The geotextile vertical permeability test is a critical procedure used to evaluate the hydraulic properties of geosynthetic materials. This test helps determine how effectively a geotextile allows water to pass through it under controlled conditions, which is essential for applications in civil engineering, environmental protection, and construction.
The vertical permeability instrument is a specialized device developed by Tianjin Wanshen Test Equipment Technology Co., Ltd. It is designed to measure the flow rate of water through a geotextile sample under a specific head difference. The testing process involves several steps to ensure accurate and reliable results.
First, the sample must be properly prepared. The geotextile is soaked in a solution containing a wetting agent—typically 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 wetting agent helps reduce surface tension, allowing water to penetrate more easily into the fabric.
Next, the high-pressure chamber is removed, and the test specimen is carefully placed into the holder. The sample should be clean, free from dirt, creases, or folds, and laid flat without any external load. Once the sample is in place, the high-pressure chamber is reinstalled, and the cylinder nut is tightened evenly to maintain pressure equilibrium.
Afterward, the water valve is opened, and a clean water source is introduced into the high-pressure water tank. The water level on both sides of the specimen is monitored until it reaches a head difference of 50 mm. If the water levels do not balance within 5 minutes, the system is checked for air leaks. If necessary, the exhaust valve is opened to release any trapped air, and this is noted in the test report.
Once the initial setup is complete, the water flow is adjusted to achieve a head difference of 70 mm ± 5 mm. This value is recorded with an accuracy of 1 mm. The system is allowed to stabilize for 30 seconds, after which the volume of permeated water is collected using the osmotic water collection tube. The volume is measured accurately to the nearest 10 mL, and the time is recorded to the nearest second. At least 1000 mL of water must 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 for each step.
Throughout the test, the water temperature is also recorded, accurate to 0.2°C, as temperature can affect the viscosity of water and thus the permeability results.
Finally, after completing all measurements, the drain valve is opened to release all remaining water from the system. The instrument is then cleaned thoroughly to prepare for future tests.
All results are calculated according to the standard T1141-2006, ensuring consistency and compliance with industry requirements.
This detailed procedure ensures that the geotextile’s vertical permeability is accurately assessed, providing valuable data for engineers and designers working with geosynthetic materials.
For Asus Glass,Asus Rog Phone 2 Glass Screen,Asus Glass Front Glass,Outer Glass Front Screen
Dongguan Jili Electronic Technology Co., Ltd. , https://www.jlglassoca.com