Approach for Numerical Modeling of Strain-Hardening Materials Using Double-Yield Model.

The strain-hardening behavior of soils and rocks under compression is critical for evaluating the construction stability in geological and mining engineering. Numerical simulation is an effective approach and widely used in the stability analysis of constructions. To ensure the accuracy of the simulation results, it is necessary to select appropriate constitutive models and determine the correct model parameters. The double-yield model, built in FLAC3D, is often used to describe the strain-hardening behavior of geotechnical materials. On the assumption that there is only volume yielding in the material, a relationship between the cap pressure, plastic strain in the double-yield model, and the axial stress–strain in the compression test with axial loading and four lateral-face constraints was established. Then, the cap pressure and plastic strain could be calculated directly by a series of known axial stress–strain data. With this calculation method, the double-yield model parameters can be determined quickly and accurately. This method was derived based on the constitutive equation of the double-yield model and could quickly determine the model parameters by reverse calculation according to the expected results, so it was more efficient and credible than the more widely used trial-and-error method. Based on comparisons between the calculation and trial-and-error methods, some case studies also proved its efficiency and effectiveness. Moreover, there are no requirements for the source of known stress–strain data. Therefore, this method can be applied to the model parameter assignment based on the stress–strain data from experimental tests, theoretical analyses, empirical formulas, and other numerical simulations. Highlights: A relationship between the double-yield model parameters and the axial stress-strain in a uniaxial loading test with lateral constraints was established. An approach for accurate numerical modeling of strain-hardening materials using a double-yield model was developed. Some contrastive analyses with similar studies were conducted to verify the accuracy and efficiency of the approach in this paper. [ABSTRACT FROM AUTHOR]