A Preliminary Study On Seismic Safety Evaluation Index And Method Of Concrete Dams

The seismic response and its ultimate ability of high dam engineering are the core contents of seismic safety evaluation.At the same time,it is very important to simulate the damage process of concrete dam realistically under strong earthquake.The basis of seismic response analysis is the need to consider all the key factors that can affect the structural behavior,such as the constitutive model of simulated concrete performance,the comprehensive seismic safety evaluation system and the corresponding indicators dam-foundation-reservoir water interaction is discussed.The contents of the above three aspects are of corresponding discussion.The main contents and results are as follows:(1)Based on the theory of damage and plasticity,and taking into account the practical application of constitutive model,this paper comprehensively analyzes the research results of constitutive relation of concrete materials both at home and abroad,drawing lessons from the concrete stress-strain curve proposed in the current concrete structure design specification,a concrete damage plastic model is presented,which provides a theoretical basis for further study of nonlinear seismic response of concrete dam.(2)The structure and characteristics of the FEPG platform are studied.Based on the component workflow of the FEPG platform,the weak solution form of the static/dynamic equilibrium equation of the plasticity of the concrete structure is deduced.At the theoretical level,the iterative steps of the nonlinear algorithm of damage constitutive model are discussed,and the algorithm based on damage model is clarified.(3)The theoretical formulas for the viscoelastic boundary and the additional mass of moving water are introduced,and based on the ABAQUS finite element software secondary development script interface,compiled the Python version of the automatic application program,the validity and practicability of the developed program are illustrated by two examples.(4)The seismic evaluation method,evaluation criteria and quantitative performance indexes of the US hydraulic engineering design specification(ER&EM)based on performance are analyzed,and the relevant results at home and abroad are compared and analyzed.At the same time,the domestic and foreign related results based on the seismic evaluation are compared and studied.Combined with the existing high concrete dam seismic assessment,referenced the method of on the first line of elasticity evaluation and then nonlinear response analysis,introducing the quantitative parameters such as demand-capacity ratio,cumulative inelastic duration in the USACE evaluation procedure.Combined with the existing norms from the dam key parts,horizontal joints and other aspects of non-linear response correction in a step by step implementation to establish a quantitative evaluation framework for the seismic performance of concrete high dams.The research results provide a reference for the evaluation of seismic performance of concrete dam.