Mechanical Properties and Constitutive Model of Artificially Frozen Sandy Soils Under Different Intermediate Principal Stresses

Abstract

Triaxial compression tests were conducted on frozen sandy soils under a constant minimum principal stress (σ3 = 1.6 MPa) and various intermediate principal stresses (σ2 = 1.6, 3.4, 5.2, 7.0, 8.8, 9.8 MPa). The purpose of the research was to investigate the influence of intermediate principal stress (σ2) on the characteristic stress levels and the deformation characteristics. The test results obtained demonstrated that the crack damage stress and failure stress initially increase and then decrease with an increase in the σ2. However, the crack initiation stress exhibits an initial increase up to a specific value, after which it stabilizes. The difference in deformation between the σ2 and σ3 directions increased with increasing σ2. From the perspective of crack propagation, the influence mechanism of σ2 on the strength is discussed. The deformation difference was revealed using the stress superposition principle and Poisson’s effect. Finally, the constitutive model based on the Weibull distribution and Drucker-Prager strength criterion can accurately represent the stress-strain relationships of frozen sandy soils under various σ2 conditions.