中文摘要：

本文研究现场浇筑大坝混凝土与湿筛混凝土起裂韧度的换算关系。利用中国某特高拱坝施工现场拌合楼生产混凝土拌合物,浇注成型不同试件尺寸的骨料最大粒径150 mm的大坝混凝土试件,以及骨料最大粒径40 mm的湿筛混凝土试件。通过试验分别获得了大坝混凝土及湿筛混凝土各试件的起裂荷载,进而由有限元计算得到其起裂韧度。分析了大坝混凝土与湿筛混凝土的起裂韧度随试件尺寸变化而变化的规律,研究发现,不论大坝混凝土试件,还是湿筛混凝土试件,当韧带高度与骨料最大粒径比值大于等于6.0后,起裂韧度均趋于稳定值。基于试验结果,建立了小尺寸湿筛混凝土试件推求大尺寸大坝混凝土试件起裂韧度的关系式。

英文摘要：

This paper studies the conversion relationship between the initial fracture toughness of site-cast-ing dam concrete and that of sieved concrete. The concrete mixture produced by the mixing tower systemon the construction site of a super-high arch dam is used to cast and mold different sizes specimens, ofwhich the maximum aggregate size of dam concrete specimens is 150 mm and that of sieved concrete speci-mens is 40 mm. Based on the experimentally acquired initial cracking loads, the initial fracture toughness KiniIcof the dam concrete and the sieved concrete were obtained using the finite element method. Furthermore,the effect of dam concrete and sieved concrete specimens size on initial fracture toughness was ana-lyzed and discussed. The results show that, regardless of the dam concrete specimen or sieved concretespecimen, when the ratio of the ligament height to the maximum aggregate size is equal to or larger than6.0,the stable values of initial fracture toughness can be obtained. Based on the test results,the calculat-ing formulas for the initial fracture toughness of large dam concrete specimens are derived from that ofsmall sieved concrete specimens.