A semi‐analytical solution for displacement‐controlled elliptical cavity expansion in undrained MCC soil

Abstract

AbstractConventional cavity expansion theory is a one‐dimensional problem and is not applicable for the two‐dimensional cavity expansion issue, which is also required for geotechnical problems. This paper proposes a novel semi‐analytical solution for displacement‐controlled elliptical cavity expansion (DC‐ECE) in undrained soil. The displacement and strain fields for DC‐ECE are obtained from the strain path method (SPM) with the aid of conformal mapping theory. The effective stress can be subsequently obtained by the incremental stress‐strain calculation using a suitable constitutive model such as the MCC model. Then, the computed effective stress results are substituted into the stress equilibrium equation to give the pore pressure solution. The new semi‐analytical solution reveals the non‐axisymmetric characteristics of DC‐ECE and allows the elastic‐plastic (EP) boundary, excess pore pressure, stress, and displacement to be calculated. The proposed method provides a solution to non‐axisymmetric cavity expansion issues and it can be applied to geotechnical engineering problems, including vertical drain installation, flat dilatometer tests and noncylindrical pile penetration in clay.