单轴压缩条件下含圆形孔洞脆性岩石的断裂演化（英文）

Fracture evolution around pre-existing cylindrical cavities in brittle rocks under uniaxial compression

应用物理模型和声发射技术,研究预制圆形孔洞脆性岩石的断裂演化过程。结果表明:在单轴压缩条件下,含单圆形孔洞岩样的破坏主要表现为在孔顶底产生平行于加载方向的拉伸劈裂裂纹,在孔两侧产生压缩裂纹,在孔的周边产生远场裂纹,而且其断裂破坏具有尺寸效应;对含有半长圆孔的开挖花岗岩样,首先在圆孔两侧壁产生压应力集中,诱发产生剪切裂纹的初始、扩展和贯通。对含有多个平行孔洞的岩样,其破坏主要是相邻圆形开挖产生的拉、压、剪共同作用的结果。结果表明,拉、压应力是造成含圆形孔洞试样断裂的关键因素。

The development of fracture around pre-existing cylindrical cavities in brittle rocks was examined using physical models and acoustic emission technique. The experimental results indicate that when granite blocks containing one pre-existing cylindrical cavity are loaded in uniaxial compression condition, the profiles of cracks around the cavity can be characterized by tensile cracking （splitting parallel to the axial compression direction） at the roof-floor, compressive crack at two side walls, and remote or secondary cracks at the perimeter of the cavity. Moreover, fracture around cavity is size-dependent. In granite blocks containing pre-existing half-length cylindrical cavities, compressive stress concentration is found to initiate at the two sidewalls and induce shear crack propagation and coalescence. In granite blocks containing multiple parallel cylindrical cavities, the adjacent cylindrical cavities can influence each other and the eventual failure mode is determined by the interaction of tensile, compressive and shear stresses. Experimental results show that both tensile and compressive stresses play an important role in fracture evolution process around cavities in brittle rocks.