Surrounding rock control technology of overlarge drop fault fracture zone in deep soft rock high stress roadway

Abstract

In view of the unfavorable geological conditions such as weak broken surrounding rock, low self-bearing capacity, complex stress field and dynamic disturbance, we propose a new fault management technology based on surrounding rock modification + local strengthening + active and passive combined support, which is the combined support technology of advance grouting cover, small cycle grouting reinforcement and local floor strengthening of reverse bottom arch. Through numerical simulation, different support schemes are compared and selected to obtain the optimal support parameters. The numerical simulation results show that ｗith the increase of support strength, the stress of anchor cable tends to be uniform, the range of bearing arch gradually increases, the bearing capacity increases, the maximum shear force of shotcrete layer decreases, and the maximum bending moment decreases first and then increases; the plastic zone of surrounding rock gradually decreases, and the distribution position of the plastic zone gradually changes from two sides and floor to two sides, and the area decreases by about 75%. The industrial test results show that the surrounding rock tends to be stable after 28 days, the maximum roof subsidence is about 15 mm, the floor heave is about 25 mm, and the sidewall displacement is about 35 mm. The surrounding rock stability is well controlled.

Keywords

• deep mine
• soft rock roadway
• high stress
• fault
• surrounding rock control
• roadway support