中文摘要：

为了满足大体积混凝土结构进行非线性分析和设计的需要,通过试验比较了三级配混凝土大试件和湿筛二级配混凝土小试件在双轴拉压、三轴拉压压受力情况下的强度和变形特性。三级配混凝土试件尺寸为25cm×25cm×40cm,最大骨料粒径为80mm;湿筛试件尺寸为15cm×15cm×30cm,最大骨料粒径为40mm。试验数据表明,同一种应力状态下,混凝土大试件的强度和变形均低于小试件,大尺寸试件的应力-应变曲线的初始斜率一般大于相应的湿筛小试件的初始斜率。试验结果证实对处在复杂应力状态下的大体积混凝土结构,尺寸效应和骨料湿筛效应的影响是很显著的,在设计中必须考虑。最后分别在主应力空间和八面体应力空间建立大骨料混凝土的破坏准则,这为水工大体积混凝土按多轴强度理论进行设计提供了试验依据。

英文摘要：

In order to meet the requirement of the nonlinear analysis and design for the mass concrete structures, the deformation behavior and strength of three-graded concrete specimens 25 cm ×25 cm ×40 cm with the maximum aggregate size 80 mm and the corresponding wet-screened concrete specimens 15 cm×15 cm×30 cm with the maximum aggregate size 40 mm are studied experimentally. The specimens are subjected to biaxial compression-tension and triaxial compression-compression-tension stress states The test data indicate that both the deformation and strength of the mass concrete specimens are lower than those of the corresponding wet-screened concrete small specimens, but the initial tangent modulus of the stress-strain curve of the former is greater than that of the latter. The test results show that the wet-screened effect and size effect of the specimens under complex stress states are obvious so that it should be considered in the design for the mass concrete structures. In addition, respective failure criteria for mass concrete in principal stress space and octahedron stress space are proposed. The present work provides an experimental basis for the design and analysis of hydraulic mass concrete structures which should be designed according to the multiaxial strength theory.