基于光纤测温的浇筑仓顶面保温被保温效果反馈分析

Feedback Analysis of the Insulation Effect of Insulation Pads on Pouring Cube Surface Based on Distributed Optical Fiber

在低温季节间歇期间对混凝土浇筑仓顶面进行表面保温是温控防裂的一个重要环节,保温效果也一直备受关注。以往对保温效果进行探讨,常采用浇筑仓内部的点温度计实测温度与计算温度建立目标函数进行保温被保温效果反馈,由于点温度计的单一以及埋设在浇筑仓内部,因此得到的反馈结果具有一定的随机性且精度值得商榷。结合西南某建设中混凝土坝工程,在典型浇筑仓顶面附近埋设分布式光纤实时在线监测低温季节间歇期间的温度状态,然后采用三维温度场仿真技术和优化算法反馈了浇筑仓顶面保温被保温效果,分析表明,该工程在浇筑仓顶面覆盖的保温被反馈的等效表面放热系数为8.11kJ/(m2.h.℃),满足该坝施工技术要求给出的覆盖5cm厚的聚乙烯保温被后,表面放热系数≤10kJ/(m2.h.℃)。

In low temperature season intercritical periods,insulating for the pouring cube surface is an important part of temperature control and crack prevention,the insulation effect always attracts a lot of attention.In the past,the actual temperature inside measured by the point thermometer and the calculated slab temperature is always selected to establish objective function to feedback the effect of heat preservation quilt,while the point thermometer is single and buried in the inside of the pouring cube,so the result of feedback has some degree of randomness and its accuracy is questionable.In this paper,based on one concrete dam under construction in southwestern China,distributed optical fiber in the typical pouring cube surface with on-line real-time is buried to inspect the state of temperature during the intercritical period in low temperature seasons,then the 3-D FEM in computer technology and the inverse analysis method is used to feedback the insulation effect of the pouring cube surface.The calculated equivalent surface heat convection is 8.11kJ/（m^2.h.℃）,and the analysis shows that it meets the requirement of construction technology that the surface heat convection is no larger than 10kJ/（m^2.h.℃）after covering 5cm heat preservation quilt.