Requirements for Laying of Bentonite Blanket, HDPE Geomembrane and Non-woven Fabric
1. Before laying the bentonite blanket and HDPE geomembrane, the supervision engineer should fully confirm the site conditions to ensure that the foundation surface of the landfill reservoir area is flat and free of unevenness, cracks, no spiked particles, hard debris, etc. Various foreign objects that may damage the geomembrane, and strictly check the quality of the impervious material (whether there are bubbles, holes, wrinkles, damages, etc. on the surface of the known performance indicators), and confirm that it is correct before laying.
2. The sampling of the bentonite blanket and HDPE geomembrane acceptance inspection shall be based on the continuous production of products of the same brand of raw materials, the same formula, the same specifications and the same process. Use the sodium-based bentonite recommended by the manufacturer and the same as in the bentonite blanket, and check for damage, breakage and other phenomena during transportation. The product identification must be verified.
3. Each roll of material should be numbered and laid in order. The geomembrane number is filed by the supervision engineer for testing.
4. The geomembrane materials on site construction shall not be exposed for a long time and away from the fire source. The storage of bentonite waterproof blankets and the matching bentonite powder must be covered with plastic cloth or anti-seepage membrane. Premature hydration.
5. During the laying process, workers shall not wear shoes that are damaged to the bentonite waterproof blanket and geomembrane, and shall not smoke or perform other activities that can damage the bentonite waterproof blanket and geomembrane at the laying site.
6. Before laying the bentonite carpet, pay attention to the front and back directions. When laying, the bentonite carpet should be minimized to prevent the bentonite carpet from being damaged. If necessary, a layer of temporary geotextile can be placed on the ground. To reduce friction.
7. Lay out the soil-proof bag in time to prevent the wind from being blown away.
8. The outdoor construction of geomembrane should be carried out at a temperature above 5 ℃ and a wind level below four, without rain or snow.
9. No vehicles are allowed to drive directly on the bentonite blanket, HDPE geomembrane and non-woven fabric.
10. In order to avoid material shrinkage, wrinkling or stress caused by temperature changes, the HDPE geomembrane should be welded in time after the approval of the supervision engineer, and protective materials should be laid after passing the inspection.
11. During the welding construction process of HDPE geomembrane, the supervisory engineer should be promptly inspected for operation procedures, laying and welding quality, and any quality problems should be repaired in time.
12. The anchoring ditch of the middle platform of the geomembrane and the anchoring ditch of the slope roof should not have tree roots, stones and large particles, and it should be smoothed and compacted.
13. The length of the bent length of the bentonite blanket should not be less than 150mm. If the non-woven fabric at the end of the bentonite blanket is not cut in a groove, you need to use bentonite in the arched area to reinforce it. The lateral end overlap of the bentonite blanket needs to be at least 600mm long. All knitted stiffened transverse end laps require reinforcement with bentonite. The amount of reinforced bentonite should not be less than 0.4kg / m.
14. When the bentonite blanket is damaged, you can cut a patch on the new bentonite blanket. The length of the four sides of the patch must not be less than 300mm from the damaged place. Before laying the “patch”, you should sprinkle some granular bentonite or bentonite around the damage. Paste, if necessary, with some adhesive to prevent “patch” displacement.
15. HDPE geomembrane welding position and welding technology requirements:
(1) When welding the geomembrane on the slope, the overlap seam should be parallel to the direction of the slope, and the position of the lateral overlap seam of the slope should be more than 1.0 m from the edge of the bottom of the slope.
(2) Formal welding shall not be started until the samples welded by the welding equipment have passed the test welding inspection or confirmed by the supervision engineer.
(3) Before welding, dust, dirt, and other foreign matter on the surface of the geomembrane must be cleaned.
(4) The overlap of two welded geomembrane shall not be less than 10 mm.
(5) When the temperature is lower than 5 ° C or higher than 40 ° C, the construction unit shall provide a written description of the welding quality equivalent to the specified temperature range, and ask the supervision engineer for confirmation before proceeding with the construction.
(6) The geomembrane welding form adopts double welding seam overlap. Extrusion welding is used for repairing (such as repairing holes) and cannot be reached by fusion welding equipment.
(7) The joint strength of the geomembrane weld should be greater than the strength of the parent material.
16. The construction site should be equipped with sufficient welding equipment to ensure continuous welding construction.
17. The construction site should be equipped with a testing laboratory and equipped with the necessary testing equipment. On-site testing should be performed non-destructive tests (such as aeration and vacuum tests) and destructive tests (such as shear peeling) on HDPE geomembrane welds. Trials, etc.).
18. On-site inspection of geomembrane welding is completed. All the piercers of the inflatable raincoats made during the test should be immediately plugged with the squeeze weld method.
19. Welding joints for false or missing welds should be timely repaired, and vacuum inspection should be performed on the repaired parts.
20. The construction unit must have a complete construction organization plan, and arrange the materials reasonably according to the size of the construction site, GCL and HDPE geomembrane to reduce the loss of the geomembrane.
21. The construction of the anti-seepage system needs GCL and HDPE geomembrane suppliers to guide the construction or installation.