凯德隆电站取水泵房沉井结构有限元分析

凯德隆电站取水泵房采用沉井结构,原设计综合考虑外部荷载及后期顶管作业的便利,提出了三个结构布置方案以供选择,分别为整体浇筑方案、预留二期混凝土方案和预留二期混凝土加支撑方案中,后两者是在整体浇筑方案的基础上增加二期混凝土部位或钢管支撑所得。三个方案的结构受力体系有较大差异,以传统的平面分析方法难以进行计算。基于大型有限元软件Midas GTS nx分别建立了三个方案对应的三维沉井结构模型,采用结构-荷载法分析了各方案下沉井主要构件的受力情况,并进行了承载力和抗裂验算。结果表明:在预留二期混凝土方案以及预留二期混凝土加支撑方案中,沉井外壁的最大弯矩较整体浇筑方案分别增长了23.33%、22.19%;第二道中隔墙最大弯矩增长了79.05%、68.39%;第一道胸墙的最大弯矩增长了65.95%、57.66%。此二者不能保证沉井结构的承载力以及抗裂要求,故最终建议采用整体浇筑方案。

Structural analysis for the caisson of the pump room of Kidurong Power Plant based on finite element method

The pump room of Kidurong Power Plant was designed with caisson structure． Considering the external load and the convenience for pipe jacking operation in the later stage，three structural layout schemes were put forward，which were as follows: integral cocrete pouring scheme，two-step concrete pouring scheme and its brace were reserved． The latter two were obtained by adding the second-step concrete or steel tube brace on the basis of the integral concrete pouring scheme． The mechanical systems of the three schemes are quite different，and it is difficult to calculate by traditional plane analysis method． In this paper，based on large-scale finite element software Midas GTS nx，three-dimensional caisson structure models corresponding to the three schemes were established respectively． The structure-load method was used to analyze the force of the main components of the caisson under each scheme，and the bearing capacity and anti-cracking calculation were carried out． It was found that the maxi- mum bending moment of the outer wall under the two-step concrete pouring scheme and its brace was 23. 33% and 22. 19% higher than that of the integral pouring scheme respectively． The maximum bending moment of the second partition wall increased by 79. 05%，68. 39%，and the maximum bending moment of the first chest wall increased by 65. 95%，57. 66%． These two schemes can not guarantee the bearing capacity and crack resistance of caisson structure，so it was suggested that the integral pouring scheme should be adopted．