Double-Ring Permeameters test permeability of soil compacted in a conventional 4in (102mm) soil compaction (Proctor) mold. A special double-ring permeameter base has a stainless steel ring dividing the sample into two equal portions. The mold is secured between top and bottom plates with threaded tie rods and clamp knobs. Water is introduced through the top plate valve. The double-ring method is preferred in ASTM D5856 because it can identify erroneous measurements caused by side-wall leakage. Both units can be used with constant head or falling head methods.
Permeameters come with three porous stones, one of which is donut-shaped for containing the outer perimeter of the sample. There are also three valves for controlling water flow both in and out of the sample. Model 3851 also includes a mold and collar. Flow through the center and perimeter of the sample is monitored using two pipettes (2cc capacity) that connect to the lower control valves. The unit requires a Constant Head Tank for water supply or a Single Tube Manometer for falling head tests.
- Preferred method for ASTM D5856 test procedure
- Can be used for either constant head or falling head methods
- Available with or without 4in soil compaction mold
- 4in Double-Ring Permeameter
- Three Porous Stones
- Two 2cc Pipettes
- Upper and Lower Plates with Valves and Fittings
ASTM D 5856