观音阁水库混凝土大坝越冬面水平施工缝的开裂原因及处理措施

Analysis on Crack Cause and Treatment of Horizontal Winter Construction Joint

应用温度及温度徐变应力仿真计算和线弹性断裂力学理论，分析了观音阁大坝越冬面水平裂缝的原因是，越冬面混凝土上下层温差及内表温差的温度应力超过混凝土的抗裂强度，和越冬面附近混凝土层间抗拉强度低于本体抗拉强度所致．分析表明，随着高程的降低，其相应部位的裂缝及坝体层间稳定性越小，如不处理，其危害性越大．依据分析结果，各高程裂缝的处理原则亦不同．高程２１８．２５ｍ裂缝的上游面进行防渗处理；高程２３３．２５ｍ水平裂缝只作简单处理．具体防渗措施是采用沥青混凝土防渗面板．

The crack cause of horizontal winter construction joint in Guanyinge dam is analyzed on the basis of the theory of linear elastic fracture mechanics. Besides the inner and outer dam temperature difference, the difference between concrete layers is much larger, as well as the tensile strength near the winter concrete surface is smaller than other layers concrete, which results in horizontal cracks in dam concrete. The dam stability and the fracture safety of horizontal crack are smaller as the elevation of cracks is lower, so that the harm of crack located a low elevation is much serious. According to the analysis of crack safety and dam stability, the treatment principle is different for every elevation crack. Besides the impervious treatment on upstream surface, the dam water pipes must be set for cracks below EL. 209. 25. The impervious treatment on upstream surface is selected for EL. 218. 25 crack. Simple treatment is enough safe for EL. 233. 25 crack.