Installation procedures of TENAX geonets and geocomposites for landfill applications, Tenax geosynthetics

Installation procedures of TENAX geonets and geocomposites for landfill applications

Handling and placement
1. After the geomembrane has been installed, seamed, tested and approved by the Quality Control Engineer, the surface shall be cleaned and free of excess dirt and debris.

2. The Contractor and the Installer shall handle all geocomposites or geonets in such a manner as to ensure it is not damaged in any way. Precautions shall also been taken to prevent damage to underlying layers during placement of the geocomposite or geonet. Whenever the single components of the geocomposite are installed separately (i.e.: geotextile/geonet/geotextile) then the composite structure shall be regarded as geocomposite in the following text.

3. The geocomposite roll should be installed in the direction of the slope. The geocomposite directs flow predominately in the machine direction (along the roll length) and thus should be installed in the intended direction of flow or as specified by the Engineer.

4. If the project contains long and steep slopes, special care shall be taken so that only full-length rolls are used at the top of the slope.

5. If the project includes an anchor trench at the top of the side slopes, the geocomposite shall be properly anchored to resist sliding. Anchor trench compacting equipment shall not come into direct contact with the geocomposite.

6. In the presence of wind, all geocomposite shall be weighted with sandbags or the equivalent. Such sandbags shall be installed during placement and shall remain until replaced with cover material.

7. If necessary, the geocomposite shall be positioned by hand after being unrolled to minimize wrinkles.

8. In applying fill material, no equipment can drive directly across geocomposite. The specified fill material shall be placed and spread utilizing vehicles with a low ground pressure. The cover soil shall be placed on the geocomposite in a manner that prevents damage to the geocomposite. Placement of the cover soil shall proceed immediately following placement and inspection of the geocomposite. Unless otherwise specified by the Engineer, all equipment operating on soil material overlying the geocomposite shall comply with the following:

Seams and Overlaps (if required)
1. Each component of the geocomposite (geotextile(s) and geonet) will be secured or seamed to the like component at overlaps.

2. Geonet Component

Adjacent edges of geonet along the length of the geocomposite, should be overlapped 0.10 m, or if approved by the Engineer based on the site-specific conditions, placed with the edges of each geonet butted against each other. These overlaps shall be joined by tying the geonet cores together with coloured plastic fasteners or polymeric braid. These ties shall be spaced every 1.5 m along the roll length.
Adjoining geocomposite rolls (end to end) along the roll width should be done with the geonet portion of the top geocomposite overlapping the geonet portion of the bottom geocomposite a minimum of 0.30 m across the roll width. Geonet should be tied every 0.30 m across the roll width and every 0.15 m in the anchor trench or as specified by the Engineer.

The bottom layer geotextile (if any) shall be overlapped.
The top layer of geotextile shall be joined by heat bonding or sewn at the discretion of the Engineer. Geotextiles shall be overlapped a minimum of 0.10 m prior to heat bonding or seaming. If heat bonding is to be used, care must be taken to avoid burn through of the geotextile. If sewing of geotextiles seams is to be used, a flat (pray) seam, "J" seam, or "butterfly-folded" seam is recommended, and the seam shall be a two-thread, double-lock stitch, or a double row of single-thread, chain stitch.

Repairs
1. Prior to covering the deployed geocomposite, each roll shall be inspected for damage resulting from construction.

2. Any rips, tears or damaged areas on the deployed geocomposite shall be removed and patched by placing a patch extending 0.30 m beyond the edges of the damaged area. The patch shall be secured to the original geonet by tying every 0.15 m with approved tying devices. If the hole or tear width across the roll is more than 50 percent of the width of the roll, the damaged area shall be cut out and the two portions of the geonet shall be joined in accordance with the previous subsection.