 The research found that pre-existing cracks can cause additional cracks to form around the hole, which can lead to instability. This phenomenon was observed when the angle of the pre-existing cracks ranged between 45 and 90 degrees. These cracks were also able to connect with the free surface or other cracks, leading to overall instability. This article was authored by Junwei Zhang, Duanying Wang, Widing Gao, and others.