首页|重力坝地震断裂的多边形比例边界有限元模型研究

重力坝地震断裂的多边形比例边界有限元模型研究

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为研究重力坝的地震断裂破坏机理,基于线弹性断裂力学和多边形比例边界有限元法(Polygon SBFEM)提出一种全自动的重力坝动态断裂分析模型.该模型继承了 SBFEM在断裂分析中高精度和高效率的优势,通过建立多边形比例边界有限单元广义动态应力强度因子的时域分析方法实现任意时刻断裂参数的求解,并结合裂缝扩展准则可实时判定裂缝稳定性;对达到临界状态的裂缝采用多边形网格局部重剖分技术,开发了考虑裂缝张开-闭合行为的动态接触模拟算法,进而实现了裂缝动态扩展高效自动化模拟.以Koyna重力坝为研究对象,考虑大坝库水动力相互作用,模拟了地震作用下坝体裂缝扩展过程,获得了断裂路径,验证了模型的正确性.其后,进一步探讨了数值模型中网格密度和裂缝扩展步长等因素的影响,结果显示仅用粗网格即可获得满意的计算结果,且三种裂缝扩展步长模拟的大坝裂缝扩展轨迹接近,但随着裂缝扩展步长增大,大坝更早失效破坏.研究成果可为混凝土坝的地震断裂分析提供有力的技术手段.
Dynamic fracture modelling of concrete gravity dams by polygon Scaled Boundary Finite Element Method under earthquake
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.

scaled boundary finite element methoddynamic fracture modellingpolygon elementconcrete grav-ity damcrack propagationlocal remeshing

蒋新新、钟红、李云途、牛景太、邓志平、黄红元

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南昌工程学院,江西南昌 330099

流域水循环模拟与调控国家重点实验室,中国水利水电科学研究院,北京 100038

比例边界有限元 动态断裂 多边形单元 重力坝 裂缝扩展 局部网格重剖分

国家自然科学基金国家自然科学基金国家自然科学基金国家自然科学基金江西省自然科学基金赣鄱俊才支持计划·青年科技人才托举项目

5197929252378344519690185176901720224BAB2040762023QT08

2024

10.13243/j.cnki.slxb.20230584

水利学报
中国水利学会

水利学报

CSTPCD北大核心
影响因子：1.778
ISSN：0559-9350
年,卷(期)：2024.55(1)
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