| The construction and operation of Gravity Dams are faced with extreme loads such as earthquakes,which seriously threaten their safety and stable operation.Therefore,the development of reasonable and efficient dynamic analysis model and calculation method for Gravity Dams to calculate the dynamic response of extreme loads and evaluate their safety has been a subject of concern in the engineering field.Based on the recommended methods of the Seismic Code,considering the structure foundation dynamic interaction,different dynamic calculation model and calculation method are used to analyze the typical dam section of a pumped-storage power station.To further studying the interaction of dam and foundation,the viscoelastic artificial boundary model is applied to evaluate the seismic performance.Moreover,the variation of elastic modulus of the foundation is studied for seismic performance of gravity dam.It mainly includes the following contents:(1)This paper introduces the relevant theories and solution methods of static and dynamic analysis for Gravity Dams,and lists the basic solution formulas and corresponding solution models of material mechanics method,vibration mode decomposition reaction spectrum method and finite element time history analysis method.By using these methods,the dynamic characteristics,crest displacement response,the stress distribution and the safety factor of stability against sliding of the typical dam section are evaluated.(2)The dynamic interaction of soils and dams has become a hot research topic,so the viscous elastic artificial boundary method is introduced in this paper.Based on the formulas of viscoelastic artificial boundary model,the methods of two and three dimensional viscoelastic artificial boundary model are realized,and the numerical accuracy and stability of the methods are verified by numerical examples.Then the seismic response of Gravity Dams is studied by massless foundation model and viscoelastic artificial boundary model.Results show that the dynamic response of the dam with viscoelastic artificial boundary model is smaller than that of the massless foundation model.(3)The Viscoelastic artificial boundary model is used to analyze the influence of the variation of elastic modulus of foundation on the seismic response of gravity dam.With the increase of the elastic modulus of foundation,the natural vibration frequency of the dam increases,and so does the maximum principal tensile stress and principal compressive stress.The strength check shows that the maximum tensile stress is not satisfied due to the increase of the elastic modulus of the foundation,which should be paid attention to in the design.To sum up,the seismic performance of typical gravity dam section is evaluated bythe methods of material mechanics,vibration mode decomposition response spectrum method and the finite element time history analysis method respectively in this paper.In view of the current research hotspots-structure foundation dynamic interaction,the viscoelastic artificial boundary model and traditional massless foundation model are used to calculate the dynamic response of the dam body,and some useful corresponding conclusions are summarized.What is more,the variation of elastic modulus of foundation on the seismic performance of dam body is deeply analyzed,and the engineering application of dynamic interaction model of structure is further understood,which more engineering experience is accumulated for further study. |
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