The time-rate of swelling is investigated. The variation of the consolidation coefficient in swelling process and the similarity between absorbing water and absorbing air during the process are studied through experiments. The test results show that the coefficient of consolidation keeps changing in both processes of the consolidation and swelling, ranging up to 3 orders of magnitude. The coefficient of consolidation is not a fixed parameter but a process factor which repeats in each loading and unloading. ...