Construction Precautions for Composite Geomembrane
(1) Use should be embedded: The thickness of the covering should not be less than 30 cm.
The seepage prevention system should consist of: a cushion layer, a seepage prevention layer, a transition layer, and a protective layer.
Soil must be firm to prevent uneven settlement and cracking. Grass and tree roots within the seepage prevention area must be cleared. A protective layer made of fine sand or clay should be laid on the surface in contact with the membrane.
(4) Do not stretch the geotextile membrane too tightly during installation. It's better for the ends buried in the soil to form a wavy pattern. Especially when anchored to rigid materials, some degree of expansion and contraction should be allowed.
During construction, it is advisable to avoid placing stones or heavy objects directly on the geotextile membrane. It is best to construct, lay the membrane, and cover with a protective layer simultaneously.
Composite geomembrane seams
Seam treatment of composite geomembranes is a critical process, directly affecting the impermeability effect.
General seam methods include:
① Joints: The overlap width should be greater than 15cm; ② Hot Welding: Suitable for slightly thicker geomembrane base materials, the overlap width of the weld should not be less than 5cm. (Not recommended for adhesive bonding, as it is prone to delamination after long-term water immersion, resulting in poor waterproofing effect.)
Seam Handling Precautions
(1) The joint treatment of composite geomembranes is a critical construction process, directly affecting the service life of the project. Quality inspections indicate that the thermal welding method is ideal (special adhesive may also be used). The thermal welding method involves heating the surface of the PE geomembrane to melt it, then fusing it together under pressure.
(2) Geotextile membranes should be laid in a specific direction. Both sides of the geotextile membranes should have a certain amount of PE film and PET non-stick layer reserved. During laying, adjust the direction of each unit of the geotextile membrane to facilitate the welding of two units of geotextile membranes.
After the geotextile membrane is laid, sandbags should be used to hold it down to prevent wind movement. The edges and seams must be free of dirt, moisture, and dust.
Ensure that the two edges of the PE single film at the weld joint are adjusted prior to welding, so that they overlap a certain wide width, and are flat and wrinkle-free.
(5) It is best for experienced technicians to perform the welding, using a dedicated welding machine. Adjust the temperature and speed (adhesive bonding may also be used).
