大体积混凝土分期通水冷却技术研究与应用

Research and application of staged water cooling technology for mass concrete

大藤峡船闸主体混凝土浇筑总量约160万m 3,面对如此大体量的混凝土浇筑,需采取一定措施降低水化热,防止裂缝产生。本工程针对不同时段浇筑的混凝土采取分期通水冷却方式,混凝土浇筑开始时即开始通水,其中当年高温季节(4—10月)浇筑的船闸混凝土进行二期通水冷却,通水时间不小于30天;低温季节(11月—次年3月)浇筑的混凝土采用一期通水冷却,连续通水时间不小于20天。通过对埋设冷却水管进行闷水测温,同时结合通水前和通水过程中已埋设测温仪器的观测,大部分温控成果均满足设计要求。大藤峡船闸工程通过设置冷却水系统分期通水,同时提高施工工艺、加强覆盖保温等温控措施,最终极大降低了结构混凝土水化热,有效减少了温度回升、温度倒灌,确保了船闸主体工程混凝土表观质量。

The total amount of concrete poured for the main body of Dafengxia Lock is approximately 1.6 million cubic meters.Faced with such a large volume of concrete pouring,measures need to be taken to reduce heat hydration and prevent cracks.For this project,staged water cooling is adopted for concrete pouring at different stages.Water is introduced from the beginning of the concrete pouring process.During the high-temperature season(April to October),the lock concrete poured undergoes a second-stage water cooling with a minimum water circulation period of 30 days.For concrete poured during the low-temperature season(November to March of the following year),a first-stage water cooling is employed with a continuous water circulation period of no less than 20 days.By monitoring the temperature of the buried cooling water pipes and combining them with the observations from temperature measuring instruments installed before and during the water circulation process,most of the temperature control requirements have been met.The Dafengxia Lock Project effectively reduces the heat hydration of structural concrete by implementing staged water circulation through a cooling water system,improving construction techniques,and enhancing insulation measures.This significantly reduces temperature rise and temperature inversion,ensuring the apparent quality of the lock’s main concrete structure.