某碾压混凝土重力坝温控方案优化研究

温度裂缝主要通过坝体温度控制、施工措施和结构优化来防止。结合实际工程典型溢流坝段,根据边值条件和坝体各分区混凝土热力学参数,通过稳定温度场、基础温差、层间温差和内外温差的计算,确定了坝体温度控制标准;以温控标准为依据,采用有限元法对表面保温、浇筑温度、水管冷却、纵缝设计、开浇时间、升程高度等因素进行了敏感性分析,优化了温控措施。分析表明,温控措施能满足混凝土连续上升浇筑的温度场和应力场的要求,为大坝混凝土施工提供科学的依据。

Optimization of Temperature Control Measures for an RCC Gravity Dam

Crack of RCC gravity dam is caused directly by thermal stress. It can be mainly prevented by temperature control, construction measures and structure optimization of the dam. A typical overflow dam section of a hydroproject is taken as an example. On the basis of boundary value conditions and thermodynamic parameters of the concrete of each dam zone, the standard of temperature control for the dam body is determined by calculating the stable temperature field, foundation temperature difference, temperature difference between layers and the temperature difference between the interior and exterior of dam body. In line with the temperature control standard, finite element method is employed to conduct sensitivity analysis on some factors such as surface thermal insulation, concrete placing temperature, cooling of water pipes, design of longitudinal structure joints, placing time and lift height. In consequence, measures of temperature control are optimized. The analysis shows that the temperature control measures can meet the requirement of the temperature and stress field of the dam, and ensure the continuous concrete placement. This research provides scientific basis for dam concrete construction.