Research on surrounding rock support technology of gob-side entry in deep mines

In order to solve the problem of large deformation and broken surrounding rock along the gob-side entry of Guqiao Coal Mine 1126 （1） deep mines, using theoretical analysis, numerical simulation and field tests, considering the effect of the basic roof on the inclined extrusion of the direct roof, a mechanical model of the narrow coal pillar along the gob-side entry is established, by analyzing the deformation characteristics of narrow coal pillars along the direct roof of gob-side entry, the maximum value of bending moment and deflection of the roof of the roadway is not in the middle of the roadway, but is shifted to the side of the coal pillar by 1.25 m, of which 8.5-10.5 m is the area with the largest deformation. Based on the above analysis, the asymmetric anchor mesh cable support scheme with high preload anchor + anchor cable + steel belt + metal mesh is adopted, three different scenarios are also proposed, and numerical simulation methods are used to compare and analyze the support scenarios, the results show that the depth of roof damage in the plastic zone of the roadway is reduced from 10 m to 2 m in Scenarios 2 and 3 compared to Scenario 1, a reduction of 80%, the depth of solid coal-side damage is reduced from 5 m to 3 m, a reduction of 40%, and the vertical stress on the roof increased by 90.4% and 142.9%, significantly lower top plate unloading capacity, the internal stresses in the coal pillar increased by 21.4% and 21.9%, respectively, and the roof displacement decreased by 26.9% and 34.5%, respectively. Comprehensive consideration of the scene and the actual production of various factors to determine the second program for the scene support program, engineering practice shows that the second program effectively control the deformation of the roadway surrounding rock, improve the stability of the roadway surrounding rock, in line with the actual requirements of safe production.