A semi-analytical undrained solution for cylindrical cavity expansion in K 0-consolidated anisotropic soils under plane stress condition

Abstract

To remove the limitation that the plane stress problem cannot be considered using cylindrical cavity expansion and to explore surface response of cylinder expansion in shallow soil, a semi-analytical undrained solution is developed for cylindrical cavity expansion in anisotropic modified Cam-clay model soils under the plane stress condition. The constitutive relationship is described by the K 0-consolidated anisotropic modified Cam-clay (K 0-AMCC) model, which can properly simulate the mechanical behaviour of the K 0-consolidated natural clays. The problem is equivalent to solving ordinary differential equations to determine the effective stresses, vertical strain, and excess pore water pressure (EPWP). Parametric analyses are conducted to investigate the effective stresses, vertical strain, and EPWPs around the expanded cavity under plane stress condition. The results show a clear influence of over-consolidation ratio on the stresses, vertical strain, EPWP around the cavity, and effective stress paths for a soil particle at the cavity wall. Axial expansion or uplift of soil and negative pore water pressure are observed during cavity expansion under the plane stress condition. There are obvious differences in effective stress components around the cavity under two plane conditions. The effective axial stress around the cavity wall is generally smaller than that under the plane strain condition.