Abstract: To study the influence of principal stresses on the stability of roadway intersection, five numerical models of roadway intersection are developed based on the engineering project in Wujiagou coal mine, and the rotation of the disturbance stress field due to roadway excavation is investigated. By introducing the pointwise safety factor method, the influence of principal stress and the angle of roadway intersection is analyzed on the displacement field and the disturbed broken zone around the surrounding roadway intersection. The results show that the orientation of principal stress in the vicinity of the intersection rotates after the excavation of the main roadway, and thus the stress field changes from σh type to σv type. In addition, during the excavation at the intersection, the surrounding rockmass is influenced by the σv-type stress field, and the surrounding rockmass at the intersection becomes more stable when the intersection angle (α≤90°）increases. At the same intersection angle, the intersection point on the direction of the maximum horizontal principal stress becomes more stable in a newly excavated tunnel. These results are confirmed by the monitoring data at the intersection in Wujiagou coalmine.

Key words: roadway intersection, stability of rock, angle of roadway intersection, pointwise safety factor