How to install HDPE geomembrane and inspect weld seam

A. Site foundation treatment

1, Before laying HDPE geomembrane should be laid substrate for a comprehensive inspection, laying substrate should be solid, flat, vertical depth of 25mm can not have roots, rubble, stones, concrete particles, steelhead, glass chips and other debris that may damage the geomembrane. Compaction with wheel compactor to remove the car marks, footprints and ground bumps. In addition, ground bumps larger than 12mm should also be shoveled or compacted.

2, When HDPE geomembrane is laid on the backfill, the compaction of the backfill should not be less than 95%.

3, the site foundation should be free of seepage, silt, water, organic residues and harmful substances that may cause environmental pollution, the corner of the foundation should be rounded and smooth, in general, the radius of its arc should not be less than 500 mm

B, HDPE geomembrane installation technical requirements.

1, The laying and welding of HDPE geomembrane should be carried out at a temperature above 5°C and wind force below level 4 without rain or snow.

2、Construction process: Geomembrane laying → lap welding seam → welding → site inspection → repair → re-inspection → backfill (fish ponds backfill or not according to need).

3、The lap width of the seam between the membrane and the film is not less than 80mm, and usually the seam should be arranged in a direction equal to the maximum slope line, that is, along the slope direction.

4, When laying, should try to avoid the production of artificial folding. When laying, the amount of expansion and deformation caused by temperature change should be reserved according to the magnitude of local temperature change and the performance requirements of HDPE geomembrane, in addition, the amount of expansion and contraction of geomembrane should be reserved according to the topography of the site and geomembrane laying to adapt to the uneven settlement of the foundation.

5, After laying, should minimize walking on the membrane surface, handling tools, etc. Any objects that can cause harm to the HDPE geomembrane should not be placed on the geomembrane or carried on the geomembrane to avoid accidental damage to the HDPE membrane.

6, HDPE membrane construction site of all personnel are not allowed to smoke, do not wear shoes with iron nails or high-heeled hard-soled shoes to walk on the film surface, not allowed to engage in all activities that may damage the impermeable membrane.

7, HDPE geomembrane laying is completed,  before not covered with a protective layer, one 20-40Kg heavy sandbag should be placed in the corners of the membrane every 2m-5m distance to prevent the geomembrane is scraped up by the wind.

8, HDPE geomembrane should be affixed with the support layer and should not be folded or overhung.

9, When the geomembrane is constructed in sections, the upper layer should be covered in time after laying, and the exposure time in the air should not exceed 30 days

10, The HDPE geomembrane anchoring must be constructed according to the design. In places where the terrain is more complex in the project, the construction unit proposes other anchoring methods, which should be approved by the design unit and the supervision unit.

C. HDPE geomembrane welding requirements:

1, The lap surface of HDPE geomembrane welds shall not have impurities such as dirt, sand, accumulated water (including dew) that affect the welding quality, and should be cleaned up during welding.

2, At the beginning of welding every day (early morning and after lunch break), trial welding must be carried out on-site first, and then formal welding must be carried out after passing the test.

3, The welding of HDPE geomembrane should be welded by double-track hot-melt welding machine. Extrusion welding or hot-air gun welding should only be used in places where repair, covering or hot-melt welding machine cannot reach.

4, During welding, the working temperature and speed of the welding machine should be adjusted and controlled at any time according to the temperature and material properties.

5, The HDPE film at the welding seam should be fused as a whole, and there should be no virtual welding, missing welding or excessive welding. The joined two layers of HDPE geomembrane must be lapped flat and soothed.

D, Welding seam quality control

1, With the progress of construction, it is required to check the quality of HDPE film welding in time, and to make up the welding with a hot air gun or plastic welding gun at any time for leakage and false welding parts. The inspection is carried out in three steps, namely visual inspection, inflation inspection and damage test.

2, Visual inspection: see if the two welds are flat, clear, wrinkle-free, transparent without slag, bubbles, leaks, melting points or weld set wraps, etc. Visual inspection is mainly for detailed inspection of the appearance of the laid geomembrane, weld quality, T-welding, substrate debris, etc. All constructors should carry out this work in the whole construction process.

3, In addition to visual inspection of the tightness of all welds, vacuum testing should also be used, and the parts that cannot be vacuum tested should be strengthened self-inspection.

4, Inflatable inspection: inflation strength is 0.25Mpa, no air leakage for 2 minutes, considering that the coil is soft and easy to deform, the allowable pressure drop by 20%

5, When the samples taken on the double-track weld are subjected to the tensile test, the standard is that the weld is not torn apart and the mother is torn and damaged during the peeling and shearing tests. At this time, the welding is qualified. If the sample is unqualified, a second piece should be taken from the original weld, and if three pieces are unqualified in a row, the entire weld should be reworked

6, The samples that pass the test will be archived.

7, Defects found in visual inspection, inflatable inspection, and damage test should be repaired in time, and those that cannot be repaired immediately should be marked to prevent omission during repair.

8, In the visual inspection, it is found that there are defects such as holes on the film surface, and if there are missing welding, virtual welding, or damage in the welding process, it should be repaired with fresh base metal in time, and each side of the repair scar exceeds the damaged part by 10-20cm. and keep records.

9, For the repaired weld, a detailed visual inspection is generally required to confirm that the repair is reliable before releasing.

Company Profile

Shandong Lianxiang Engineering Materials Co., Ltd. is a trade subsidiary belonging to Lianxiang group. The group are founded in 2009 owns several trade branches and production lines.

Shandong Lianxiang Engineering Materials Co., Ltd. is registered in 2014, 40 employees with sales, technical and construction teams, focus on domestic and foreign trade, products research 

and  design. Supply self-produced and externally sourced products, various geosynthetics and other related products, such as geomembrane, geocell, geotextile, GCL, 

geocomposite, accessories and so on. Total annual sales is more than 100 million dollars in 2020. Relying on our strong sales and trading capabilities, as well as supply chain control ability,

 we keep expanding more quality products and assist local factories without export teams to go out of China to the world, connecting foreign customers with quality factories.

The production lines focus on production and development all kinds of geosynthetics, such as geomembrane, geocell, geonet, woven and nonwoven geotextile, GCL, geocomposite and so on.

Our products are widely used in basic construction fields such as highways, railways, airports, coal mines, water conservancy, electric power, soil and water conservation, and green environment.

We have passed the ISO9001 quality management system and SGS audit, has a complete production and quality control system, sales, service and warehouse management system to ensure 

product quality and supply ability.

We are aiming to provide customers with the most satisfactory products and services, and are working on protecting our global environment.