Humboldt H-4202A Dynamic Cone Penetrometer Set - Manual (Page 4)

5. Maintaining the assembly in a plumb position, drive the cone point l-3/4 in.
(44mm) using the ring weight and allowing it to free fall 20 in. (bringing the
ring weight to the uppermost position against the pullout anvil will assure a
20 in. drop). Count and record the number of blows required to achieve l-3/4
in. (44mm) penetration.
6. If desired, perform a second and third penetration test by driving the cone
additional 3/4 in. (44mm) increments. Beyond three increments the effect of
shaft friction may become apparent.
7. Remove the DCP assembly from the borehole taking care not to place hands
between the anvil and keeping clear of the sliding weight.
8. Auger to the next test location and repeat steps) through 7.
Experience has shown that the DCP can be effectively used in auger holes
to depths of 15 to 20 ft. Beyond these depths it becomes cumbersome to
handle the string of rods by hand. Also, correlations have not been verified
for deeper depths where energy losses from thread joints and rod inertia
have not been considered
Drive Tube Accessory
The Cone and Adapter Rod Assembly can be
replaced with the H-4202.7A Drive Tube Assembly
for taking 3 x 10" tube, H-4202.10, samples
in augered holes.