Abstract: Based on the actual stress state of frozen walls, true triaxial tests on frozen sandy soil under various initial conditions were conducted, and the influence of the b on the strength and deformation characteristics of frozen sandy soil was analyzed. Utilizing PFC^3D numerical simulation software, the magnitude and distribution of normal contact forces between particles were studied. This approach addresses the limitation of laboratory tests, which cannot directly observe inter-particle force distributions within specimens. The simulation provides a data support for revealing the influence mechanism of b on the strength of frozen sandy soil. The test results indicate that: as the intermediate principal stress approaches the maximum principal stress, distinct failure modes are observed in the principal stress directions. The deformation of frozen sandy soil in the direction of σ₂ shifts from expansion to compression, with the longitudinal wave velocity in this direction first increasing and then decreasing. In the direction of σ₃, the expansion deformation increases significantly, while the longitudinal wave velocity gradually decreases. The mechanism of deformation differences in the horizontal direction of frozen sandy soil is analyzed upon the principles of stress superposition and of the Poisson's effect. The stress-strain curves derived from numerical simulations exhibited a close agreement with test data. Furthermore, the failure modes predicted by the simulations closely matched those observed in laboratory tests. With the increase of b value, the normal contact force in the direction of intermediate principal stress increases gradually, while the direction of minor principal stress decreases slightly. The strength of frozen sandy soil under different conditions of minor principal stress, of temperature, and of moisture content initially rises and then declines, reaching the peak when (b=0.5~0.6). The mechanism by which the intermediate principal stress influences the strength of frozen sandy soil is revealed through the analysis of multi-source information, including stress-strain curves, failure modes, longitudinal wave velocity.