Evolution Characteristics of Principal Stress Transmission Path of Surrounding Rock in Adjacent Parallel Roadway Excavation

In order to solve the problems that the three‐dimensional principal stress state and stress transmission path of surrounding rock are unclear in the process of parallel roadway excavation (PRE), based on field stress monitoring, elastic mechanics and numerical simulation, the principal stress data processing program is developed to study the magnitude gradual change and direction rotation law of maximum principal stress σ1, intermediate principal stress σ2 and minimum principal stress σ3 in the process of adjacent PRE. The evolution characteristics of the principal stress transmission path of the roadway under superimposed disturbance are quantitatively described. Furthermore, the evolution difference of stress path and failure degree of surrounding rock between excavation direction parallel to σ1 and perpendicular to σ1 is discussed. The research results show that, during the PRE from left to right along σ1 direction, the stress rotation trajectories of the left and right roadsides have the characteristics of asymmetric distribution, and the stress peak value and rotation angle of the left roadside are larger than those of the right roadside. The principal stress at the shallow part of the roof and the roadside rotates approximately about σ2 and σ1 directions, respectively. If the excavation direction of the roadway is perpendicular to σ1, the magnitude change amplitude and the direction rotation angle of principal stress are larger, which leads to more severe failure and instability of the surrounding rock. The research results emphasize the significance of reasonable excavation direction to control surrounding rock failure from the perspective of principal stress path.