Modeling of Compaction Grouting Considering the Soil Unloading Effect

Previous studies have given little consideration to the influence of the soil unloading effect on compaction grouting. The theoretical relationship model between the soil unloading degree and the soil deformation modulus is first derived and verified. A compaction grouting diffusion model considering the soil unloading effect is proposed based on the previous soil unloading model, cavity expansion theory, and Unified Strength Theory (UST) under large strain conditions. The compaction grouting model is compared and verified with other theoretical models. The formula of ultimate compaction grouting pressure is established, and the analysis results show that the ultimate compaction grouting pressure P-u increases with increasing soil cohesive force c, soil internal friction angle phi, soil dilatancy angle psi, soil initial static pressure p(0), and soil intermediate principal stress coefficient b. A parametric study with the proposed model is performed, and the characteristics of grout bulb diffusion and soil plastic zone development and the distribution of stress and displacement fields in the soil are analyzed.