The geotextile vertical permeability test is an essential procedure for evaluating the hydraulic performance of geosynthetic materials. This method helps determine how effectively a geotextile allows water to pass through under different pressure conditions, which is crucial for applications in civil engineering, environmental protection, and soil stabilization.
The vertical permeability testing equipment used for this purpose is independently developed by Tianjin Wanshen Test Equipment Technology Co., Ltd. It is designed to simulate real-world conditions and provide accurate measurements of permeability. The process involves several key steps to ensure reliable results.
First, the test sample must be properly prepared. The geotextile should be soaked in a solution containing a wetting agent (0.1% V/V sodium alkyl benzene sulfonate) for at least 12 hours. This ensures that the material becomes fully saturated and any trapped air bubbles are removed. The sample must be clean, free from dirt, wrinkles, or folds, and placed flat without any applied load.
Next, the high-pressure chamber is installed. The test piece is placed into the holder, and the high-pressure chamber is reassembled and tightened evenly. Afterward, the water valve is opened, and clean water is injected into the high-pressure tank until the water level on both sides reaches a head difference of 50 mm. If the water levels do not stabilize within 5 minutes, it may indicate the presence of air in the system, and the exhaust valve should be opened to release any trapped air.
Once the system is ready, the head difference is adjusted to 70 mm ± 5 mm, and this value is recorded with precision up to 1 mm. The system is allowed to stabilize for 30 seconds. Then, the amount of permeated water is collected using the osmotic water collection tube. The volume is measured accurately to 10 mL, and the time is recorded to the nearest second. At least 1000 mL of water should be collected, and the process should take no less than 30 seconds.
The test is repeated at different head differences—0.8, 0.6, 0.4, and 0.2 times the maximum head difference. The procedure starts from the highest flow rate and moves to the lowest, recording the corresponding permeate volume and time at each stage. This allows for a comprehensive analysis of the geotextile’s permeability characteristics across varying pressure conditions.
During the test, the water temperature is also recorded, accurate to 0.2°C, as temperature can affect the viscosity of water and thus influence the results. Finally, after completing the test, the drain valve is opened to release all water from the system, and the instrument is cleaned thoroughly to maintain its accuracy for future tests.
All results should be calculated according to the relevant standard, such as T1141-2006, to ensure consistency and compliance with industry requirements. This detailed procedure ensures that the geotextile's vertical permeability is assessed accurately, providing valuable data for design and application purposes.
Dongguan Jili Electronic Technology Co., Ltd. , https://www.jlglassoca.com