Guide to Selecting Geomembrane Thicknesses (0.5mm, 1.0mm, 2.0mm)

Geomembrane has become an essential component in water conservancy reservoirs, landfills, sewage treatment plants, agricultural irrigation ponds, and mine tailings ponds. Its excellent impermeability, chemical corrosion resistance, and durability effectively prevent the leakage and diffusion of liquids, gases, and pollutants. The selection of geomembrane thickness has also gradually become one of the important decisions in the design and construction process.

Definition and Measurement Standards of Geomembrane Thickness

Before selecting a geomembrane of appropriate thickness, it's crucial to understand the true meaning of "thickness" and its measurement standards. Thickness is not merely a physical dimensional parameter; it directly affects the geomembrane's impermeability, tensile strength, puncture resistance, and service life. Incorrect measurement or understanding can lead to material selection errors, consequently impacting the overall impermeability and safety of the project.

Classification of Common Geomembrane Thicknesses

Geomembranes are produced in various thicknesses to meet different engineering requirements. The thickness not only affects the product’s mechanical strength but also determines its long-term durability and impermeability performance. Below is a general classification of common geomembrane thicknesses and their typical applications.

Analysis of the relationship between geomembrane thickness and performance

Relationship between Thickness and Impermeability

• Impermeability is the core function of geomembranes, and its quality directly determines the sealing effect and environmental safety of a project.

  
  

• The greater the thickness, the lower the permeability coefficient. The permeability coefficient of HDPE geomembranes is typically below 1×10⁻¹⁴ cm/s, but during long-term service, thicker membranes are more effective than thinner membranes in resisting molecular diffusion and micropore permeation.

  
  

• The impermeable layer has stronger integrity; thicker membranes are less likely to be punctured or scratched during construction, transportation, or welding, thus reducing the risk of leakage.

  
  

• Thinner membranes are suitable for low-pressure or short-term projects; a 0.5mm membrane can still meet the impermeability requirements when used in landscape ponds or irrigation ponds, but if used for long-term liquid storage or high water pressure conditions, it is prone to seepage risks.

Relationship between Thickness and Mechanical Properties

Mechanical properties, including tensile strength, elongation at break, and puncture resistance, are important indicators of a geomembrane's resistance to external damage.

1. Tensile Strength

Increasing thickness directly increases the tensile strength per unit width.

The tensile strength of a 0.5mm HDPE membrane is approximately 15–18 MPa, while a 2.0mm membrane can reach 25–30 MPa.

During installation, thicker membranes can better withstand construction machinery, sand and gravel friction, and thermal stress.

2. Elongation at Break

Thicker membranes typically have a slightly lower elongation at break than thinner membranes (i.e., slightly less flexibility), but they have stronger tear resistance.

LLDPE membranes, due to their more flexible molecular structure, maintain good ductility even at greater thicknesses.

3. Puncture Resistance

Increasing the thickness from 0.5mm to 2.0mm can increase the puncture resistance by 3 to 4 times. For applications with sharp gravel or uneven substrates, a thickness of ≥1.5mm should be preferred, supplemented with a protective layer (such as non-woven geotextile).

Relationship between Thickness and Aging Resistance

• Geomembranes are subject to ultraviolet radiation, oxidation, temperature changes, and chemical erosion during long-term use. Thickness plays a crucial "time buffer" role in this process:

• Thicker membranes age more slowly; ultraviolet radiation and oxygen molecules can only react within a limited depth of the membrane surface. The greater the thickness, the smaller the relative proportion of the oxidation reaction zone.

• Thicker membranes delay stress crack formation; HDPE membranes are prone to stress cracking (ESC) under long-term stress, while thicker membranes effectively disperse stress concentration.

• Thicker membranes have stronger resistance to temperature changes; they have higher heat capacity and lower thermal expansion and contraction rates, making them suitable for areas with large diurnal temperature variations.

Typical application scenarios of geomembranes of different thicknesses

Applications of 0.5mm geomembrane:

• Agricultural irrigation ponds and water storage ponds

• Landscape engineering and garden water features

• Temporary seepage prevention or covering projects

Applications of 1.0mm geomembrane:

• Sewage treatment plants and regulating ponds

• Leachate collection ponds and seepage channels

• Artificial lakes and wetland restoration

• Agricultural and aquaculture projects

Applications of 2.0mm geomembrane:

• Landfill seepage prevention systems

• Mine tailings ponds and heap leaching fields

• Reservoirs and seepage prevention dam foundations

• Hazardous waste storage and chemical pools

Relationship Between Thickness and Construction Process

Construction Characteristics of Thin-Film Geomembranes (0.3mm～0.75mm)

• Thin geomembranes are lightweight, flexible, and easy to lay, and are commonly used in landscape ponds, agricultural irrigation canals, or short-term water storage projects.

