有限元等效应力法在重力坝强度分析中的应用

采用有限元法进行重力坝坝体应力分析时，坝踵、坝址的应力计算结果一直无法作为设计坝体断面的依据。本文将有限单元法所求得的应力合成截面内力，用材料力学公式求出重力坝建基面上任意点对应的线性化等效应力，并分析了影响有限元等效应力的各种因素。研究结果表明，有限元等效应力法有效地避免了坝踵、坝址的应力集中现象，解决了坝踵应力随网格的变化而变化的问题，计算出的建基面应力具有数值稳定性，得出的应力结果可以按现行的重力坝设计规范规定的应力标准评价重力坝坝体安全度。因此，结合有限元结果和等效应力法计算的坝踵、坝址应力结果，可为重力坝坝体强度的综合评定提供相应的依据。

Application of finite element equivalent stress method to analyze the strength of gravity dam

The stress at heel and toe of gravity dam calculated by FEM is always not applicable in determining the section of the dam. In this paper, the internal forces are solved based on the stresses calculated by FEM and the linear equivalent stresses of the base surface are calculated by the formulas of material mechanics. Case study shows that by using this method the problem of stress concentration in dam heel and toe can be avoided. The equivalent stresses are somewhat mesh independent and not influenced by the size of calculation grids. The result of calculated stress can be used to asses the safety of gravity dam according to the national design code.