Modeling of granular soil-structure interface under monotonic and cyclic loading with the nonlinear approach

Abstract

A constitutive model that can accurately predict the behavior of the soil-structure interface is beneficial to the analysis and design for foundation engineering performance. This paper develops a new model with the nonlinear approach for simulating the monotonic and cyclic behaviors of the granular soil-structure interface. Based on the hyperbolic function, the concept of normalized shear displacement is proposed, and the basic model for the effects of the normal stress, the nonlinear shear modulus, and the friction angle on shear strength during shearing is deduced. On this basis, the Pyke criterion is modified to describe the cyclic loading responses. The relation between the friction angle and the state parameter of the interface in different interface states is established under the framework of critical state soil mechanics (CSSM) theory to further reflect the interface behaviors corresponding to the changes of void. Taking the phase transformation state as a reference state of volume increment, the incremental equation of stress-dilatancy induced by shearing is developed. In addition, the basic model is extended to be able to describe the interface mechanical behaviors under constant normal load (CNL), constant stiffness (CNS), and constant volume (CV) conditions by considering the characteristics of three typical stress loading paths. Only 10 calibrated parameters are required to reproduce the complex properties in the monotonic and cyclic behaviors. The predictive performance of the proposed interface model is examined by the previous experimental results.