Artificial ground freezing is an effective method for underground constructions in deep alluvium. To study the compressive strength of frozen soil under high ground pressure and high hydraulic pressure, it is necessary to understand the mechanical behaviour of ice that is formed under triaxial compressive stress. A low-temperature triaxial test system was developed and used to study both formation and deformation of columnar ice under hydrostatic pressure. Cylindrical ice specimens 125 mm in height and 61.8 mm in diameter were prepared and tested under constant strain rates. At a strain rate of 5 × 10⁻⁵ s⁻¹, the peak axial stress showed a linear increase as the confining pressure increased from 2 to 30 MPa, while the peak deviatoric stress exhibited a slight decrease. At a confining pressure of 30 MPa, the peak deviatoric stress showed a logarithmic increase with the strain rate increasing from 5 × 10⁻⁶ to 5 × 10⁻⁴ s⁻¹, and the failure strain nearly doubled. A power law relationship between the time to failure and the strain rate was also observed. In this study, each test consistently demonstrated a ductile failure mode, with a noticeable reduction in cracking as the confining pressure increased. Due to the effect of the high confining pressure, crack propagation was suppressed, and an apparent recrystallization after peak stress was observed.

The mechanical properties of high-pressure frozen ice are critical design parameters for deep artificial ground freezing and ice sheet drilling operations, making their investigation fundamentally significant. In this study, ice specimens were prepared at −10 °C under freezing pressures of 10, 20, 30, 40, and 50 MPa. In situ axial loading simulation experiments were conducted to investigate their mechanical behavior and macroscopic deformation characteristics during failure. The experimental results indicate that the deviatoric stress–axial strain curves of the ice specimens exhibited a rapid yet smooth transition before and after reaching the peak deviatoric stress, with all samples exhibiting ductile failure. The peak deviatoric stress initially increased and then decreased with increasing freezing pressure, reaching a maximum value of 8.61 MPa at a critical transition pressure of 20 MPa, eventually declining to a minimum of 1.66 MPa at 50 MPa. The residual deviatoric stress decreased significantly with increasing freezing pressure, declining from approximately 3.5 MPa at 10 MPa to 0.85 MPa at 50 MPa. The peak tangent modulus demonstrated a fluctuating trend with increasing freezing pressure, ranging from 1.76 to 2.37 GPa. As the freezing pressure increased, the failed ice specimens transitioned from a densely cross-cracked state to a highly transparent phase, and finally to a sparsely cross-cracked morphology.