Discrete element simulation of the influence of anisotropy on the mechanical properties of soft soil

The initial and induced anisotropy has a significant effect on the mechanical properties of soft soil in preloading engineering. However, there is a lack of unified research methods for the initial and induced anisotropy. Discrete element method is adopted in this study, and the length-width ratio of particles is used as the quantitative evaluation index. Five types of initial anisotropy samples with different deposition angles are generated. The effects of initial anisotropy and induced anisotropy on the mechanical properties of soft soil are studied by vertical and horizontal loading. At the micro level, the contact form and rotation angle of particles are examined from the point of view of particles, and the development trend of coordination number and contact normal to anisotropy is studied from the point of view of contact. The relationship between shear strength index and anisotropy is explored. The results show that initial and induced anisotropy influences the mechanical properties of the samples. When the loading direction is perpendicular to the soft soil deposition direction, the soil mass has the maximum peak strength. In the particle contact form, the proportion of surface contact gradually increases with loading. The initial modulus and shear strength are influenced. The coordination number and contact normal anisotropy have different evolutions under the influence of particle contact form, and tend to be stable at the later loading stage. In terms of shear strength parameters, the initial anisotropy will increase the cohesion of the sample, and the induced anisotropy will mainly change the internal friction angle, which is consistent with the law of shear strength.