泵站施工期温控防裂敏感性分析研究

Analysis and study on sensitivities of temperature control and cracking prevention during construction of pumping station

以化子闸泵站工程为例,考虑冷却水温度、通水流量、水管间距、混凝土浇筑温度、保温层厚度以及后浇带宽度等因素,利用三维有限元计算程序,对泵站施工期的混凝土温度与应力进行数值模拟。结果表明,改变水管间距对混凝土冷却效果的影响较为明显;设置后浇带对温度应力有较大的释放;水管通水水温、混凝土浇筑温度与产生的拉应力呈现线性增长。水管通水流量超过一定值时泵站冷却效果不佳。保温措施能有效避免低温季节浇筑早期产生的表面裂缝。同时,选取优化温控方案对化子闸泵站施工期温度、应力场进行了仿真分析。结果表明:温控措施优选合理,泵站内外温差、早期表面拉应力及后期内部拉应力均处于安全可靠范围,可为泵站工程安全运行提供参考依据。

By taking Huazizha Pumping Station as the study case, the temperature and stress of concrete during the construction of pumping station are numerically simulated by means of the relevant 3-D finite element calculation program under the consideration of the factors of cooling water temperature, water-passing flow rate, space among water pipes, insulation layer thickness, post-placing concrete belt, etc. The results show that the influence from changing the space among water pipes is more significant on the cooling effect of concrete, while the temperature stress can be largely released after arranging post-concrete pouring belt. Meanwhile, the water-passing temperature of the pipe and the concrete placing temperature linearly increase with the produced tensile stress. When the water-passing flow rate of the pipe exceeds a certain value, the cooling effect of the pumping station is poor. The insulation measures can effectively avoid the early surface cracking of concrete during the placement carried out during low-temperature season. Simultaneously, the optimized temperature control scheme is selected to simulate and analyze the temperature and stress field of Huazizha Pumping Station during the construction. The result shows that the temperature control measures are reasonably optimized, while the difference between the internal and external temperatures, the early surface tensile stress and the later-period tensile stress are all in safe and reliable ranges, which can provide a referential basis for the safe operation of pumping station.