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温度裂缝严重影响水工衬砌结构的耐久性和安全性。白鹤滩水电站导流洞导流任务重、使用时间长、尾水段与尾水洞结合为永久结构。为限制温度裂缝,使用低热水泥、预冷混凝土、通水冷却、冬季挂帘等综合温控措施,使混凝土裂缝大幅减少。通过统计现场监测数据及裂缝特征,论证了温控措施的合理性,分析了裂缝的一般规律。利用有限元法分析裂缝影响因素的敏感性,结果表明,大量裂缝出现在冬季昼夜温差变化较大时;低温季节当气温变化幅度较小,选择自然入仓也能满足温控要求;断面尺寸越小、分仓长度越短、分期施工对限制混凝土裂缝有利;围岩越完整,约束作用越强,衬砌混凝土开裂风险越大。研究成果可为类似工程提供参考和借鉴。
Temperature cracks seriously affect the durability and safety of hydraulic linings. The diversion tunnel of Baihetan Hydropower Station has heavy diversion tasks and long service life, and the tailrace section and tailwater tunnel are combined into a permanent structure. To limit the temperature cracks, the use of low-heat cement, pre-chilled concrete, water cooling, winter curtain and other comprehensive temperature control measures, so that a substantial reduction in concrete cracks. Through statistical monitoring data and the characteristics of cracks, the rationality of temperature control measures is demonstrated and the general rules of cracks are analyzed. Finite element method is used to analyze the sensitivity of the influencing factors of cracks. The results show that a large number of cracks occur when the temperature difference between day and night is large. In the low temperature season, when the variation of temperature is small, Small, sub-warehouse length is shorter, staged construction is beneficial to limit the concrete cracks; the more complete the surrounding rock, the stronger the constraint, the greater the risk of lining concrete cracking. The research results can provide reference and reference for similar projects.