三峡水电站直埋式蜗壳结构的非线性分析

本文结合三峡水电站，采用三维非线性有限元法对右岸某机组段直埋式蜗壳结构的受力和变形特性进行分析。数值计算模型考虑了钢衬和外围混凝土之间的摩擦接触、混凝土材料的拉伸软化和损伤特性，对外围混凝土的损伤指标及分布、各钢部件应力、结构位移等进行了分析研究，并在蜗壳外围混凝土发生损伤的情况下对座环柔度进行了复核。结果表明，在内水压力等设计荷载作用下，直埋式蜗壳的钢材强度完全能够得到保证；混凝土的损伤密集区出现在上下环板附近，且损伤指标较大；在蜗壳腰部、顶部混凝土损伤程度较小；考虑蜗壳外围混凝土含有损伤情况下的座环柔度值远大于按线弹性理论得到的结果。

Nonlinear FEM analysis on stress and strain of directly_embedded large_scale spirals

The stress and strain of a directly_embedded spiral case in the Three Gorges Project was analyzed by using 3_D nonlinear FEM. The elastic contact between steel liner and surrounding concrete as well as the softening of concrete and damage under tension were considered. The analysis results of concrete damage in different parts surrounding the spiral case and vertical displacement of turbine and generator foundations were obtained. In addition, based on the damage analysis of concrete the flexibility check for stay ring was also carried out. The results show that under the high HD of the project, the strength safety of the steel members can be ensured. The concentrated damage area in concrete with high damage factor was in the vicinity of stay ring, while the damage area with relative low factors was located at the waist and top of spiral case. The flexibility of the stay ring is great than that calculated from linear elastic theory, if the damage of concrete is considered.