Nonlinear shear expansion model forgeocell reinforced coarse-grained soil and its finite element implementation

Abstract:

In order to overcome the inadequacy of the current geocell reinforced coarse-grained soil constitutive model and the limitations of its finite element analysis method. Based on the three-parameter nonlinear shear expansion model and the mechanism of geocell reinforced additional constraints surrounding the pressure action, a nonlinear shear expansion model for geocell reinforced coarse-grained soil is proposed. In addition, a subroutine for the model was developed using the user-defined material subroutine UMAT interface provided by ABAQUS software. The triaxial test results of strain-softened and strain-hardened geocell-reinforced sandy soils were compared and verified with the simulation results of the model, respectively, and the computational results of the reinforced composite model in this paper were further compared and analyzed with those of the reinforced-soil-separated model. The level of performance of geocell parameters on the reinforcing effectiveness of coarse-grained soil was also evaluated. The results show that the constructed reinforced coarse-grained soil model can accurately simulate and reflect the shear expansibility characteristics of geocell-reinforced coarse-grained soil during the stressing process and its complex nonlinear mechanical behavior. Through the secondary development of this model, it can accurately predict the stress-strain curve relationship of different degree types of geocell strength under different perimeter pressures and relative density conditions of sand and soil. In the stage of reaching peak strength and before, the calculation accuracy of the reinforced composite model is basically comparable to that of the separated model, and it also has the advantages of simple modeling and efficient calculation. At the same time, the reinforced composite model solves the problem that the separated model cannot calculate the damage of the fill in geocells up to the Mohr-Coulomb yield function. The results of this research are of great value to the field of numerical analysis of geocell reinforced soil structures and can promote their application in engineering practice.