Three-Dimensional Numerical Realization And Application Of Collapsible Loess Constitutive Model Considering Initial Water Content

The structural evolution of loess under load and humidification plays an important role in the safety evaluation of engineering in loose area. A simplified constitutive model is developed by incorporating the structural composition of collapsible loess in this paper. The user defined material subroutine (UMAT) of this model is programmed using an improved Euler integration algorithm with error control. A stress correction technique is incorporated in the UMAT subroutine to improve the computational accuracy and efficiency. Comparisons between UMAT subroutine simulation results, existing experimental results and result from the MATLAB program shows the validity and stability of this UMAT subroutine. Examples of three-dimensional square foundation and pit excavation using the UMAT subroutine is analysed, the simulation results demonstrates its reliability in capturing the general features of the wetting collapse for collapsible loose. These results can provide reference for the secondary development of relevant critical state models and offer a new approach for the engineering application of constitutive models for collapsible loess.