• Laying Requirements: Due to the membrane's flexibility, it can easily adapt to uneven ground during laying, reducing cutting and splicing. However, care must be taken to prevent punctures by sharp objects, and the foundation must be flat and free of stones.

• Welding Methods: Hot wedge welding or extrusion welding can be used. Temperature should be kept low (approximately 300–350°C) to prevent over-melting and edge curling.

  
  

• Construction Speed: Membrane welding is relatively fast; one person can complete 4000–6000 square meters per day.

  
  

• Quality Control: The focus of inspection is on appearance defects (bubbles, wrinkles) and weld continuity. Due to the membrane's relatively weak tensile and tear resistance, strict control of tension and handling methods is necessary.

Medium-thickness membrane (0.75mm～1.0mm) construction characteristics

• Laying requirements: Medium-thickness membranes have slightly higher rigidity, requiring a combination of manual and mechanical operation during laying. The roll width is typically 6-8 meters, and construction must be carried out when the ground flatness is ≤2cm/m.

  
  

• Welding method: Double-rail hot wedge welding is used, with a weld width of approximately 15mm and a 5mm test air channel. The welding temperature is controlled between 350–420°C.

  
  

• Construction efficiency: Medium-thickness membranes offer moderate construction speed and are adaptable to most climatic conditions.

  
  

• Quality control: In addition to visual inspection, vacuum testing or air-filling testing is required to ensure weld sealing.

  
  

• Application recommendations: A 1.0mm thickness is the standard choice for most medium-sized seepage prevention projects (such as landscape lakes or sewage treatment plants), balancing economy and durability.

Thick Membrane (1.5mm～2.0mm) Construction Characteristics

• Laying Requirements: Due to the heavy weight of the thick membrane (approximately 1.4～1.9kg/m²), mechanical laying is typically used. The substrate must be compacted and a protective layer (such as 300g/m² non-woven geotextile) laid to prevent puncture.

  
  

• Welding Method: A high-power dual-rail hot wedge welder or extrusion welding machine is used. The temperature needs to be controlled between 420–480°C. The welding speed is relatively slow, but the strength is high.

  
  

• Construction Conditions: Wind speed should be below 5m/s, and the ambient temperature is recommended to be between +5°C and +40°C to prevent stress cracking.

• Quality Control: Multiple non-destructive tests are required, such as ultrasonic testing, vacuum testing, air inflation testing, and shear testing. All weld records should be archived.

Geomembrane, as the most critical barrier material in seepage control projects, significantly impacts not only seepage control performance and service life but also the overall project's economy and safety. This article compares the performance, construction, and application of three typical thicknesses: 0.5mm, 1.0mm, and 2.0mm, leading to the following conclusions:

**0.5mm Geomembrane:** Suitable for lightweight, short-term projects or those in mild environments, such as landscape lakes, agricultural irrigation ponds, and temporary reservoirs. Its advantages include low cost, simple construction, and good flexibility, but it is not suitable for environments with long-term high water pressure or mechanical loads. In windy, uneven terrain, or areas with significant temperature differences, it should be thickened or a composite structure should be used.

**1.0mm Geomembrane:** The most versatile thickness, balancing flexibility, seepage control performance, and economy. Suitable for medium-sized projects such as sewage treatment plants, artificial lakes, and aquaculture ponds. It maintains excellent seepage resistance for a relatively long period and effectively resists UV aging and temperature changes. For projects with a lifespan exceeding 10 years, a 1.0mm thickness typically provides ideal durability.

2.0mm geomembrane: Represents a high level of impermeability and is the standard configuration for long-term projects. It is widely used in landfills, reservoirs, tailings ponds, and large industrial seepage control projects. Its thickness provides higher puncture resistance and chemical resistance, enabling long-term resistance to acid and alkali erosion and stress concentration. Although initial investment and construction requirements are higher, it offers significant advantages in life-cycle cost analysis.