November 26, 2022
Human activities have distorted nature in many ways through the development of infrastructure. However, the distortions can be remedied by using engineering practices. For example, geotextiles which are engineered geosynthetics, made from polymers in the forms of polypropylene and polyesters, can be deployed to serve several purposes.
The selection and use of a geotextile depend on the soil characteristics, the nature of the problem to be solved, and the quality of the geotextile. Geotextile may be permeable or impermeable and deployed to achieve certain objectives of separation, reinforcement, or soil drainage. For drainage purposes, the permeability coefficient of the geotextile is of prime importance where rapid drainage is required, like in retaining walls, to reduce the pore lateral pressure to enhance structural stability.
In road construction where the natural soil needs to be stabilized or reinforced, geotextiles may provide viable alternatives to the traditional method of excavating the in-situ soil and backfilling with granular materials like coarse clean sand. A properly selected geotextile, with adequate CBR and tensile strength values, may be laid directly on the well-prepared foundation of the natural soil to receive the road soil embankment.
Different layers of soil, if required, may be separated using geotextiles to avoid the loss of fine soil particles from a layer into the coarser particles of another layer. Such geotextiles should be adequate in their puncture and permeability coefficient values. Excessive uncontrolled seepage that could lead to soil piping has been a major cause of hydraulic structures such as dams.
The seepage can be controlled using impermeable geotextile to elongate the flow net, thereby decreasing the upward pore pressure, like at the stilling basis or toe-drain of a dam. This method is comparatively cheaper and more effective than the laying of clay blankets involving in-situ and borrow-pit excavations, transportation, laying, and compaction of the clay soil materials. The impermeable geotextile could be a hybrid of a layer of water-proof geomembrane sandwiched on both sides with the protective permeable geotextiles.
The constructionism of water canals can also gain from geotextiles. Uneven settlement of a solid protective layer of concrete or stone-pitching may be prevented with a geotextile serving as an underlay to the solid protective layer lining the canals. Temporary water canals may be achieved by lining the surface with a suitable geotextile to prevent erosion from the current.
Special geotextiles may be deployed for the construction of soil retaining walls eliminating the use of concrete. The retaining wall is constructed in layers with compacted soil sandwiched between the geotextiles. The unique advantage presented by this method is that the permeable geotextile permits the expulsion of water from the backfill for structural stability enhancement.
Geotextiles could serve as underlays in landfills and water ponds lined with a geomembrane. The function will not be to prevent the geomembrane from a puncture but also helps in the distribution of the induced tensile stress on the geomembrane. Gabions and geotextile may be used together to resolve erosion and shore protection problems. The geotextile is laid under the gabion and reno mattress structures to prevent the migration of soil particles into the voids of the stone mass while allowing water to pass through.
However, it needs to be emphasized that the serviceability of geotextile structures is a function of not only the design but also the quality of the geotextiles and workmanship involved. As professional engineers, we import only high-quality geotextiles, gabions, reno-mattresses, HDPE geomembrane, geomatics, geocells, and other geosynthetics at competitive prices. We remain available to offer free technical advice to our customers.
Contact us at Geomembrane Gabions & Geotextile Ltd in Kaduna. +234 703 784 5174, [email protected]