受压混凝土试件应力状态与强度分析

The Stress State and Strength Analysis of a Compression Concrete Specimen

为研究受压混凝土试件的强度以及强度变化机理，通过数值模拟不同长径比的混凝土轴心受压试件的破坏过程，研究受压混凝土试件轴心受压时内部应力状态和裂纹的损伤演化过程，及混凝土试件不同围压作用下，强度的变化机理，分析表明，混凝土试件随着长径比增大，强度减小，试件的破坏面逐渐减小，强度随着内部应力状态变化而变化，围压越小混凝土试件的强度越小，试件的破坏形式由剪切破坏面逐渐到受拉破坏面。推荐将长径比1：10时为受拉破坏面为作为无侧限的受压时极限拉应变。

In order to study the compression strength and its changing mechanism of the concrete specimen, the numerical simulation method is applied. By simulating the failure process of con- crete with different length/diameter ratios under axial compression, the internal stress state and the damage evolution process of crack are studied. Moreover, the changing mechanism of con- crete strength under different confining pressures is also analyzed. The result shows that with the increase of length/diameter ratio, the intensity of the concrete specimen is reduced, and the fail- ure surface of the specimen gradually decreases. The concrete intensity change with the internal stress state the smaller the confining pressure, the weaker the concrete strength. The fracture mode of specimen also changes gradually from shear failure to tensile fracture. The tensile failure surface with a length/diameter ratio of 1 ： 10 is recommended as the ultimate tensile strain in unconfined compression condition.