Study Of Hydrodynamic Pressure On High Concrete Gravity Dam Model In Earthquake By Shaking Table Model Test

Since the founding of new China,the state make full use of China's southwest region rich in water resources,our country had built a large number of large water conservancy projects,which had made outstanding contributions to the sustainable development of China's energy structure.High dams are important large infrastructures,it's safety must be guaranteed.However,the complex geological environment in the southwest led to frequent earthquakes,that makes the dam at all times threatened by earthquakes,so the seismic safety of dam had been paid close attention by academia.Dam-reservoir interaction under earthquake action is one of the important factors of seismic safety of dam,so this paper focuses on the dam-reservoir interaction.Due to the limitation of the size of the shaking table,we can't carry out large-size or prototype dam dynamic model test,the dam model generally has a few tenths or even one hundredth of the geometric scale.When the model has a smaller geometric scale,the model material needs to have a low stiffness to obtain a larger dynamic deformation to facilitate the data collection of strain,deformation and other parameters.At the same time,the dam model material has a large density to ensure that the structure has a large inertial force under the seismic input conditions to obtain the appropriate initial failure acceleration.According to the requirements of similar theory,the test model solid and liquid materials should have the same density scale,while increasing the density of the dam model's material,the density of the simulated reservoir water also needs to be improved accordingly.However,it is difficult to find an appropriate high density liquid to simulate reservoir water,which leads to an important problem in the current dynamic dam model test.In order to solve this problem,this paper uses the equivalent substitution method to simulate the dam-reservoir interaction under earthquake action.The spring group is used to simulate the hydrostatic pressure,and the hydrothermal pressure is provided by the additional mass.As the first time at home and abroad for this method of research,in the initial stage,we first conducted a pre-experimental study.Based on the model of a pier,we fully studied the mechanism of the simulation,control methods,and underwater piers hydrodynamic pressure experiment.Through a series of experimental studies,we have mastered the form of the simulation method,verified the feasibility and applicability of the experimental method,and made sufficient preparations for the subsequent formal test of the dam.After the pre-experiment,we carried out a series of dynamic model test of gravity dam.The experiment is divided into empty reservoir and full reservoir condition,we provide the reservoir which meet the similar theory in the reservoir condition.The experimental results show that the experimental method can effectively simulate the effect of reservoir water on the dam body.After the application of the simulation device,the dynamic and destructive characteristics of the dam are obviously changed.In order to fully verify the experimental results of the dam,the finite element model of the dam model is established.Through the finite element calculation of the dam model,the damage form and dynamic characteristics are obtained.The correctness of the experimental results is verified by the comparison between the finite element results and the experimental results.The numerical model which satisfies the solid-liquid similarity scale is compared with the numerical model using the natural water as the reservoir water.Contrast by simulation results,we found that the reservoir water which satisfies the similarity theory for the dam has an important influence on the dam body destruction,thus confirming the rationality of the experiment method.