Model Test Study Of Arch Dam On Shaking Table Considering Transverse Joints And Reservoir Water Pressure Simulation System

With the rapid development of China’s economy and technology,energy consumption and demand of various industries are increasing.Hydroelectric power generation is a renewable and clean energy source,which has attracted more and more attention,As a large-scale infrastructure for the benefit of the country and the people,the seismic safety of arch dams is the focus of many experts and scholars.Nonlinear opening and closing of transverse joints and interaction between dam body and reservoir water are important factors affecting seismic safety of arch dams under earthquake.Therefore,it is very important to study transverse joints and reservoir water action for further evaluation of seismic safety performance of dams.The basic assumption of linear elasticity of arch dam structure is inconsistent with the actual situation because of the normal opening of transverse joints under strong earthquakes.The seismic response of arch dam is considered to be a complex three-dimensional boundary contact non-linear dynamic problem.In the aspect of numerical simulation of transverse joints,there are some ideal assumptions in the establishment of the model.If the assumptions are inappropriate,the accuracy of the calculation results will not be guaranteed.At this time,model test as another commonly used analytical method in hydraulic structures,often plays a vital role in dealing with such problems.Firstly,the dynamic model tests of slotted arch dams and holistic arch dams with transverse joints are carried out.The results show that the transverse joints have an effect on the vibration characteristics and seismic response of the dam.The transverse joints can not be neglected in the study of seismic safety and stability of arch dams.Due to the limitation of shaking table conditions,the geometric scale of the model can be selected in a small range.The size of the prototype is usually tens or even hundreds of times larger than that of the model.Therefore,it is necessary for the model material to have low elastic modulus and high density so that the dam body has enough inertia force to cause damage at appropriate acceleration.Simulated concrete is used as model material in the experiment.The material has low modulus of elasticity and high density by adjusting mix ratio.According to the similarity theory of dynamic model test,the material density scale of arch dam is equal to the reservoir water density scale.The natural water density used in model tests is insufficient,and the static and dynamic water pressures are low.In order to solve the problem that it is difficult to find liquid satisfying the density scale as the reservoir water in the experiment,a spring-added mass simulation system is proposed to replace the reservoir water.By measuring the hydrodynamic pressure distribution curve in front of the dam and adjusting the additional mass value through several groups of pre-test,replacing hydrostatic pressure with compression spring and inertia force provided by additional mass,a set of reservoir water pressure simulation system with good simulation accuracy and repeatable test is designed step by step.On this basis,the dynamic model test of arch dam shaking table is carried out.In the two-year post-graduate study of the research group,Taking an arch dam as the research object,Four working conditions are analyzed: jointed empty reservoir,holistic empty reservoir,dam-reservoir interaction and dam-reservoir water simulation system,Simultaneous numerical damage analysis of prototype arch dam.The results show :the influence of transverse joints on seismic response of dam body and failure modes between arch beams;The simulation system has a high control precision,and can apply static and dynamic water pressure to the dam face.After the simulation system acts,the dynamic response and damage of the dam body are obviously different from that of the empty reservoir state;Considering the combination of transverse joint and reservoir water pressure simulation system,the failure mode of the upper and lower beam of the dam and the numerical damage results of the prototype are mutually verified.It is considered that the simulation method can be used as a research method to reveal the true response of the dam model..