Study On Seismic Analysis And Aseismic Measures Of Concrete Gravity Dam

Now with the rapid development of water conservation and RCC dam technology, some high RCC gravity dams will be constructed in western region with plentiful water resources and frequent earthquake. The adopted design level of earthquake ground motion reached to nine degrees in these regions. It is very significant that aseismic safety for industrial and agricultural production and the safety of the people's life and property in the large region of downstream under high intensity seismic action. Therefore, in order to study deeply the dynamical characteristics and aseismic safety of Long Kai Kou RCC gravity dam in high earthquake intensity, dynamical analysis of the finite element method is used. Finally, weak zones of the dam are determined and the reasonable aseismic measures are also proposed. Thus it ensures the reliable design of dam. The main works of this paper are as follows:(1) The known studies indicate that peak tensile stress occurred at the upper portion of concrete gravity dam is much higher than the dynamic tensile strength of concrete during strong earthquake which resulted in the inevitably happening of cracking.The paper mainly studies the dynamic characteristics, damage distribution, plastic distribution, equivalent plastic distribution, damage course, acceleration amplification and dissipated energy of LKK non-flow dam under dead weight,hydrostatic pressure and seismic load. On this base, the influence of typical seismic waves,structural damping ratio and design horizontal acceleration on the safety reliability of dam were studied.(2) Due to the tensile stresses at dam heel are too high, the value often exceeds concrete strength of extension, so cracks come into being in dam heel easily, which then effects stability of dam body. According to the conclusion of " the dam foundation fracture played main role in the relaxation of stress concentrate in the dam heel" ,which calculated by Xiao Wan arch dam. In order to improve the stress distribution in the dam heel zone, the author assumes an induced joint on the bed rock of dam body upstream. On this basis induced joint arrangement under earthquake action and the effect of dam stress have been discussed. Morever, the optimal solutions are achieved through optimization design.(3) Based on the detailed analysis of dam cracking phenomena, the cracking mechanism, reinforced concrete fracture energy and prestressed anchor cable numerical simulation are studied. Pointing to this condition aseismic measures are put forward. It mainly includes reinforcement and prestressed anchor, also provides the result of tension damage factor comparative analysis, and demonstates the efficiency of the reinforcement measures.