Macro and micro grouting process and the influence mechanism of cracks in soft coal seam

Abstract Grouting is an important method to reinforce soft coal roadway, and the presence of primary cracks in body has influence on grouting effect. With discrete element simulation method, process seam was simulated. The mechanism revealed, while fracture characteristics pressure effect analyzed. results demonstrated that involves stages seepage, rapid splitting, slow stability. Due cracks, diffusion radius increased significantly. Under slurry pressure, tensile stress concentration formed at crack tip, split once splitting reached. In addition, distribution fractures are found have a great It observed smaller spacing associated with larger thus easier penetration tips. angle affects direction propagation. secondary by fracture, which more likely extend along parallel maximum principal stress. Overall, these guiding significance for setting reasonable holes practice engineering.