Composite geomembranes, including types such as “two-fabric-one-membrane,” “one-fabric-one-membrane,” and “multi-fabric-multi-membrane,” are non-woven composite geomembranes fabricated using non-woven geotextiles as the base material and polyethylene (PE), polyvinyl chloride (PVC), or other polymers as the membrane material, combined through a composite process. These geomembranes offer features such as isolation, reinforcement, drainage, slope protection, as well as high impermeability and excellent flexibility.
Composite geomembranes are produced using two main processes:
1. Thermal composite blown-film process
2. Lamination process
A comparative analysis between the thermal composite blown-film production process and the traditional lamination process is as follows:
a. Quality and Performance
The thermal composite blown-film process produces geomembranes with stable quality and uniform thickness, delivering superior impermeability. Additionally, it allows for real-time quality monitoring of both the geomembrane and geotextile during production.
In contrast, geomembranes produced via the lamination process exhibit lower permeability coefficients due to process limitations and are constrained by engineering requirements.
b. Tensile Strength Uniformity
Geomembranes manufactured using the thermal composite process demonstrate uniform tensile strength in both longitudinal and transverse directions.
The lamination process, however, often results in uneven tensile strength adjustment, leading to lower transverse strength due to process-related issues.
c. Membrane Uniformity
The thermal composite process ensures uniform membrane production through controlled extrusion of raw materials.
The lamination process produces membranes with poor uniformity, resulting in inconsistent thickness during composite fabrication.
d. Edge Treatment and Durability
In the lamination process, edge trimming can cause thinning of the edge membrane, making it weaker than the base membrane and prone to tearing.
The thermal composite edge-trimming process, which incorporates water cooling and other temperature control methods, prevents edge thinning and maintains the required tensile strength.
