箱形渡槽越冬期间表面保温能力计算

Calculation of superficial insulation capacity for box aqueduct during the winter

对于寒冷地区的混凝土结构,常采用表面保温措施来防止裂缝的产生.根据朱伯芳院士提出的计算公式进行理论分析,以引洮工程柳林沟渡槽为例,分别计算不保温、采用3和5 cm厚的聚氨酯保温板3种情况下的温度变化和温度应力,并分析不同厚度保温层的保温效果.计算结果表明:箱形渡槽在越冬期间降温快,会产生可观的温度应力,需要选用合适厚度的保温材料来减小槽身表面和棱角处的温度变化和温度应力,避免槽身产生裂缝,从而影响槽身结构的整体性和稳定性.

For concrete structures in cold regions, surface insulation measures are often used to protect them from cracks. Based on the theoretical analysis of a formula proposed by Academician Zhu Bo-fang, taking the Liulingou aqueduct of the Gansu Tao diversion project as an example, temperature variation and thermal stress are calculated under conditions without heat insulting and with 3 cm and 5 cm polyurethane insulation board. Moreover, the superficial effects of different-thickness insulation layers are analyzed in this paper. The analysis results show that the temperature of box aqueduct decreases quickly along with a greater thermal stress during the winter, so the insulation materials with suitable thickness are chosen to reduce the temperature variation and thermal stress in the body surface and corners of the aqueduct, and cracking will be avoided, which may affect the integrity and stability of the aqueduct structure.