大藤峡水利枢纽大坝混凝土温控参数敏感性分析

Sensitivity Analysis of Concrete Temperature Control Parameters for Datengxia Water Project Dam

在施工过程中和运行期间,大体积混凝土结构中往往产生较大的温度应力,进而产生裂缝。混凝土结构施工前,为了筛选适时合理的温控防裂措施,对各温控参数作敏感性分析,确定不同温控参数的影响程度和特征,从而确定影响温度应力的主要因素。采用三维有限单元法,以大藤峡水利枢纽工程挡水坝段为对象,分析浇注温度、冷却水管间距、初期通水时间、初期冷却水温、基础混凝土浇筑时间等因素对坝体温度和应力的敏感性。结果表明,浇筑温度、水管间距、浇筑时间对坝体最高温度和应力的影响较为明显,而通水时间和初期冷却水温的影响有限,且通水时间不易过长,水温不易过低、也不能明显高于混凝土的入仓温度。

In the process of construction and operation,the large volume concrete structure often produces a large temperature stress,and then cracks.Before concrete construction,in order to select proper temperature control and crack prevention measures,the sensitivity of each temperature control parameter is analyzed,and the influence degree and characteristics of different temperature control parameters are determined,thus the main factors affecting temperature stress are determined.In this paper,the three-dimensional finite element method is applied to the dam section of Datengxia water project,the sensitivity of pouring temperature,distance between cooling pipes,initial time of opening water,initial temperature of cooling water and pouring time of foundation concrete to dam temperature and stress is analyzed.The results show that the influence of pouring temperature,pipe spacing and pouring time on the maximum temperature and stress of the dam is obvious,but the influence of water flowing time and initial cooling water temperature is limited,and the time of water flowing is not easy to be too long,the water temperature is not easy to be too low,nor can it be significantly higher than the temperature of concrete.