Assessment for Thermal Conductivity of Frozen Soil Based on Nonlinear Regression and Support Vector Regression Methods

Table 2

Partial correlation analysis between frozen soil thermal conductivity, dry density, water content, and unfrozen soil thermal conductivity.

Soil categories	Related variables	Control variables	Unfrozen soil thermal conductivity	Frozen soil thermal conductivity
Fine-grained soil	Water content	Dry density	0.312	0.450
	Unfrozen soil thermal conductivity		—	0.880
	Dry density	Water content	0.456	0.385
	Unfrozen soil thermal conductivity		—	0.891
Coarse-grained soil	Water content	Dry density	0.501	0.608
	Unfrozen soil thermal conductivity		—	0.927
	Dry density	Water content	0.530	0.502
	Unfrozen soil thermal conductivity		—	0.930