SHPB加载下含不同倾角裂隙的类岩石试样力学特性

 为研究裂隙倾角对类岩石试样的强度与变形特性、裂纹扩展规律及破坏过程的变化趋势的影响，对含有不同倾角的预制裂隙类岩石试样进行霍普金森杆（SHPB）加载试验。研究发现，SHPB加载作用下类岩石试样的应变阶段分段不明显，基本不存在应变软化阶段以及残余强度段。SHPB加载作用下，类岩石试样的峰值强度的变化趋势与静载荷作用下基本相同。随着预制裂隙倾角变化呈先变大后减小的V字形变化。在裂隙倾角为45°时，试样的峰值强度最小，0°和90°试样的峰值强度与完整试样极其接近。且SHPB加载作用下的类岩石试样的强度增加比较缓慢，峰值强度基本都小于相同条件下静载荷的峰值强度。随着预制裂隙倾角的增大，起裂角逐渐减小。当预制裂隙倾角较小时（0°，15°），起裂角接近90°。与静载荷作用下的变化趋势是一致的。SHPB加载过程与静载荷不同，类岩石试样从开始加载至完全破坏总时间为约为2 s，速度极快。

Experimental study of mechanical properties of rocklike specimens containing single cracks of different inclination angles under SHPB loading

In order to study the influence of the crack obliquity on the strength, the deformation, the crack propagation and the failure process of rocklike specimens, the SHPB loading test is carried out for rocklike specimens, with prefabricated cracks containing different inclinations. It is found that the strain phase segment is not obvious under the SHPB loading and the strain softening stage and residual strength section are almost of non-existence. Under the SHPB loading, the peak strength of the rock specimens is almost the same as that under the static loading, that is, it is in a V shape against the angle of the rocklike specimens and it increases before it decreases. The peak strength of the specimens is the minimum, when the crack obliquity is 45°, and the peak strength of the specimens is very close to that of the complete specimens when the crack obliquity is 0° or 90°. The strength of the rocklike specimens under the SHPB loading increases slowly and the peak strength is less than the peak strength under the static loading under the same condition. The crack angles decrease with the increase of the prefabricated crack inclinations. When the prefabricated crack inclinations are relatively small (0°,15°), the crack angle is close to 90°. This trend is consistent with the static loading. The SHPB loading process is different from that of the static loading, it lasts about 2s from the beginning of the loading to the complete failure of the rocklike specimens, with an extremely fast speed.