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 Nc for deep foundations and the excess pore pressure set up during driving of piles in a saturated clay.