A versatile triaxial apparatus for frozen soils

•A versatile triaxial apparatus for frozen soils was developed with 3 new features in addition to traditional functions.•The first is the accurate temperature control.•The second feature is used to measure K0 of frozen soils.•The third is precise measurement of the volumetric strain through the displacement of axial and radial loading pistons.•The capabilities of the triaxial apparatus are shown using a series of test results.

Settlement and damage to infrastructures in permafrost regions depend in part on the mechanical properties of permafrost layers. In order to get a better understanding of the mechanical behavior of frozen soils, a triaxial apparatus was developed with three new features in addition to the traditional functions. The first is the accurate temperature control, which allows temperature to fluctuate within ± 0.1 °C during the loading period, and ± 0.02 °C before loading, so as to get a better understanding of the mechanical properties of frozen soils under temperatures close to thawing point. The second feature is used to measure K0 of frozen soils. A highly-sensitive radial strain measurement device was designed and the K0 state can be accurately maintained by automatically adjusting the radial pressure when radial deformation changes more than ± 10 μm. The third is the precise measurement of the volumetric strain through the displacement of axial and radial loading pistons. The capabilities of the triaxial apparatus are shown using a series of test results. It is considered to be a promising tool to investigate the mechanical properties of frozen soils.