Humboldt HM-2415 Soil Volume Change Meter (PVC) - Manual (Page 4)

6. Compact the last layer with a blows. After compaction, the last layer
should extend approximately 1/4" (6.35 mm) into the spacer ring
(#16). If it is significantly below this point, remove entire sample and
recompact.
D. Put assembly on table and remove the 3 bolts {#23). Rotate spacer
ring (#16}, to break bond between ring and soil, and remove carefully
from sample. Rotate compaction ring (#15), to break bond between
base and soil, and remove ring with sample from assembly.
E. Trim top of the sample in the compaction ring (#15) with a knife.
1. Hold knife against the compaction ring (#15) at all times during
trimming to avoid dislodging sample.
2. Trim in a sawing motion, taking off only a small amount of soil at a
time. Rotate the ring as you trim. Work from the edge toward the
center.
3. When sample is almost level, do final leveling by drawing a metal
straight edge over sample.
4. The final surface of the soil sample should be firm and smooth. Fill
any voids by pressing additional soil into them with the knife or
spoon.
5. Clean soil from base and from all holes in rings and base. With a
toothpick or paperclip, remove soil in the groove of the spacer ring
(#16) and from the holes in the spacer ring and the compaction ring
{#15).
Test Procedure
The swell index test is essentially a measurement of the pressure exerted by a
sample of compacted soil when it swells against a restraining force after being
wetted.
A. Place spacer ring (#16 Figure 1) on base (#10) with radial grooves on top.
Align bolt holes with those on base.
8 . Place thoroughly dry porous stone (#14) in spacer ring (#16).
C. Pick up compaction ring (#15) containing sample, trimmed side up.
Carefully turn upside down the compaction ring containing sample and
place flush against porous stone in spacer ring (#16).
D. Align bolt holes in the two rings. Move compaction ring (#15) with as little
disturbance of sample as possible. Boll rings tightly to base.
E. Place a dry porous stone (#14) on top of sample inside compaction ring
(#15).