Differentiation Between Permeable Geotextile and Impermeable Geotextile (Two-Layer Geotextile with One Membrane, One-Layer Geotextile with One Membrane)

Permeable geotextile and impermeable geotextile are two distinct types of geosynthetic materials, differing in material composition, performance characteristics, and application scenarios:

1. Material Composition

1. Permeable Geotextile: Typically made of synthetic fibers (e.g., polyester, polypropylene) with a porous structure, allowing water to pass through while preventing soil particle loss.
2. Impermeable Geotextile: Also known as composite geomembrane, including “two-layer geotextile with one membrane” and “one-layer geotextile with one membrane”. It is composed of a plastic film (e.g., polyvinyl chloride (PVC) or polyethylene (PE)) as the impermeable base material, laminated with non-woven geotextile. The impermeability of the plastic film is the primary source of its anti-seepage performance.

2. Performance Characteristics

1. Permeable Geotextile: Features high permeability, good air permeability, high tensile strength and elongation, capable of withstanding certain water pressures, and equipped with filtration and isolation functions.
2. Impermeable Geotextile: Mainly characterized by impermeability, high tensile strength and elongation, capable of withstanding water pressure and adapting to dam deformation, with puncture resistance and protective properties.

3. Application Scenarios

1. Permeable Geotextile: Commonly used in drainage systems, filter layers, soil reinforcement, and prevention of soil erosion.
2. Impermeable Geotextile: Widely applied in water conservancy projects (e.g., reservoirs, dams), environmental engineering (e.g., landfills), subways, underground structures of buildings, and other scenarios requiring anti-seepage.

4. Chemical Corrosion Resistance

Both materials exhibit good chemical corrosion resistance, capable of resisting erosion from acids, alkalis, and salts.

5. Aging Resistance

Impermeable geotextile generally has better aging resistance, particularly in terms of UV resistance and decomposition resistance.

6. Construction Methods

1. Construction of permeable geotextile is typically simpler.
2. Construction of impermeable geotextile may require more precise positioning and fixation; for projects with high anti-seepage requirements, overlapping areas of the geomembrane need to be welded.

Through the above distinctions, it is clear that permeable geotextile and impermeable geotextile each have their own applicable fields and advantages. The choice should be based on specific engineering requirements and environmental conditions.