Laying Of HDPE Geomembrane

Before laying HDPE geomembrane, the corresponding qualified acceptance certificate of civil engineering should be obtained.
Before cutting HDPE film, its relevant dimensions should be accurately measured and then cut according to the actual size. Generally, it is not advisable to cut according to the dimensions shown in the diagram. Each piece should be numbered and recorded in detail on a dedicated form.
When laying HDPE geomembrane, efforts should be made to minimize the number of welds, and raw materials should be saved as much as possible while ensuring quality. It is also easy to ensure quality.
4. The overlap width between membranes is generally not less than 10cm, and the welding seam is usually arranged parallel to the maximum slope, that is, along the slope direction.
5. Usually, in corners and deformed areas, the joint length should be minimized as much as possible. Unless otherwise specified, welding seams should be avoided as much as possible within a range of 1.5 meters from the top slope or stress concentration area on slopes with a gradient greater than 1:6.
During the laying of HDPE geomembrane, artificial wrinkles should be avoided. When the temperature is low, it should be tightened and leveled as much as possible.
7. After the HDPE geomembrane is laid, walking and moving tools on the membrane surface should be minimized as much as possible. Any objects that can cause harm to the HDPE membrane should not be placed on or carried on the membrane to avoid accidental damage to the membrane.
Welding of geomembrane
1. The welding process of the hot wedge welding machine is divided into: adjusting the pressure, setting the temperature, setting the speed, inspecting the overlap of the weld seam, installing the film into the machine, starting the motor, and applying pressure for welding.
2. There should be no oil stains or dust at the joints, and the overlapping section of HDPE geomembrane should not contain mud or other debris. If there are any debris, they must be cleaned before welding.
3. At the beginning of each welding day, a 0.9mm × 0.3mm sample must be tested and welded on site, with a lap width of not less than 10cm, and a tensile machine must be used for peeling and shearing tests on site. After the sample is qualified, it can be welded with the adjusted speed, pressure, and temperature at that time. During the welding process of the hot wedge welding machine, it is necessary to pay attention to the operation of the welding machine at all times and adjust the speed and temperature according to the actual situation on site.
4. The weld seam should be neat, beautiful, and free from any sliding or jumping phenomena.
When encountering insufficient length of geomembrane, longitudinal splicing is required. The transverse welds should be welded first, and then the longitudinal welds should be welded. If the distance between the transverse welds is greater than 50cm, they should form a T shape and not cross each other.
6. Adjacent geomembrane welds should be staggered and overlapped as much as possible. The nodes formed between the membrane blocks should be T-shaped, and cross shaped joints should be minimized as much as possible. Extrusion welding machines should be used to strengthen the intersection points of the longitudinal mold and weld seams.
7. When welding the film, it is not allowed to press out dead folds. When laying HDPE geomembrane, the expansion deformation caused by temperature changes should be reserved according to the local temperature change amplitude and the performance requirements of HDPE geomembrane.
When the temperature control of the handheld welding machine indicates that the welding machine temperature is below 200 ℃, it should be wiped off with a clean cloth or cotton yarn before welding, and if necessary, re polished. Do not wipe it with your hands.
When there is condensation, moisture, mud, or other factors affecting the joint, welding should be carried out after treatment.
10. Welding cannot be carried out during rainy periods or when there is moisture, dew, or large sand in the joints, except for taking protective measures.
When the temperature is below 5 ℃, construction should not be carried out according to the specifications. If construction is necessary, the welding machine should be preheated before welding.
During the welding process of the extrusion welding machine, the slider of the gun head should be checked regularly. If the wear is severe, the slider should be replaced in a timely manner to avoid damaging the film surface.
13. Geomembranes should be powered by generators with good voltage stabilization performance during welding. In special cases where local electricity is used, a voltage stabilizer must be used.