A test device has been invented for determining three-dimensional consolidation properties of soils, using a flexible ring permitting displacements and dissipation of the excess pore pressures in both horizontal and vertical directions, and affording determination of coefficients of consolidation in the horizontal and vertical directions, and the modulus of elasticity. The flexible ring consists of a filter fabric around the soil specimen, a rubber membrane around the filter, circular shaped segmented stainless steel plates around the membrane and rubber bands around the plates. Both the incremental loading or triaxial type loading systems can be used with this device. A calibration device for calibration of the flexible ring is used to determine the modulus of elasticity of elastic elements, required for calculating lateral resistance provided by the flexible ring during the test.