A Study on the Mechanism and Controlling Techniques of Roadway Deformations Under High In Situ Stress Conditions

To successfully control the roadway deformations under high in situ stress conditions, first, field investigations were conducted on the haulage roadway deformation at the -850 section in Qu Jiang mine. Besides, an analysis was performed on the roadway deformation characteristics. Moreover, four supporting strategies were proposed based on the geological conditions and the roadway deformation characteristics. And these strategies were simulation using FLAC3D. Furthermore, the supporting mechanism of the first, the second and grouting supports was analyzed. The first supporting was the preliminary support installed at the stress release stage of surrounding rocks, and limited deformations were permitted in this stage. To permanently stabilize the roadway, the second supporting then was installed to restrain the creep deformation and improve the strength and integrity of the fissured rock masses. Grouting, which can infill and cement the fissures, was used to improve the anchor forces of the bolts and cable and promote the delivery and diffusion of the supporting resistances. Simulation results indicate that roadway deformations are successfully controlled by the proposed strategies where bolts, steel nets, concrete spraying, cables, and grouting were applied.