Abstract: Taking vertical working intersection in a mine as the background, the distribution law of disturbed principal stress vector (including the value and the deflection rule of the direction of such disturbed principal stress vector) of vertical working intersection, which keeps a different spatial location relationship with the in-situ stress, has been revealed through VB programming to dispose the data of numerical analysis. And the law of both the deformation and loose circle of intersection surrounding rock changing along the spatial location mentioned above has been studied by introducing the method of point safety factor. The result shows that such stress vector is mainly influenced by the in-situ stress but hardly by the spatial location and the excavation sequence of vertical working, and from the shallow of surrounding rock to the deep, the value of such stress vector decreases to in-situ stress after the first in crease; the maximum disturbed principal stress in the roof and floor of intersection is horizontal stress, while such stress in the two sides of intersection is vertical stress; the closer the axes in the vertical intersection is to the two horizontal principal stress normal bisector , the more stable the surrounding rock of intersection is. What is more, the surrounding rock is more stable when the roadway of intersection near the maximum horizontal principal stress is excavated firstly than the other excavation sequence.

Key words: principal stress vector, intersection, point safety factor, excavation sequence, strength reduction