Abstract: When constructing tunnels in landslide areas, the stability of landslide is severely affected by the crossing position of tunnel. At present, the problems of tunnel excavation and the stability of landslide were separately investigated by many researchers. However, very little attention has been made on these two kinds of engineering problems together. In this study, a formula was deduced to calculate the disturbance range of surrounding soil and rock mass induced by tunnel excavation, according to the slip line theory. Combined with the analysis of loosened rock over the tunnel opening, an analytical expression was developed for the minimum safety distance of the tunnel orthogonally crossing the landslide. Moreover, its influencing factors were discussed. Besides, the stability of landslide body above the tunnel was analyzed using Sarma method, and the corresponding safety factor was also obtained. At last, a series of numerical simulations was carried out to investigate multiple examples of tunnel orthogonally crossing landslide. The accuracy of the deduced formula was verified by the analysis of rock plastic zones. Therefore, the results can provide a theoretical basis for the accurate selection of tunnel position in the landslide area.

Key words: tunnel, landslide, orthogonally crossing, safety distance, stability, theoretical analysis, numerical simulation