Mechanism and application of grouting reinforcement on surrounding rock of roadway with high stress and large section

In order to solve the problem of serious deformation of roadway with high stress and large section during service period, Mohr-Coulomb criterion and mechanical balance principle are used to analyze the mechanism and mechanical model of grouting reinforcement of roadway loose ring. FLAC^3D simulation software is used to conduct numerical simulation of four different support forms, study the evolution laws of roadway deformation under different support states, and carry out field engineering practice. The results show that increasing the length of the bearing layer can effectively improve the stability of the surrounding rock of roadway, and grouting reinforcement can strengthen the cohesive broken rock mass to form the skeleton structure. Stratification excavation can reduce the free surface of surrounding rock and slow down the stress release speed. Delayed grouting can strengthen the fractured rock mass to the maximum extent after the basic stress release, and the reinforced loose ring forms a whole structure and is supported with anchor cable, which can effectively reduce the damage of surrounding rock and the development of plastic zone. The practice has proved that after the support scheme of “stratification excavation + delayed grouting + anchor cable reinforcement” is adopted, during excavation, the maximum displacement of the top and floor is about 50 mm, the maximum displacement of the two walls is about 140 mm, and the floor heave is about 75 mm. During the mining period of 5303 working face, the maximum displacement of the top and floor is about 125 mm, the maximum displacement of the two walls is about 350 mm, and the floor heave is about 173 mm. Although the deformation of the roadway is large during mining, the overall deformation is controllable, it can meet the support requirements of deep roadway with large section. The support scheme of “stratification excavation + delayed grouting + anchor cable reinforcement” can effectively solve the serious deformation problem of high stress and large cross-section tunnels, and can be promoted in mines with similar geological conditions.