Effects of Soil Fabric on the Thermal Expansion Coefficient of Clay with Reference to the Crack Formation in Landfill Barriers

Thermal expansion coefficient (TEC) of clay is an important parameter for evaluating the crack formation in landfill barriers during heating and cooling. To investigate the influences of soil fabric on the TEC of clay, saturated reconstituted, intact and recompacted loess were tested using a thermo-controlled invar oedometer. The linear TEC of each specimen was measured through thermal volume changes during cooling. Results showed that the linear TEC of the reconstituted specimen was almost three times larger than those of the intact and recompacted specimens. On the other hand, the void ratio has an insignificant effect on the linear TEC of reconstituted specimen. These observed differences in the linear TECs of reconstituted, intact and recompacted specimens are likely attributed to different distributions of clay particles in soil specimens (with 28% clay content). In the intact and recompacted specimens, most of clay particles formed silt-size aggregates which were less sensitive to temperature changes than clay particles founded in the reconstituted specimen.