How to overlap composite geomembrane?

As a new type of polymer material, composite geomembrane is widely used in water conservancy projects and environmental protection projects. The connection methods between composite geomembrane and membrane include different methods such as overlapping, bonding, and welding.

Due to its fast operation speed and high degree of mechanization, welding construction can greatly reduce the number of on-site personnel and shorten the construction period, and has gradually become the main method for on-site installation and construction of composite geomembranes.

Welding methods include electric wedge, hot melt extrusion and high temperature gas welding.

Among them, electric wedge welding is the most widely used. Domestic experts and scholars have conducted in-depth research on hot wedge welding technology and obtained some regular descriptions and quantitative indicators. According to relevant field tests, the tensile strength of the composite geomembrane joint is more than 20% of the strength of the base material, and most fractures occur in the non-welded parts of the weld edge.

However, there are also some specimens whose tensile failure strength is far less than the design requirements or the fractured part starts directly from the weld position. This is related to the operation of the construction site, the selection of the welding process, the responsibility of the operator, proficiency and other factors. Directly affects the realization of the anti-seepage effect of the composite geomembrane.

Especially if welding occurs during composite geomembrane welding, the appearance of the weld meets the design requirements, but the tensile strength of the weld often fails to meet the design requirements, and there may not be any problems in the short term. However, considering the durability of the project, it will directly affect the realization of the anti-seepage life of the project. If problems occur, the consequences may be more serious.
To this end, we have tracked and analyzed the welding construction of high-density polyethylene composite geomembrane, and classified common problems during the construction process in order to conduct differentiated research and find out quality improvement measures.

Common quality problems in composite geomembrane welding construction mainly include over-welding, over-welding, missing welds, wrinkles, partial welding of weld beads, etc.