The crack propagation process of the cubic concrete specimens containing single cracks under lateral confinement was studied experimentally and numerically. The experimental study was conducted on some pre-cracked cubic specimens under compressive loading condition. Then, the two-dimensional particle flow code (PFC2D) was used to numerically model these specimens considering different lateral applied stresses. Both the experimental test and the numerical modeling showed that the lateral stress has a profound effect on the crack propagation mechanism of concrete compared to that of the uni-axially loaded specimens (containing cracks). In the present work, each specimen contained a single crack so that at the first stage of loading the wing or tensile cracks initiated and extended in the direction of maximum applied load. The mixed mode crack propagation scenarios were observed due to both tensile (wing cracks) and shear (secondary cracks) under different confining stresses. These results are compared with those of the zero confinement cases for both the experimental tests and the numerical models. This comparison exhibited that the confined stress may effectively influence the process of crack initiation and crack propagation in the pre-cracked concrete specimens under compressive loading condition.

实验和数值研究了横向约束下含单个裂纹的立方混凝土试件的裂纹扩展过程。在压缩载荷条件下，对一些预破裂的立方试样进行了实验研究。然后，考虑到不同的横向施加应力，使用二维粒子流代码（PFC2D）对这些样本进行数值建模。实验测试和数值模拟均表明，与单轴加载试件（含裂纹）相比，侧向应力对混凝土的裂纹扩展机理具有深远的影响。在目前的工作中，每个试样都包含一个裂纹，因此在加载的第一阶段，机翼或拉伸裂纹在最大施加载荷的方向上开始并延伸。在不同的限制应力下，由于拉伸（翼形裂纹）和剪切（二次裂纹）而观察到混合模式裂纹扩展的情况。将这些结果与零约束案例的实验测试和数值模型进行了比较。该比较表明，在压缩载荷条件下，预应力混凝土中的约束应力可能会有效地影响裂纹萌生和裂纹扩展的过程。