水电站充水保压蜗壳结构的改进算法

Improved simulation method of preloading filling spiral case in hydropower station

在充水保压蜗壳传统简化算法的基础上提出了改进算法,据此主要分析运行工况下蜗壳进口不平衡水推力对外围混凝土应力和配筋量的影响.计算结果表明,传统简化算法未考虑不平衡水推力的作用,外围混凝土的应力和配筋量偏小,结构偏不安全.在蜗壳进口端施加不平衡水推力的做法,对设伸缩节的情况会导致直管段外围混凝土的应力和配筋量偏大,而对无伸缩节的情况则不能考虑不平衡水推力的作用.本文提出的在蜗壳进口断面下游侧转弯区域以面力的形式施加不平衡水推力的做法,对有无伸缩节的情况均能实现,可使外围混凝土的应力和配筋计算更加精确、合理,建议在充水保压蜗壳结构的设计和研究中采用.

Based on the traditional simplified simulation method of the preloading filling spiral case,an improved simulation method is proposed.By means of the method,the influence on the stress and reinforcement of the surrounding concrete is mainly analyzed,which is caused by the unbalanced hydraulic thrust under the operating condition.The results show that the stress and reinforcement quantity of surrounding concrete from the traditional simplified method are relatively small and the structure tends to become insecure insecure because of neglecting the unbalanced hydraulic thrust.If the unbalanced hydraulic thrust is regarded as concentrated force acting on the inlet section of the spiral case with the expansion joint,the stress and reinforcement quantity of surrounding concrete may be larger at inlet side of the spiral case.Meanwhile,the unbalanced hydraulic thrust can not be considered by this simulation method under no expansion joint condition.If the unbalanced hydraulic thrust is regarded as surface pressure acting on the downstream area of the spiral case,it can be achieved in this simulation method whether the spiral case is with expansion joint or not;and the stress and reinforcement quantity of the surrounding concrete are more accurate and reasonable.Therefore,the improved simulation method can be adopted during the design and study of the preloading filling spiral case structure.