Study and Practice on Supporting Pre-stress Field of Truss and Anchor Rope in Large Section Coal Roadway

Based on the surrounding rock control problem of large section coal roadway, the excellence of truss and anchor rope for large section coal roadway was analyzed. The relationship between supporting pre-stress field and truss and anchor length, angle, distance between orifice and side, pre-tightening force was analyzed by FLAC^3D numerical simulation under large section coal roadway. Results show that effectiveness of control was significant when truss anchor length was from 6 m to 8 m, angle was from 15° to 20°, and distance between orifice and side was from 1.4 to 1.6 m. What's more, rock tension fracture situation and roof subsidence were decreased greatly when pre-tightening force was increased. Based on this, the combined support technology of high pre-stressing truss cable & traditional bolt and cable was proposed. Large section coal roadway was self-stabilization after it was digged out for 15 days, roof convergence was less than 95 mm, two sides convergence was less than 80 mm, total roof separation was less than 5 mm.