抑制预裂缝端部翼裂纹起裂动焦散实验研究

为了抑制预裂缝尖端产生翼裂纹,保护保留岩体,采用爆炸加载式动焦散系统对空孔影响预裂缝端部翼裂纹起裂规律开展研究。结果表明:空孔不仅可以引导裂纹扩展,而且可以抑制裂纹尖端产生新的翼裂纹向保留岩体扩展;在爆炸荷载作用下空孔周围形成复杂应力场,出现应力集中现象,随着空孔半径增大,主应力差的峰值逐渐减小,特征点连线与水平线夹角逐渐增大,空孔壁更难断裂产生新翼裂纹。研究成果为实际工程控制翼裂纹向保留岩体扩展提供了可靠依据。

Experimental study on dynamic caustics of suppress wing crack initiation at pre-splitting crack tip

In order to suppress the occurrence of wing cracks at the tip of the pre-crack and protect the retained rock mass, the blasting loading dynamic caustics system was used to study the effect of hole on the wing crack initiation at pre-splitting crack tip. The test results show that the empty hole can not only induced crack propagation, but also inhibit the new wing cracks at the crack tip from propagating to the retained rock mass. A complex stress field is formed around the empty hole under the blast load, and stress concentration occurs. As the empty hole radius increases, the peak value of the principal stress difference gradually decreases, and the included angle between the line connecting the characteristic points and the horizontal line gradually increases, and it is more difficult for the hole wall to break and generate new wing cracks. The research results provide a reliable basis for the actual engineering to control the wing cracks to extend to the retained rock mass.