Static And Dynamic Analysis And Research On Anti-seismic Safety Of Concrete Gravity Dam

On the basis of a large number of related literatures at home and abroad, combining the characteristics of the engineering example of a Hydro-power station in the Yellow River upstream and adopting the technical route which combines the theoretical analysis with numerical simulation. The main research work was the static powerhouse dam section and retaining dam stress and earthquake load stress state. The main results of the research were:1.Through the analysis of the overall stress state of the dam in different working condition and load combination condition, analyzed the dam foundation stress and the safety factors of anti-sliding and anti-floating stability using the formula of basic mechanics combined with ANSYS numerical simulation. The maximum base pressure of the dam is0.936 MPa when the earthquake occurred(excluded the uplift pressure). The maximum tensile stress of the dam is 0.579 MPa when unit maintain(included the uplift pressure). Both stresses are less than the allowable base. The influence of the uplift pressure is between 0.2 and0.366 MPa. The safety factors of anti-sliding and anti-floating stability is greater than the required minimum safety factor under each working condition.2.In order to describe the displacements and the stress distributions of plant dam, the whole structure was divided into 5 parts of EL1751.0m beam slab, sluice pier and flood discharge sluice base plate, power flow(including the flow surface, pipe shaped base, the inlet and outlet of the roof and floor etc.) and ground contact surface, described and analyzed the stress and displacement of each part under different conditions. Considered the influence of the dam sluice pressure and earthquake inertia force on the structure of dam, the value is smaller. Under the action of static and dynamic forces, the stress of EL1751 m beam plate is mainly controlled by the live load above, the maximum normal stress is 2.52MPa;The maximum vertical tensile stress of side sluice pier is 0.59 MPa, the side pier is in eccentric loading condition; The sluice floor stress is mainly affected by the flood discharge pressure.1.30 MPa tensile stress will be happen when release flood waters; Generator runner stress is controlled by internal water pressure and water machine load, the maximum tensile stress is4.90MPa(perpendicular to the flow direction). The maximum tensile stress was located in tubular seat and the top floor near the junction under various conditions; Ground contact surface stress is compressive stress, tensile stress distribution in a small area.3.Through the analysis of data, the structure of the corresponding parts is proposed,according to the calculation of the stress distribution and the ratio of the minimum reinforcement ratio. The tension stress can be solved by replacing the bottom of the river bed and ground contact surface with concrete. The osmotic pressure of the permanent joint between the units has a positive effect on reducing the flow of the flow channel.4.Two dimensional finite element models of ANSYS were used to analyze the static and dynamic analysis of the dam. Through the study on seismic performance of dam using themethod of response spectrum analysis, the dam's displacement and stress nephogram under static loads, and the vibration mode map under the action of earthquake were simulated. The maximum location displacement stress and the law of seismic response are proposed.The content of this paper is based on the engineering example. The theoretical analysis and calculation results can be used for reference and applied to the seismic design of gravity dams to a certain extent. The dynamic response of gravity dams under strong earthquakes is very complex. Because of the limited conditions, the modeling and calculation of the dam is simplified in the analysis, such as, without consideration of the contact coupling between the dam surface and the water body, and water is deemed to in compressible fluid, and the dam is homogeneous medium. But it is reasonable and feasible to calculate structure in general.