Mechanism of grouting diffusion and consolidation of rock mass based on D-Rb-C coupled model

Grouting reinforcement is an effective method for controlling the stability of engineering rock mass. The mechanism is mainly to inject or infiltrate the grout into the fracture of rock mass to form a grouting entity, and strengthen the stability of rock mass and the ability to resist failures. In order to realize the calculation of the whole process of grouting diffusion and consolidation in broken surrounding rock, a diffusion-consolidation mechanism of grouting based on discrete element method was proposed. Also, the model checking and example analysis were carried out, and the results show that: ① In the full-length grouting of single fracture scenario, the shear peak strength of the post-fractured rock mass is higher than that of the non-grouting fracture, which depends on the frictional resistance generated by the solidification and cohesion of the slurry. ② In the point grouting simulation experiment, as the grouting pressure increases, the grout continues to diffuse. Therefore, the pre-peak shear yielding and post-peak phases of the rock mass are strengthened. ③ For the engineering-scale simulation test, as the grouting pressure increases, the diffusion radius increases in two stages. When the grout expands to the high-stress area, it needs to overcome a greater compressive stress to achieve flow. After reaching a relative higher grouting pressure, the diffusion area of adjacent boreholes is superimposed to form a grouting whole body that surrounds the roadway. When the solidification bond strength of the grout is low, the failure of contact is still the main controlling factor to determine the failure and instability of the roadway.