A stable mesh-independent approach for numerical modelling of structured soils at large strains

Abstract

We describe the large strain implementation of an elasto-plastic model for structured soils into G-PFEM, a code developed for geotechnical simulations using the Particle Finite Element Method. The constitutive model is appropriate for naturally structured clays, cement-improved soils and soft rocks. Structure may result in brittle behavior even in contractive paths; as a result, localized failure modes are expected in most applications. To avoid the pathological mesh-dependence that may accompany strain localization, a nonlocal reformulation of the model is employed. The resulting constitutive model is incorporated into a numerical code by means of a local explicit stress integration technique. To ensure computability this is hosted within a more general Implicit-Explicit integration scheme (IMPLEX). The good performance of these techniques is illustrated by means of element tests and boundary value problems.

Modelling the behaviour of sensitive clays experiencing large deformations using non-local regularisation techniques

“…[26], Mánica et al [27], and Monforte et al [28]. In this method, the strainsoftening at a material point is linked to the state of plastic deformation in the material points surrounding the current integration point, rather than being solely a function of the strain at the current integration point.…”

“…Simulation of a classical element test: biaxial compression3.1. Analyses detailsClassical biaxial compression simulations have previously been used to demonstrate the mesh dependency of local strain-softening models and efficacy of the non-local techniques in regularising FE solutions involving strainsoftening[25,42,27,28]. In this work, a series of undrained and drained small strain FE analyses have been performed for biaxial compression using the local and the non-local strain-softening methods.…”

A Nonlocal Elasto-Plastic Model for Structured Soils at Large Strains for the Particle Finite Element Method

“…Finally, associative plasticity is assumed. This elasto-plastic model is integrated with an explicit stress integration technique (Monforte et al, 2014(Monforte et al, , 2019 based on Sloan et al (2001). The algorithm includes adaptive substepping and a yield surface drift correction algorithm.…”

On the efficiency of coupled discrete-continuum modelling analyses of cemented materials

“…Large-deformation problems in geotechnical engineering, such as pile penetration, are notoriously difficult to simulate using continuum approaches due to both material and geometrical non-linearities (Monforte et al, 2019) and because of mesh distortion related issues (Yang et al, 2020). To overcome these difficulties advanced numerical methods have been developed.…”