Dynamic behaviors of rockslides subjected to brittle failure of locked segments

Locked segments are recognized as a critical role that controls the stability of rock slopes but remain an unclear and challenging problem with respect to their role incorporated into the failure mechanism. In order to study the effect of the locked segments on the initial failure process of rockslides, thirty-six groups of locked segment specimens with three different lithologies were prepared, direct shear tests were carried out to obtain the accelerations caused by brittle failure of the locked segment specimens. Experiment results showed that the maximum accelerations caused by the brittle failure of locked segment specimens was 2.91 g in the horizontal direction, and 3.18 g in the vertical direction. We took the Wangjiayan rockslide in 2008 Wenchuan earthquake as an example, the critical balance condition of the sliding mass under combined effect of gravity and accelerations induced by brittle failure of locked segment was analyzed, which indicated that the initial failure process of the Wangjiayan rockslides was notably influenced by the existence of the locked segment. The departure acceleration and direction of the Wangjiayan rockslide were proposed. The study results can provide a new insight into the understanding of the initial failure mechanism of rockslides with locked segments.