重力坝模型的尺寸效应

利用两个不同比尺预制缝重力坝模型的试验成果，以有限元富集技术进行非线性断裂分析，建立了极限承载力和长度比尺的确定性尺寸效应公式。混凝土重力坝的断裂尺寸效应满足指数衰减关系，用三次指数衰减公式可以准确地预测原型的极限承载力。断裂过程区的相对长度是引起模型试验尺寸效应的主要原因。数值计算结果表明，断裂过程区相对长度不仅是与材料有关的参数，能否充分发展还取决于结构尺寸和几何形状；断裂过程区相对长度的尺寸效应不同于统计尺寸效应和断裂参数尺寸效应，具有尺寸范围效应。断裂过程区相对长度在小试件、大试件和相对无穷大试件的发展程度不同。

Size effect in gravity dam model

Based on laboratory test results of pre-notched gravity dam models with different size scales and the enriched finite element method developed by the authors, the deterministic size effect formulation for load capacity of model and length scale is established by using nonlinear fracture analysis. Size effect in fracture of concrete gravity dam obeys the law of exponential degression and the three order exponential degression formulation gives accurate prediction of load capacity of prototype, which can provide theoretical formulation for calculating the ultimate load capacity of prototype dam using model test result. Numerical results show that size effect in fracture of model test is mainly induced by the relative length of fracture process zone. The length of fracture process zone is not only dependent on material parameter, but also the structural size and geometry shape. Other than the statistical size effect and fracture parameter size effect, the size effect of relative length of fracture process zone possesses the characteristics of size-shape effect and size-range effect.