Experimental study on crack initiation mechanism of loess containing non-penetrating fissures

Numerous joints and fissures characterise loess and the evolution of fissures under an external load is closely associated with landslides, collapses and other disasters, severely endangering the engineering construction in loess areas. The crack initiation mechanism of fissured loess was investigated by fabricating preset fissures of different lengths and inclination angles. Uniaxial compression tests were conducted on the non-penetrating fractured loess to obtain the damage mode and crack initiation location, revealing the crack initiation mechanism based on the maximum circumferential stress theory. The results showed that the preset fissure’s inclination angle and length significantly affected the specimens’ peak strength and crack initiation stresses. The peak strength and crack initiation stress decrease and then increase with the increase in preset fissure inclination and decrease with the increase in preset fissure length and the crack initiation stress level ranges from 0.5 to 0.8. The maximum circumferential stress criterion can better characterise the crack initiation angle quantitatively and resolve the cracking characteristics of fissured loess with a single fissure under axial compression load.