A Weibull-based damage model for the shear softening behaviours of soil-structure interfaces

The shearing mechanical properties of an interface are of great significance to the stability analysis of soil-structure interaction in practice. Based on the theory of damage mechanics, an interface subjected to shearing conditions can be divided into two parts: damaged and undamaged, together bearing the entire shear load. Under the action of shear load, the damaged part gradually increases and the area of the undamaged part simultaneously decreases. Eventually, the interface is completely damaged. The damage variable modelled as a Weibull distribution is introduced to describe the damage evolution of the interface. According to the principle of force equilibrium on the interface, the shear damage softening model is established, which can describe the shear softening behaviours as well as estimate the residual strength of the interface. The physical meaning of each parameter in the model is elaborated and the relationship with normal stress is established. A method to determine each parameter is proposed. Based on the Abaqus software platform, the model is coded into the friction subroutine, and numerical simulation is carried out with reference data. The shear damage model is validated using experimental data and numerical simulation results.