Finite Element Method (FEM) Update: Geonet Anisotropy and its Effect on the Planar Flow in Drainage Geocomposites

The increasing popularity of finite element seepage analysis is making it possible to understand the use of planar anisotropy in geonets. Drainage geocomposites are manufactured as large panels that range in size and the thickness of most drainage geocomposites is generally less than 15mm with the flow normally being planar. Liquid percolates down the overlaying mass and enters the geonet and flows down the slope almost immediately because of a very high hydraulic conductivity compared to the underlying geomembrane and overlying soil or waste mass. Flow normally takes place in one direction for a single slope such as a geocomposite that is installed on a peripheral berm of a landfill cell, or within a dam embankment, or behind a retaining wall. The design procedures for the selection of drainage geocomposites use the hydraulic conductivity in the machine direction as the materials are installed with the machine direction oriented down the slope and for short slopes panels are installed in the cross-direction. This article describes how most geosynthetics have different properties in machine and cross-machine direction. There are many cases in field conditions that currently exist where the flow is multi-directional and it is necessary to account for both the machine and the cross machine direction hydraulic conductivity of drainage geocomposites. The article presents some examples of such applications that involve three-dimensional (3-D) slopes and include highways, green roofs, sports fields, landfill cells and heap leach pads.

Language

  • English

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 10-13
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 01519219
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Mar 11 2014 2:50PM