Pocket Penetrometer
29-3729
3
9907X0072 Issue 1
1
General
The Pocket Penetrometer was developed by Soiltest Inc for use by field engineers to check
the visual classification of soils. The readings of the Penetrometer were compiled from
several thousand unconfined compression tests of silty and clay-like soils.
2
Operation
2.1
The red ring on the barrel of the Penetrometer holds the maximum reading of the
scale for easy reading.
2.2
Slide the ring down against the instrument handle.
2.3
Grip the knurled portion of the handle and push the tip of the Penetrometer into the
soil to the groove located
¼” from the top.
2.4
Read the unconfined compression strength directly in tons per square foot (TSF) or
kilograms per square centimetre (kg/cm
2
) from the scale. The reading is located on
the lower side of the red ring
– side closest to the knurled handle.
3
Special Notes
3.1
Select test spots with a smooth surface.
3.2
Hold the Pocket Penetrometer at right angles to the surface being tested.
3.3
To minimise errors, take several readings near each other, discard those readings
which may vary significantly from the majority and average the readings.
3.4
When the 29-3729/10 Adaptor Foot is used for very soft soils, divide the reading by
16 to obtain the correct compression strength of the soil. Push the foot into the soil
the total thickness of the Adaptor Foot.
