Novel approach to apply existing constitutive soil models to the modelling of interfaces

Abstract

A novel scheme to apply constitutive (continuum) soil models to the mechanical modelling of soil-structure interfaces is presented. Opposite to existing approaches, all normal stress components of the interface depend directly on the normal stress components of the adjacent continuum. This allows to satisfy boundary conditions not only for the continuum but also for the interface. Interface models based on Hypoplasticity with intergranular strain extension and on Sanisand (version of 2004) are formulated. They are implemented in the framework of a mortar contact discretisation technique in a finite element code, which is available for download. A numerical differentiation scheme is used to secure consistent derivatives of contact forces with respect to displacement. The performance of the proposed interface models is evaluated by comparison with data from (cyclic) simple interface shear tests and an existing (hypoplastic) interface model proposed by Stutz et al. (2016). Subsequently, a large-scale cyclic interface shear test with complex geometry is simulated using the different interface models. It is concluded that only the novel interface formulation allows to appropriately consider the boundary conditions of the large-scale interface shear test in the interface.

Long-Term Response of Piles to Cyclic Lateral Loading Following Vibratory and Impact Driving in Water-Saturated Sand

“…The pile is modelled with single phase elements with 27 nodes (u27). The contact between soil and pile is discretised using a mortar contact discretisation technique, which implementation is discussed in detail in (Staubach et al, 2022d). A simple Coulomb friction model with the same parameters as applied for the simulation of the installation is applied.…”

Insight into numerical characteristics of embedded finite elements for pile‐type structures employing an enhanced formulation

“…In the former case, geometrical details of individual D-SSE are typically discretized by means of the standard conformal FEM 24 using solid FE, thereby imposing full 3D surfaceto-surface mesh tying problems at MSE-SSE contacts; for example, see Refs. [35][36][37] With regard to the modelling of piles through D-SSE, solid FE corresponding to the pile domain may be additionally circumscribed by contact formulations, such as isoparametric contact elements [38][39][40][41][42] in order to account for SSI. In the context of computational geotechnics, this expanded D-SSE modelling approach is often termed standard FE approach (SFEA).…”