To install the rings without disturbing the soil structure inside the measurement area, ASTM D3385-18 requires the use of a driving cap and a hammer or mallet. A backhoe may be required for larger, heavy-duty rings.
The "double-ring" design is critical for accuracy because it forces water in the inner ring to flow . The outer ring acts as a buffer, saturating the surrounding soil to prevent lateral (sideways) spreading from the inner measurement area. Requirement under ASTM D3385-18 Method Constant Head Method (water level is kept steady) Ring Depth Driven typically to 150 mm (6 inches) Measurement astm d338518 pdf
While ASTM D3385-18 provides a valuable tool for evaluating geotextiles, there are challenges and limitations, including variability in testing results and the influence of test conditions on the measured pore size distribution. Additionally, field performance can sometimes differ from laboratory results due to installation conditions, soil properties, and long-term degradation. To install the rings without disturbing the soil
You can buy the ASTM D3385-18 standard directly from ASTM International through their official website ( www.astm.org ). The outer ring acts as a buffer, saturating