Geotekstil: Fungsi, Pengertian dan Aplikasi

For those working in geotechnical engineering, geotextiles may be familiar. Geotextiles are frequently used in civil engineering projects, particularly those involving geotechnical issues. According to PU Guidelines No. 003/BM/2009, a geotextile is any textile material that is generally permeable and installed with foundations, soil, rock, or other geotechnical materials as part of a structural system.

Geotextiles are classified based on the method used to combine the filaments or tapes into a sheet structure. The main types of geotextiles are non-woven and woven. Woven geotextiles are made from monofilaments, multifilaments, fibrillated yarns, or from film and tape strips. The weaving process for woven geosynthetics is similar to that for conventional textiles. Non-woven geotextiles are made using sophisticated technology, where polymer fibers or filaments are forced out and continuously twisted, blown, or placed on a conveyor belt. The filament or fiber mass is then joined together mechanically using small needle punctures or heat-welded, where the fibers are "welded" by heat and/or pressure at the point of contact between the fibers and the non-woven textile mass.

Geotekstil Woven

Geotekstil Non Woven

Geotextiles are made from polymers. Polymers commonly used in geotextile manufacturing include polypropylene, polyester, polyethylene, and polyamide. The types of polymer fibers commonly used in geotextiles can be seen in the following image.

Polymer Fiber Type

Based on Geotechnical Design Requirements referring to AASHTO M288, geotextiles are divided into 3 classes as follows.

Geotextile Classification Table

Installation conditions generally determine the required geotextile class. Class 1 is specifically for severe conditions where the potential for geotextile damage is higher. Classes 2 and 3 are for less severe conditions. All strength requirement values ​​indicate the minimum Average Roll Value in the weakest principal direction. This geotextile is the most widely used type of geosynthetic. Its functions can also be varied. The functions of these geotextiles are as follows.

1. Separation

Geotextiles are considered separators when placed between different materials, thus maintaining the function and integrity of each material. An illustration of the function of geotextiles as separators can be seen in the following image.

Separation-Free System

System With Separation

From the two images above, we can see that separation prevents contamination between the embankment material and the subgrade. Therefore, the effective embankment thickness remains the same as the design thickness.

2. Strengthening

Geotextiles are said to have a reinforcing function when geotextiles (good in tensile conditions) are placed on soil (good in compression conditions, but poor in tensile conditions), thereby increasing the strength of the system. An illustration of the function of geotextiles as reinforcement can be seen in the following image.

Unreinforced System

Reinforced System

The image above shows the potential for landslides in the embankment body, particularly in a relatively high embankment structure built on soft soil. The landslide line was cut using the tensile strength of the geotextile. The presence of geotextile reinforcement can increase the safety factor of the embankment structure.

3. Filtration

Geotextiles are said to have a filtration function when water can pass through (perpendicular to) the geotextile but retains soil particles. An illustration of the filtration function of geotextiles is shown below.

Geotextile Illustration for Filtration

From the image above, you can see that water can still pass through the geotextile pores, while soil particles can be retained.

4. Drainage

Geotextiles are said to have a drainage function when water can flow in the same direction as the geotextile. An illustration of the geotextile's function as drainage can be seen in the following image.

Geotextiles as Drainage