严寒地区某高RCC重力坝温控设计与优化

针对严寒地区极端气候环境对高碾压混凝土重力坝温控防裂不利的问题,以兼顾安全可靠和保障施工进度、控制成本为原则,运用经过二次开发的ANSYS有限元计算程序对多个温控方案进行了仿真优化。结果表明:在无任何温控措施的情况下,混凝土最高温度达到42.3℃,采取水管冷却措施后,最高温度仍达到35.6℃,均超过了设计拟定的最高温度控制要求;选用较低的浇筑温度但不考虑水管冷却时,最高温度为33.8℃,仍不能满足要求。综合考虑浇筑温度和通水冷却后,混凝土最高温度分别为29.5℃和31.5℃,可满足温度控制要求。因此,建议坝体混凝土浇筑温度应不超过16℃并需通水冷却,施工中应采用2 cm厚保温被对仓面临时保温,越冬层顶面应覆盖至少14 cm厚保温被,坝体应采用10 cm厚XPS挤塑板永久保温。研究成果对严寒地区制定科学合理的大坝温控方案具有参考价值。

Optimization and design of temperature control of a high RCC gravity dam in severe cold area

Aiming at the problem from the adverse impact of the extreme climate environment of severe cold area on the temperature control and crack prevention of the construction of high RCC gravity dam and taking account of the principle of safe and reliable construction， ensuring construction progress and controlling construction cost， a secondary developed ANSYS finite element program is applied to the simulative optimizations of several temperature control schemes. The result shows that the maximum temperature of the concrete reaches to 42.3 ℃ under the condition without any temperature control measures， and even to 35.6 ℃ after cooling with water pipe yet， thus both of them exceed the control requirement for the maximum temperature planned in the design. After selecting lower concrete placing temperature without the consideration of water pipe cooling， the maximum temperature is 33.8 ℃，which still cannot meet the requirement concerned. Through the comprehensive consideration of both the concrete placing temperature and water cooling， the maximum temperatures of concrete are 29.5 ℃ and 31.5 ℃ respectively， thus can meet the requirement of the temperature control. It is suggested that the concrete placing temperature for the dam body must not exceed 16 ℃ and water cooling is necessary at the same time， furthermore， the temporary insulation must be adopted for the concrete placing surface with the insulation quilt with the thickness of 2 cm and the top surface of the overwinter layer must be at least covered with the insulation quilt with the thickness of 14 cm during the construction， while the permanent insulation with extruded polystyrene board （XPS）with the thickness of 10 cm must be adopted for the dam body as well. The study result has reference value for making a scientific and reasonable temperature control scheme for the dam construction in severe cold area.