Comparative discrete element modelling of geogrid-stabilised aggregates and pavement performance

The traditional method of specifying geogrids for subgrade reinforcement has relied upon defining such characteristics as tensile strength and strain with the inference that such properties are important when geogrid is incorporated into unbound aggregate layers in roads. This particularly applies to unpaved roads where the geosynthetic reinforcement is intended to function as a tensioned membrane. However, such reinforcement designs rely on significant deformation of the geosynthetic in order to support loads, which can lead to rutting at the surface and at subgrade formation level. Design methods that use geogrids to stabilise, rather than reinforce an aggregate, are intended to largely avoid deformations and are therefore more suited to permanent road applications. Confinement of aggregate particles by stiff geogrids is the basis of a geogrid stabilisation function. Recent discrete element modelling simulating the effect of a moving wheel over an aggregate layer stabilised with both biaxial and multi-axial geogrids has shown that geogrid tensile strength is not important to the trafficking performance of a road. For roads designed to work with stabilisation as the geogrid function there are other geogrid features that more closely influence how well such a mechanically stabilised layer performs in use. This supports previous work that has also shown that trafficking performance is not a function of geogrid tensile strength. This paper describes how a geogrid-stabilised aggregate layer overlying a soft soil was modelled and subjected to a simulated moving wheel load. Comparisons were made of non-stabilised, and stabilised construction cases with both a biaxial and multi-axial geogrid. It shows aggregate particle movements, geogrid deformation and generated forces in the geogrid materials for each construction case. Forces and strains within the geogrid structure under trafficking were found to be low. The significance of isotropic stiffness in the plane of the geogrid in providing optimum stabilisation performance is discussed and a theory is explored for the development of tension rings within a multi-axial (hexagonal) geogrid structure to accommodate the dynamic surface loads to help explain the performance of these geogrid-stabilised pavements.

• Record URL:
  http://arrbknowledge.com
• Authors:
  • Horton, M
  • Oliver, T
  • Buckley, J
  • Jas, H
• Conference:
  • AAPA International Flexible Pavements Conference, 16th, 2015, Gold Coast, Queensland, Australia
• Publication Date: 2015-9

Language

• English

Media Info

• Pagination: 10p
• Monograph Title: Innovation driving value: AAPA International Flexible Pavements Conference, 13-16 September 2015, Gold Coast, Queensland

Subject/Index Terms

• TRT Terms: Aggregates; Geogrids; Loads; Pavement design; Pavement performance; Pavements
• Uncontrolled Terms: Pavement technology
• ATRI Terms: Aggregate; Geogrid; Load; Pavement design; Pavement performance; Stabilization
• ITRD Terms: 3688: Roadbase stabilization
• Subject Areas: Highways; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 01588879
• Record Type: Publication
• Source Agency: ARRB
• Files: ITRD, ATRI
• Created Date: Jan 29 2016 10:21AM