Experimental study of the damage characteristics of rocks containing non-penetrating cracks under cyclic loading

The damage evolution process of non-penetrating cracks often causes some unexpected engineering disasters. Gypsum specimens containing non-penetrating crack(s) are used to study the damage evolution and characteristics under cyclic loading. The results show that under cyclic loading, the relationship between the number of non-penetrating crack(s) and the characteristic parameters (cyclic number, peak stress, peak strain, failure stress, and failure strain) of the pre-cracked specimens can be represented by a decreasing linear function. The damage evolution equation is fitted by calibrating the accumulative plastic strain for each cycle, and the damage constitutive equation is proposed by the concept of effective stress. Additionally, non-penetrating cracks are more likely to cause uneven stress distribution, damage accumulation, and local failure of specimen. The local failure can change the stress distribution and relieve the inhibition of non-penetrating crack extension and eventually cause a dramatic destruction of the specimen. Therefore, the evolution process caused by non-penetrating cracks can be regarded as one of the important reasons for inducing rockburst. These results are expected to improve the understanding of the process of spalling formation and rockburst and can be used to analyze the stability of rocks or rock structures.