随机骨料模型形态对大坝混凝土弯拉强度的影响

Influence of random aggregate shapes on flexural strength of dam concrete

建立反映混凝土实际骨料级配、含量及其形态的随机骨料模型是进行混凝土细观力学数值模拟分析的前提和基础。球形骨料模型和基于瓦拉文公式生成的圆形骨料模型基本上能够接近卵石、砾石等球状或浑圆状的骨料,但与一般碎石骨料的形态差异较大。本文分别采用随机圆形骨料、球骨料与多边形、多面体骨料模型,通过对全级配大坝混凝土试件弯拉破坏过程的细观数值模拟,对比分析了不同骨料模型形态对计算结果的影响,探讨了用球形骨料或圆形骨料简化实际碎石骨料的有效性。

An appropriate random aggregate model,considering gradation,content and shape of aggregates in concrete and so on,is the basis of successful simulation of meso-mechanical behaviors of dam concrete.The sphere aggregate model and the circle aggregate model based on Walraven formula can usually be used to approximate gravel aggregates and spherical aggregates,but it can not be applied for detritus aggregates.Random circle and sphere aggregate models,convex polygon and convex polyhedral aggregate models are separately adopted in the paper to simulate the flexural fracture process of concrete specimens in view of meso-mechanics.Influences of different aggregate-shape models on computational results are examined.The validity of substitution of sphere and/or circle aggregates for detritus aggregates in order to simplify practical modeling is evaluated.