泵站进水流道混凝土施工期温控防裂研究

Research of the inlet concrete temperature control and cracking prevention under construction for pump station

大型泵站流道部分结构复杂且厚薄不均,其施工期混凝土开裂问题尤为突出.结合南水北调洪泽泵站工程,借助于有限单元法,对高温季节浇筑的泵站肘形进水流道混凝土施工期的温度场及应力场进行了动态仿真,在分析进水流道的易裂部位和开裂机理的基础上,提出有效防裂措施,包括控制浇筑温度在28℃以内,同时采用塑料管冷却及拆模后的表面保温措施.现场实际施工结果表明:仿真结果合理、防裂方法有效可行.

The inlet structures of large scale pump stations are complicated and have different concrete thickness. The concrete cracking problem of such structures is very serious, especially in construction period. According to the Hongze Pump Station of the South-to-North Water Diversion Project, with the aid of finite element method, the temperature field and the stress field of the elbow-shaped inlet concrete poured in high temperature seasons are simulated dynamically. The cracking mechanism of the inlet is analyzed. The valid crack prevention measures and the temperature control index are put forward ; the main measures include concrete pouring temperature, which is controlled at 28℃ ; plastic pipes are used to cool concrete; and surface insulation measures are used after template is dismantled. The construction application on site shows that the simulated results are reasonable, and that the crack prevention method is effective and practical.