关键词: 跨尺度精细应力分析, 心墙基座, 四分树网格, 比例边界有限元, 沥青心墙坝

Abstract: The concrete base-support is a key component of concrete asphalt core dam connecting the core wall and the cut-off wall. Its mechanical characteristics are vital to the structural safety evaluation. In this paper, five cross-scale analysis models with different grid density are established by using rapid quadtree discretization technology. The stress behavior of the base-support during construction period and the improvement measures are investigated by using the coupled nonlinear polygon scaled boundary finite element method and traditional FEM. The results demonstrate that the grid size of the base-support and surrounding soil has a great influence on the interaction between soil and structure. The more refined the grid is, the higher the stress extreme values are, and the maximum difference of the compressive stress extreme value is about 57.4%, while the difference of the tensile stress extreme value is about 59.3%. However, the ultimate stress distribution and the numerical value tend to converge eventually. Local clay area around the base-support can effectively improve the stress state. In the refined analysis of asphalt core dam, it is suggested that the grid size of base-support should be 0.05~0.10m. The dimension of surrounding soil should be 0.1~0.2m, and the width of clay zone could be 1.0~1.5 times of the base width. The cross-scale analysis method based on SBFEM can achieve efficient, refined modeling and analysis, and the safety of high dam seepage control system can be evaluated more reasonably.

Key words: cross-scale refined stress analysis, base-support of core wall；quadtree mesh；scaled boundary finite element method；asphalt core dam