循环压缩荷载下岩石的疲劳裂纹扩展机制

Rock fatigue crack propagation mechanism based on far field cyclic compression

通过有限元方法建立3种几何条件的岩石裂纹模型.考虑岩石裂纹面接触问题,对循环载荷作用下的裂纹萌生扩展进行分析.研究结果表明,裂尖区域在循环压缩载荷作用下的残余拉伸应力是导致裂纹扩展的重要因素.同时,还对不同裂尖几何在裂纹描述的合理性方面提出了一些看法.研究结果表明,裂纹在循环压缩载荷作用下的扩展能力是有限的、稳定的.

It was demonstrated that rock crack could grow under far field cyclic compression load in experiments. However, this kind of rock crack growth phenomena is difficult to be observed and described accurately by mathematic methods because the tension residual stress area is too small and crack face contact exists. Finite element method was used to calculate the residual stress fields of three crack tip geometries. It was found that tension residual stress is a key factor for crack growth under cyclic compression. The rationality of different crack tip geometries is discussed. Meanwhile, this research shows that crack propagation is limited and stable under cyclic compression.