METHOD TO DETECT AIR CONTENT IN THAWED SOIL Russian patent published in 2013 - IPC G01N9/00 

FIELD: measurement equipment.

SUBSTANCE: after taking a soil sample, weighing and detection of its volume, moisture, the soil sample is additionally dried. Then the volume of solid soil particles is determined, as well as density of dry soil, density of solid particles. Afterwards the relative air content is determined in thawed soil, besides, calculation of air content in thawed soil is carried out according to the formula $$\frac{Va}{V}=1-{\rho }_d\left(\frac{1}{{\rho }_s}+\frac{w}{{\rho }_w}\right),$$ where V_a - volume of air in the thawed soil sample; V - sample volume; $${\rho }_d=\frac{m_d}{V},$$ density of dry soil, where m_d - mass of dry soil sample; density of solid particles $${\rho }_s=\frac{m_d}{V_d},$$ where V_d - volume of solid particles of the sample - soil moisture $$w=\frac{m-m_d}{m_d},$$ where m - mass of soil sample; ρ_w - water density.

EFFECT: expanded area of application due to possibility of accurate measurement of air content and accordingly specification of assessment of deformation properties of soil.