Safety Analysis And Simulation Of Flood Discharge Of High Arch Dam And Counter-arch Plunge Pool

Although our country has made great achievement in the construction, design and research of the high arch dams, the design of high arch dams is still far from reaching the"realm of freedom"and some major problems still need to be solved. These problems include: rational design principle, standard and requirements of high arch dams; accurate dynamic analysis and seismic measures of high arch dams; hydraulic problems of flood discharging, energy dissipating and anti-scouring; model test of high arch dams, etc. This thesis aims to study the problems of model test of high arch dams, flow-induced vibration response and the stability of protective structure in plunge pool. Hydroelastic model test, theory analysis and finite element analysis are adopted in the study. Besides, in this paper the calculation method and some useful conclusion are presented.The fluid-structure coupling system, which consists of dam, water, foundation and fluctuation pressure, is simulated by the hydroelastic model which can satisfy hydraulics similarity principle and structural dynamics similarity principle simultaneously. The similarity principle and the influence of both simulation context and material characteristics on dynamic characteristics of the arch dam are discussed in this paper, and then the proper simulation context is obtained. The hydroelastic model with a scale of 1:100 is adopted to measure and analysis the flow-induced vibration response of Laxiwa high arch dam and counter-arch plunge pool.In the prototype or model test of project, there is always no enough survey points to reflect the vibration characteristic of hydro-structure overall, especially the survey points in the prototype test. Based on positive-back analysis algorithms of flow-induced vibration response, in this paper, three vibration sources are regard as three independent, incorrelate equivalent loads, genetic algorithm is adopted to get the equivalent loads, and then the positive analysis method is utilized to receive the whole structure's vibratory response and carry on source analysis. Furthermore, aimed at having a lot of survey points'result by synchronous measure, a back analysis method is provided which is base on modal superposition. In essence, it is a similar method to solve the vibratory response which is base on the modal orthogonality and expansion theorem. The two above-mentioned methods are utilized to study an instance about hydroelastic model of Laxiwa arch dam. The safety of protecting structure in high dam plunge pool is the key to the success of energy dissipation. Under the hydrodynamic load, the stress and movement course are complicated. In the numerical calculation three factors should be taken into account: the bond-slip between the anchor and slab or foundation, the contact action between slab and slab, slab and foundation, slab and abutment, and the fluid-structure coupling action. Based on bond-slip theory, nonlinear contact theory and fluid-structure coupling theory, a finite element model for counter-arch plunge pool is proposed in this paper. In the model, three-dimension nonlinear spring element is used to simulate the displacement cooperation between anchor and foundation, contact element is adopted to simulate the joint of slab and the collision or slip action among the slab, abutment, foundation and slope, the added mass is used to consider the fluid-structure coupling action, so this model reflects the stress characteristic and interaction of the slab, abutment, anchor and foundation overall. The case of the Changtangang plunge pool is demonstrated the rationality and practicability of the proposed model. As an engineering application, the structural stability under some important work condition of the plunge pool of Laxiwa arch dam is analyzed. Then based on the finite element model and destabilization mode of counter-arch plunge pool, the influence of the type of plunge pool is analyzed.