Humboldt HS-4210 Digital Static Cone Penetrometer - Manual (Page 5)

Procedures
(continued)
C) Testing Sequence (continued)
3) Apply Force: The DSCP device is held in position, either vertically or
horizontally. The operator applies consistent force to handles for cone to
penetrates the material. Readings are monitored during penetration to
obtain information related to soft spots, averages or peaks. Soil friction
on the outside rod is not an influence in the reading. The applied force
is read directly from the cone via the inside rod onto the load cell and
displayed on the screen.
4) Depth of Penetration: The depth of penetration will vary with
application.
5) Refusal: The presence of aggregates or rock strata will either stop
penetration or deflect the cone. If slight increase in applied force does
not get penetration, do not try to force penetration. Continuing to try
to force penetration could result in inaccurate readings and could
damage the cone, rod or load cell.
CAUTION!
• DO NOT force penetration.
• DO NOT rock the DSCP side to side or forward and back in an
attempt to achieve penetration or to loosen it from the ground
during extraction.
Correlations
A) Correlation with other tests may be made with the Humboldt DSCP on
local materials. Examples are Standard Penetration (blow counts), CBR and
Unconfined. Readings of the cone index (Q
c
) and soil constants are not
absolute. General correlations have been determined as a guide. Additional
verification with your local soil type is recommended. The following
calculations should be made using kg/cm 2 or tsf for your cone index
reading.
Standard Penetration
Q
c
= 4 “N”
Strength and Cohesion
Q
u
= Unconfined Compression (kg/cm 2 )
C – Cohesion
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