基于扩展有限元法的重力坝强震潜在失效模式

扩展有限元法（XFEM）通过在相关节点的影响域上富集非连续位移模式，使得对非连续位移场的表征独立于单元边界，可以有效描述混凝土中的裂纹扩展。以Koyna重力坝为例，采用XFEM方法对大坝的动力渐进破坏过程进行计算分析，数值模拟结果与文献中的模型试验结果基本一致，验证了计算模型的有效性。考虑地震动频谱特性的影响，应用黏弹性人工边界，采用合理的地震波动模型对国内某混凝土重力坝强震下的动力破坏过程进行了数值仿真分析，得到不同地震波在不同强震等级作用下的大坝潜在失效模式，并概化出地震作用下坝体的潜在失效模式，为大坝抗震设计、特定失事模式下的工程安全风险率分析及洪水演进提供计算基础。

Seismic potential failure mode of gravity dam based on extended finite element method

The extended finite element method(XFEM) through enriching discontinuous displacement mode on the influence domain of related nodes, making the characterization of discontinuous displacement field independent of cell boundaries, can effectively describe the crack propagation in concrete. The damaged process of Koyna gravity dam during earthquake was analyzed, the distribution of cracking damage is consistent with the actual condition and the model test results in literature, which verifies the validity of the calculation model. Consider the spectral characteristics of ground motion, Based on viscous-spring artificial boundary, using a reasonable model of the seismic wave of a concrete gravity dam on the domestic dynamic earthquake damage under the process of numerical simulation analysis, the different seismic waves at different levels under the action of earthquake potential dam failure modes, and generalizability of the dam under seismic potential failure modes, provides the basis for the seismic design, construction safety hazard rate analysis under particular failure mode and flood routing.