Finite Element Analysis of Pullout Resistance and Progressive Failure of Strip Anchors in Strain-Softening Soils based on the Cosserat Continuum Method

Abstract

Given the limited research on regularization mechanisms in finite element analysis of the ultimate pullout resistance of plate anchors, particularly considering soil strain softening, this paper employs a Cosserat continuum regularization mechanism combined with a Mohr-Coulomb matched Drucker-Prager constitutive model (MC-matched DP model) to address this issue. Implementing the User-Defined Element (UEL) function in ABAQUS, the numerical solution was developed and validated against existing literature to verify the accuracy of the MC-matched DP model for analyzing plate anchor pullout resistance. This study demonstrates that the Cosserat continuum model effectively resolves common issues such as numerical convergence difficulties and mesh dependency encountered in finite element calculations for softening soils. Subsequently, the model was applied to conduct a detailed analysis of the ultimate pullout resistance of plate anchors and the progressive failure process of the soil. Parametric analyses were performed to explore the combined effects of plate anchor inclination, burial depth, and degree of strain softening on ultimate resistance and failure mechanisms. Based on these analyses, an expression for the ultimate resistance coefficient Nc, incorporating the influences of plate anchor inclination, burial depth, and strain softening, was formulated, providing a valuable reference for geotechnical engineers in practical applications.