基于SCSCC试样的岩石复合型裂纹动态扩展特征研究

中文摘要: 侧开单裂纹半孔板（singlecleavagesemicirclecompression，SCSCC）试样是一种改进后的矩形板试样。采用分离式霍普金森压杆(SHPB)试验装置进行冲击试验，完成了SCSCC试样纯Ⅰ型及Ⅰ-Ⅱ复合型裂纹动态断裂试验，并进行数值分析，研究其扩展路径及扩展过程中的止裂问题。结果表明：SCSCC试件在试验过程中，纯Ⅰ型裂纹扩展过程中尖端沿着原方向朝试件右侧移动，Ⅰ-Ⅱ复合型裂纹扩展过程中朝着试件中轴线方向（最大应力区）移动，且可以观察到止裂现象；应变片法是一种监测断裂时刻的有效方法。使用修正的最大主应力准则及引入能量释放率的拉伸断裂软化损伤（cracksoftening，CS）破坏准则可有效解决岩石类材料的动态破坏问题，且可以描述材料全应力-应变破坏过程。Ⅰ-Ⅱ复合型裂纹SCSCC试件构型在研究岩石裂纹止裂领域具有较大优势；且SCSCC构型是一种大尺寸试样，可减小岩石非均匀性带来的影响。
Abstract:The single cleavage semi circle compression (SCSCC) plate specimens of sandstone,which are the sample of improved rectangular plate,were subjected to the split Hopkinson pressure bar.The model Ⅰ and mixed model Ⅰ Ⅱ rock dynamic fracture tests were conducted，the numerical simulation under the same condition with that of experiments was analyzed,and the failure modes for both tests and simulation were studied.Meanwhile, the crack arrest was also studied.The results showed that during the crack propagation,the model Ⅰ crack grew towards the right of the specimen which along the original direction,and the mixed model Ⅰ Ⅱ crack grew towards the axis of symmetry(maximum stress zone) of the specimen,meanwhile, the crack arrest phenomenon can be observed.Strain gauge method was an effective way to monitor the failure time.It was feasible to solve the dynamic destruction of rock materials in numerical simulation by using the modified maximum principal stress criterion and crack softening (CS) failure criterion,in additions,it described the complete stress strain failure process of material.The SCSCC specimens of mixed model Ⅰ Ⅱ had obvious advantages in the field of crack arrest.And because it was a large dimension specimen,it can reduce the effect that caused by the non uniformity of the rock.