改进的拱坝等效应力分析方法

An improved method for analysis of arch dam equivalent stress

对有限元内力法求解拱坝等效应力分析进行了进一步改进,假定拱、梁方向上的正、剪应力在拱、梁截面上的面单元内呈双线性分布,从而导出根据截面约束内力求解等效节点应力的公式,并在此基础上导出拱梁向应力为直线分布时的上、下游面等效应力的求解方程和主应力求解公式.对典型的圆筒拱坝用本文方法进行应力分析,得出的拱及梁向应力结果与试载法分析结果基本一致,表明用本文分析方法得出的应力结果可以按现行的拱坝设计规范规定的应力标准评价拱坝坝体安全度.

The finite element internal force method is improved for solution and analysis of the arch dam equivalent stress. On the assumption that the normal and shear stresses in the directions of arch and beam accord with the bilinear distribution in the plane elements of arch and beam sections, a formula is developed for calculation of the equivalent nodal stress from the constraining inner force along the sections. Furthermore, equations for solution of the equivalent stress and formulas for calculation of the main stress in the upstream face and downstream face are derived on the assumption of linear distribution of arch stress and hoop stress. The present method is applied to stress analysis for a typical cylindrical arch dam, and the calculated results of the arch stress and hoop stress conform to those obtained by the trial load method. Therefore, the calculated results of the arch dam stress by the present method can be used for safety assessment of arch dams according to the national arch dam design code.