大型泵站混凝土底板施工期温控防裂研究
首发时间:2012-12-10
摘要:泵站混凝土结构浇筑完早期,因水化反应的不断进行将会产生大量水化热,内部热量较难散发,形成较大的内外温差,同时表面出现较大的拉应力。本文综合考虑混凝土浇筑温度、水泥水化热、环境气温变化、昼夜温差以及浇筑间歇期等主要影响因素,通过多种工况对泵站的底板三维温度场、应力场进行了仿真计算,重点对比了混凝土内、外部温度应力变化、冷却水管管壁周围的应力,揭示了泵站在高温季节施工期的温度及温度应力变化规律。根据三维温度场、应力场的仿真计算成果,指出泵站施工期混凝土结构可能出现开裂的部位、重点控制预防区域及出现时间;并综合考虑冷却效果和工程成本,提出了经济合理的温防裂方案。
关键词: 水工结构 泵站 冷却水管 温度应力 仿真分析 温控防裂
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Research on Temperature Control and Crack Preventionof Concrete Floor for Large Pump Station During the Construction
Abstract:After the concrete floor of large pump station is poured, it produces a large amount of cement heat of hydration at early age, internal heat is difficult to send out, the surfaces of concrete floor generate thermal stress induced by temperature difference. Main influencing factors, such as placing temperature of concrete, the heat of hydration of cement, surrounding temperature, diurnal amplitude, the intermission of pouring and so on are considered in the present paper to establish a fine finite element meshes which contains concrete floor, elbow-shaped inlet conduit, the pump layer, outlet conduit of pump station. Many simulation conditions are computed in this paper. The tensile stress state of concrete floor is compared. Simulation results show that the internal tensile stress of the concrete structure will vary in the late period, the stress will emerge around cooling pipes and the surface stress of the structure will rebound after the template is disassembled, revealing the real temperature and stress of the pump station concrete structure during construction in high temperature season. According to the simulation results of 3-D temperature filed and thermal stress filed during the construction of pump station, the position of cracking and the area of prevention and control are pointed out.; Taking into the cooling efficiency and construction cost account comprehensively and then provide a reasonable and economical arrangement of temperature control and crack prevention in the process of design and construction.
Keywords: Hydraulic Structure Pump Station Pipe Cooling Temperature Stress Simulation Analysis Temperature Control and Crack Prevention
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