Expansion of a Cavity in a Saturated Clay Medium

A method of calculation is presented which makes it possible to determine the stress, strain, and pore pressure distribution resulting from the expansion of a spherical or a cylindrical cavity in an infinite medium. It is assumed that the medium consists of a saturated clay and that the expansion occurs in undrained conditions. The calculation is based directly on the stress-strain curves of the clay obtained by conventional consolidated-undrained triaxial tests. The numerical calculations show that for a given type of cavity the shape of the total and effective stress-distribution curves is considerably influenced by the value of overconsolidation ratio. The method has been tentatively applied for calculating the bearing capacity factor N_c for deep foundations and the excess pore pressure set up during driving of piles in a saturated clay.