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大坝混凝土力学性质受诸多因素影响,变化规律复杂,最新研究表明:不同的温度条件对混凝土的变形规律有着明显的影响.对此,在西南某混凝土特高拱坝冬季混凝土浇筑现场,结合冷却水管周围不同位置处单支应变计测值和每支应变计附近同样温度条件下设置的专用无应力计监测的该温度条件下自由体积变形,通过建立大坝无应力计统计模型分析无应力计测值得出混凝土热膨胀系数,并分离出自生体积变形,采用考虑混凝土徐变特性的计算程序,将应变计测值转化为实际应力以分析冷却水管周围不同部位混凝土应力分布.试验结果表明:由于该大坝采取“小温差、早冷却、缓慢冷却”的通水冷却方式,在现有的通水冷却方案下,冷却水管周围混凝土应力不大;该试验能给现场混凝土冷却通水方案以及防裂施工提供指导,为关键部位混凝土温度应力仿真反馈分析提供实测资料.
The mechanical properties of dam concrete are affected by many factors and the changing rules are complex. The latest research shows that different temperature conditions have a significant influence on the deformation of concrete.In this paper, in the winter concrete pouring site of a concrete arch dam in southwest China, A single strain gauge at different locations around the water pipe and a free-form strain gauge under the same temperature condition set near each strain gauge to measure the free-volume deformation at this temperature. The stress-free meter The coefficient of thermal expansion of concrete is obtained and the self-deformation of volume is obtained. The calculation program of creep property of concrete is adopted to transform the strain gauge measurement into practical stress to analyze the stress distribution of concrete in different parts around the cooling pipe. The experimental results show that, The dam adopts the water-cooling method of “small temperature difference, early cooling and slow cooling”. Under the existing water-cooling scheme, the stress of the concrete around the cooling water pipe is not big; this test can give the on-site concrete cooling water- Provide guidance for crack prevention construction, provide concrete for the key parts of the temperature stress simulation feedback analysis Information.