Seismic Stability Analysis Of Shapai Roller Compacted Concrete Arch Dam

With rapid developing of China’s water conservancy project and improvement of newRCC dam technology level, a lot of ultra high arch dams whose height is in200~300m(such as Xiaowan Arch Dam292m&Jinping hydropower station305m) were built in thesouthwestern region with the water resources and frequent earthquake. The adopted designlevel of earthquake ground motion reachs to eleven degrees in these region. Oncedamaged, the seismic safety of the dam will be directly related to the safety of people’s lifeand property downstream and the consequences will be disastrous.Therefore, it is verysignificant that anti-seismic safety and stability of the high dam under high intensityseismic action.The practical project of Shapai RCC arch dam is simulated. the original seismicfortification intensity of Shapai arch dam is seven degrees, but resistance to the8level ofWenchuan violent earthquake which exceed its seismic fortification intensity (Shapai damarea is eight degrees), the results showing the super loading capacity of arch dam.Therefore, this paper uses0.2g as the maximum peak earthquake acceleration, the same aseight degree earthquake condition, makes the seismic safety review of Shapai arch dam.The influence of the weak layers which are on the interlayer binding of the concrete to thedam is studied, the modelⅠwithout weak story and modelⅡwith the exist of theinterlayer are established by ANSYS. Firstly, the vibration performance of the two kindsof models was respectively compared and analyzed by modal analysis in the condition ofno water, dead water level and normal water level to obtain the vibration characteristicsand the vibration distribution ruler of the two calculating models in different water levelconditions.Secondly, the two models are dynamically analyzed by the method of modedecomposition response spectrum and dynamic time-history analysis, the vibrationresponse of the dam, its displacement and stress distribution regulation were comparedand analyzed. The calculation results show that, the weak layer of RCC interlayer bindingwas taken into consideration when the boundary conditions and loads are in the samesituation will make the dam displacement and stress becomes large, even exceed thepermissible value of the specification, indicating that the weak layer can reduce the overallstability of the dam.Combined with the finite element model calculation of static and dynamic analysis,the Shapai arch dam was analyzed by seismic safety and stability according to the strength of the most adverse stress superposition and the most unfavorable stress superpositionprinciple. The static and dynamic comprehensive stress distribution results indicate theShapai arch dam abutments are the weak parts of dam seismic, and put forward safetymeasures for earthquake resistant in view of construction and design based on the resultsof numerical simulation.All works of this paper is combined with the practical project and the researchconclusion can provide practical reference to the design and similar projects. At the sametime, dynamic response of the high dam is still a very complex in high earthquakeintensity, the problems for further research are pointed out in the dynamic analysis.