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220 Analysis and Design of Energy Geostructures

Figure 5.6 Relationship between the thermal expansion coefficient and overconsolidation ratio for
the kaolin tested by Cekerevac and Laloui (2004). Redrawn after Liu, H., Xiao, Y., McCartney, J.S., Liu,
H., 2018. Influence of temperature on the volume change behavior of saturated sand. Geotechn. Test.
J. 41 (4), 747 758.

According to Liu et al. (2018), a linear increase of the volumetric thermal expan-
sion coefficient of fine-grained soils, β, may be considered with the OCR. For the
clay tested by Cekerevac and Laloui (2004), that is kaolin, the following relationship
between β and OCR is found (Liu et al., 2018)

β 5 a exp 1 b exp ðOCR 2 1Þ ð5:4Þ

where a exp and b exp are material constants whose value is reported in Fig. 5.6.
An alternative approach to describe the volumetric behaviour of fine-grained soils
subjected to temperature variations is in terms of the loading sequence. Details about
the considered framework have been presented by Coccia and McCartney (2016a,b).
In summary, thermally accelerated creep may provide closer thermal volume change
predictions than thermal softening.

5.4.3 Volumetric behaviour of fine-grained soils for multiple thermal
cycles
Experimental results on volumetric behaviour of fine-grained soils subjected to multi-
ple thermal cycles have been presented, for example by Campanella and Mitchell
(1968), Fleureau (1979), Hueckel et al. (1998), Vega and McCartney (2014) and Di
Donna and Laloui (2015). These results show that the first heating cooling cycle
under drained conditions induces most of the irreversible volume change and the
related hardening in NC materials. Subsequent thermal cycles of the same magnitude