Main points of laying bentonite waterproof blanket
On the upper part of the anti-seepage structure, there are structures such as a leachate drainage pipe network, an exhaust pipe network, and a drainage pipe network. The anti-seepage structure belongs to a new type of composite anti-seepage liner system using bentonite cushion + HDPE geomembrane (hereinafter referred to as geomembrane) + compacted anti-seepage clay. The permeability is nearly 4 orders of magnitude lower than that of a single-layer geomembrane anti-seepage structure. The composite anti-seepage liner system of geomembrane + compacted anti-seepage clay is about one order of magnitude smaller, and the anti-seepage effect is better.
The main construction process of the impermeable structure is: foundation treatment→aggregate paving→non-woven geotextile laying→cohesive soil impermeable layer laying→bentonite mat laying→geomembrane laying→non-woven geotextile laying→aggregate paving→ Geomembrane laying is the most important process, and the construction quality determines the anti-seepage effect of the entire anti-seepage structure.
Problems in laying bentonite waterproof blankets in landfills and their solutions
The bentonite pad is made of nano-grade natural sodium-based bentonite particles and corresponding admixtures and is made by a special process. After the laying is completed, the bentonite particles can expand 15 to 17 times in volume when exposed to water, forming a dense colloidal membrane structure that is difficult for water molecules to penetrate, thereby achieving the purpose of anti-seepage. The single bentonite pad is 30m long, 6m wide, and has a density of 4810g/m2. The bentonite mat should be inspected for quality, strength, expansion coefficient, water absorption, permeability coefficient, montmorillonite content, and other technical indicators before construction. A continuous sunny day should be selected for construction, and there should be no sharp objects on the laying base. Geomembrane or Covered with tarpaulin.
Main points of laying bentonite waterproof blanket
1. The laying should be smooth and close to the base layer. The seam arrangement direction is parallel to the maximum slope line so that the seam is beautiful and the stress is small. Strictly control the lap width of the bentonite cushion, and the horizontal and vertical lap widths are both (0.3±0.05)m.
2. The bentonite cushion can be opened freely from the top of the slope downward under the action of gravity. Generally, 18-20 workers are required to work at the same time.
3. When laying on a sloping surface, it must be fixed by anchoring trenches, and the overlapping part must be installed perpendicular to the bottom.
4. Place bentonite powder on the surface of the overlap area with a width of 0.15m and a dosage of 0.45kg/m. The dosage should be checked.
5. The surface of the bentonite pad is forbidden to drive by gravity equipment to avoid damage.
6. If the bentonite pad is damaged during the laying process, use the spare bentonite pad as a patch to cover the damaged area, and the surrounding area should exceed the damaged area by 0.3m. Before placing the patch, place bentonite lap powder around the damaged area to make the patch and the original bentonite pad firmly connected.