摘要
特高拱坝由于底宽大、岸坡陡，故采用通仓浇筑时施工期的温度控制难度大。特高拱坝的温度场和温度应力有如下几个特点：（1）约束面长且约束强，在二期水冷时约束区会存在上下两个约束面；（2）最低温度出现在封拱灌浆水冷终了时，此时也是拉应力最大的时刻，因此二次水冷是温度控制的关键时刻；（3）陡坡坝段应力大，温控难度大。结合如上特点，以小湾、溪洛渡两座拱坝为例，通过仿真分析结果，讨论施工期温度场、应力场仿真分析的基本要求，及温度控制中需注意的几个关键问题。结论认为：（1）除强约束区很容易出现裂缝要特别注意外，非约束区同样要严格进行温度控制；（2）二期冷却前或过冬前要进行一次大范围中期冷却，以降低二期水冷的降温幅度，同时要严格控制降温速率；（3）冷却区高度要大于2个灌区高度或0．3～0．4L；（4）应以精细仿真分析的结果作为特高拱坝温度控制的依据，如有条件应进行全坝仿真，无条件时则须以3个以上坝段为对象进行仿真分析。
The long base width and steep slope of super high arch dams have make it difficult to control the temperature when adopting full-silo casting method. The temperature and stress fields in such dams have the following characteristics ： 1 ） Two constraint faces form in the constraint region due to the long constraint face and its strong constraints ; 2） The time of minimum temperature occurs in transverse joint grouting is also the time when the tensile stress is maximum, making secondary cooling the critical moment for temperature controlling ; 3 ） Temperature control of the slope monolith is very difficult because of the high stress. In this paper, basic requirements of simulation analysis of temperature and stress fields will be discussed based on the characteristics mentioned above, with both Xiaowan Arch Dam and Xiluodu Arch Dam as the examples. The following conclusions are thus made： 1 ） Special attentions need to be paid not only to strong constraint region, but also to non-constraint region with strict temperature controlling; 2 ） A large-scope middle-stage cooling is needed before secondary cooling or winter season to decrease the temperature drop range, while at the same time temperature drop rate should be strictly controlled ; 3 ） The height of cooling region needs to be larger than two casting heights or 0.3 - 0.4 L ; 4） Temperature controlling for super high arch dams should be based on precise simulative analysis. If possible, the whole dam should be analyzed with simulation. If it is not allowed, at least three dam sections should be taken as objects to conduct simulative analysis.
出处
《水利水电技术》
CSCD
北大核心
2008年第10期36-40,共5页
Water Resources and Hydropower Engineering
基金
自然科学重点基金(E50539120
50539010)
"十一五"国家科技支撑计划重大项目:南水北调工程若干关键技术研究与应用
关键词
特高拱坝
温度应力仿真
温度控制
super high concrete arch dam
thermal stress simulation
temperature controlling
