To investigate the seismic fracture mechanism of gravity dams,a fully automated dynamic fracture model for gravity dams is proposed based on linear elastic fracture mechanics and the Polygon Scaled Boundary Fi-nite Element Method(Polygon SBFEM).This model inherits the advantages of SBFEM in terms of high accuracy and efficiency in fracture analysis.It achieves the determination of dynamic fracture parameters by proposing a time-domain method of generalized dynamic stress intensity factors using polygonal scaled boundary elements.The nu-merical model evaluates the crack stability based on crack propagation criteria.For the cracks reaching critical states,the local remeshing algorithm for polygons are utilized to simulate crack propagation.Additionally,a dy-namic contact simulation algorithm considering crack opening and closure behavior is developed to efficiently auto-mate the crack propagation.Taking the Koyna gravity dam as a case study,the cracking process of the dam is sim-ulated,with the interaction between the dam and reservoir under earthquake being considered,and the crack pro-file of Koyna dam is predicted and validated.Furthermore,the influence of parameters such as mesh density and crack propagation step size in the model is investigated.It is shown that a coarse mesh can result in satisfactory re-sults,and three crack propagation step sizes lead to close crack profiles of the Koyna dam.However,as the step size increases,the dam is more prone to early failure.The research findings presented above provide powerful tech-nical means for the dynamic fracture analysis of practical concrete dams.
维普
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