Case Study: Prevention of Geomembrane Bubbles
Problem: Preventing Geomembrane Bubbles “whaling” that develop under the liner. These “whales” generally occur due to the production of methane thru decaying organics or other
means and the inability to vent the methane adequately.
Solutions: There are primarily two types of venting used for this application. Strip drain is composed of a polymeric perforated core wrapped in spunbonded geotextile. Geocomposite rolls, which are more readily used because it lays flatter under the liner and width can be customized. The venting allows gases to collect and flow to air vents located at top of slope.
Construction Details: All 3 lagoons embankments are constructed at a 3:1 slope. The Geocomposite was selected and cut down into minimum 1’ width. For this size and shaped cell, the geocomposite venting is typically distributed by five equally spaced across the bottm of the cell running North and South. Five more equally spaced strips across the bottom of cell running east and west. At the corners, two diagnol strips per corner extending to the third lateral on each side of cell. Liner vents would need to be installed at top of dike over the geocomposite. After the venting grid is established liner will be deployed on top. The geocomposite venting strips will mitigate gas bubbles and whaling that can potentially harm liner and seams.
Location: Warm Springs, Montana
Engineer: Anderson-Montgomery
Contractor: MRC
Liner Installer: Northwest Linings & Geotextile Products Inc.
Materials: Materials utilized for this project includes: agru HDPE 60 mil GRI-GM13 DS microspike and SKAPS geocomposite TN 250 1-6.
Area: 95,031 SqFt