不同MgO掺量下闸坝混凝土的温控研究

Study of sluice dam concreting temperature control at different MgO contents

高陂水利枢纽闸坝混凝土主要为碾压混凝土,采用厚层碾压快速筑坝方案,对混凝土进行外掺MgO的温控措施。通过三维有限元仿真计算,对闸坝混凝土不同MgO掺量下的温度应力场进行研究,结果表明,MgO掺量对温度场几乎没有影响,对闸坝基础强约束区内的混凝土应力影响较大。MgO掺量越大,应力补偿作用越显著,即混凝土应力越小,对温控防裂更有利。外掺5.5%MgO时闸坝混凝土水平拉应力基本控制在允许拉应力范围内。

The sluice dam of Gaobei Water Conservancy Project is a rolled compacted concrete dam, for which rapid construction scheme with thick layer roller compaction was adopted;concrete was mixed with MgO for temperature control. Three-dimensional finite element simulation calculation was conducted to study the temperature stress field of dam concrete with different MgO contents. The results of study show that the MgO content has little effect on the temperature field, and has great influence on the concrete stress in the strong confinement zone of dam foundation. The higher the MgO content is, the more significant the stress compensation effect will be, i.e. the lower the concrete stress will be, which is more favorable for temperature control and crack prevention. At the MgO mix proportion of 5.5%, the horizontal tension stress of dam concrete is basically controlled within the allowable range.