Analysis of Undrained Cylindrical Cavity Expansion Considering Three-Dimensional Strength of Soils

Abstract

Undrained cylindrical cavity-expansion solutions that were based on the modified Cam-clay model have been widely used to predict and interpret geotechnical problems, such as pile installation, and in pressuremeter tests in saturated clay. However, the yield and failure of soils around the cavity might not be properly modeled by the extended Mises criterion adopted in the modified Cam-clay model. To consider the three-dimensional mechanical properties of soils during cavity expansion, an analytical solution with the spatially mobilized plane criterion-based Cam-clay model is derived for the undrained cylindrical cavity-expansion problem by using the stress-transformed method. The presented solution is verified by two well-documented pile-installation tests and is compared with the modified Cam-clay model–based solutions in detail. The results show that the prediction from the presented solution is closer to the actual stress field induced by the undrained cylindrical cavity expansion. However, the radial stress and excess pore-water pressure are overestimated, whereas the plastic zone radius is underestimated by the conventional modified Cam-clay model–based solutions.