中文摘要：

该文在细观层面上将混凝土看作粗骨料、砂浆、界面、初始缺陷组成的四相复合材料，给出了三维随机缺陷界面弹簧元模型模拟混凝土单轴抗压强度的数值方法。讨论了初始缺陷含量及其分布的确定方法以及界面细观计算参数的取值范围。数值模拟结果表明：混凝土的抗压强度随着初始缺陷含量的增加有大幅度降低；当界面初始缺陷含量为30％时，混凝土抗压强度的计算值与试验值吻合较好。

英文摘要：

An interfacial spring element model （ISEM） is employed to simulate the strength of concrete under uniaxial compressive loading. In this model, the concrete was considered as a composition consisting of aggregate, matrix, interracial transition zone （ITZ） and initial defects in ITZ at meso level. The distribution and contents of the initial defects, and the ITZ properties parameters are discussed, accordingly which, the range of meso-parameters are suggested. The results show that the compressive strength of concrete decreases with the increase of the ITZ initial defects. When the initial defects in ITZ achieves to 30 percent of ITZ elements, the numerical simulation results of concrete compressive strength agree well with the experimental results.