Study on the characteristics of plastic failure and supporting countermeasures of the surrounding rock of deep high-stress coal roadway

Addressing issues such as significant deformation of surrounding rock and difficulties in support after deep coal roadway excavation, this paper takes the transportation roadway of the Zhujixi 11101 working face as its research object. The plastic deformation radius of the surrounding rock after roadway excavation is theoretically calculated, and a support scheme centered on “high preload anchor bolts （cables） + metal mesh” is proposed. Subsequently, the deformation characteristics and stress distribution patterns of the surrounding rock under six different roof support densities are simulated and analyzed, and the optimal support scheme is selected for field implementation. The results show that while increasing the number of anchor bolts and reducing the spacing between anchor bolts can both improve rock mass control effectiveness, economic benefits should also be considered while ensuring roadway rock mass control effectiveness. The optimal support scheme selected has a spacing of 800 mm × 700 mm between roof anchor bolts, a spacing of 1 800 mm and 1 600 mm between anchor cables, and a spacing of 800 mm and 800 mm between side anchor bolts. Compared with other support schemes, scheme 3 reduces the maximum roof settlement from 72 mm to 60 mm, a decrease of 16.67%, the maximum floor bulge decreases from 150 mm to 90 mm, a reduction of 40.00%, and the peak horizontal stress decreases from 36.73 MPa to 31.20 MPa, a reduction of 15.06%. The support scheme effectively reduces the peak stress in the surrounding rock and minimizes deformation of the tunnel walls, verifying the reliability of the support scheme. The monitoring results from the test section indicate that scheme 3 provides good support performance. During the monitoring period, the cumulative subsidence of the roadway roof is 61 mm, the cumulative bottom bulge is 102 mm, and the cumulative lateral displacement of the roadway walls is 156 mm, effectively containing deformation and damage to the surrounding rock.