1999年三峡大坝混凝土温控防裂研究与实践

1999年，为三峡工程二期施工阶段由开挖为主转入混凝土浇筑高峰期的关键一年，面临混凝土浇筑强度高、进度紧、温控设计要求严、高温季节浇筑基础约束区混凝土和施工设备投产晚的严峻局面。长江委设计院对1999年高温季节浇筑大坝基础约束区混凝土进行了专题研究。通过对大坝温度应力仿真研究和夏季各种温控措施效果分析，提出了夏季浇筑基础约束区混凝土的综合温控防裂措施。通过三峡工程参建各方共同努力，全面实施综合温控防裂措施，达到了预期效果，避免了大坝基础约束区产生危害性贯穿裂缝，并为顺利完成混凝土年度计划和形象面貌创造了有利条件。

Study and practice of concrete temperature control and crack prevention for the Three Gorges dam in 1999

In the year 1999, the focal points of the Three Gorges Project construction were turned from earth-rock excavation into larg-scale concrete placement. Builders faced a serious situation of high concrete placement intensity, urgent schedule, strict requirements for temperature control design, concrete placement in restrained zones of foundation in hot seasons, delayed deployment of construction equipment. The Design institute of the Changjiang Water Resources Commission conducted a monographic study on concrete placement in restrained zones of the dam foundation in the hot season of the year 1999. Through emulation study on temperature stresses in the concrete dam and through analysis of the effects of temperature control measures, the Design Institute put forward comprehensive temperature control and crack prevention measures for concrete to be placed in restrained zones of the dam foundaton in summer. Through common efforts made by all sides participating in the Three Gorges Project construction, these comprehensive temperature control and crack prevention measures were implemented in an all-round way, achieving expected results to avoid formation of harmful Penetrating cracks in restrained zones of the dam foundation and create favorable conditions for fulfilling the annual plan of concrete placement.