Influence of axial stress on failure characteristics of deep arched hard rock roadway

To study the influence of axial stress on the failure characteristics of deep arched roadway considering structural effect, true triaxial compression tests were conducted on cubic granite specimens with a three-centered arched hole structure. A video monitoring device was utilized to record the failure process of surrounding rocks. The test results show that under 10−60 MPa axial stress, the surrounding rock failure process included the calm stage, particle ejection stage, fragment ejection stage, and rock slice buckling and spalling stage. Under higher axial stresses (70 and 80 MPa), the failure process is characterized by violent fragment spray during the fourth stage. As the axial stress increases, the failure of surrounding rock increases, while the initial vertical failure stress first increases and then decreases. According to the failure characteristics of roadway under different axial stresses, arranging the roadway along the direction of a moderate axial stress level is desired.