Geosynthetic products have changed every facet of civil engineering. They have significantly simplified the process of constructing huge, durable, and strong structures. Traditional construction materials were expensive and not readily available. Geosynthetic materials, though manmade, are easily available and less expensive. One such geosynthetic material that plays a significant role as a barrier is a geomembrane sheet. In this article, we shall understand more about geomembrane sheets and their role in constructing a structure, application and installation process.
Definition of geomembrane sheet
A geomembrane sheet is a synthetic and man-made sheet with a unique advantage: it has comparatively low permeability. This makes it an ideal barrier between the soft subgrade and the foundation, preventing contaminants from leaking into the surroundings. These thin, continuous polymer sheets offer a reliable and efficient solution for environmental protection in construction projects. It is also very often used to store irrigation water, as it is an excellent material for preventing leakages and storing water.
Need for a geomembrane sheet
A geomembrane sheet has a versatile role in the civil engineering industry. Whether a mega industrial and infrastructural project or just maintaining a recreational pond, these multipurpose sheets are required everywhere. Here are some significant roles that it plays:
- It significantly prevents harmful and hazardous substances from contaminating soil and groundwater.
- Using these geosynthetic sheets significantly reduces the maintenance cost as they offer a long-term water containment solution.
- These sheets are critical for environmental protection applications and are often required by regulatory authorities for projects like landfills and containment facilities.
- It is an excellent geosynthetic material for storing water for irrigation purposes. These sheets efficiently prevent water seepage and leakage and enhance the overall irrigation efficacy.
Application of geomembrane sheets
Geomembrane sheets have a wide range of applications. Practically, these sheets are required in almost every industry. Here are some common applications of these geosynthetic sheets:
- Mining industry: These long polymer sheets provide a protective solution for heap leach pads and evaporation ponds. The heap leach pads are designed and constructed to prevent exposure to harmful chemicals in the surroundings. Engineers use geomembrane sheets as a protective layer for this purpose. These geosynthetic sheets also play a significant role during mine restoration. HDPE liners are used to prevent harmful waste from seeping into the surroundings.
- Water industry: HDPE geomembrane sheets are often used as protective liners in dams, canals, and reservoirs. The sheets’ major role is to keep contamination away from clean water and prevent infiltration into the groundwater levels. Another purpose of these elongated polymer sheets is secondary containment for solar ponds, brine pits, and underground storage units.
- Agricultural industry: Geomembrane sheets are extensively used in the agricultural industry as cost-effective, reliable, and efficient containment options. HDPE liners are also used for other requirements, such as waterproofing, storing fertilisers and pesticides, or creating a soil containment zone.
Types of geomembrane sheets
Geomembrane sheets are available in several types depending upon the parent resin used to manufacture them. Here are some common types of these stretched polymer sheets:
- HDPE Geomembrane: High-density polyethene (HDPE) is the most common and preferred choice. It offers high strength and durability and is also cost-effective. Due to its high chemical resistance, it is used as a protective layer to preserve water in reservoirs, canals, and ponds.
- LLDPE Geomembrane: Linear Low-Density Polyethene (LLDPE) is more flexible than HDPE. While slightly more permeable than HDPE due to its lower density, its flexibility makes it ideal for applications requiring conformance to subgrade irregularities and where differential settlement is expected. It is created from virgin polyethylene resins and, with the proper additive package, is highly resistant to ultraviolet rays and low temperatures. This type of geomembrane sheet has excellent resistance to stress cracking and puncturing. While HDPE has higher tensile strength, LLDPE’s flexibility provides superior performance in certain containment applications.
- PVC Geomembrane: Made from PVC resin, stabilisers, and plasticizers, Polyvinyl Chloride (PVC) is a thermoplastic waterproofing geosynthetic material. PVC geomembrane is made by splitting the ethylene dichloride. Then, it is polymerised, which results in PVC resin. It is highly flexible. Its density (approx. 1.2-1.4 g/cm³) is higher than that of polyolefins like HDPE, causing it to sink in water.
- EPDM Geomembrane: EPDM or Ethylene Propylene Diene Monomer is specially designed to resist extreme weather and high temperatures. It is a rubber-like structure with excellent elongation properties and weather resistance. Compared to HDPE, it has lower tensile strength but far greater flexibility. Since it is easily installed, it is mostly used for recreational water structures like swimming pools, recreational ponds, and irrigation ponds.
Geomembrane sheets are an integral part of the irrigation and construction industry. These polymeric sheets act as a protective shield, preventing harmful chemicals and other contaminants from entering the water. They are mainly used in irrigation ponds, storing water for construction, recreational ponds, and storing clean water for industrial use. Geomembrane sheets are available in different types depending on their parental resin. In a nutshell, these elongated geosynthetic sheets are versatile, long-lasting, and highly preferred construction materials, which has significantly improved the construction industry.