Capturing strain localization behind a geosynthetic‐reinforced soil wall

Abstract

SUMMARYThis paper presents the results of finite element (FE) analyses of shear strain localization that occurred in cohesionless soils supported by a geosynthetic-reinforced retaining wall. The innovative aspects of the analyses include capturing of the localized deformation and the accompanying collapse mechanism using a recently developed embedded strong discontinuity model. The case study analysed, reported in previous publications, consists of a 3.5-m tall, full-scale reinforced wall model deforming in plane strain and loaded by surcharge at the surface to failure. Results of the analysis suggest strain localization developing from the toe of the wall and propagating upward to the ground surface, forming a curved failure surface. This is in agreement with a well-documented failure mechanism experienced by the physical wall model showing internal failure surfaces developing behind the wall as a result of the surface loading. Important features of the analyses include mesh sensitivity studies and a comparison of the localization properties predicted by different pre-localization constitutive models, including a family of three-invariant elastoplastic constitutive models appropriate for frictional/dilatant materials. Results of the analysis demonstrate the potential of the enhanced FE method for capturing a collapse mechanism characterized by the presence of a failure, or slip, surface through earthen materials.

Modeling deformation banding in dense and loose fluid-saturated sands

“…10) where the parentheses signify a symmetric operator, whereas the square brackets signify a skew-symmetric operator. For example, Similarly, a second-order tensor ∇ x is mapped into a 9 × 1 vector, i.e., ∇ x = { 1,1 , 2,2 , 3,3 , 2 (1,2) , 2 (2,3) , 2 (3,1) , 2 [1,2] , 2 [2,3] , 2 [3,1] } t (A.12)…”

“…It is well known that appearance of bands of intense localized deformation significantly reduces the load-carrying capacity of any structure that develops them [1,2]. Furthermore, when dealing with fluid-saturated geomaterials, the interplay between the contraction/dilation of pores and the development of pore fluid pressures is expected to influence not only the strength of the solid matrix but also its ability to block or transport such fluids [3].…”

Capturing strain localization in reinforced soils

“…Four analyses were carried out: one without reinforcement, and three with one layer, four layers, and seven layers of geosynthetic reinforcement. It is noteworthy that Lai et al [13] were successful in analyzing a GRS retaining wall using the finite element method with Lade's elasto-plastic model and provisions for shear banding. 2 Lade's single hardening model (SHM) and Cosserat rotation It has been acknowledged by many researchers that classical continuum mechanics laws fail to describe the phenomenon of strain localization that takes place prior to failure in soils.…”

Strain Localization in Solid Cylindrical Clay Specimens Using Digital Image Analysis (DIA) Technique

“…Therefore, strain localization is considered to be a major factor, which controls the overall observed mechanical response of the specimen, at or near failure. Strain localization manifests in the form of a shear band, a narrow zone of intense straining (Jirasek, 2002;Lai et al, 2003;Lade, 2003). Although, shear banding is one of the possible deformation modes, it is usually a precursor to catastrophic failure.…”