An Analytical Approach of Cylindrical Cavity Expansion for a Compaction Grouting Problem under Nonlinear Seepage Based on Unified Strength Criterion

In this study, an analytical approach of large-strain cylindrical cavity expansion is carried out for the cylindrical compaction grouting problem considering pressure filtration based on the nonlinear seepage and unified strength theory. First, based on the theory of cylindrical cavity expansion and the first law of thermodynamics, the expansion process of cylindrical cavity in rock and soil mass is regarded as an energy conversion problem. Second, the seepage theory is introduced into the traditional cylindrical cavity expansion theory, and the new analytical approaches such as expansion radius, stress, and strain are derived for rock and soil mass under the consideration of seepage volume force. Then, considering the large-strain characteristics of geomaterials, the energy dissipation approach for the cavity expansion problem is further analyzed based on the thermodynamic theory. Finally, the effectiveness of the proposed approach is proved by comparing with the existing solution. The results show that the plastic region of rock and soil mass around the cavity increases with the increase of intermediate principal stress coefficient b, seepage water pressure difference, and nonlinear seepage coefficient. The overall trend is that the radial and tangential stresses around the cavity also increase with the increase of seepage coefficient. This theoretical approach provides a necessary reference for revealing the design of compaction grouting reinforcement in water-rich underground rock and soil mass.