基于XFEM的强震区砼重力坝开裂与配筋抗震措施研究

已有震害表明，混凝土坝遭遇强烈地震将不可避免地产生开裂。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。基于扩展有限元模型，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分析；针对大坝破坏情况，应用嵌入式滑移模型模拟了混凝土重力坝配筋前后的地震响应和破坏状况，据此评价局部配筋的抗震效果。研究表明，局部配置抗震钢筋虽无法防止裂缝的发生，但可有效限制坝体裂缝的开裂扩展范围及深度，减少裂缝的开度，有效改善坝体的抗震性能。

Seismic cracking and reinforcement analysis of concrete gravity dam based on XFEM

The known seismic damages of concrete dams indicate that cracks will appear during strong earthquakes. The extended finite element method (XFEM) can make the characterization of discontinuous displacement field independent of cell boundaries through enriching discontinuous displacement mode on the influence domain of related nodes. Therefore, the crack propagation in concrete can be effectively described using XFEM. In the paper, we used a reasonable model of seismic wave to analyze the process of the dynamic damage of a domestic concrete gravity dam. The dynamic responses and failure modes of the dam before and after strengthening have been simulated by using the embedded slip model，based on which the effect of the seismic reinforcement is evaluated. Our studies demonstrate that although the seismic reinforcement in dams cannot prevent cracks from initiating, it is capable of controlling the development and extension of cracks and reducing the crack opening displacement. In conclusion, it is an effective measure to improve the earthquake-resistant performance.