Characterization of the secondary swelling of compacted Maryland clay

This paper presents the result of a multi-scale experimental investigation on the phenomenon of secondary swelling. Specimens of compacted Maryland clay were prepared under different initial conditions (void ratio and water content), loaded at different levels of vertical stress and inundated until secondary swelling was observed. One test was also performed with suction control and incremental swelling. These tests were complemented by micro structural analyses via mercury intrusion porosimetry. The coefficient of secondary swelling, defined as the gradient of the evolution of void ratio with logarithm of time was calculated and correlated to the macro scale strain. Several trends were observed and it was showed that, under low confinement, the secondary swelling mostly takes place in the macro pores.