dynamic reaction and the mechanism of damage of the arch dam are studied.4. Through the dynamic centrifuge test carried on the dam model made of brittle material, both the elastic dynamic response and the whole damage process of the dam are obtained. These results reveal the characteristic of dynamic response characteristic and the damage mechanism of the arch dam. The research results show that, the dynamic centrifuge test is a very useful method for study on the arch dam-abutment system. The ability of satisfying all similarity relationship and all kinds of loading technique makes the dynamic centrifuge test more powerful than the common shaking table test.5. Numerical solution is applied to calculate the frequency characteristic and the harmonic response of the model, and then compared with the experiment results. These researches verify the correctness of dynamic centrifuge test, and show the rationality of distinct element method on the study of arch dam-abutment system.