龙滩高RCC重力坝夏季不同浇筑温度的温控防裂研究

Temperature control and cracking prevention of Longtan High RCC Gravity Dam with different concrete placement temperatures in summer

根据龙滩RCC重力坝的设计情况和施工组织计划 ,采用非均质层合单元的三维有限元仿真模拟大坝的施工及运行过程 ,计算夏季采用不同浇筑温度时典型溢流坝段的温度场和应力场。计算结果表明 ,当夏季浇筑温度为自然浇筑温度时 ,龙滩大坝出现贯穿性裂缝将在所难免 ;如果降低夏季的浇筑温度 ,可明显地降低混凝土的最高温升和拉应力 ;当浇筑温度控制在 16℃左右时 ,基本能满足大坝的温控防裂要求 。

Under the conditions of design and construction program of the Longtan high RCC gravity dam, a three-dimensional finite element analysis of simulating the whole process from the construction to operation of the dam is carried out with the help of an inhomogeneous elemental model. The temperature field and thermal stress distribution of the studied overflow block of the dam during construction and operation period in different placement temperatures in summer are calculated and analyzed. According to the results, the occurrence of through cracks of the Longtan dam is unavoidable without any thermal control measures for the concrete placement temperature in summer. If the placement temperature in summer is decreased, the maximal temperature and extreme tension stress in the dam body could be obviously reduced. When the placement temperature in summer is controlled to about 16℃, the requirement of the cracking control could be met essentially. But some temperature control and crack prevention measures such as heat insulation should be taken on some local surfaces of the dam body.