There is a macro-crack and micro-crack system in rocks, which affects almost all the mechanical properties of rocks, especially the failure mechanism and the strength criterion.
The macro profile and physicochemical examination of the tread oblique crack shows that the crack falls into the category of rolling contact fatigue type.
踏面斜裂纹及断口的宏观形貌和理化检验与分析表明，踏面斜裂纹伤损属于滚动接触疲劳裂纹伤损类型。
3
Depending on their extension, a differentiation is made between macro and micro-crack.