加强混凝土坝面保护尽快结束“无坝不裂”的历史

Strengthen superficial insulation of concrete dams to terminate the history of "on dam without cracks

混凝土坝裂缝绝大多数是表面裂缝,但其中一部分可能发展为深层裂缝甚至贯穿裂缝,表面保护是防止混凝土坝裂缝的重要措施。通过给出的表面放热系数计算公式,计算分析了表面保温效果,指出混凝土表面养护和保温28d的时间太短,建议在坝体上下游表面采用聚苯乙烯泡沫塑料板长期保温,水平层面和坝块侧面用聚乙烯泡沫塑料板保温。这套措施,保温效果好,保护时间长,兼有保湿功能,施工方便,价格低廉,同时要做好基础混凝土温度控制,有可能很快结束“无坝不裂“的筑坝历史。

28d is too short for the curing and superficial insulation of dam concrete. It is suggested to insulate the upstream and downstream faces of the dam by foamed polystyrene plates which are fixed to the inner faces oi the forms and remain there after the removal of the forms. The horizontal and lateral surfaces of the dam blocks are insulated by the foamed polythene plates.Beside thermal insulation, they have also the effect of humid insulation. Together with the control of temperature differences in the concrete near the foundation, it is possible to prevent cracks in dam concrete and terminate the history of 'no dam without cracks'.