As a new type of polymer material, composite geomembrane is widely used in hydraulic engineering and environmental protection engineering. The connection methods of composite geomembrane and membrane include different methods such as lap joint, 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 description and quantitative indicators. According to the relevant field tests, the tensile strength of the composite geomembrane joint is more than 20% of the strength of the base material, and the fracture mostly occurs at the non-welded part of the weld edge. However, there are also some specimens whose tensile failure strength is far from the design requirements or the fractured part starts directly from the weld position. It directly affects the realization of the anti-seepage effect of the composite geomembrane. Especially in the welding of composite geomembrane, if welding occurs, 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 there is a problem, the consequences may be more serious.
To this end, we have tracked and analyzed the welding construction of HDPE composite geomembrane, and classified common problems in the construction process, so as to conduct differentiation research and find out quality improvement measures. Common quality problems in the construction of composite geomembrane welding mainly include excessive welding, excessive welding, missing welding, wrinkling, and partial welding of the weld bead.
Post time: Apr-20-2022