Abstract: The failure of geological discontinuities often plays a significant role in controlling the failure of a rockslide. The second order work criterion can be used to analyse physical instabilities, except flutter instabilities. Hence, this study was to investigate the instabilities of geological discontinuities using the second order work criterion. First, regarding the instability of the major geological discontinuity, the advantage of this failure criterion was explained in mathematical approach; Second, the criterion was implemented into the FLAC finite-difference calculation software, and a two-dimensional numerical analysis was carried out to predict the occurrence of the rockslide in Nanfen Iron Mine, according to the corresponding monitoring data. Rockslides can be considered as a quasi-static to the dynamic transition, in which the sudden burst of kinetic energy indicates the occurrence of quasi-static-dynamic transition. Moreover, there is a direct relationship between the second order work and the second order kinetic energy. Therefore, the kinetic energy evolution curve can be estimated, which can prove the validity of the second-order work on identifying the failure of the rockslide.

Key words: rockslide, geological discontinuity, static-dynamic transition, bifurcation instability, kinetic energy, second order work