碾压式导电混凝土越冬期温控特性分析

Analysis of temperature control characteristics of electrically conductive roller-compacted concrete during overwintering period

摘要

高寒地区极端气温低、冬季时间长的气候增大混凝土坝开裂风险，当前覆盖隔热材料的保温措施被动隔热，安装和拆卸程序繁杂。导电混凝土由胶凝材料、导电材料等组成，兼具混凝土材料良好的力学性能和独特的电热性能，应用于混凝土坝越冬层等关键部位，既能满足坝体材料性能需求，又可维持越冬层温度稳定。建立了高寒区碾压混凝土坝典型坝段的有限元模型，并依据坝体抵御低温所需供能的U-ΔT模型设计了6种越冬保温方案，开展了常规保温材料和导电混凝土通电加热的温控仿真。结果表明：导电混凝土通电加热温控可使上游测点温度维持在18℃,下游测点温度维持在23℃,顶部测点温度维持在30℃。根据含导电混凝土越冬层的碾压混凝土坝施工期温度场计算，可以发现冬季导电混凝土越冬层通电后对坝体表面温度场影响显著，坝体内外温差减小，有利于大坝温控，可为解决高寒区混凝土坝的温控防裂提供新的研究思路。

Abstract

The climate of low extreme temperatures and long winter time in alpine regions increases the risk of cracking of concrete dams, and the current thermal insulation measures covered with thermal insulating materials are passive insulation, with cumbersome installation and dismantling procedures. Conductive concrete consists of cementitious materials, conductive materials, etc., both good mechanical properties of concrete materials and unique electro-thermal properties, applied to the overwintering layer of concrete dams and other key parts, both to meet the needs of the dam material performance, but also to maintain the temperature stability of the overwintering layer. Therefore, a finite element model of a typical dam section of a crushed concrete dam in the alpine zone was established, and six overwintering insulation schemes were designed based on the U-ΔT model of the energy supply required for the dam body to resist low temperature, and the temperature control simulation of conventional thermal insulation materials and electrically heated conductive concrete was carried out.The result show that the temperature control of conductive concrete with electric heating can maintain the temperature at the upstream measurement point at 18 ℃, the temperature at the downstream measurement point at 23 ℃, and the temperature at the top measurement point at 30 ℃.[Conclusion]According to the temperature field calculation during the construction period of the crushed concrete dam containing conductive concrete wintering layer, it can be found that the conductive concrete wintering layer electrified in winter has a significant effect on the surface temperature field of the dam, and the temperature difference between the inside and outside of the dam is reduced, which is favorable to the temperature control of the dam, and it can provide new research ideas for solving the temperature control and anti-cracking of the concrete dams in high alpine areas.

关键词

碾压式导电混凝土 / U-ΔT模型 / 温度控制 / 大坝温度场

Key words

electrically conductive roller-compacted concrete / U-ΔT model / temperature control / dam temperature field

Author summay

杨 进(1984—), 男, 高级工程师, 硕士, 主要从事大坝运行安全管理研究。E-mail: [e-mail]

基金资助

国家自然科学基金项目(52309166)

中国长江电力股份有限公司科研项目(Z222302036)