In order to study the effect of loading rate on fracture behavior of dam concrete, wedge splitting tests of various loading rates (0.1, 0.01, and 0.001 mm/s) are carried out on two kinds of full-graded dam concrete notched cubes with side lengths of 300 and 450 mm, respectively. Digital image correlation and acoustic emission technique are used to measure the deformation and acoustic emission parameters of the dam concrete. Test results show that: the peak load and fracture energy of dam concrete specimens increases with the increase of loading rate. And the higher the loading rate is, the fracture of concrete shows more obvious brittleness. Influenced by the boundary effect, the CTOD increases with the increasing of loading rate, however, the length of crack decreases as loading rate increases. With the loading rate increases, the energy mutation area is more obvious, while the accumulated acoustic emission energy is affected by both the loading rate and the maximum aggregate size. The number of acoustic emission three-dimensional locating points and the shear signal decrease with the increase of loading rate, which is attributed to that the faster the loading rate is, the less sufficient the development of micro cracks in concrete is. The test results can supply experimental data to the fracture mechanics of dam concrete.

为研究加载速率对大坝混凝土断裂行为的影响，对两种全级配大坝混凝土缺口立方体进行了不同加载速率（0.1、0.01和0.001 mm/s）的楔裂试验。长度分别为 300 和 450 毫米。采用数字图像相关和声发射技术测量大坝混凝土的变形和声发射参数。试验结果表明：坝体混凝土试件的峰值荷载和断裂能随着加载速率的增加而增加。加载速率越高，混凝土的断裂表现出越明显的脆性。受边界效应的影响，CTOD随着加载速率的增加而增加，但裂纹长度随着加载速率的增加而减小。随着加载速度的增加，能量突变区更为明显，而累积的声发射能量受加载速率和最大聚集体尺寸的影响。声发射三维定位点的数量和剪切信号随着加载速率的增加而减少，这是由于加载速率越快，混凝土中微裂缝的发展越不充分。试验结果可为大坝混凝土的断裂力学提供实验数据。混凝土中微裂缝的发展越不充分。试验结果可为大坝混凝土的断裂力学提供实验数据。混凝土中微裂缝的发展越不充分。试验结果可为大坝混凝土的断裂力学提供实验数据。