Thixotropy of soft clay: A review

Thixotropy of soil is, after softening by remoulding, a process of time-dependent return to a harder state under constant water content and constant volume conditions. This paper presents a critical review of previous investigations on the thixotropy of soft clay. Thixotropic behavior is primarily a structural effect accompanied by the spontaneous dissipation of excess internal energy, and some microstructural observations provide a deeper insight into its mechanism. Mathematical theories and models to simulate thixotropic strength recovery of soil are introduced. Different test methods to evaluate the thixotropic behavior of soil are summarized. Correlations between the thixotropic behavior of soil and some basic indexes, such as water content, Atterberg limits, mineralogy, activity and salt concentration, are described. Some remarks on future improvement for thixotropy of soil are also provided based on the results of up-to-date research.