Experimental and Numerical Study on the Behavior of Energy Piles Subjected to Thermal Cycles

Table 2

Material parameters of the sands.

		Yangzhou sand (test sand)	Loose Sacramento River sand	Dense Sacramento River sand
Thermal parameters	Dry density, ()	1490	1450	1670
	Thermal conductivity of soil particle, ()	2.4	2.4	2.4
	Specific heat of soil particle, ()	930	930	930
	Linear thermal expansion coefficient of soil particle, ()	10.0	10.0	10.0
MC model	Elastic modulus, ()	3.34	—	—
	Poisson’s ratio,	0.3	—	—
	Cohesion, ()	0	—	—
	Friction angle, ()	30.6	—	—
	Dilation angle, ()	0.0	—	—
BS model	Initial void ratio,	0.78	0.87	0.61
	Elastic swelling modulus,	0.01	0.01	0.0075
	Poisson’s ratio,	0.3	0.2	0.2
	Critical void ratio at 100 kPa,	0.60	0.97	0.84
	Slope of the critical state line,	0.12	0.076	0.076
	Ellipse aspect ratio,	2.0	2.2	1.65
	Residual friction angle in compression, ()	30.6	34.6	36.2
	Residual friction angle in tension, ()	30.6	34.6	36.2
	Peak friction angle, ()	32.0	35.7	43.8
	Plastic modulus,	1.0	2.0	2.0
	Elastic modulus at 100 kPa, ()	12.0	18.7	21.5