大坝混凝土施工期温控措施的时间和空间优化

Temporal-Spatial Optimization of Temperature Control Measures for Dam Concrete Construction

以西藏高海拔地区街需混凝土重力坝为例,针对筑坝材料性能对温控防裂不利这一特点,采用三维有限元仿真模拟分析方法,研究高海拔地区气象条件下混凝土的温控标准及温控防裂措施,认为可在时间上优化混凝土温降过程和控制温降速率,防止降温幅度和降温速率过大,空间上优化温度梯度,减小基础温差、上下层温差和内外温差。研究表明,该大坝的推荐温控防裂措施可以较好地减小温度应力,防止裂缝产生。

Taking Jiexu Concrete Gravity Dam in Tibet region for an example,this study explored the temperature control standards,as well as temperature control and crack prevention measures for concrete in high-altitude regions using three-dimensional finite element methods and based on one concrete gravity dam in Tibet in combination with the characteristics of material properties that were disadvantageous to temperature control and crack prevention.The temperature drop process could be optimized in time and the temperature drop rate could be controlled to prevent excessive scale and temperature drop rates.Moreover,the temperature gradient could be spatially optimized,thus the differences in foundation temperatures,upper and lower layer temperatures and internal and external temperatures could also be reduced.The research shows that the recommended temperature control and crack prevention measures can effectively reduce temperature stress.