What is the aperture size of geosynthetic materials?
Geosynthetic materials have an important coefficient to perform the function of geotechnical project applications, such as reinforcement of the soil, filtration, and drainage. The value of this parameter can be measured depending on the specific type and application; it reflects the size or spacing of reinforcement elements in the material. For instance, the apparent opening size (AOS) of geogrids in geosynthetic reinforced embankments can be from 0.8 to 3 inches, while for geotextiles used in separation applications, the AOS should be below or equal to 0.6 mm. This property affects how geosynthetic materials interact with the soil and the mechanical characteristics of the materials. According to the application and the specific property of the soil for the desired performance, the selecting of the right aperture size is very critical.
Some geosynthetics from Strata Geosystems come with varied aperture sizes, different for the application of the geosynthetic product to a geotechnical project. For example, Strata Global offers geogrids with an aperture size ranging from 0.8 to 3 inches in reinforcement of the embankment, made of geosynthetic materials. This minimizes interactions between the soil and the geosynthetics to ensure better load distribution. Geotextiles, on the other hand, have an aperture size at 0.6 mm, good for separation from migration of soil and its particles. The aperture size of geotextiles is very significant in this case, like the drainage systems, where the soil needs to be retained, but at the same time, water has to flow.
Why is it important to know the aperture size of a geosynthetic material?
By knowing the aperture size, engineers and designers can select geosynthetic materials in accordance with various parameters:
Filtration efficiency: A geotextile appropriate in terms of aperture size can act as an effective filter, preventing the migration of soil particles while allowing water to pass. This is especially important when using geotextiles in applications like drainage systems, where the geotextile should retain the soil but allow water to flow freely.
Drainage capacity: With larger apertures, geosynthetic materials facilitate better water flow, which makes them ideal for applications like drainage layers. They facilitate the removal of excess water and dampness.
Soil retention: Geosynthetic materials that have appropriate aperture sizes in context to soil reinforcement applications provide for strong interlocking with the soil, thereby helping in improving the stability and load-bearing capacity of reinforced structures.
Reinforcement strength: An engineer will find the degree of tensile strength and stiffness for the geosynthetic material maintained by having been selected aperture sizes. With the right selection of the aperture size, the engineer can optimize the material for the application.
Particle retention: Geotextiles can retain soil particles using proper aperture sizes that have given them the ability to retain during erosion control.
How to measure aperture size of a geosynthetic materials?
Various ways of measuring the aperture size of geosynthetic materials are listed in the search results. Some of the common techniques include:
1. Dry sieving: Here, material is sieved using dry glass beads through the material. The AOS (Apparent Opening Size) is determined according to the size of the largest glass bead that can go through the geotextile.
2. Wet sieving: In this technique, high-frequency vibrations compel soil particles to flow through a wet geotextile sample. The opening size will be determined by sieving the soil particles passing through the geotextile.
3. Capillary flow: This technique employs the properties of liquid-air surface tension and liquid-solid wettability of the geotextile. It involves drainage of the liquid from the geotextile to determine the entire pore size distribution of the material.
4. Particle-Geogrid Aperture Interaction: This is a theoretical analysis based on probabilistic mechanics that considers how aperture size will interact with particles in geogrids.
5. Aperture Stability Modulus: This test method measures the in-plane shear modulus of a geogrid as a function of geogrid characteristics, e.g., junction stability, flexural rib stiffness, and tensile modulus.
These methods are such that they determine the aperture size of various types of geosynthetic materials, such as geotextiles and geogrids. The tests are conducted to ascertain the suitability of the geosynthetics for certain applications. The results of these tests can differ depending on which specific test method is used, and in turn, the results need to be interpreted with a lot of caution.