Pocket penetrometer
The pocket penetrometer is a world-wide known instrument. It is used by geotechnicians, geologists, agronomists, etc. to obtain quickly and easily an approximate measure of the shear resistance at failure of cohesive and semicohesive soils.
The device is made from hard anodized aluminum, consists of two telescopic cylinders containing a compression spring. The inner cylinder ends with a tip of constant cross section that is penetrated within the soil sample.
A value of the unconfined compressive strength (UCS) can be directly read from the scale of the instrument, expressed in kg/cm2 or in tons/ft2, derived from the force required to penetrate the soil.
Measured strength values can assist the classification and description of cohesive soils and also give useful preliminary information about the shear strength in terms of total stresses.
