Volumetric calculation method and temperature characteristics of frozen soil in mechanical testing

To accurately measure the volume strain of sample in mechanical testing for frozen soils, eliminate the influence of hydraulic oil and testing system on the volume strain of sample, and analyze the influence of oil temperature change on sample temperature, a series of isotropic loading and shearing tests on No. 10 Kunlun Aviation Oil, commonly used in the pressure chamber, were carried out under different conditions. The results show that during the isotropic loading, the oil compression will be different with time, confining pressure, loading rate, initial oil temperature and total oil, and the oil temperature only changes with confining pressure and loading rate, which impacts on the temperature of sample dipped in the oil; during the shearing, the relationship between stretch amount of axial piston and oil discharge from volumetric piston is constant with different shear rates, that is, the sample volume only relates to the systematic error of testing machine. At last, a simple calculation formula of sample volume strain is presented, respectively in isotropic loading and shearing stages, as well as some suggestions and problems which should be paid special attention in testing process to ensure the reliability of testing data.