堆石混凝土拱坝施工期温度监测与分析

Temperature Monitoring and Analysis for RFC Arch Dam in Construction Period

贵州省境内的龙洞湾堆石混凝土拱坝采取了不分横缝整体浇筑,未采取任何温控措施,期间赶上炎热夏季施工。为了研究堆石混凝土中堆石与自密实混凝土的温度传导规律,针对龙洞湾拱坝开展了夏季晴天和持续降雨两个工况下详细的施工期温度监测工作。通过对自密实混凝土、堆石、环境气温等监测数据进行分析,结果显示:①堆石接触到自密实混凝土后能迅速吸热升温,在自密实混凝土水化热的过程中由于二者温差有明显的吸热过程;②堆石混凝土的整体温升幅度较低,该筑坝技术能有效抑制温度裂缝的产生,在气候温和地区可采取不分横缝的整体浇筑方式;③夏季施工时,适当采用遮光布等方式避免堆石被阳光直晒,降低堆石的入仓温度,能有效提升堆石对混凝土水化热的吸热能力。

Longdongwan rock-filled concrete(RFC)arch dam in Guizhou Province adopts the integral pouring method without transverse joints,and the pouring is conducted out without temperature control measures during the hot summer period.In order to study the temperature conduction between rock and self-compacting concrete(SCC)in RFC,the temperature monitoring during construction period is carried out for the arch dam under two conditions of sunny day and continuous rainfall in summer.Based on the analysis of the monitoring data of SCC,rock and air temperature,the results show that:(a)the rock can absorb heat rapidly once contacting SCC,and there is an obvious heat absorption during the hydration heat of SCC due to the temperature difference;(b)the overall temperature rise of RFC is relatively low,which can effectively inhibit the generation of temperature cracks,and therefore,the integral pouring method without transverse joints can be applied in moderate climate region;and(c)the proper use of shading cloth to cover rock,which can avoid direct sunlight in summer and can reduce the placement temperature of rock,may probably enhance the heat absorption capacity of rock.